@article{katuwal_rafsan_ashworth_kolar_2023, title={Poultry Litter Physiochemical Characterization Based on Production Conditions for Circular Systems}, volume={18}, ISSN={["1930-2126"]}, DOI={10.15376/biores.18.2.3961-3977}, abstractNote={Poultry litter is a useful product as a fertilizer, energy feedstock for thermochemical conversion, and a precursor for synthesis of adsorbents and catalysts. Detailed characterization of baseline properties is necessary for enhanced environmental and economic utilization of this valuable resource. Baseline physicochemical characterization was carried out at two broiler production facilities (Arkansas, PL1, and North Carolina, PL2). Greater concentrations of inorganic nitrogen, phosphorus, and potassium were obtained for PL1, suggesting greater nutrient value compared to PL2. PL2 had greater carbon content and water-holding capacity than PL1. X-ray photoelectron spectroscopy (XPS) of PL1 and PL2 indicated a similarity between litters in terms of the presence of carbon, nitrogen, and oxygen bonds. Both poultry litters had oxygen, nitrogen, sulfur, and phosphorous functional groups, as confirmed by infrared spectroscopy. Time of flight – secondary ion mass spectroscopy of negative ions also indicated similarity of the surface charge distribution between PL1 and PL2. Overall, poultry litters evaluated had similar surface chemistries, with nutrient composition varying based on rearing conditions, which has implications for downstream use in thermochemical conversion and other value-added products.}, number={2}, journal={BIORESOURCES}, author={Katuwal, Sheela and Rafsan, Nur-Al-Sarah and Ashworth, Amanda J. and Kolar, Praveen}, year={2023}, month={May}, pages={3961–3977} }
 @misc{graves_kolar_shah_grimes_sharara_2022, title={Can Biochar Improve the Sustainability of Animal Production?}, volume={12}, ISSN={["2076-3417"]}, url={https://doi.org/10.3390/app12105042}, DOI={10.3390/app12105042}, abstractNote={Animal production is a significant contributor of organic and inorganic contaminants in air, soil, and water systems. These pollutants are present beginning in animal houses and impacts continue through manure storage, treatment, and land application. As the industry is expected to expand, there is still a lack of affordable, sustainable solutions to many environmental concerns in animal production. Biochar is a low-cost, sustainable biomaterial with many environmental remediation applications. Its physicochemical properties have been proven to provide environmental benefits via the adsorption of organic and inorganic contaminants, promote plant growth, improve soil quality, and provide a form of carbon sequestration. For these reasons, biochar has been researched regarding biochar production, and application methods to biological systems have a significant influence on the moisture content, pH, microbial communities, and carbon and nitrogen retention. There remain unanswered questions about how we can manipulate biochar via physical and chemical activation methods to enhance the performance for specific applications. This review article addresses the positive and negative impacts of biochar addition at various stages in animal production from feed intake to manure land application.}, number={10}, journal={APPLIED SCIENCES-BASEL}, author={Graves, Carly and Kolar, Praveen and Shah, Sanjay and Grimes, Jesse and Sharara, Mahmoud}, year={2022}, month={May} }
 @article{kasera_augoustides_kolar_hall_vicente_2022, title={Effect of Surface Modification by Oxygen-Enriched Chemicals on the Surface Properties of Pine Bark Biochars}, volume={10}, ISSN={["2227-9717"]}, url={https://doi.org/10.3390/pr10102136}, DOI={10.3390/pr10102136}, abstractNote={Sustainable waste utilization techniques are needed to combat the environmental and economic challenges faced worldwide due to the rising population. Biochars, due to their unique surface properties, offer opportunities to modify their surface to prepare application-specific materials. The aim of this research is to study the effects of biochar surface modification by oxidizing chemicals on biochar properties. Pine bark biochar was modified with sulfuric acid, nitric acid, hydrogen peroxide, ozone, and ammonium persulfate. The resulting biochars’ pH, pH at the point of zero charges, and concentration of acidic and basic sites were determined using laboratory experimentation. Instrumental techniques, such as infrared and X-ray photoelectron spectroscopy, were also obtained for all biochar samples. X-ray photoelectron spectra showed that oxygen content increased to 44.5%, 42.2%, 33.8%, 30.5%, and 14.6% from 13.4% for sulfuric acid, ozone, nitric acid, hydrogen peroxide, and ammonium persulfate, respectively. The pH at the point of zero charges was negatively correlated with the difference in concentration of acidic and basic sites in biochar samples, as well as the summation of peak components representing C=O double bonds and carboxylic groups. The results suggest that designer biochars can be prepared by understanding the interaction of oxygenated chemicals with biochar surfaces.}, number={10}, journal={PROCESSES}, author={Kasera, Nitesh and Augoustides, Victoria and Kolar, Praveen and Hall, Steven G. and Vicente, Billie}, year={2022}, month={Oct} }
 @misc{kasera_kolar_hall_2022, title={Nitrogen-doped biochars as adsorbents for mitigation of heavy metals and organics from water: a review}, volume={4}, ISSN={["2524-7867"]}, url={https://doi.org/10.1007/s42773-022-00145-2}, DOI={10.1007/s42773-022-00145-2}, abstractNote={Abstract Mitigation of toxic contaminants from wastewater is crucial to the safety and sustainability of the aquatic ecosystem and human health. There is a pressing need to find economical and efficient technologies for municipal, agricultural, aquacultural, and industrial wastewater treatment. Nitrogen-doped biochar, which is synthesized from waste biomass, is shown to exhibit good adsorptive performance towards harmful aqueous contaminants, including heavy metals and organic chemicals. Incorporating nitrogen into the biochar matrix changes the overall electronic structure of biochar, which favors the interaction of N-doped biochar with contaminants. In this review, we start the discussion with the preparation techniques and raw materials used for the production of N-doped biochar, along with its structural attributes. Next, the adsorption of heavy metals and organic pollutants on N-doped biochars is systematically discussed. The adsorption mechanisms of contaminant removal by N-doped biochar are also clearly explained. Further, mathematical analyses of adsorption, crucial to the quantification of adsorption, process design, and understanding of the mechanics of the process, are reviewed. Furthermore, the influence of environmental parameters on the adsorption process and the reusability of N-doped biochars are critically evaluated. Finally, future research trends for the design and development of application-specific preparation of N-doped biochars for wastewater treatment are suggested. Graphical abstract}, number={1}, journal={BIOCHAR}, author={Kasera, Nitesh and Kolar, Praveen and Hall, Steven G.}, year={2022}, month={Dec} }
 @article{shah_earnest_oviedo-rondon_kolar_singletary_2022, title={SIMULTANEOUS REDUCTION OF THERMAL STRATIFICATION AND AMMONIA CONCENTRATIONS IN POULTRY HOUSE DURING BROODING AND IN COOL WEATHER}, volume={38}, ISSN={["1943-7838"]}, DOI={10.13031/aea.14862}, abstractNote={HighlightsPen-scale system eliminated thermal stratification while full-scale system reduced thermal stratificationPen-scale system was moderately effective in trapping ammonia and reduced pen ammonia concentrations modestlyAmmonia trapping performance was mainly affected by dust build-upDust build-up was partly mitigated by a shakerCitric acid coated burlap placed upstream of livestock barn exhaust fans may reduce ammonia and dust emissionsAbstract. High ammonia (NH3) concentrations during poultry brooding can reduce bird performance and welfare. Thermal stratification during brooding can increase energy use and reduce bird welfare. A proof-of-concept heat recovery and NH3 control (HRAC) system consisting of a low-cost NH3 filter consisting of citric acid treated burlap placed upstream of a fan was evaluated for its ability to reduce barn NH3 concentration and thermal stratification. In the lab, 5% citric acid on burlap trapped 13 times more NH3 per unit mass of sorbent than activated carbon reported in the literature. Pen-scale and barn-scale HRAC prototypes using 15% citric acid on burlap eliminated and greatly reduced thermal stratification, respectively. The pen-scale HRAC had significant NH3 removal efficiencies ranging from the 17% to 42% in seven of nine events and compared, to the Control pens (no HRAC), significantly reduced floor [NH3] in two of nine events by 26% and 42%. The pen-scale HRAC also reduced footpad dermatitis at 15 d. Performance of the full-scale HRAC was highly variable. Clogging of the filter with particulate matter reduced airflow rates that was partially mitigated using a shaker. A vertical HRAC with a shaker might improve performance. There is need to investigate the effectiveness of 5% citric acid. The citric acid-treated burlap screen placed upstream of barn exhaust fans could reduce dust and NH3 emissions. Keywords: Breakthrough curve, Burlap, Citric acid, Emissions, Energy use, Footpad dermatitis.}, number={2}, journal={APPLIED ENGINEERING IN AGRICULTURE}, author={Shah, Sanjay B. and Earnest, Kathleen and Oviedo-Rondon, Edgar O. and Kolar, Praveen and Singletary, Isaac}, year={2022}, pages={375–386} }
