State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
J Hazard Mater. 2017 Oct 5;339:182-190. doi: 10.1016/j.jhazmat.2017.06.038. Epub 2017 Jun 19.
Efficient removal of toxic metals using low-pressure membrane processes from contaminated waters is an important but challenging task. In the present work, a conducting microfiltration membrane prepared by embedding a stainless steel mesh in the active layer of a polyvinylidene fluoride membrane is developed to remove Cu(II) ions from contaminated waters. Results showed that the conducting membrane had favorable electrochemical properties and stability as cathode. Batch tests showed that Cu(II) removal efficiency increased with the increase of voltages and leveled off with the further enhancement of electric field. The optimal voltages were determined to be 1.0V and 2.0V for the influent Cu(II) concentrations of 5mg/L and 30mg/L, respectively. X-ray photoelectron spectroscopy and X-ray diffraction results demonstrated the presence of Cu(0) and Cu(OH) on the membrane surface. The removal mechanisms involved the intrinsic adsorption of membrane, electrosorption of membrane, adsorption of deposited layer, chemical precipitation of Cu(OH) and deposition of Cu(0) which were aided by electrophoresis and electrochemical oxidation-reduction. Long-term tests showed that the major contributors for Cu(II) removal were the deposition of Cu(0) by electrochemical reduction-oxidation (47.3%±8.5%) and chemical precipitation (41.1%±0.2%), followed by electrosorption, adsorption by the fouling layer and membrane intrinsic sorption.
利用低压膜过程从受污染的水中高效去除有毒金属是一项重要但具有挑战性的任务。在本工作中，通过将不锈钢网嵌入聚偏二氟乙烯膜的活性层中，制备了一种用于从受污染的水中去除 Cu(II)离子的导电微滤膜。结果表明，导电膜作为阴极具有良好的电化学性能和稳定性。批处理实验表明，Cu(II)去除效率随电压的增加而增加，随着电场的进一步增强而趋于稳定。对于进水 Cu(II)浓度分别为 5mg/L 和 30mg/L，最佳电压分别确定为 1.0V 和 2.0V。X 射线光电子能谱和 X 射线衍射结果表明膜表面存在 Cu(0)和 Cu(OH)。去除机制涉及膜的本征吸附、膜的电吸附、沉积层的吸附、Cu(OH)的化学沉淀和 Cu(0)的沉积，这些过程受到电泳和电化学氧化还原的辅助。长期测试表明，Cu(II)去除的主要贡献者是电化学还原-氧化（47.3%±8.5%）和化学沉淀（41.1%±0.2%）沉积的 Cu(0)，其次是电吸附、污垢层的吸附和膜本征吸附。
