The wastewater containing high concentration (5562.71mg/L) of nickel ion was first completely precipitated at pH 9, and subsequently treated by a ceramic microfiltration membrane with a pore diameter of 0.5μm. During the concentration process, the membrane flux (J) dropped significantly at the initial stage, then declined slowly, and finally decreased at a rapid rate again. The nickel rejection coefficient (RNi) was found to be approx. 1. When the volume concentration factor (VCF) increased from 1to 10, the nickel concentration in the retentate (Cr) increased from 5562.71 to 55507.76mg/L, whereas the nickel concentration in the permeate (Cp) remained nearly constant at approx. 13.26mg/L. Then, the complexation-ultrafiltration process was studied using the permeation fluid from the microfiltration process as the feed solution. Poly (ethylene imine) was employed as the complexing agent. The effects of the polymer/metal mass ratio (rp/m), pH, temperature and operating pressure on RNi and J were investigated. Further, the process of ultrafiltration concentration was studied. The results showed that RNi increased with increasingrp/m or pH and decreased slightly with temperature, and that the operating pressure exerted no effect on RNi;J increased with temperature or operating pressure. With increasing pH,Jincreased at first, and then reached a constant value. The effect of rp/m on J was insignificant. The ultrafiltration concentration experiment was carried out at rp/m=7 and pH=9. When VCF increased from 1to 30,J only declined by 9.76%.Cr increased linearly from 13.26to 396.64mg/L, whereas Cp remained roughly unchanged at about 0.04mg/L. Nickel ions were concentrated effectively, and the permeation solution from the ultrafiltration process was discharged directly.%在pH=9下,镍离子浓度为5562.71mg/L的镍废水经充分沉淀后,以0.5μm孔径陶瓷膜微滤处理,发现浓缩时膜通量(J)先快速降低,经缓慢下降后,再较快降低,镍截留系数(RNi)接近1,当体积浓缩因子(VCF)从1增大到10时,截留液镍浓度(Cr)从5562.71mg/L浓缩至55507.76mg/L,渗透液镍浓度(Cp)为13.26mg/L.以陶瓷膜渗透液为料液,以聚乙烯亚胺为络合剂,考察聚合物与金属质量比(rp/m)、pH值、温度和操作压力对恒容超滤RNi和J的影响,并研究超滤浓缩过程.结果表明,RNi随rp/m或pH增大而增大,随温度升高而略下降,与操作压力无关;J随温度或操作压力增大而增大,随pH增大而增大至不变,rp/m对J影响甚微.超滤浓缩时,控制rp/m=7和pH=9,当VCF从1增大到30时,J仅下降9.76%,Cr从13.26mg/L增大至396.64mg/L,Cp约0.04mg/L,镍离子被浓缩,超滤渗透液可直接排放.
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