@article{wu_akoto-ampaw_elbaccouch_hurrey_wallen_grant_2004, title={Quartz crystal microbalance (QCM) in high-pressure carbon dioxide (CO2): Experimental aspects of QCM theory and CO2 adsorption}, volume={20}, ISSN={["0743-7463"]}, DOI={10.1021/la035502f}, abstractNote={The quartz crystal microbalance (QCM) technique has been developed into a powerful tool for the study of solid-fluid interfaces. This study focuses on the applications of QCM in high-pressure carbon dioxide (CO2) systems. Frequency responses of six QCM crystals with different electrode materials (silver or gold) and roughness values were determined in helium, nitrogen, and carbon dioxide at 35-40 degrees C and at elevated pressures up to 3200 psi. The goal is to experimentally examine the applicability of the traditional QCM theory in high-pressure systems and determine the adsorption of CO2 on the metal surfaces. A new QCM calculation approach was formulated to consider the surface roughness contribution to the frequency shift. It was found that the frequency-roughness correlation factor, Cr, in the new model was critical to the accurate calculation of mass changes on the crystal surface. Experiments and calculations demonstrated that the adsorption (or condensation) of gaseous and supercritical CO2 onto the silver and gold surfaces was as high as 3.6 microg cm(-2) at 40 degrees C when the CO2 densities are lower than 0.85 g cm(-3). The utilization of QCM crystals with different roughness in determining the adsorption of CO2 is also discussed.}, number={9}, journal={LANGMUIR}, author={Wu, YT and Akoto-Ampaw, PJ and Elbaccouch, M and Hurrey, ML and Wallen, SL and Grant, CS}, year={2004}, month={Apr}, pages={3665–3673} }
 @article{elbaccouch_bondar_carbonell_grant_2003, title={Phase equilibrium behavior of the binary systems CO2 plus nonadecane and CO2 plus soysolv and the ternary system CO2 plus soysolv plus quaternary ammonium chloride surfactant}, volume={48}, ISSN={["0021-9568"]}, DOI={10.1021/je020201d}, abstractNote={Liquid phase and molar volume data were measured for the binary system CO 2 + soysolv at (298.15, 313.15, 323.15, 333.15, and 343.15) K and the ternary system CO 2 + soysolv + quaternary ammonium chloride surfactant at (298.15, 313.15, and 333.15) K, where the composition of soysolv to the surfactant is 99:1 wt % and 80:20 wt % on a CO 2 -free basis. Data were collected stoichiometrically with a high-pressure Pyrex glass cell, where no sampling or chromatographic equipment is required. The accuracy of the experimental apparatus was tested with phase equilibrium measurements for the system CO 2 + nonadecane at 313.15 K. A pressure-decay technique was used to calculate the mass of CO 2 loaded into the equilibrium section of the apparatus, and its accuracy was verified with a blank nitrogen experiment. The generated data show that CO 2 modified soysolv is an effective transport medium for the quaternary ammonium chloride surfactant.}, number={6}, journal={JOURNAL OF CHEMICAL AND ENGINEERING DATA}, author={Elbaccouch, MM and Bondar, VI and Carbonell, RG and Grant, CS}, year={2003}, pages={1401–1406} }