@article{park_yoo_cho_park_cruz_kelley_park_2024, title={Exploring potential of cellulose acetate sulfate films for sustainable packaging: tuning characteristics via sulfate group variation}, volume={1}, ISSN={["1572-882X"]}, DOI={10.1007/s10570-023-05713-8}, journal={CELLULOSE}, author={Park, Seonghyun and Yoo, Seunghyun and Cho, Seong-Min and Park, Hyeonji and Cruz, David and Kelley, Stephen S. and Park, Sunkyu}, year={2024}, month={Jan} }
 @article{park_yoo_cho_kelley_park_2023, title={Production of single-component cellulose-based hydrogel and its utilization as adsorbent for aqueous contaminants}, volume={243}, ISSN={["1879-0003"]}, DOI={10.1016/j.ijbiomac.2023.125085}, abstractNote={The growing concern for the environment has resulted in renewed interest in bio-based resources. This study aims to produce a hydrogel adsorbent from cellulose and examine its adsorption performance. In pursuit of this goal, we report a simple one-pot synthesis of cellulose acetate sulfate (CAS), followed by the formation of CAS hydrogels and their subsequent adsorption performances. The CAS includes both hydrophilic and hydrophobic functional groups, enable the formation of a single-component hydrogel through intermolecular interactions in deionized water. The thermal reversibility of CAS hydrogels makes them easily processable into various shapes. The durability of the CAS hydrogel adsorbents can be improved by introducing divalent cations (e.g., Ca2+), which create ionically crosslinked hydrogels. The ionically a crosslinked CAS hydrogel adsorbent exhibits a maximum adsorption capacity of 245 mg/g for methylene blue (MB) at 23 °C and a pH of 7. The adsorption behavior of MB on the CAS hydrogel follows both the pseudo-second-order model and the Langmuir adsorption isotherm model. Furthermore, the CAS hydrogel adsorbent maintains a 70 % removal ratio after five cycles. The simplicity of synthesis and hydrogel formation opens up new possibilities for producing and utilizing cellulose-based hydrogels as adsorbents for aqueous contaminants.}, journal={INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES}, author={Park, Seonghyun and Yoo, Seunghyun and Cho, Seong-Min and Kelley, Stephen S. and Park, Sunkyu}, year={2023}, month={Jul} }
 @article{jang_yoo_park_kan_2019, title={Engineered biochar from pine wood: Characterization and potential application for removal of sulfamethoxazole in water}, volume={24}, ISSN={["2005-968X"]}, DOI={10.4491/eer.2018.358}, abstractNote={The adsorption of sulfamethoxazole (SMX) onto a NaOH-activated pine wood-derived biochar was investigated via batch experiments and models. Surprisingly, the maximum adsorption capacity of activated biochar for SMX (397.29 mg/g) was superior than those of pristine biochars from various feedstock, but comparable to those of commercially available activated carbons. Elovich kinetic and Freundlich isotherm models revealed the best fitted ones for the adsorption of SMX onto the activated biochar indicating chemisorptive interaction occurred on surface of the activated biochar. In addition, the intraparticle diffusion limitation was thought to be the major barrier for the adsorption of SMX on the activated biochar. The main mechanisms for the activated biochar would include hydrophobic, π-π interactions and hydrogen bonding. This was consistent with the changes in physicochemical properties of the activated biochar (e.g., increase in sp and surface area, but decrease in the ratios of O/C and H/C).}, number={4}, journal={ENVIRONMENTAL ENGINEERING RESEARCH}, author={Jang, Hyun Min and Yoo, Seunghyun and Park, Sunkyu and Kan, Eunsung}, year={2019}, month={Dec}, pages={608–617} }
