海藻酸钙包覆纳米Ni/Fe颗粒用于同时去除水中铜离子和氯苯

Simultaneous removal of Cu(Ⅱ) and chlorobenzene from aqueous solution by CA-Ni/Fe nanoparticles

基于纳米铁系材料易团聚、使用寿命短等缺点,本文利用"绿色"、可降解的海藻酸钙包覆Ni/Fe纳米颗粒(CA-Ni/Fe NPs)同时去除水溶液复合污染物铜离子和氯苯.结果发现,降解120 min后,CA-Ni/Fe NPs对混合液中初始浓度为50 mg·L-1铜离子的去除率为85.9%,而对于50 mg·L-1氯苯的去除率则为95.7%.这说明由于纳米Ni/Fe催化剂的高反应活性,CA-Ni/Fe NPs可以用于同时去除复合污染物.实验同时发现,铜离子和氯苯的去除率均随着体系温度、投加量、pH值的升高而增大.动力学和热力学实验研究表明,铜离子和氯苯的同步去除符合伪一级动力学,并且是化学吸附占主导的反应,提出了CA-Ni/Fe NPs对氯苯脱氯降解和还原铜离子的机理.将CA-Ni/Fe NPs用于处理废水,经过3次使用之后同时去除水溶液中铜离子和氯苯的效率分别维持在83.8%和91.7%.

Iron-based nanoparticles（Fe NPs） are often used for the degradation of individual contaminant. However,Fe NPs are susceptible to aggregation and oxidation therefore can cause the loss of their reactivity. In this study,bimetallic Ni /Fe nanoparticles were successfully dispersed on calcium alginate（CA-Ni /Fe NPs） and used for simultaneously removal of copper ions and chlorobenzene from aqueous solution. Bath experiments showed that after 120 min,the removal efficiency of Cu（II） by CA- Ni /Fe NPs was 85. 9%,and removal efficiency of chlorobenzene could reach 95. 7%,indicating the enhanced reactivity of the as-prepared material. Furthermore,the removal efficiency of Cu（II） and chlorobenzene increased with the increasing temperature,CA-Ni /Fe NPs dosages and pH values. The reduction kinetics of Cu（II） and chlorobenzene followed a pseudo-first-order rate expression and was a chemically dominated adsorption process. On the basis of these results,the chlorination mechanism of chlorobenzene and reduction of Cu（II） using CA-Ni /Fe NPs was proposed. Finally,CA-Ni /Fe NPs was used to treat wastewater and the removal efficiency of Cu（II） and chlorobenzene maintained at 83. 8% and 91. 7%,respectively,after treatment for three times. This indicated its potential for in situ remediation especially in mixed contaminated sites.