Ag@AgCl-Fe_(3)O_(4)/rGO复合材料对印染废水中染料和重金属离子的吸附和光催化降解性能

Adsorption and photocatalytic degradation of dyes and heavy metals in printing and dyeing wastewater by Ag@AgCl-Fe_(3)O_(4)/rGO composites

依次利用溶剂热法和原位沉积法制备了Ag@AgCl-Fe_(3)O_(4)/还原氧化石墨烯(rGO)复合材料,并对其进行结构和形貌表征。分别以罗丹明B(RhB)和Cd^(2+)为研究对象,探讨了Ag@AgCl-Fe_(3)O_(4)/rGO复合材料吸附和可见光光催化印染废水中重金属离子和芳香族染料的性能,考察了Ag@AgCl-Fe_(3)O_(4)/rGO复合材料中rGO含量、与RhB共存的亚甲基蓝(MB)和Cd^(2+)对RhB降解效果的影响;同时研究了溶液的初始pH值及与Cd^(2+)共存的MB对Cd^(2+)吸附效果的影响。结果表明:Ag@AgCl-Fe_(3)O_(4)/rGO复合材料对RhB的吸附量为47%,可见光照50 min的光催化降解率可达98%;Ag@AgCl-Fe_(3)O_(4)/rGO复合材料的吸附-光催化降解活性随rGO含量的增加而提高;废水中与RhB共存的MB使Ag@AgCl-Fe_(3)O_(4)/rGO复合材料对RhB的降解效率和循环性能受到一定抑制,而与RhB共存的Cd^(2+)对RhB的降解效率和循环性能几乎没有影响。Ag@AgCl-Fe_(3)O_(4)/rGO复合材料对Cd^(2+)也有良好的吸附性能,具有一定的pH值依赖性,在pH值为5时,复合材料对Cd^(2+)的吸附量可达68 mg/g,但废水中MB染料的存在会抑制复合材料对Cd^(2+)的吸附。

The Ag@AgCl-Fe_(3)O_(4)/reduced graphene oxide(rGO)composites were obtained by solvothermal and insitu precipitation method.The structure and morphology of the Ag@AgCl-Fe_(3)O_(4)/rGO composites were characterized.The effects of rGO content,other organic dyes(such as methylene blue(MB))and heavy metal ions(such as Cd^(2+))co-existing with Rhodamine B(RhB)on the degradation of RhB were investigated,and the effects of initial pH value and other organic dyes(such as MB)co-existing with Cd^(2+)on the adsorption of Cd^(2+)were also studied.The results show that about 47%of RhB can be absorbed to Ag@AgCl-Fe_(3)O_(4)/rGO composites in the dark and the degradation of RhB could reach 98%within 50 min visible-light irradiation,and the adsorption-photocatalytic activity of the Ag@AgCl-Fe_(3)O_(4)/rGO composites increases with the increasing rGO content.The degradation efficiency on RhB and the good cycle performance of the catalyst will be suppressed by the coexisted MB,but are almost unaffected by the coexisted Cd^(2+).For the Cd^(2+)solution system,the adsorption amount of Cd^(2+)on Ag@AgCl-Fe_(3)O_(4)/rGO composites varies with the pH value and the adsorption capacity at pH=5 can be up to 68 mg/g.However,the adsorption of Cd^(2+)will be restrained by the presence of MB in wastewater.