title: Two novel multi-functional magnetic adsorbents for effective removal of hydrophilic and hydrophobic nitroaromatic compounds.
abstract: Two novel multi-functional magnetic resins named GMA30-1 and GMA30-2 were fabricated and investigated for the removal of 4-nitrotoluene-2-sulfonic acid (NTS) and 2-nitrotoluene (o-MNT). Strong base resin (GMA30-1) and weak base resin (GMA30-2) possess large surface area of 718m(2)/g and 559m(2)/g, and anion exchange capacity of 1.49mmol/g and 1.81mmol/g, respectively. The adsorption isotherms of o-MNT onto two resins were both well described by Langmuir equation. While the adsorption isotherms of NTS could be separated into two segments at a certain initial concentration and each segment followed different trends. At lower concentrations, the adsorption of NTS was driven by Van der Waal's force, exhibiting an exothermic process. With the increase of concentrations, the electrostatic force dominated and the enthalpy change (ΔH) turned to positive, indicating an endothermic process. In binary systems, the decrease in the uptake of NTS was slighter than that of o-MNT because of the additional anion exchange interaction. The adsorption capacity of NTS decreased as pH increased while the adsorption of o-MNT was not significantly affected by pH. Chloride ions reduced the adsorption of NTS by competitive effect. The desorption efficiency of NTS and o-MNT was close to 100% for 10 cycles.
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Wei
authors: W
authors: Wang
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Yan
authors: Y
authors: Ma
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Aimin
authors: A
authors: Li
authors: 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: Qing
authors: Q
authors: Zhou
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Weiwei
authors: W
authors: Zhou
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Jing
authors: J
authors: Jin
mesh_terms: D000327:Adsorption; D001557:Benzenesulfonates / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007475:Ion Exchange Resins / Q000737:chemistry*; D060328:Magnetic Phenomena; D014050:Toluene / Q000031:analogs & derivatives* / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D001557:Benzenesulfonates; D007475:Ion Exchange Resins; D014874:Water Pollutants, Chemical; C448316:4-nitrotoluene-2-sulfonic acid; D014050:Toluene; C029955:2-nitrotoluene
keywords: Adsorption; Ion exchange; Multi-functional magnetic resin; Nitroaromatic compounds