 @misc{paul_kolar_hall_2021, title={A review of the impact of environmental factors on the fate and transport of coronaviruses in aqueous environments}, volume={4}, ISBN={2059-7037}, DOI={10.1038/s41545-020-00096-w}, abstractNote={Abstract The ongoing severe acute respiratory syndrome-coronavirus (SARS-CoV-2) has triggered the coronavirus pandemic (COVID-19) that has claimed hundreds of thousands of lives worldwide. This virus spreads predominantly by human-to-human transmission via respiratory droplets. However, the presence of this virus in the fecal and anal swabs of infected patients has triggered the need for research into its waterborne transmission. The various environmental factors that impact the persistence of coronavirus in different water matrices include temperature, UV exposure, organic matter, disinfectants as well as adversarial microorganisms. This review summarizes the most recent research data on the effect of various factors on coronavirus in aqueous environments. The available data suggest that: (i) increasing temperature decreases the overall persistence of the virus; (ii) the presence of organic matter can increase the survivability of coronavirus; (iii) chlorine is the most effective and economic disinfectant; (iv) membrane bioreactors in wastewater treatment plants are hosts of competitive microorganisms that can inactivate coronaviruses; (v) ultraviolet irradiation is another effective option for virus inactivation. However, the inactivation disinfection kinetics of coronaviruses are yet to be fully understood. Thus, further research is needed to understand its fate and transport with respect to the water cycle so that effective strategies can be adopted to curb its effects. These strategies may vary based on geographic, climatic, technical, and social conditions around the globe. This paper explores possible approaches and especially the conditions that local communities and authorities should consider to find optimal solutions that can limit the spread of this virus.}, number={1}, journal={NPJ CLEAN WATER}, author={Paul, Diplina and Kolar, Praveen and Hall, Steven G.}, year={2021} }
 @article{kasera_hall_kolar_2021, title={Characterization data of N-doped biochars using different external nitrogen precursors}, volume={35}, ISSN={["2352-3409"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85101092311&partnerID=MN8TOARS}, DOI={10.1016/j.dib.2021.106870}, abstractNote={The development of waste-derived functional materials for environmental and energy applications is a sustainable approach to fight global warming, and address energy and materials challenges. In this regard, many scientists are interested in the supercapacitor, adsorbent, and catalyst applications of nitrogen-doped biochars. In this article, we report the data that was collected as a part of our research on the effects of different external nitrogenous sources on the properties of biochar [1]. The data on infrared spectra of the modified samples at various temperatures is valuable to study the changes in functional groups on biochar as a function of temperature as well as nitrogen precursors. Raw data from Time-of-flight Secondary ion mass spectroscopy, surface profilometry, and scanning electron microscopy-energy dispersive X-ray spectroscopy are also provided. We expect that the data will benefit researchers around the world working in the field of nitrogen modifications of biochar.}, journal={DATA IN BRIEF}, author={Kasera, Nitesh and Hall, Steven and Kolar, Praveen}, year={2021}, month={Apr} }
 @article{kasera_hall_kolar_2021, title={Effect of surface modification by nitrogen-containing chemicals on morphology and surface characteristics of N-doped pine bark biochars}, volume={9}, ISSN={["2213-3437"]}, url={https://doi.org/10.1016/j.jece.2021.105161}, DOI={10.1016/j.jece.2021.105161}, abstractNote={In this study, pine bark-derived biochar was modified with melamine, urea, ammonium chloride, and ammonium nitrate to synthesize nitrogen-doped biochars. The effect of chemical modification on the extent of N-doping and surface properties were investigated. The elemental analysis suggested that melamine modified biochar samples had 4.75% nitrogen, higher than nitrogen in other modified biochars. The surface morphology and surface profile were studied with scanning electron microscopy and confocal laser scanning microscopy. X-ray photoelectron spectra showed that N-doped samples' surface nitrogen content increased to 8.3%, 3.9%, 2.3%, and 2.9% for melamine, ammonium chloride, ammonium nitrate, and urea, respectively. X-ray photoelectron spectroscopy results also revealed that among the nitrogen fractions in the N-doped biochars, melamine modified biochar has the highest percentage of pyrrolic and pyridinic nitrogen (35.2% and 36.8%, respectively) compared to others. Urea modified biochar had the highest percentage of graphitic nitrogen (26.6%). Our results suggest that application-specific nitrogen-enriched biochar can be prepared by understanding how different nitrogen precursors interact with carbon surfaces.}, number={2}, journal={JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING}, publisher={Elsevier BV}, author={Kasera, Nitesh and Hall, Steven and Kolar, Praveen}, year={2021}, month={Apr} }
 @article{baker_blackman_cooper_smartt_walser_boland_kolar_beck_chinn_2021, title={Exploratory analysis of Spirulina platensis LB 2340 growth in varied concentrations of anaerobically digested pig effluent (ADPE)}, volume={7}, ISSN={["2405-8440"]}, DOI={10.1016/j.heliyon.2021.e08065}, abstractNote={<h2>Abstract</h2> There is a significant interest in novel waste management solutions to treat wastewater from swine operations. Anaerobic digestion is a rising and prominent solution, but this technology still generates highly concentrated effluent that requires further remediation. Therefore, the aim of this study was to explore the feasibility of cultivating the cyanobacterium <i>Spirulina platensis</i> in swine effluent for future applications in biological waste treatment and value-added fermentation. To accomplish this goal, growth of <i>S. platensis</i> was characterized in varying proportions of ideal, synthetic Zarrouk medium and anaerobically digested pig effluent (ADPE) to obtain growth rate models. Results yielded a positive correlation between <i>S. platensis</i> growth rate and Zarrouk medium proportion, with the highest growth rate in 100% Zarrouk media but comparable growth in the 50/50% Zarrouk/ADPE mixture. This study demonstrates the potential for <i>S. platensis</i> to further improve the treatment efficacy of anaerobic digestion systems, and the exploratory analysis also highlights that further testing is required to investigate possible carbon availability, chemical inhibition, and overall nutrient reduction in ADPE. This research contributes important data toward the feasibility of producing value-added cyanobacterial biomass while simultaneously consuming excess nutrients to aid in agricultural wastewater management efforts and generate cost-effective products in a more sustainable manner.}, number={9}, journal={HELIYON}, author={Baker, Matthew and Blackman, Sam and Cooper, Erin and Smartt, Kevin and Walser, David and Boland, Megan and Kolar, Praveen and Beck, Ashley E. and Chinn, Mari S.}, year={2021}, month={Sep} }
 @article{ansanay_kolar_sharma-shivappa_cheng_arellano_2021, title={Pretreatment of Switchgrass for Production of Glucose via Sulfonic Acid-Impregnated Activated Carbon}, volume={9}, ISSN={["2227-9717"]}, DOI={10.3390/pr9030504}, abstractNote={In the present research, activated carbon-supported sulfonic acid catalysts were synthesized and tested as pretreatment agents for the conversion of switchgrass into glucose. The catalysts were synthesized by reacting sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid with activated carbon. The characterization of catalysts suggested an increase in surface acidities, while surface area and pore volumes decreased because of sulfonation. Batch experiments were performed in 125 mL serum bottles to investigate the effects of temperature (30, 60, and 90 °C), reaction time (90 and 120 min) on the yields of glucose. Enzymatic hydrolysis of pretreated switchgrass using Ctec2 yielded up to 57.13% glucose. Durability tests indicated that sulfonic solid-impregnated carbon catalysts were able to maintain activity even after three cycles. From the results obtained, the solid acid catalysts appear to serve as effective pretreatment agents and can potentially reduce the use of conventional liquid acids and bases in biomass-into-biofuel production.}, number={3}, journal={PROCESSES}, author={Ansanay, Yane and Kolar, Praveen and Sharma-Shivappa, Ratna and Cheng, Jay and Arellano, Consuelo}, year={2021}, month={Mar} }
