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研究报告

Performance and mechanism of chloramphenicol degradation by electrocatalytic reduction with carbon felt cathode

摘要：为实现氯霉素（CAP）的稳定高效去除，通过阴极材料筛选优化，构建了以碳毡为阴极的电化学还原体系.实验分别考察了阴极材料、阴极电位、pH、电解质种类和CAP初始浓度对CAP降解效果的影响.结果表明：以碳毡为阴极，电流密度为2.5 mA·cm^-2时，反应30 min后初始浓度为10 mg·L^-1的CAP去除率达到了94.9%，60 min内CAP得以完全去除；CAP中氯的脱除是其降解的重要途径，60 min内氯离子的转化率可达60.5%；碳毡阴极电位降低至-1.4 V （vs.SCE）利于还原降解过程；硝酸根的存在对CAP还原有一定的抑制作用；重复降解实验和扫描电镜（SEM）实验证明了碳毡阴极降解CAP效能的稳定性；通过电子自旋共振（ESR）自由基捕获和猝灭实验初步探讨了CAP的脱氯还原机制，发现原子H^*的生成和电子还原作用是CAP快速降解的主要机制.

Abstract：In order to achieve the efficient removal of chloramphenicol (CAP), a simple electrocatalytic reduction system with carbon felt as cathode was developed through the comparison of different cathode materials. The effects of cathode materials, cathode potential, pH, electrolyte, and initial CAP concentration for CAP degradation were studied. Results showed that the removal efficiency of 10 mg·L^-1 CAP in the system with carbon felt as the cathode was 94.9% after 30 min at a current density of 2.5 mA·cm^-2, and CAP was completely removed within 60 min. The removal of CAP was accompanied with the removal of chlorine, and the conversion rate of chloride ions reached 60.5% at 60 min. The cathode potential of carbon felt decreased to -1.4 V (vs. SCE) was conducive to the reduction and degradation process, and the presence of nitrate inhibited the removal of CAP. Recycle tests of CAP degradation and scanning electron microscopy (SEM) experiments demonstrated the stability of carbon felt cathode for efficient degradation of CAP. The mechanism of dechlorination and reduction of CAP was preliminarily discussed by electron spin resonance (ESR) and quenching experiments, and it was found that the formation of atomic H^* and the reduction of electron were the predominate removal mechanisms of CAP removal.