Degradation of chloramphenicol in soil with catechin-enhanced ferric iron/persulfate system

Abstract

Chloramphenicol (CAP) is a broad-spectrum antibiotic that has been commonly used in the world for the past few decades because of its high antibacterial activity. Although CAP has been banned, high concentration is still detected in the soil environment because of its low self-degradation. In the present research, the polluted soil was treated in situ in a sulfate radical (SO4•−) based process. CAP was degraded by persulfate (PS) activated with Fe(III) and catechin (CAT). Fe(II) could be produced efficiently via complexation and reduction through Fe(III) and CAT reaction to enhance the PS activation efficiency. The optimal dosages of PS, CAT and Fe(III) were investigated. The degradation rate of CAP could reach 94.3% after 120 min of reaction. The contribution of free radicals on CAP degradation was also detected, and the results showed that SO4•− and HO• resulted in pollutant removal of 83.8% and 16.2%, respectively. The reaction between CAT and Fe(III) mainly occurred on the surface of soil particles because of the strong adsorption of CAT. However, the oxidation process between radicals and CAP mainly occurred in the liquid phase. Moreover, the biological toxicity of the reaction system and the total organic carbon of organic matter were also significantly reduced.