ABSTRACT
The calorific value of post-fermentation biogas is a way down below standard and quite low due to the presence of high amount level of carbon dioxide (CO2) biogas mixture. Therefore, it raises the need to process the biogas, separating it from CO2 in order to obtain high-purity biogas as well as to maximize its calorific value. One widely available material that can be used as a sustainable carbon capture adsorbent is silica extracted from bamboo leaves. However, so that silica can act as CO2 adsorber, it is necessary to modify the surface of silica with CTAB and APTES (3-aminopropyl triethoxysilane). In this study, 2-stage method was carried out, namely preparation of mesoporous silica and surface modification using APTES on the mesoporous silica. Experiments in synthesizing APTES-modified silica were obtained by varying its composition: CTAB (1.5-5%w), (HCl 1.5-5 N), and APTES (10-30%). A central composite design (CCD) was employed in exploring the interaction between all variables and also performed for the optimization. Through analysis of variance, it shows that optimum CO2 adsorption capacity reaches 47.02 mg g-1, by applying 4.98% of CTAB, 4.28 N of HCl and 10.08% of APTES. Pseudo-second-order kinetic and Redlich-Peterson isotherm models are more representative to show the adsorption behavior of CO2 into the modified silica. The results show that the modified silica with APTES shows a prospective application of silica for CO2 removal from biogas.
Subject(s)
Biofuels , Propylamines , Silanes , Silicon Dioxide , Cetrimonium , Carbon DioxideABSTRACT
The modification of titanium dioxide (TiO2) using noble metal nanoparticles is considered as a promising technique to make electrode with outstanding photocatalytic performance. In this paper, self-organized anodic TiO2 nanotube arrays were decorated with well-distributed small Cu nanoparticles through a novel technique that combines magnetron sputtering and thermal dewetting. The obtained nanocomposite catalyst exhibited 4-fold increase in the photodegradation rate of methylene blue aqueous solution under solar light irradiation than anatase TiO2 prepared with same anodization conditions. The enhanced photocatalytic activity was attributed to the synergistic effect of Schottky barrier and Surface plasmon resonance. The influence of post annealing process, sputtering time and thermal dewetting temperature on photocatalytic performance was studied and the optimal preparation conditions were proposed. The results of this study may provide a new strategy to improve photocatalytic efficiency of TiO2 without using high-cost noble metals.