磁性氮掺石墨烯活化过硫酸钾降解水中亚甲基蓝  

Activation of potassium persulfate by magnetic nitrogen doped graphene used for degradation of methylene blue

作　　者：庞娅 罗琨 李雪 李亮亮 黄溢才 刘甜 PANG Ya LUO Kun LI Xue LI Liangliang HUANG Yicai LIU Tian(Department of Biology and Environmental Engineering, Changsha University, Changsha 410002)

机构地区：[1]长沙大学生物与环境工程学院,长沙410002

出　　处：《环境科学学报》2017年第11期4100-4108,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.51409024);湖南省自然科学基金青年基金(No.2017JJ3341);长沙市科技计划项目(No.Z1601018)~~

摘　　要：活化过硫酸盐产生硫酸根自由基的高级氧化技术在水环境污染物治理中引起了广泛的关注和研究.本研究采用水热法制备磁性氮掺石墨烯(M-N-G)作为催化剂.利用SEM、BET、XRD和VSM等手段表征材料,系统研究了该材料活化过硫酸盐降解亚甲基蓝的效能.结果表明:M-N-G的比表面积为94.35 m2·g-1,磁性Fe3O4分布在材料表面,能有效的活化过硫酸钾降解亚甲基蓝.当催化剂的用量为200 mg·L^(-1),过硫酸钾浓度为0.4~0.5 mmol·L^(-1)时,在p H=3~6时对10 mg·L^(-1)亚甲基蓝的降解率达90%以上.体系温度在15~32℃时,降解速率常数在0.0227~0.0488 min-1,反应活化能为33.7 k J·mol-1.EPR分析及自由基漼灭实验证明了体系中有羟基自由基和硫酸根自由基产生.TOC分析结果表明:TOC去除率可达50%.M-N-G经过简单的稀硫酸和水洗后,可高效重复利用4次.该技术方法简单、高效、无二次污染,能为有机污染物废水处理提供一种新的方法选择.Advanced oxidation based on sulfate radical is an effective way for water pollutants treatment. In this study,magnetic nitrogen doped graphene（ M-N-G） was synthesized with hydrothermal method,and then characterized by SEM,BET,XRD and VSM. In addition,the catalytic performances of M-N-G were investigated. The results show that the BJH surface area of M-N-G was 94.35 m2·L^-1 and magnetic Fe3 O4 distributed on its surface. M-N-G was able to activate potassium persulfate and formed sulfate radical to degrade methylene blue effectively. More than 90% of 10 mg·L^-1 methylene blue could be removed by using 200 mg·L^-1 M-N-G and 0.4 ～ 0.5 mmol·L^-1 potassium persulfate,in the pH ranging from 3 to 6. The pseudo-first order rate constant was 0.0227 ～ 0.0488 min^-1 in the temperature of 15 ℃ to 32 ℃,and the corresponding activation energy was Ea= 33. 7 kJ·mol^-1. The radical scavenger experiments and EPR analysis indicate that both hydrogen radical and sulfate radical are formed in the catalytic system. TOC results show that the removal efficiency of TOC was 50%. What is more,M-N-G could be re-used for four times. The proposed technology is simple,effective without secondary pollution,and could be an excellent alternative for waste water treatment.

关 键 词：氧化石墨烯 磁性复合材料 高级氧化技术 硫酸根自由基 亚甲基蓝 

分 类 号：X703[环境科学与工程—环境工程]