 @article{park_yoo_lim_rojas_hubbe_park_2019, title={Impact of oxidative carbonization on structure development of loblolly pine-derived biochar investigated by nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy}, volume={96}, ISSN={["1879-0062"]}, DOI={10.1016/j.diamond.2019.05.001}, abstractNote={Biochar produced at an oxidative atmosphere shows distinct chemical properties compared to those of biochar produced at an inert atmosphere. However, there has been little investigation on the relationship between the oxidative atmosphere and the structure development of biochar, which can be useful information for the utilization of derived products. In this study, the effect of the oxygen atmosphere on the structure development of loblolly pine-derived biochar during thermal treatment was investigated. Quantitative analysis using solid-state direct polarization/magic angle spinning 13C nuclear magnetic resonance spectroscopy presented the existence of large fractions of aromatic and non-protonated carbons in the biochars treated at an oxidative atmosphere, implying highly condensed aromatic structures with large cluster sizes. Simultaneous thermogravimetic analyzer-differential scanning calorimetry was employed to demonstrate the difference in heat flow during the thermal treatment at two different atmospheres. Relatively large exothermic heat flow was observed when woody biomass was treated at 350 °C under an oxidative atmosphere which might be responsible for the difference in structural alteration. The series of observations suggested that compared to inert atmospheric conditions, admitting a limited amount of oxygen during thermal treatment of woody biomass could promote the evolution of condensed aromatic carbon structures.}, journal={DIAMOND AND RELATED MATERIALS}, author={Park, Junyeong and Yoo, Seunghyun and Lim, Kwang Hun and Rojas, Orlando J. and Hubbe, Martin A. and Park, Sunkyu}, year={2019}, month={Jun}, pages={140–147} }
 @article{jang_yoo_choi_park_kan_2018, title={Adsorption isotherm, kinetic modeling and mechanism of tetracycline on Pinus taeda-derived activated biochar}, volume={259}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2018.03.013}, abstractNote={The objective of this study was to evaluate the adsorption of tetracycline (TC) on the Pinus taeda-derived activated biochar (BC). After NaOH activation, the well-developed porous surface structure was observed with a significantly increase in surface area (959.9 m2/g). The kinetic and isotherm studies indicated that hydrogen bonding and π-π interaction on the heterogeneous surface would be the possible mechanisms, while intra-particle diffusion was considered as the major limitation for the adsorption of TC on the activated BC. The maximum adsorption capacity of the activated BC (274.8 mg TC/g BC) was higher than those of various activated BCs from the previous studies while it was similar to those of commercial activated carbons. It indicated that the activated BC had the high potential for TC removal in water.}, journal={BIORESOURCE TECHNOLOGY}, author={Jang, Hyun Min and Yoo, Seunghyun and Choi, Yong-Keun and Park, Sunkyu and Kan, Eunsung}, year={2018}, month={Jul}, pages={24–31} }
 @article{yoo_chung_kelley_park_2018, title={Graphitization Behavior of Loblolly Pine Wood Investigated by in Situ High Temperature X-ray Diffraction}, volume={6}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.8b01446}, abstractNote={Graphitization is a complex process involving chemical and morphological changes, although the detailed mechanism for different starting materials is not well understood. In this work, in situ high temperature X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to examine the phase transition occurring between 1000 and 1500 °C in loblolly pine wood-derived carbon materials. Electron energy loss spectroscopy (EELS) was also used to study these wood-derived carbon materials. XRD data showed the disappearance of a disordered carbon phase between 1300 and 1400 °C, followed by the formation of a crystalline graphitic phase between 1400 and 1500 °C. Lattice parameters and the crystal structure of the loblolly pine wood-derived graphite were systematically calculated from the empirical data. The presence of a large endothermic peak at 1500 °C in the DSC thermogram supported this observation. Selected area electron diffraction patterns showed the growth of graphitic crystallites after he...}, number={7}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Yoo, Seunghyun and Chung, Ching-Chang and Kelley, Stephen S. and Park, Sunkyu}, year={2018}, month={Jul}, pages={9113–9119} }