 @article{jung_savithri_sharma-shivappa_kolar_2020, title={Effect of Sodium Hydroxide Pretreatment on Lignin Monomeric Components of Miscanthus x giganteus and Enzymatic Hydrolysis}, volume={11}, ISSN={["1877-265X"]}, DOI={10.1007/s12649-019-00859-8}, number={11}, journal={WASTE AND BIOMASS VALORIZATION}, author={Jung, Woochul and Savithri, Dhanalekshmi and Sharma-Shivappa, Ratna and Kolar, Praveen}, year={2020}, month={Nov}, pages={5891–5900} }
 @article{jung_sharma-shivappa_park_kolar_2020, title={Effect of cellulolytic enzyme binding on lignin isolated from alkali and acid pretreated switchgrass on enzymatic hydrolysis}, volume={10}, ISSN={["2190-5738"]}, DOI={10.1007/s13205-019-1978-z}, abstractNote={In this research, the binding of cellulolytic enzymes in Cellic® CTec2 on six lignin isolates obtained from alkali (0.5, 1.0, and 1.5% NaOH at 121 °C for 30 min) and acid (1, 2, and 3% H2SO4 at 121 °C for 60 min) pretreated switchgrass was investigated. Briefly, the hydrolysis of cellobiose and Avicel with and without (control) lignin isolates was performed via CTec2 (5 and 10 FPU g−1 carbohydrate) to determine whether the presence of lignin and binding of cellulolytic enzymes to the isolated lignin can affect the sugar production using three carbohydrate-lignin loadings, namely, 0.5:0.25, 0.5:0.5, and 0.5:1.0% (wv−1). Based on SDS-PAGE results, β-glucosidase (BG) was significantly bound to all lignin isolates. Some enzymes in CTec2 presumed to be cellobiohydrolases, endo-1,4-β-glucanases, and xylanase, were also observed to partially bind to the lignin isolates. Up to 0.97 g glucose g−1 cellobiose was produced via hydrolysis (72 h and pH 4.8) with CTec2 (5 and 10 FPU g−1 carbohydrate). Similarly, up to 0.23 and 0.46 g glucose g−1 Avicel were produced via hydrolysis (72 h and pH 4.8) with 5 and 10 FPU g−1 carbohydrate, respectively. Results indicated that the addition of lignin isolates during cellobiose and Avicel hydrolysis did not significantly (p > 0.05) reduce glucose production regardless of type and amount of lignin isolate. Hence, even though BG was significantly bound to lignin isolates, it could maintain its functionality as a biological catalyst in this study.}, number={1}, journal={3 BIOTECH}, author={Jung, Woochul and Sharma-Shivappa, Ratna and Park, Sunkyu and Kolar, Praveen}, year={2020}, month={Jan} }
 @article{karoshi_kolar_shah_gilleskie_2020, title={Recycled eggshells as precursors for iron-impregnated calcium oxide catalysts for partial oxidation of methane}, volume={7}, ISSN={["2197-4365"]}, DOI={10.1186/s40643-020-00336-4}, abstractNote={Abstract There is a significant interest in converting eggshells into value-added products. Therefore, the goal of this research is to synthesize and study iron-impregnated eggshells as a catalyst for partial oxidation of methane. The objectives of this research were to test the effects of iron loading, flow rate, oxygen concentration, and temperature on methane oxidation. The catalysts were synthesized using ferric chloride hexahydrate at various loadings and tested in a heated stainless-steel reactor under different experimental conditions. The reaction products included C 2 –C 7 hydrocarbons, carbon monoxide, and carbon dioxide depending on the reaction conditions. Results indicated that iron loading beyond 5 wt% caused a decrease in methane conversion. A decrease in oxygen concentration enhanced methane conversion with a substantial drop in the production of CO 2 . Besides, an increase in temperature resulted in a decrease in methane conversion with a simultaneous increase in the production of CO 2 via overoxidation. The reusability experiments indicated that the catalyst was active for four reaction cycles. Our results indicate that eggshells can be used as catalyst support for methane partial oxidation and can simultaneously solve the waste disposal problems faced by the poultry industry.}, number={1}, journal={BIORESOURCES AND BIOPROCESSING}, author={Karoshi, Gourishankar and Kolar, Praveen and Shah, Sanjay B. and Gilleskie, Gary}, year={2020}, month={Aug} }
 @article{karoshi_kolar_shah_gilleskie_2020, title={Valorization of Eggshell Waste into Supported Copper Catalysts for Partial Oxidation of Methane}, volume={14}, ISSN={["2008-2304"]}, DOI={10.1007/s41742-019-00238-0}, number={1}, journal={INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH}, author={Karoshi, Gourishankar and Kolar, Praveen and Shah, Sanjay Bikram and Gilleskie, Gary}, year={2020}, month={Feb}, pages={61–70} }
 @article{kolar_jin_2019, title={Baseline characterization data for raw rice husk}, volume={25}, ISSN={["2352-3409"]}, DOI={10.1016/j.dib.2019.104219}, abstractNote={There is a significant interest in using agricultural wastes such as rice husk as a precursor for the synthesis of adsorbents and catalysts. In this article, readers will find valuable baseline characterization data related to physical and chemical properties of raw rice husk including BET specific surface area, acid value, the point of zero charge, elemental analysis, Time-of-Flight Secondary Ion Mass Spectrometric Analysis X-Ray Photoelectron Spectroscopic Analysis, and Scanning Electron Microscope-Energy Dispersive Spectroscopic Analysis. It is expected that the baseline raw data presented in this article will be useful for researchers around the world who are working on chemically modifying rice husk for valorizing them for applications in adsorption, catalysis, and energy storage.}, journal={DATA IN BRIEF}, author={Kolar, Praveen and Jin, Han}, year={2019}, month={Aug} }
 @article{jung_sharma-shivappa_kolar_2019, title={Effect of Enzyme Interaction with Lignin Isolated from Pretreated Miscanthus x giganteus on Cellulolytic Efficiency}, volume={7}, ISSN={["2227-9717"]}, DOI={10.3390/pr7100755}, abstractNote={The effect of binding between the lignin isolates from an alkali (NaOH)– and an acid (H2SO4)– pretreated Miscanthus and cellulolytic enzymes in Cellic® CTec2 was investigated. Additonally, cellobiose and Avicel were enzymatically hydrolyzed with and without lignin isolates to study how enzyme binding onto lignin affects its conversion to glucose. Three carbohydrate–lignin loadings (0.5:0.25, 0.5:0.5, and 0.5:1.0% (w/v)) were employed. The results indicated that β-glucosidase (BG) had a strong tendency to bind to all lignin isolates. The overall tendency of enzyme binding onto lignin isolate was similar regardless of pretreatment chemical concentration. Though enzyme binding onto lignin isolates was observed, hydrolysis in the presence of these isolates did not have a significant (p > 0.05) impact on glucose production from cellobiose and Avicel. Cellobiose to glucose conversion of 99% was achieved via hydrolysis at both 5 and 10 FPU/g carbohydrate. Hydrolysis of Avicel with 5 and 10 FPU/g CTec2 resulted in 29.3 and 47.7% conversion to glucose, respectively.}, number={10}, journal={PROCESSES}, author={Jung, Woochul and Sharma-Shivappa, Ratna and Kolar, Praveen}, year={2019}, month={Oct} }
 @article{hess_kolar_classen_knappe_cheng_2019, title={Effects of Co-occurring Species Present in Swine Lagoons on Adsorption of Copper on Eggshell}, volume={13}, ISSN={["2008-2304"]}, DOI={10.1007/s41742-019-00203-x}, number={4}, journal={INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH}, author={Hess, Brianna J. and Kolar, Praveen and Classen, John J. and Knappe, Detlef and Cheng, Jay J.}, year={2019}, month={Aug}, pages={613–622} }
 @article{kolar_classen_hall_2019, title={Physicochemical data of p-cresol, butyric acid, and ammonia}, volume={26}, ISSN={2352-3409}, url={http://dx.doi.org/10.1016/j.dib.2019.104356}, DOI={10.1016/j.dib.2019.104356}, abstractNote={There is a renewed interest in treating odorous contaminants such as butyric acid, p-cresol, and ammonia that are emitted from animal farming operations. However, developing newer treatment technologies require quantitative information regarding the properties of the target pollutants. Therefore, in this communication, baseline data related to physicochemical and thermodynamic properties of butyric acid, p-cresol, and ammonia were predicted using computational chemistry. Density functional theory was employed via B3LYP functional coupled with polarized 6-31G (d) basis set without any solvent effects using Gaussian 16W and GaussView6. The predicted baseline properties collected here are expected to be useful to scientists and engineers working in environmental mitigation technologies in developing treatment processes and make the animal agricultural industry environmental friendly and sustainable.}, journal={Data in Brief}, publisher={Elsevier BV}, author={Kolar, Praveen and Classen, John and Hall, Steven G.}, year={2019}, month={Oct}, pages={104356} }
