title: Adsorption of pharmaceuticals onto trimethylsilylated mesoporous SBA-15.
abstract: The adsorption of a complex mixture of 12 selected pharmaceuticals to trimethylsilylated mesoporous SBA-15 (TMS-SBA-15) has been investigated by batch adsorption experiments. The adsorption of pharmaceuticals to TMS-SBA-15 was highly dependent on the solution pH and pharmaceutical properties (i.e., hydrophobicity (logKow) and acidity (pKa)). Good log-log linear relationships between the adsorption (Kd) and pH-dependent octanol-water coefficients (Kow(pH)) were then established among the neutral, anionic, and cationic compounds, suggesting hydrophobic interaction as a primary driving force in the adsorption. In addition, the neutral species of each compound accounted for a major contribution to the overall compound adsorption onto TMS-SBA-15. The adsorption kinetics of pharmaceuticals was evaluated by the nonlinear first-order and pseudo-second-order models. The first-order model gave a better fit for five pharmaceuticals with lower adsorption capacity, whereas the pseudo-second-order model fitted better for seven pharmaceuticals having higher adsorption capacity. In the same group of properties, pharmaceuticals having higher adsorption capacity exhibited faster adsorption rates. The rate-limiting steps for adsorption of pharmaceuticals onto TMS-SBA-15 are boundary layer diffusion and intraparticle diffusion including diffusion in mesopores and micropores. In addition, the adsorption of pharmaceuticals to TMS-SBA-15 was not influenced by the change of initial pharmaceutical concentration (10-100μgL(-1)) and the presence of natural organic matter.
authors: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea.
authors: Tung Xuan
authors: TX
authors: Bui
authors: Center of Environment and Sustainable Development, College of Science, Vietnam National University, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam.
authors: Viet Hung
authors: VH
authors: Pham
authors: Faculty of Chemistry, College of Science, Vietnam National University, 19 Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam.
authors: Son Thanh
authors: ST
authors: Le
authors: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea. Electronic address: hcchoi@gist.ac.kr.
authors: Heechul
authors: H
authors: Choi
mesh_terms: D000327:Adsorption; D001578:Benzopyrans / Q000737:chemistry; D006812:Humic Substances; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014297:Trimethylsilyl Compounds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D006812:Humic Substances; D004364:Pharmaceutical Preparations; C509969:SBA-15; D014297:Trimethylsilyl Compounds; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; C005023:fulvic acid