 @article{yoo_kelley_tilotta_park_2018, title={Structural Characterization of Loblolly Pine Derived Biochar by X-ray Diffraction and Electron Energy Loss Spectroscopy}, volume={6}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/ACSSUSCHEMENG.7B04119}, DOI={10.1021/acssuschemeng.7b04119}, abstractNote={Biochar from lignocellulosic biomass is emerging as a sustainable material with versatile applications, but its detailed properties are poorly understood because of its structural complexity. We propose a biochar structural development model based on experimental results including composition analysis, surface area and pore analysis, X-ray diffraction analysis, electron microscopy imaging, and electron energy loss spectroscopy. Loblolly pine derived biochars were produced at different carbonization temperatures between 300 to 1000 °C. Fixed carbon, sp2 content, and number of graphene layers increased with increased carbonization temperature. Alternating average C–C bond length, interlayer spacing distance, and layer coherence length were observed. Bulk plasmon excitation energy was correlated to the average C–C bond length, and it serves as a good indicator of the carbon structure development when compared to the perfect graphitic carbon structure. On the basis of the experimental results, four different ...}, number={2}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Yoo, Seunghyun and Kelley, Stephen S. and Tilotta, David C. and Park, Sunkyu}, year={2018}, month={Jan}, pages={2621–2629} }
 @article{he_yoo_meng_yildiz_bradford_park_gao_2017, title={Engineering biorefinery residues from loblolly pine for supercapacitor applications}, volume={120}, ISSN={["1873-3891"]}, DOI={10.1016/j.carbon.2017.05.056}, abstractNote={Recycling agricultural waste biomass into high-value-added products is of great importance to offset the cost of biofuel production. Here, we make biochar-based activated carbons (BACs) from loblolly pine chips via different carbonization recipes and chemical activations. BACs were then assembled into electrochemical double-layer capacitors (EDLCs) as electrode materials. Surprisingly, pyrolysis at lower temperatures (300 °C and 350 °C) rendered better electrochemical performance of BACs than those done at higher temperatures (500 °C and 700 °C). This is mainly due to the large surface area and high pore volume generated at the lower temperatures. Among all the pyrolysis recipes, flash pyrolysis at 300 °C produced the BAC with the highest specific capacitance (74 F g−1 at 20 mV s−1), exceeding the specific capacitance of commercial activated carbon (NORIT®) by 45%. This report demonstrates the great potential of our refinery recipe to engineer BACs from the sustainable, affordable, and abundant natural wastes for energy-storage applications, which opens the door for a group of biorefinery residues for value-added applications.}, journal={CARBON}, author={He, Nanfei and Yoo, Seunghyun and Meng, Jiajia and Yildiz, Ozkan and Bradford, Philip D. and Park, Sunkyu and Gao, Wei}, year={2017}, month={Aug}, pages={304–312} }
 @article{park_shin_yoo_zoppe_park_2015, title={Delignification of Lignocellulosic Biomass and Its Effect on Subsequent Enzymatic Hydrolysis}, volume={10}, ISSN={["1930-2126"]}, DOI={10.15376/biores.10.2.2732-2743}, abstractNote={The effect of delignification on the enzymatic hydrolysis of biomass was investigated to determine how different delignification processes affect enzymatic hydrolysis conversion yields. Oxygen, hydrogen peroxide, and sodium chlorite treatments were performed, and the structural and chemical changes in the biomass were evaluated. Sodium chlorite delignification proved the most effective process to remove lignin in hardwood samples, followed by oxygen delignification. Hydrogen peroxide delignification was not as effective as the other two methods. As for the enzymatic conversion of carbohydrates after delignification processes on hardwood, oxygen and sodium chlorite treatments substantially improved conversion yields as the number of successive treatments was increased, compared to untreated hardwood samples. Changes in α-cellulose after delignification were less substantial than those of hardwood samples, and corresponding conversion yields were also lower. Delignification-induced structural changes in treated substrates might be responsible for the changes in carbohydrate conversion yield observed following subsequent enzymatic hydrolysis.}, number={2}, journal={BIORESOURCES}, author={Park, Junyeong and Shin, Heenae and Yoo, Seunghyun and Zoppe, Justin O. and Park, Sunkyu}, year={2015}, pages={2732–2743} }