 @article{lentz_kolar_classen_2019, title={Valorization of Swine Manure into Hydrochars}, volume={7}, ISSN={2227-9717}, url={http://dx.doi.org/10.3390/pr7090560}, DOI={10.3390/pr7090560}, abstractNote={There is a significant interest in valorizing swine manure that is produced in enormous quantities. Therefore, considering the high moisture content in swine manure, the objective of this research was to convert manure slurry into hydrochars via hydrothermal carbonization and analyze the yields, pH, energy contents, and thermal and oxidation kinetic parameters. Experiments were performed in triplicate in 250 mL kettle reactors lined with polypropylene at 180 °C, 200 °C, 240 °C, 220 °C, and 260 °C for 24 h. Analyses of the results indicated that the process temperature affected the hydrochar yields, with yield generally decreasing with increasing temperature, but it had little effect on the composition of the hydrochar. The hydrochars were found to have higher volatile contents and H/C and O/C ratios and about 85% of the energy compared to coal. However, the presence of high fraction (35–38%) of ash in hydrochars is a serious concern and needs to be addressed before the complete utilization of hydrochars as fuels. The surface characterization of hydrochars coupled with wet chemistry experiments indicated that hydrochars were equipped with nitrogen functional groups with points of zero charges between 6.76 and 7.85, making them suitable as adsorbents and soil remediation agents and energy storage devices.}, number={9}, journal={Processes}, publisher={MDPI AG}, author={Lentz, Zac and Kolar, Praveen and Classen, John J.}, year={2019}, month={Aug}, pages={560} }
 @article{uzuner_sharma-shivappa_cekmecelioglu_kolar_2018, title={A novel oxidative destruction of lignin and enzymatic digestibility of hazelnut shells}, volume={13}, ISSN={1878-8181}, url={http://dx.doi.org/10.1016/J.BCAB.2017.12.003}, DOI={10.1016/J.BCAB.2017.12.003}, abstractNote={This study investigated the effect of sequential oxidative (ozonolysis) pretreatment and enzymatic hydrolysis of hazelnut shells on production of fermentable sugars. Two factors (ozone concentration and pretreatment time), which were determined to be significant by the Box-Behnken response surface methodology, were further maximized for total lignin removal, solid recovery, and total reducing sugar yield via enzymatic hydrolysis of the pretreated biomass using full-factorial design. The ozonolysis was performed by passing 30, 40, and 50 mg/L of ozone gas through a packed bed of ground hazelnut shells for up to 120 min at a flow rate of 0.25 L/min. The highest lignin reduction (20.5%) was obtained in the shells with 30% moisture content subjected to ozone concentration of 50 mg/L for 120 min, which corresponded to a high biomass recovery (94%). The reducing sugar yield also increased from 119.9 mg/g dry untreated biomass to 284.6 mg/g dry untreated biomass for hazelnut shells ozonated at 30 mg/L for 60 min. Thus, these results indicate remarkable benefits of ozonolysis during pretreatment of hazelnut shells.}, journal={Biocatalysis and Agricultural Biotechnology}, publisher={Elsevier BV}, author={Uzuner, Sibel and Sharma-Shivappa, Ratna R. and Cekmecelioglu, Deniz and Kolar, Praveen}, year={2018}, month={Jan}, pages={110–115} }
 @article{jung_savithri_sharma-shivappa_kolar_2018, title={Changes in Lignin Chemistry of Switchgrass due to Delignification by Sodium Hydroxide Pretreatment}, volume={11}, ISSN={["1996-1073"]}, DOI={10.3390/en11020376}, abstractNote={Switchgrass was pretreated with sodium hydroxide (NaOH) at various concentrations and pretreatment times to investigate how delignification caused by NaOH affects its lignin chemistry. NaOH resulted in significant delignification ranging from 44.0 to 84.6% depending on pretreatment intensity. While there was no significant glucan loss due to NaOH pretreatment, higher NaOH concentrations removed xylan by up to 28.3%. Nitrobenzene oxidation (NBO) was used to study changes in lignin chemistry, and indicated that at higher NaOH concentrations, the amount of 4-hydroxygenzaldehyde (Hy) degraded from p -hydroxyphenyl propanol (H) lignin units was significantly reduced ( p 0.05) change with 15 min pretreatment, but it increased to 0.75 and 0.72, respectively, with 30 and 60 min pretreatments ( p 0.05) change S/G ratio, but H/G ratio (=0.48 raw switchgrass) decreased significantly to 0.14 regardless of pretreatment times. Overall, the H unit was found to be more susceptible to NaOH than S and G unit monolignols. Though changes in lignin chemistry due to NaOH concentration were observed, their impact on cellulolytic enzyme action during hydrolysis could not be fully understood. Further studies on lignin isolation may help to determine how these changes in lignin chemistry by NaOH impact cellulolytic enzymes.}, number={2}, journal={ENERGIES}, author={Jung, Woochul and Savithri, Dhanalekshmi and Sharma-Shivappa, Ratna and Kolar, Praveen}, year={2018}, month={Feb} }
 @article{zhu_kolar_shah_cheng_lim_2018, title={Simultaneous mitigation of p- cresol and ammonium using activated carbon from avocado seed}, volume={9}, ISSN={2352-1864}, url={http://dx.doi.org/10.1016/J.ETI.2017.10.006}, DOI={10.1016/J.ETI.2017.10.006}, abstractNote={Avocado seed was used as a precursor to prepare an activated carbon (AAC-MA) via physiochemical activation with methanesulfonic acid. The AAC-MA was systematically tested in batch systems for the removal of p-cresol (single-solute) and p-cresol and ammonium (binary solute). It was found that the kinetic data of p-cresol adsorption conformed to a pseudo-second-order model suggesting a predominantly chemisorption process. Additionally, the equilibrium data of p-cresol adsorption in a single solute system were found to follow Redlich–Peterson isotherm. Data analysis of the binary solute studies indicated that extended Langmuir isotherm was the most suitable to describe adsorption of p-cresol and ammonium on AAC-MA. It is also observed that the presence of ammonium did not affect adsorption of p-cresol. On the other hand, presence of p-cresol negatively influenced adsorption of ammonium. Our research suggests that AAC-MA can potentially serve as a waste management tool for mitigation of ammonium and p-cresol from aqueous systems.}, journal={Environmental Technology & Innovation}, publisher={Elsevier BV}, author={Zhu, Yiying and Kolar, Praveen and Shah, Sanjay B. and Cheng, Jay J. and Lim, P.K.}, year={2018}, month={Feb}, pages={63–73} }
 @article{das_kolar_sharma-shivappa_classen_osborne_2017, title={Catalytic Valorization of Lignin Using Niobium Oxide}, volume={8}, ISSN={["1877-265X"]}, DOI={10.1007/s12649-016-9717-8}, number={8}, journal={WASTE AND BIOMASS VALORIZATION}, author={Das, Lalitendu and Kolar, Praveen and Sharma-Shivappa, Ratna and Classen, John J. and Osborne, Jason A.}, year={2017}, month={Dec}, pages={2673–2680} }
 @article{ansanay_kolar_sharma-shivappa_cheng_park_arellano_2017, title={Pre-treatment of biomasses using magnetised sulfonic acid catalysts}, volume={48}, number={2}, journal={Journal of Agricultural Engineering}, author={Ansanay, Y. and Kolar, P. and Sharma-Shivappa, R. and Cheng, J. and Park, S. and Arellano, C.}, year={2017}, pages={117–122} }
 @article{lentz_classen_kolar_2017, title={THERMOCHEMICAL CONVERSION: A PROSPECTIVE SWINE MANURE SOLUTION FOR NORTH CAROLINA}, volume={60}, ISSN={["2151-0040"]}, DOI={10.13031/trans.12074}, abstractNote={Abstract. The growth of North Carolina’s swine industry in recent decades has led to a subsequent increase in the production of swine manure. This manure represents a potential threat to environmental and human health, as well as an opportunity to add value to pork production. Technologies for treating swine manure safely while generating products to offset costs are part of an expanding field of research centered on sustainable food production for our growing population. Thermochemical conversion processes use heat to degrade organic feedstocks and drive chemical reactions, which generate valuable products. The high moisture content of swine manure is prohibitive for most thermochemical processes, but gasification and hydrothermal carbonization may be more accommodating. Gasification, a time-tested thermochemical conversion process, yields a combustible gas through a series of endothermic reactions, and hydrothermal carbonization yields a solid, coal-like char that can be used as a fuel or chemical precursor. Advances in thermochemical conversion processes have indicated the potential for yielding valuable products from swine manure, but viable scalable processes are still under development, requiring further research to apply these processes to swine manure management and evaluate the usefulness of their products. This review (1) describes, generally, thermochemical conversion via both hydrothermal gasification (HTG) and hydrothermal carbonization (HTC), (2) shows the usefulness of each conversion process for biomass, and (3) discusses the potential of HTG and HTC of swine manure to enhance the value of pork production. Keywords: Energy, Gases, Hydrothermal carbonization, Hydrothermal gasification, Pig manure, Pigs, Sustainable.}, number={3}, journal={TRANSACTIONS OF THE ASABE}, author={Lentz, Z. and Classen, J. and Kolar, P.}, year={2017}, pages={591–600} }
