Shizong Wang1, Haiyang Liu2, Jianlong Wang3. 1. Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing, 100084, PR China; Beijing Key Laboratory of Radioactive Wastes Treatment, Tsinghua University, Beijing, 100084, PR China. 2. Datang Environment Industry Group Co., Ltd., Beijing, 100097, PR China. 3. Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing, 100084, PR China; Beijing Key Laboratory of Radioactive Wastes Treatment, Tsinghua University, Beijing, 100084, PR China. Electronic address: wangjl@tsinghua.edu.cn.
Abstract
In this study, nitrogen, sulfur and oxygen co-doped carbon armored cobalt sulfide (Co/Co9S8@N-S-O-C) composite was synthesized, characterized and used to activate peroxymonosulfate (PMS) for the degradation of sulfamethoxazole (SMX). SMX (0.04 mM) can be completely degraded within 20 min in the presence of 0.8 mM PMS and 0.1 g/L Co/Co9S8@N-S-O-C composite. The first-order kinetics constant of SMX degradation was 0.307 min-1, and the mineralization of SMX was 30.1 %. The Quenching experiments of the free radicals and the identification of degradation products demonstrated that sulfate radicals played a dominant role in SMX degradation. The degradation rate of SMX increased with temperature, and activation energy was calculated to be 48.6 kJ/mol. The degradation rate of SMX increased firstly then decreased with increase of pH. Chloridion and humic acid decreased the degradation rate of SMX no matter what their initial concentration was. The effect of carbonate on SMX degradation depended on its initial concentration. Co/Co9S8@N-S-O-C composite showed good stability, the removal efficiency of SMX was 98.4 % in the fifth experiment. Based on the characterization results of the catalyst before and after use, it was concluded that cobalt, sulfur, pyridnic N and graphitic N were responsible for PMS activation.
In this study, nitrogen, n class="Chemical">sulfur and oxygenco-doped carbon armored cobalt sulfide (Co/Co9S8@N-S-O-C) composite was synthesized, characterized and used to activate peroxymonosulfate (PMS) for the degradation of sulfamethoxazole (SMX). SMX (0.04 mM) can be completely degraded within 20 min in the presence of 0.8 mM PMS and 0.1 g/L Co/Co9S8@N-S-O-Ccomposite. The first-order kinetics constant of SMX degradation was 0.307 min-1, and the mineralization of SMX was 30.1 %. The Quenching experiments of the free radicals and the identification of degradation products demonstrated that sulfate radicals played a dominant role in SMX degradation. The degradation rate of SMX increased with temperature, and activation energy was calculated to be 48.6 kJ/mol. The degradation rate of SMX increased firstly then decreased with increase of pH. Chloridion and humic acid decreased the degradation rate of SMX no matter what their initial concentration was. The effect of carbonate on SMX degradation depended on its initial concentration. Co/Co9S8@N-S-O-Ccomposite showed good stability, the removal efficiency of SMX was 98.4 % in the fifth experiment. Based on the characterization results of the catalyst before and after use, it was concluded that cobalt, sulfur, pyridnic N and graphitic N were responsible for PMS activation.