title: Enhanced removal of Cu(II) and Ni(II) from saline solution by novel dual-primary-amine chelating resin based on anion-synergism.
abstract: A novel dual-primary-amine chelating resin (EDTB) was newly synthesized for the effective removal of Cu(II) and Ni(II) from saline solutions. NaNO3 as well as Ca(NO3)2, NaCl and CaCl2 unexpectedly promoted the adsorption of Cu(II) or Ni(II) by up to 63.42% or 133.49% in single heavy-metal species systems. Meanwhile, inorganic salts enhanced both Cu(II) and Ni(II) uptake capacities in binary heavy-metal species systems. Anions significantly increased the amount of adsorption sites by condensing the double electric layer. Interestingly, increasing Ni(NO3)2 concentrations elevated the adsorption capacity of EDTB for Cu(II) by 2.10-11.69% in aqueous media without salts while in the presence of salts, rising Ni(NO3)2 concentrations suppressed Cu(II)-adsorption by 2.42-7.68%. The marginal analysis of anion-synergism depending on salt concentrations quantitatively explained such opposite effects using a promotion index. Furthermore, the solid characterizations and a newly-proposed metastable-state model based on pre-loading experiments conformably indicated the reciprocal relationships between cations and anions involving site competition, displacement effect and anion enhancement. Because of such salt-enhanced removal performance and excellent regeneration efficiency higher than 99%, EDTB is potentially eligible for reusing heavy-metals from actual wastewaters especially containing high-concentration salts.
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Changqing
authors: C
authors: Zhu
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China; State Environmental Protection Engineering Center for Organic Chemical Industrial Waste Water Disposal Resource Reuse, Nanjing 210023, PR China. Electronic address: jogia@163.com.
authors: Fuqiang
authors: F
authors: Liu
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Chao
authors: C
authors: Xu
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Jie
authors: J
authors: Gao
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors: Da
authors: D
authors: Chen
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China; State Environmental Protection Engineering Center for Organic Chemical Industrial Waste Water Disposal Resource Reuse, Nanjing 210023, PR China.
authors: Aimin
authors: A
authors: Li
mesh_terms: D000327:Adsorption; D000588:Amines / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000588:Amines; D002614:Chelating Agents; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; D003300:Copper; D009532:Nickel
keywords: Anion enhancement; Dual-primary-amine chelating resin; Marginal effect; Metastable-state model; Promotion index