 @article{zhu_kolar_shah_cheng_lim_2016, title={Avocado seed-derived activated carbon for mitigation of aqueous ammonium}, volume={92}, ISSN={0926-6690}, url={http://dx.doi.org/10.1016/J.INDCROP.2016.07.016}, DOI={10.1016/j.indcrop.2016.07.016}, abstractNote={There is a significant interest in value-addition of agricultural residues. In the present research, a novel avocado seed-activated carbon prepared from methanesulfonic acid (denoted as AAC-MA) was systematically tested as an adsorbent for removal of ammonium for the first time. SEM characterization technique was employed to identify the structural and morphological properties of the prepared carbon. The effects of pH, adsorbent dosage, initial NH4+ concentrations, and contact time on ammonium removal from aqueous solution were also investigated. Moreover, different kinetic and isotherm models were fit to the experimental data to gain a better understanding of the efficiency and applicability of the adsorption system. The pseudo-second order kinetic model was found to best describe the ammonium adsorption. The equilibrium data were found to conform best to Langmuir isotherm model with a theoretical maximum adsorption capacity of 5.4 mg g−1 at 25 °C. The results clearly suggested that the novel avocado-derived can potentially mitigate ammonium from aqueous systems.}, journal={Industrial Crops and Products}, publisher={Elsevier BV}, author={Zhu, Yiying and Kolar, Praveen and Shah, Sanjay B. and Cheng, Jay J. and Lim, P.K.}, year={2016}, month={Dec}, pages={34–41} }
 @article{wakchaure_das_kolar_2016, title={Eggshell as an inexpensive adsorbent for removal of p-Cresol}, volume={59}, number={3}, journal={Transactions of the ASABE}, author={Wakchaure, G. C. and Das, L. and Kolar, P.}, year={2016}, pages={965–974} }
 @article{zhu_kolar_2016, title={Investigation of adsorption of p-cresol on coconut shell-derived activated carbon}, volume={68}, ISSN={["1876-1089"]}, DOI={10.1016/j.jtice.2016.07.044}, abstractNote={Mitigation of odorous volatile organic compounds, such as p-cresol from wastewater needs simple and practical technologies such as adsorption. In this research, an NaOH-activated carbon was prepared from coconut shell (CSAC-SH). Characterization of CSAC-SH suggested that the adsorbent possessed a well-developed microporous/mesoporous structure. To evaluate the performance of CSAC-SH, a series of batch experiments were conducted to investigate the effects of contact time (0–24 h), initial concentration (50–1000 mg L−1) and adsorbent dosage (1–20 mg L−1) on adsorption of p-cresol. The equilibrium data were found to conform to Redlich–Peterson, Fritz–Schluender, and Langmuir isotherms. The maximum monolayer adsorption capacity of 256.9 mg g−1 (298 K) suggested that the prepared adsorbent has a high affinity toward p-cresol. A second-order kinetic model best described the experimental data and adsorption was governed by intraparticle diffusion. The thermodynamic analysis suggested that the adsorption was feasible, spontaneous, and exothermic (298–328 K). Furthermore, a desorption study suggested that chemisorption was dominant in the adsorption process. Results indicate that sodium hydroxide-activated carbon is effective in mitigating p-cresol from wastewater.}, journal={JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS}, author={Zhu, Yiying and Kolar, Praveen}, year={2016}, month={Nov}, pages={138–146} }
 @article{hood_shah_kolar_li_stikeleather_2015, title={Biofiltration of Ammonia and GHGs from Swine Gestation Barn Pit Exhaust}, volume={58}, ISSN={2151-0032 2151-0040}, url={http://dx.doi.org/10.13031/trans.58.10949}, DOI={10.13031/trans.58.10949}, abstractNote={<abstract> <b><sc>Abstract.</sc></b> Livestock barn emissions can affect public health, the environment, and quality of life. While these emissions can be mitigated using several methods, exhaust air treatment may be required in some situations. Biofiltration is one of the most cost-effective exhaust air treatment methods. In a biofilter, polluted air passes through a moist medium (e.g., compost) where the water-soluble gases are dissolved and then degraded by microorganisms into harmless or less harmful compounds. In this study, a downflow biofilter using a compost and wood chip medium was evaluated over summer, fall, and winter (August 2010 to January 2011) for its ability to mitigate emissions of ammonia (NH<sub>3</sub>) and three greenhouse gases (GHGs): methane (CH<sub>4</sub>), nitrous dioxide (N<sub>2</sub>O), and carbon dioxide (CO<sub>2</sub>). Biofilter medium properties were analyzed at the beginning and twice during the study. Changes in medium properties and CO<sub>2</sub> data indicated greater heterotrophic microbial activity during summer through fall and greater autotrophic activity during fall through winter. Regardless of empty bed residence time (EBRT) (5.3 to 26 s), NH<sub>3</sub> removal efficiency (RE) was about 90% with inlet concentrations of ≤1.1 mg m<sup>-3</sup>. With higher NH<sub>3</sub> loading rates, the RE may differ from this study. In fall, CH<sub>4</sub> RE was 49% (EBRT = 26 s) but only 13% in summer (EBRT = 13 s). Nitrous oxide RE varied in a narrow range of 14% to 18% over the study. In summer, CO<sub>2</sub> removal was negligible but was 15% in fall and 34% in winter. While a compost based medium may be more effective for CH<sub>4</sub> and N<sub>2</sub>O mitigation, a wood chip based medium would be more economical. Care should be taken when using a photoacoustic sensor for high-frequency and low-concentration NH<sub>3</sub> measurements.}, number={3}, journal={Transactions of the ASABE}, publisher={American Society of Agricultural and Biological Engineers (ASABE)}, author={Hood, Matthew C. and Shah, Sanjay B. and Kolar, Praveen and Li, Lingjuan Wang and Stikeleather, Larry}, year={2015}, month={Jun}, pages={771–782} }
 @article{karoshi_kolar_shah_gilleskie_das_2015, title={Calcined eggshell as an inexpensive catalyst for partial oxidation of methane}, volume={57}, ISSN={["1876-1089"]}, DOI={10.1016/j.jtice.2015.05.025}, abstractNote={Calcined eggshell was evaluated as an inexpensive catalyst for selective oxidation of methane. Experiments were conducted using a packed bed reactor to determine the effects of oxygen on methane ratio (1, 3 and 7), flow rate (0.4, 0.8 and 1.2 L/min), and temperature (650, 700, and 750 °C) on methane conversion and selectivity. Our results suggested that partial oxidation of methane on calcined eggshell yielded higher hydrocarbons (C2–C7) via oxidative coupling with an average fractional methane conversion of ∼30%. Several factors including oxygen concentration, flow rate, and temperature were observed to influence fractional methane conversion and product selectivity. Catalyst characterization showed enhanced porosity and surface area upon calcination due to removal of organics and carbon dioxide. Surface deformation was observed in spent catalyst due to the physical impact of feed gas. Results from this research are expected to add value to eggshells and enhance agricultural waste management opportunities in areas where poultry industry is concentrated.}, journal={JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS}, author={Karoshi, Gourishankar and Kolar, Praveen and Shah, Sanjay B. and Gilleskie, Gary and Das, Lalitendu}, year={2015}, month={Dec}, pages={123–128} }
 @article{fitzgerald_kolar_classen_boyette_das_2015, title={Swine Manure Char as an Adsorbent for Mitigation of p-Cresol}, volume={34}, ISSN={["1944-7450"]}, DOI={10.1002/ep.11972}, abstractNote={There is a significant interest in synthesizing inexpensive adsorbents for mitigating pollutants emitted from animal agriculture industry such as p‐cresol. Biochar, a byproduct obtained from thermochemical biomass processing is one such source of adsorbent materials. However, presently there is not enough quantitative information on adsorption of p‐cresol on biochar. Hence, the goal of this research is to investigate swine manure char as an inexpensive adsorbent for removal of p‐cresol from an aqueous system. Swine manure was gasified for 15 min at 704°C to obtain gasified manure char. The char was characterized using physical and chemical techniques. Batch experiments were performed in duplicates at 25°C, 35°C, and 45°C to determine the adsorption isotherms and kinetics. Results indicated that gasification enhanced surface area and acid value of manure from 11.42 ± 0.20 to 49.12 ± 0.79 m2 g−1 and 7.81 ± 0.05 to 8.57 ± 0.01, respectively. The enhanced basicity of the resultant char promoted chemisorption of p‐cresol on char surface with maximum adsorption capacities of 7.63 mg g−1 (25°C), 14.99 mg g−1 (35°C), and 14.84 mg g−1 (45°C). Langmuir and Freundlich models suggested that adsorption of p‐cresol on char was favorable. Kinetic analysis of the data also confirmed chemisorption of p‐cresol while the analysis of transport processes suggested that internal diffusion of p‐cresol within the pores was the rate‐limiting step. Use of biochar as an adsorbent for p‐cresol will add value to gasification byproducts and simultaneously reduce water and air pollution associated with swine farming operations. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 125–131, 2015}, number={1}, journal={ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY}, author={Fitzgerald, Sterling and Kolar, Praveen and Classen, John and Boyette, Mike and Das, Lalitendu}, year={2015}, month={Jan}, pages={125–131} }
