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    Carbon molecular sieve production from defatted spent coffee ground using ZnCl2 and benzene for gas purification
    (Elsevier Sci Ltd, 2020) Kaya, M.; Atelge, M. R.; Bekirogullari, M.; Eskicioglu, Cigdem; Atabani, A. E.; Kumar, Gopalakrishnan; Yildiz, Y. S.
    The aim of the current study is to manufacture molecular sieve from the defatted spent coffee ground. The defatted spent coffee ground for the specified particle size (100 mu m) was chemically activated with different agents (ZnCl2, H3PO4, KOH) and then carbonized at different temperatures (400-900 degrees C). A thorough characterization of the produced activated carbon was performed and activated carbons with the highest BET surface area were subsequently used to produce carbon molecular sieve. The surface modification was performed with benzene vapor at different temperatures (600-900 degrees C) and different combustion times (30-90 min.). In addition to the BET analysis, SEM, TGA and FT-IR analysis were also undertaken. The results obtained through characterizations showed that the pore diameters of carbon molecular sieve produced from defatted spent coffee ground varied from 2 to 4 angstrom. To conclude, the results suggest that the fabricated carbon molecular sieve can be used for the removal of impurities such as CH4, CO2, NOx and other impurities in natural and biogas considering the porosity of the sieves.
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    Öğe
    Multi-factor kinetic modelling of microalgal biomass cultivation for optimised lipid production
    (Elsevier Sci Ltd, 2018) Bekirogullari, M.; Pittman, J. K.; Theodoropoulos, C.
    This paper presents a new quadruple-factor kinetic model of microalgal cultivation considering carbon and nitrogen concentration, light intensity and temperature, developed in conjunction with laboratory-scale experiments using the well-studied chlorophyte microalgal species Chlamydomonas reinhardtii. Multi-parameter quantification was exploited to assess the predictive capabilities of the model. The validated model was utilized in an optimization study to determine the optimal light intensity and temperature for achieving maximum lipid productivity while using optimal acetate and nitrogen concentrations (2.1906 g L-1 acetate and 0.0742 g L-1 nitrogen) computed in a recent publication. It was found that the optimal lipid productivity increased by 50.9% compared to the base case, and by 13.6% compared to the previously computed optimal case. Optimization results were successfully validated experimentally. Such comprehensive modelling approaches can be exploited for robust design, scale-up and optimization of microalgal oil production, reducing operating costs and bringing this important technology closer to industrialization.