title: Selective adsorption mechanisms of antilipidemic and non-steroidal anti-inflammatory drug residues on functionalized silica-based porous materials in a mixed solute.
abstract: The selective adsorption mechanisms of naproxen (NAP), acetaminophen (ACT), and clofibric acid (CFA) on silica-based porous materials were examined by single and mixed-batch adsorption. Effects of the types and densities of surface functional groups on adsorption capacities were determined, including the role of hydrophobic and hydrophilic dissolved organic matters (DOMs). Hexagonal mesoporous silica (HMS), superparamagnetic HMS (HMS-SP) and SBA-15 were functionalized and applied as adsorbents. Compared with powdered activated carbon (PAC), amine-functionalized HMS had a better adsorption capacity for CFA, but PAC possessed a higher adsorption capacity for the other pharmaceuticals than HMS and its two derivatives. In contrast to PAC, the adsorption capacity of the mesoporous silicas varied with the solution pH, being highest at pH 5. Electrostatic interactions and hydrogen bonding were found to be the main mechanisms. Increase in grafted amine group density on silica surfaces can enhance the CFA adsorption capacity. Further, hydrophilic DOM can decrease CFA adsorption capacities on amino-grafted adsorbents by adsorption site competition, while hydrophobic DOM can interfere with CFA adsorption by the interaction between hydrophobic DOM and CFA. Finally, in a competitive adsorption study, the adsorption capacity of hydrophilic adsorbents for acidic pharmaceuticals varied with their pKa values.
authors.affiliation: International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand.
authors.forename: Nakorn
authors.initials: N
authors.lastname: Suriyanon
authors.affiliation: International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand.
authors.forename: Jutima
authors.initials: J
authors.lastname: Permrungruang
authors.affiliation: International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand.
authors.forename: Jidanan
authors.initials: J
authors.lastname: Kaosaiphun
authors.affiliation: Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand; Department of Environmental Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Aunnop
authors.initials: A
authors.lastname: Wongrueng
authors.affiliation: Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Chawalit
authors.initials: C
authors.lastname: Ngamcharussrivichai
authors.affiliation: Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand; Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand; Research Unit Control of Emerging Micropollutants in Environment, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: patiparn.p@chula.ac.th.
authors.forename: Patiparn
authors.initials: P
authors.lastname: Punyapalakul
mesh_terms: D000082:Acetaminophen; D000327:Adsorption; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002606:Charcoal; D057927:Hydrophobic and Hydrophilic Interactions; D009288:Naproxen; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C509969:SBA-15; D012996:Solutions; D014874:Water Pollutants, Chemical; D002606:Charcoal; D000082:Acetaminophen; D009288:Naproxen; D012822:Silicon Dioxide
keywords: Adsorption; Dissolved organic matter; Pharmaceutical residue; Silica-based porous material; Surface functional group