 @article{zhu_kolar_2014, title={Adsorptive removal of p-cresol using coconut shell-activated char}, volume={2}, ISSN={2213-3437}, url={http://dx.doi.org/10.1016/J.JECE.2014.08.022}, DOI={10.1016/J.JECE.2014.08.022}, abstractNote={Swine farming is a major contributor to the United States’ animal agriculture industry. However, it is also associated with several environmental pollutants, among which, p-cresol is one of the most odorous. In order to make swine husbandry more sustainable, its environmental impacts have to be minimized. Among several available environmental control technologies, adsorptive removal is perhaps the most effective, practical, simple, and easiest to retrofit. Hence, in this research, a highly adsorptive activated char was synthesized using coconut shells. Batch experiments were systematically carried out to investigate the adsorption performance of the prepared activated char for the removal of p-cresol from aqueous solutions. Effects of initial adsorbate concentration (25–500 mg L−1), agitation speed (0–200 rpm), solution pH (2–12), and adsorbent dosage (0.50–3 g 100 mL−1) were also investigated. Results suggest that the kinetic data followed a pseudo-second-order model and intra-particle diffusion was rate limiting during the entire adsorption process. The equilibrium data were best represented by the Langmuir isotherm model, with maximum monolayer adsorption capacities of 30.23 mg g−1 at 293 K, 31.57 mg g−1 at 303 K and 32.77 mg g−1 at 313 K. Our results suggest that physiochemical-activated coconut char is highly effective in the mitigation of p-cresol.}, number={4}, journal={Journal of Environmental Chemical Engineering}, publisher={Elsevier BV}, author={Zhu, Yiying and Kolar, Praveen}, year={2014}, month={Dec}, pages={2050–2058} }
 @article{ansanay_kolar_sharma-shivappa_cheng_2014, title={Niobium oxide catalyst for delignification of switchgrass for fermentable sugar production}, volume={52}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2013.11.044}, abstractNote={In this research, niobium oxide, a solid acid catalyst was evaluated as a pretreatment agent for delignification of Alamo switchgrass. The objectives were to determine the effects of temperature, catalyst loading, and pretreatment time on delignification and enzymatic hydrolysis of switchgrass and evaluate reusability of the catalyst. Batch experiments were performed using a Box–Behnken statistical model to study the effects of temperature, pretreatment time, and catalyst loading followed by hydrolysis using Cellic®Ctec2 (Novozymes). Niobium oxide was able to reduce total lignin concentrations up to 44.6 ± 0.97%. Hydrolysis experiments performed for 72 and 168 h (7% enzyme loading) indicated that a maximum glucose yield of 0.169 g g−1 (59.94% conversion)–0.196 g g−1 (77.51% conversion) was obtained. Catalyst reusability studies suggested that niobium oxide was able to pretreat four separate batches of switchgrass without losing activity. Niobium oxide is expected to serve as a reusable pretreatment catalyst and make ethanol production inexpensive and environmentally friendly.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Ansanay, Yane and Kolar, Praveen and Sharma-Shivappa, Ratna R. and Cheng, Jay J.}, year={2014}, month={Jan}, pages={790–795} }
 @article{das_kolar_classen_osborne_2013, title={Adsorbents from pine wood via K2CO3-assisted low temperature carbonization for adsorption of p-cresol}, volume={45}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2012.12.010}, abstractNote={A low-temperature carbonization process was evaluated to synthesize an inexpensive adsorbent from pine wood to mitigate p-cresol from aqueous system. Surface response experiments using carbonization time, impregnation ratio (IR), and carbonization temperature as variables indicated that optimum adsorbent yield and adsorption were 63.22% and 5.40 mg g−1, respectively at carbonization temperature of 266 °C, IR of 2, and carbonization time of 2 h. The equilibrium adsorption data agreed with Langmuir's model and maximum theoretical adsorption of 6.97 mg g−1 was obtained at temperature 25 °C, unadjusted pH and adsorbent dose of 10 g L−1. The kinetic analysis combined with desorption study revealed that p-cresol chemisorbed on the adsorbent surface. Additionally, adsorption of p-cresol was found to be exothermic and inhibited by presence of surface acidic oxygen groups.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Das, Lalitendu and Kolar, Praveen and Classen, John J. and Osborne, Jason A.}, year={2013}, month={Feb}, pages={215–222} }
 @article{yin_natelson_campos_kolar_roberts_2013, title={Aromatization of n-octane over Pd/C catalysts}, volume={103}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2012.06.095}, abstractNote={Abstract Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400–600 °C), weight hourly space velocity (WHSV) (0.8–∞), and hydrogen to hydrocarbon molar ratio (MR) (0–6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h−1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane.}, journal={FUEL}, author={Yin, Mengchen and Natelson, Robert H. and Campos, Andrew A. and Kolar, Praveen and Roberts, William L.}, year={2013}, month={Jan}, pages={408–413} }
 @article{panneerselvam_sharma-shivappa_kolar_clare_ranney_2013, title={Hydrolysis of ozone pretreated energy grasses for optimal fermentable sugar production}, volume={148}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2013.08.119}, abstractNote={Ozonated energy grass varieties were enzymatically hydrolyzed to establish process parameters for maximum fermentable sugar production. Conditions for ozonolysis were selected on the basis of maximum delignification and glucan retention after pretreatment. To study the effect of lignin degradation products generated during ozonolysis on cellulolytic enzymes, hydrolysis was carried out for washed and unwashed pretreated solids. Washing the solids significantly (p < 0.05) enhanced glucan conversion from 34.3% to 100% while delivering glucose yields of 146.2–431.9 mg/g biomass. Highest fermentable sugars were produced when grasses were ozonated for maximum delignification and washed solids were hydrolyzed using 0.1 g/g Cellic® CTec2. In a comparative study on alkaline pretreatment with 1% NaOH for 60 min, Saccharum arundinaceum exhibited the highest glucan conversion with maximum sugar production of 467.9 mg/g. Although ozonolysis is an effective and environmentally friendly technique for cellulosic sugar production, process optimization is needed to ascertain economic feasibility of the process.}, journal={BIORESOURCE TECHNOLOGY}, author={Panneerselvam, Anushadevi and Sharma-Shivappa, Ratna R. and Kolar, Praveen and Clare, Debra A. and Ranney, Thomas}, year={2013}, month={Nov}, pages={97–104} }
 @article{panneerselvam_sharma-shivappa_kolar_ranney_peretti_2013, title={Potential of ozonolysis as a pretreatment for energy grasses}, volume={148}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2013.08.129}, abstractNote={This study investigated the effect of ozonolysis on Miscanthus × giganteus, Miscanthus sinensis 'Gracillimus', Saccharum arundinaceum and Saccharum ravennae, collectively referred to as 'energy grasses'. Studies were conducted at three different ozone concentrations (40, 50 and 58 mg/l) using two ozone flow configurations - uni-directional and reversed flow. Pretreatment conditions for each variety were optimized based on lignin content and glucan recovery in ozonated solids. Results showed that ozonolysis was effective in removing up to 59.9% lignin without cellulose degradation. However, subsequent hydrolysis of pretreated solids with Cellic® CTec2 at 0.06 g/g raw biomass provided glucan conversion lower than untreated samples suggesting enzyme inhibition by lignin degradation products formed during ozonolysis. Future studies investigating hydrolysis efficiency of washed pretreated solids with higher enzyme loadings are therefore warranted to optimize the hydrolysis process and make it functionally feasible.}, journal={BIORESOURCE TECHNOLOGY}, author={Panneerselvam, Anushadevi and Sharma-Shivappa, Ratna R. and Kolar, Praveen and Ranney, Thomas and Peretti, Steven}, year={2013}, month={Nov}, pages={242–248} }
