SA@L-Cys@Fe3O4磁性复合材料对含Cu(Ⅱ)废水的处理效能及其机理

Performance and mechanism of Cu(Ⅱ)-containing wastewater treatment by magnetic composite of SA@L-Cys@Fe3O4

以海藻酸钠(SA)、L-半胱氨酸(L-Cys)、CaCl2和Fe3O4为原材料制备了一种环保型的磁性复合材料MSAL,以模拟废水和实际含铜电镀废水为研究对象,探索了pH、共存离子和吸附时间对Cu(II)吸附性能的影响。采用SEM-EDS、PPMS和XPS等分析手段对MSAL进行了表征,且探索了其可能的吸附机理。单因素条件优化实验结果表明:MSAL的适宜制备条件为30.0 g·L^−1 SA、6.0 g·L^−1 L-Cys、2.5 g·L^−1 CaCl2、2.0 g·L^−1 Fe3O4;MSAL对Cu(Ⅱ)的吸附性能随pH增大而明显提高,并在pH为3.0~5.0时,对Cu(Ⅱ)维持较高的去除率;在pH=5时,MSAL对电镀废水中铜去除率可高达94.02%。吸附倾向于遵循拟准二级动力学模型和Langmuir等温模型,这表明吸附以单分子层吸附为主,并受化学过程控制,最大吸附容量可达到175.45 mg·g^−1。表征结果发现:MSAL具备出色的磁响应性,容易从溶液中被去除;吸附过程主要受离子交换作用以及氨基,羧基与Cu(Ⅱ)之间的配位作用影响。以上结果可为磁性复合材料在电镀废水中重金属污染治理奠定坚实基础。

In this study,an environmentally friendly magnetic composite MSAL was prepared using sodium alginate,L-cysteine,CaCl2 and Fe3O4 as raw materials.The effects of pH,coexisting ions and contact time on Cu(Ⅱ)adsorption performance of MSAL were explored using simulated and actual copper-containing electroplating wastewater.SEM-EDS,PPMS and XPS were used to characterize MSAL and its possible adsorption mechanism was investigated.The single factor optimization experiments indicated that the suitable preparation conditions were following:sodium alginate concentration of 30.0 g·L^−1,L-cysteine concentration of 6.0 g·L^−1,CaCl2 concentration of 2.5 g·L^−1,and Fe3O4 concentration of 2.0 g·L^−1.Cu(Ⅱ)adsorption amount by MSAL increased significantly with the increase of pH and high removal rate was maintained at pHs of 3.0~5.0.When the pH was 5,Cu(Ⅱ)removal rate in electroplating wastewater reached 94.02%.Adsorption followed well with the pseudo-second-order kinetic model and Langmuir isothermal model,indicating that the adsorption was dominated by monolayer adsorption and was controlled by chemical processes,and the maximum adsorption capacity reached 175.45 mg·g^−1.Characterization results revealed that MSAL exhibited excellent magnetic responsiveness and was easily removed from the solution.The adsorption process was mainly affected by ion exchange and coordination between amino,carboxyl and copper ions.This study will lay a solid foundation for control heavy metal pollution in electroplating wastewater by magnetic composite materials.