title: Preparation of a novel magnetic microporous adsorbent and its adsorption behavior of p-nitrophenol and chlorotetracycline.
abstract: A novel method for fabricating hypercrosslinked magnetic polymer beads with improved acid resistance was developed. Magnetite nanoparticles were covered with tetraethoxysilane and vinyltriethoxysilane, followed by co-polymerization and post-crosslinking. The resulting M150 beads were highly stable at pH ≥ 2 and were superparamagnetic, with a saturation magnetization of 3.1 emu/g. M150 exhibited a specific surface area of 1022.4m(2)/g and an average pore width of 2.6 nm. The adsorption of p-nitrophenol and chlorotetracycline (CTC) onto M150 and the commercial non-magnetic resins NDA 150 and XAD-4 followed both pseudo-first-order and pseudo-second-order equations. M150 displayed much faster kinetics than the other resins because of its small particle size and abundant macropores. The adsorption isotherm of p-nitrophenol onto the three resins fitted the Freundlich equation (R(2)>0.98), whereas CTC adsorption was better described by the Langmuir isotherm. p-Nitrophenol adsorption was optimal at pH ≤ 4, whereas CTC adsorption was optimal at pH 5-6. All three sorbents showed high reusability for p-nitrophenol adsorption. XAD-4 demonstrated the highest reusability for CTC. The CTC adsorption capacities of M150 and NDA150 decreased by 12.42% and 20% after 10 adsorption-desorption cycles, respectively.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China. Electronic address: zhouqing@nju.edu.cn.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China. Electronic address: liaimin@nju.edu.cn.
authors.forename: Aimin
authors.initials: A
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Chendong
authors.initials: C
authors.lastname: Shuang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Mancheng
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D002751:Chlortetracycline / Q000737:chemistry*; D060328:Magnetic Phenomena; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry*; D016062:Porosity; D012821:Silanes / Q000737:chemistry*
chemical_list: D058185:Magnetite Nanoparticles; D009596:Nitrophenols; D012821:Silanes; C040733:tetraethoxysilane; C052671:vinyltriethoxysilane; D002751:Chlortetracycline; C024836:4-nitrophenol
keywords: Acid stable; Adsorption; Hypercrosslink; Nanocomposites; Silane-coated