 @article{athalye_sharma-shivappa_peretti_kolar_davis_2013, title={Producing biodiesel from cottonseed oil using Rhizopus oryzae ATCC #34612 whole cell biocatalysts: Culture media and cultivation period optimization}, volume={17}, ISSN={0973-0826}, url={http://dx.doi.org/10.1016/J.ESD.2013.03.009}, DOI={10.1016/J.ESD.2013.03.009}, abstractNote={The effect of culture medium composition and cultivation time on biodiesel production by Rhizopus oryzae ATCC #34612 whole cell catalysts, immobilized on novel rigid polyethylene biomass supports, was investigated. Supplementation of the medium with carbon sources led to higher lipase activity and increased the biomass immobilized on the BSPs. Statistical analysis indicates that a cultivation period of 72 h in a basal medium supplemented with both cottonseed oil and glucose is optimal for biodiesel production by R. oryzae, resulting in a fatty acid methyl ester (FAME) yield of 27.9 wt.% (228.2 g/L).}, number={4}, journal={Energy for Sustainable Development}, publisher={Elsevier BV}, author={Athalye, Sneha and Sharma-Shivappa, Ratna and Peretti, Steven and Kolar, Praveen and Davis, Jack P.}, year={2013}, month={Aug}, pages={331–336} }
 @article{jairam_kolar_sharma-shivappa_osborne_2013, title={Synthesis of solid acid catalyst from tobacco stalk for esterification of oleic acid}, volume={29}, number={3}, journal={Applied Engineering in Agriculture}, author={Jairam, S. and Kolar, P. and Sharma-Shivappa, R. S. and Osborne, J. A.}, year={2013}, pages={385–389} }
 @article{smith_kolar_boyette_chinn_smith_gangadharan_zhang_2012, title={Advanced oxidation of toluene using Ni-olivine catalysts: Part 1. syntheses, characterization, and evaluation of Ni-olivine catalysts for toluene oxidation}, volume={55}, number={3}, journal={Transactions of the ASABE}, author={Smith, V. M. and Kolar, P. and Boyette, M. D. and Chinn, M. and Smith, C. and Gangadharan, R. and Zhang, G.}, year={2012}, pages={1013–1024} }
 @article{smith_kolar_boyette_chinn_smith_gangadharan_zhang_2012, title={Advanced oxidation of toluene using Ni-olivine catalysts: part 2. Toluene oxidation kinetics and mechanism of Ni-olivine catalysts synthesized via electroless deposition and thermal impregnation}, volume={55}, DOI={10.13031/2013.42485}, abstractNote={The production of synthesis gas (syngas) involves the gasification of biomass under oxygen-limited conditions, which also produces tars. Tars pose significant problems for mechanical devices by depositing on piping, resulting in clogging and engine fouling. While recent research has shown that thermally impregnated Ni-olivine has been effective in reforming tars into H2 and CO, this technique possessed limited economic feasibility due to high input energy requirements. Thus, stable, active, and inexpensive catalysts are required for effective and efficient conditioning of syngas. This research compared the activity of Ni-olivine catalysts synthesized via electroless plating (ELP) (35°C) and thermal impregnation (TI) (1400°C) for oxiding toluene in a flow-through reactor. The objectives were to (1) determine the kinetics of toluene oxidation, (2) propose a reaction mechanism for toluene oxidation, and (3) investigate the effect of syngas on toluene oxidation. Conversion of toluene using Ni-olivine catalysts increased with increasing ozone concentration and temperature, as well as decreasing toluene molar flow rate, and facilitated the complete oxidation of toluene. The information obtained from this research is expected to provide opportunities for efficient cleanup of tars from biomass gasification facilities at lower temperatures.}, number={6}, journal={Transactions of the ASABE}, author={Smith, V. M. and Kolar, P. and Boyette, M. D. and Chinn, Mari and Smith, C. and Gangadharan, R. and Zhang, G.}, year={2012}, pages={2273–2283} }
 @article{saidu_hall_kolar_schramm_davis_2012, title={Efficient temperature control in recirculating aquaculture tanks}, volume={28}, DOI={10.13031/2013.41269}, abstractNote={Improving process control in recirculating aquaculture systems can reduce start-up and maintenance costs and increase the effectiveness of operations. Efficient control of temperature in recirculating systems may increase energy savings, improve productivity, and enhance sustainability. This study focused on cost-effective design, installation, and determination of heat transfer efficiency in small recirculating tank systems. A series of low-cost in-situ coil heat exchangers were developed and used to maintain desired operational temperatures via computer process control for several independent recirculating aquaculture systems. However no fish were in the tanks during preliminary testing. Knowledge of the functional heat transfer capability of such systems is necessary for effective design. The computerized process control system was coupled with controlled low-cost in-situ chillers and glass insertion heaters to impose desired temperature regimes in independent tanks.}, number={1}, journal={Applied Engineering in Agriculture}, author={Saidu, M. M. and Hall, S. G. and Kolar, P. and Schramm, R. and Davis, T.}, year={2012}, pages={161–167} }
 @article{shah_kolar_2012, title={Evaluation of additive for reducing gaseous emissions from swine waste}, volume={14}, number={2}, journal={Agricultural Engineering International: CIGR Journal}, author={Shah, Sanjay B. and Kolar, Praveen}, year={2012}, pages={10–20} }
 @article{kolar_shah_love_2012, title={Feasibility of extracting ammonia from broiler litter and scale-up considerations}, volume={28}, number={4}, journal={Applied Engineering in Agriculture}, author={Kolar, P. and Shah, S. B. and Love, C. D.}, year={2012}, pages={577–582} }
 @article{jairam_kolar_sharma-shivappa_osborne_davis_2012, title={KI-impregnated oyster shell as a solid catalyst for soybean oil transesterification}, volume={104}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2011.10.039}, abstractNote={Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated calcined oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine the effect of reaction variables and reaction kinetics. The catalyst was synthesized by impregnating KI on calcined oyster shells. X-ray diffraction analysis indicated the presence of portlandite and potassium iodide on the surface and a 31-fold increase in surface as a result of calcination and KI impregnation. Under the conditions tested, ideal reaction variables were 1 mmol g−1 for catalyst loading, 50 °C for temperature, 10:1 for methanol/oil, and 4 h for reaction time. The transesterification followed a first-order reaction (k = 0.4385 h−1). The option of using oyster shell for the production of transesterification catalysts could have economic benefits to the aquaculture industry in the US.}, journal={BIORESOURCE TECHNOLOGY}, author={Jairam, Suguna and Kolar, Praveen and Sharma-Shivappa, Ratna and Osborne, Jason A. and Davis, Jack P.}, year={2012}, month={Jan}, pages={329–335} }
 @article{love_kolar_classen_das_2011, title={Adsorption of ammonia on ozonated activated carbon}, volume={54}, DOI={10.13031/2013.39834}, abstractNote={In this theoretical research, we investigated ozonated granular activated carbon (OGAC) as an ammonia adsorbent in aqueous systems. Research objectives were to determine the (1) effectiveness of ozone loading on adsorption capacity of activated carbon in aqueous ammonia solutions, (2) kinetics and adsorption isotherms of ammonia adsorption, and (3) effect of volatile organic compounds on adsorption of ammonia from the aqueous phase. Batch experiments indicated that ozonation for 30 min enhanced the adsorption capacity of granular activated carbon from 0.47 ±0.065 mg g-1 to 1.02 ±0.099 mg g-1 due to increased surface oxygen species on activated carbon. These results suggested that activated carbon could be chemically modified to enhance the adsorption of ammonia from aqueous systems. Analysis of the rate data suggested that the adsorption of ammonia on OGAC followed an Elovich model with initial adsorption rate (a) and desorption constants (s) between 0.146 and 1.06 mg g-1 min-1 and 5.5 and 7.75 g mg-1, respectively (25°C to 45°C). The effect of temperature (25°C to 45°C) on adsorption was not found to be significant, suggesting that adsorption on OGAC was non-activated. However, presence of volatile organic compounds (VOCs) such as p-cresol and acetic acid inhibited adsorption of ammonia on OGAC. Future research is needed to synthesize activated carbon that can absorb ammonia and VOCs simultaneously.}, number={5}, journal={Transactions of the ASABE}, author={Love, C. D. and Kolar, P. and Classen, John and Das, L.}, year={2011}, pages={1931–1940} }
