title: Enhanced removal of sulfonamide antibiotics by KOH-activated anthracite coal: Batch and fixed-bed studies.
abstract: The presence of sulfonamide antibiotics in aquatic environments poses potential risks to human health and ecosystems. In the present study, a highly porous activated carbon was prepared by KOH activation of an anthracite coal (Anth-KOH), and its adsorption properties toward two sulfonamides (sulfamethoxazole and sulfapyridine) and three smaller-sized monoaromatics (phenol, 4-nitrophenol and 1,3-dinitrobenzene) were examined in both batch and fixed-bed adsorption experiments to probe the interplay between adsorbate molecular size and adsorbent pore structure. A commercial powder microporous activated carbon (PAC) and a commercial mesoporous carbon (CMK-3) possessing distinct pore properties were included as comparative adsorbents. Among the three adsorbents Anth-KOH exhibited the largest adsorption capacities for all test adsorbates (especially the two sulfonamides) in both batch mode and fixed-bed mode. After being normalized by the adsorbent surface area, the batch adsorption isotherms of sulfonamides on PAC and Anth-KOH were displaced upward relative to the isotherms on CMK-3, likely due to the micropore-filling effect facilitated by the microporosity of adsorbents. In the fixed-bed mode, the surface area-normalized adsorption capacities of Anth-KOH for sulfonamides were close to that of CMK-3, and higher than that of PAC. The irregular, closed micropores of PAC might impede the diffusion of the relatively large-sized sulfonamide molecules and in turn led to lowered fixed-bed adsorption capacities. The overall superior adsorption of sulfonamides on Anth-KOH can be attributed to its large specific surface area (2514 m(2)/g), high pore volume (1.23 cm(3)/g) and large micropore sizes (centered at 2.0 nm). These findings imply that KOH-activated anthracite coal is a promising adsorbent for the removal of sulfonamide antibiotics from aqueous solution.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Linzi
authors.initials: L
authors.lastname: Zuo
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ai
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Heyun
authors.initials: H
authors.lastname: Fu
authors.affiliation: College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Shourong
authors.initials: S
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Zhaoyi
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China; School of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address: zhud@pku.edu.cn.
authors.forename: Dongqiang
authors.initials: D
authors.lastname: Zhu
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry; D003031:Coal; D004136:Dinitrobenzenes; D008956:Models, Chemical; D009596:Nitrophenols; D016062:Porosity; D013420:Sulfamethoxazole; D013449:Sulfonamides / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D003031:Coal; D004136:Dinitrobenzenes; D009596:Nitrophenols; D013449:Sulfonamides; D002606:Charcoal; D002244:Carbon; C017906:3-dinitrobenzene; D013420:Sulfamethoxazole; C024836:4-nitrophenol
keywords: Batch adsorption; Fixed-bed adsorption; KOH activation; Microporosity; Molecular size; Sulfonamides