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Intense removal of Ni (Ⅱ) chelated by EDTA from wastewater via Fe3+ replacement–chelating precipitation

2022; Elsevier BV; Volume: 159; Linguagem: Inglês

10.1016/j.psep.2022.01.080

1876-4800

Sai Li, Tong Yue, Wei Sun, Chenyang Zhang, Jianyong He, Mingjun Han, Hongliang Zhang, Heng Yu, Wenyuan Li,

Analytical chemistry methods development

Efficient removal of Ni (Ⅱ) chelated by ethylenediaminetetraacetic acid (EDTA) from wastewater remains an important but challenging environmental problem. Therefore, a novel strategy of Fe3+ replacement–chelating precipitation was proposed to remove Ni (Ⅱ) chelated by EDTA from simulated Ni-EDTA wastewater and real electroless nickel plating wastewater. The strategy was proved to be thermodynamically feasible by DFT calculation. Regardless of the simulated Ni-EDTA wastewater or the real electroless nickel plating wastewater, the residual nickel in the wastewater was less than 0.1 mg/L that satisfied the discharge standard after being treated under optimal conditions using this strategy. Moreover, the strong acidity and Fe3+ could increase the proportion of free Ni2+ in Ni-EDTA wastewater, thereby enhancing the Ni removal efficiency. Additionally, the total amount of EDTA in wastewater was basically unchanged, since the structure of EDTA was not destroyed by this strategy, while its chemical form changed from Ni-EDTA complex to Fe3+-EDTA complex. Furthermore, the mechanism was systematically studied by electronic structure analysis, solution chemistry, UV-Vis spectral, FT-IR spectral and X-ray photoelectron spectroscopy. At last, this strategy is a promising approach and it can provide a reference for the treatment of other similar heavy metal wastewater.