 @article{kolar_kastner_2010, title={Low-temperature catalytic oxidation of aldehyde mixtures using wood fly ash: Kinetics, mechanism, and effect of ozone}, volume={78}, ISSN={["1879-1298"]}, DOI={10.1016/j.chemosphere.2009.12.033}, abstractNote={Poultry rendering emissions contain volatile organic compounds (VOCs) that are nuisance, odorous, and smog and particulate matter precursors. Present treatment options, such as wet scrubbers, do not eliminate a significant fraction of the VOCs emitted including, 2-methylbutanal (2-MB), 3-methylbutanal, and hexanal. This research investigated the low-temperature (25-160 degrees C) catalytic oxidation of 2-MB and hexanal vapors in a differential, plug flow reactor using wood fly ash (WFA) as a catalyst and oxygen and ozone as oxidants. The oxidation rates of 2-MB and hexanal ranged between 3.0 and 3.5 x 10(-9)mol g(-1)s(-1) at 25 degrees C and the activation energies were 2.2 and 1.9 kcal mol(-1), respectively. The catalytic activity of WFA was comparable to other commercially available metal and metal oxide catalysts. We theorize that WFA catalyzed a free radical reaction in which 2-butanone and CO(2) were formed as end products of 2-MB oxidation, while CO(2), pentanal, and butanal were formed as end products of hexanal oxidation. When tested as a binary mixture at 25 and 160 degrees C, no inhibition was observed. Additionally, when ozone was tested as an oxidant at 160 degrees C, 100% removal was achieved within a 2-s reaction time. These results may be used to design catalytic oxidation processes for VOC removal at poultry rendering facilities and potentially replace energy and water intensive air pollution treatment technologies currently in use.}, number={9}, journal={CHEMOSPHERE}, author={Kolar, Praveen and Kastner, James R.}, year={2010}, month={Feb}, pages={1110–1115} }
 @article{kastner_miller_kolar_das_2009, title={Catalytic ozonation of ammonia using biomass char and wood fly ash}, volume={75}, ISSN={0045-6535}, url={http://dx.doi.org/10.1016/j.chemosphere.2009.01.035}, DOI={10.1016/j.chemosphere.2009.01.035}, abstractNote={Catalytic ozonation of gaseous ammonia was investigated at room temperature using wood fly ash (WFA) and biomass char as catalysts. WFA gave the best results, removing ammonia (11 ppmv NH3, 45% conversion) at 23 °C at a residence time of 0.34 s, using 5 g of catalyst or ash at the lowest ozone concentration (62 ppmv). Assuming pseudo zero order kinetics in ozone, a power rate law of -rNH3=7.2×10-8CNH30.25 (r, mol g−1 s−1, CNH3 mol L−1) was determined at 510 ppmv O3 and 23 °C for WFA. Water vapor approximately doubled the oxidation rate using WFA and catalytic ozonation activity was not measured for the char without humidifying the air stream. Overall oxidation rates using the crude catalysts were lower than commercial catalysts, but the catalytic ozonation process operated at significantly lower temperatures (23 vs. 300 °C). Nitric oxide was not detected and the percentage of NO2 formed from NH3 oxidation ranged from 0.3% to 3% (v/v), with WFA resulting in the lowest NO2 level (at low O3 levels). However, we could not verify that N2O was not formed, so further research is needed to determine if N2 is the primary end-product. Additional research is required to develop techniques to enhance the oxidation activity and industrial application of the crude, but potentially inexpensive catalysts.}, number={6}, journal={Chemosphere}, publisher={Elsevier BV}, author={Kastner, James R. and Miller, Joby and Kolar, Praveen and Das, K.C.}, year={2009}, month={May}, pages={739–744} }
 @article{kolar_kastner_2009, title={Room-temperature oxidation of propanal using catalysts synthesized by electrochemical deposition}, volume={52}, DOI={10.13031/2013.27783}, abstractNote={Poultry rendering emissions contain aldehydes that are reactive and regulated volatile organic compounds requiring mitigation. This research presents an application of catalytic oxidation technology to treat aldehydes at room temperature using ozone as an oxidant and metal oxides deposited on activated carbon as catalysts. Four types of catalysts were tested: activated carbon, activated carbon impregnated with iron oxide, and activated carbon electrochemically deposited with nickel and cobalt oxides. Iron oxides were deposited on activated carbon via traditional dry impregnation, while nickel and cobalt were deposited on activated carbon via electrochemical deposition. The prepared catalysts' activities were tested in a continuous differential packed-bed reactor, using an ozone generator and gas chromatography. Propanal (50 to 250 ppmv) was tested as a representative contaminant, and ozone (1500 ppmv) was used as an oxidant. Experiments with activated carbon as a catalyst indicated that 70% removal was achieved within 0.1 s residence time, and the oxidation rates of propanal were determined to be in the range of 90 × 10-9 to 300 × 10-9 mol/g-s. However, when iron oxide-deposited activated carbon was tested for propanal oxidation, the oxidation rates decreased significantly (7 × 10-9 to 60 × 10-9 mol/g-s), probably due to the clogging of the micro- and meso-pores of the activated carbon support with iron oxide particles. When the electrochemically deposited nickel and cobalt oxide catalysts were tested, propanal oxidation rates increased by 20% to 25%. Based on the preliminary results, electrochemical deposition on activated carbon appears to be a valuable tool in synthesizing advanced catalysts for use in air pollution remediation.}, number={4}, journal={Transactions of the ASABE}, author={Kolar, P. and Kastner, J. R.}, year={2009}, pages={1337–1344} }
 @article{kastner_ganagavaram_kolar_teja_xu_2008, title={Catalytic Ozonation of Propanal Using Wood Fly Ash and Metal Oxide Nanoparticle Impregnated Carbon}, volume={42}, ISSN={0013-936X 1520-5851}, url={http://dx.doi.org/10.1021/es0707512}, DOI={10.1021/es0707512}, abstractNote={Catalytic ozonation of propanal at ambient temperatures (23-25 degrees C) was investigated by varying propanal and ozone concentrations and catalyst type. The catalysts tested included wood fly ash (WFA), magnetically separated ash, synthetic hematite and magnetite, and metal oxide nanoparticle impregnated activated carbon and peanut hull char. A power law model independent of ozone concentration for WFA (r(w), moles g(-1) s(-1)) and magnetite (r(m)) were, respectively, r(w) = k'(w) C(R(0.89)) and r(m) = k'(m)C(R(1.55)), where kw, and k'(m) were 2.36 x 10(-6) g(-1) s(-1) (moles)(-0.11) (m3)(0.89) and 6.5 x 10(-4) g(-1) s(-1) (moles)(-0.55) (m3)(1.55), respectively (5-15 ppmv). Magnetite and hematite present in the WFA were theorized to be the primary active sites, since magnetically separated WFA had a significantly higher reaction rate (approximately 12x, mol m(-2) s(-1)) than that of WFA. X-ray diffraction analysis demonstrated a qualitative increase in magnetite and hematite in the magnetically separated ash, and synthetic magnetite and hematite had reaction rates >80x and 200x that of WFA or activated carbon (surface area basis). Supercritical deposition of hematite on/in peanut hull char successfully generated a porous, pelleted catalystfrom an agricultural residue capable of oxidizing propanal at rates 12x activated carbon and similar to commercially available catalysts (per mass basis). Water vapor significantly increased the propanal reaction rate when using wood fly ash and activated carbon.}, number={2}, journal={Environmental Science & Technology}, publisher={American Chemical Society (ACS)}, author={Kastner, James R. and Ganagavaram, Rangan and Kolar, Praveen and Teja, Amyn and Xu, Chunbao}, year={2008}, month={Jan}, pages={556–562} }
 @article{kolar_kastner_miller_2007, title={Low temperature catalytic oxidation of aldehydes using wood fly ash and molecular oxygen}, volume={76}, ISSN={0926-3373}, url={http://dx.doi.org/10.1016/j.apcatb.2007.05.022}, DOI={10.1016/j.apcatb.2007.05.022}, abstractNote={Aldehydes, such a 2-methylbutanal (2-MB) and 3-methylbutanal (3-MB), are odorous and regulated VOCs generated in the poultry rendering process that are ineffectively removed in chemical wet scrubbers. It was theorized that wood fly ash or selective crystalline phases in the ash could act to catalyze the oxidation of aldehydes at room temperature in the presence of ClO2, resulting in a low-cost/energy air pollution control method. Results indicate that wood fly ash catalyzed the oxidation (i.e., breakdown) of 2-MB and 3-MB both in the presence of ClO2 and with just O2 (i.e., air) itself, potentially via a free radical mechanism. Aldehyde oxidation did not occur at measurable rates without the wood fly ash or activated carbon. The presence of ClO2 did not increase the rate, but altered the end products of oxidation. Wood fly ash also catalyzed the oxidation of 2-MB in the presence of air, leading to the appearance of 2-butanone, compared to acetone from 3-MB. Contact times of 30 s reduced 3-MB levels by ∼40% in bench scale, batch reactors. Similar results were found using activated charcoal (i.e., in terms of contact times), except that higher molecular weight compounds appeared to be formed. Continuous catalytic oxidation of 3-MB using wood fly ash was also demonstrated in a fixed-bed reactor at room temperature; the overall oxidation rate appeared to be first order with respect to 3-MB and a representative conversion of 20% at an inlet concentration of 67 ppmv and 2 s residence time (GHSV 1800 1/h, 25 °C, 1 atm) was measured. Results indicate the potential of using inexpensive solid waste materials to breakdown C5 aldehydes in rendering emissions to CO2, H2O, and less odor offensive compounds, but a carbon balance on the reaction and complete identification of end products are required for implementation.}, number={3-4}, journal={Applied Catalysis B: Environmental}, publisher={Elsevier BV}, author={Kolar, Praveen and Kastner, James R. and Miller, Joby}, year={2007}, month={Nov}, pages={203–217} }