Hydroxyl and sulfate radical mediated degradation of ciprofloxacin using nano zerovalent manganese catalyzed S2O82-

Nano zerovalent manganese (nZVMn, Mn-0) materials have been synthesized in this study and used for degradation of ciprofloxacin (CIP), an emerging water pollutant. The investigation of physiological characteristics of Mn-0 by different characterization techniques proved successful formation of Mn0 by the chemical reduction method and found it to be highly crystalline. The Mn-0 was highly efficient and resulted in 63% degradation of CIP using [CIP](0)= 10 mg/L and [Mn-0](0)= 1.0 g/L at a reaction time of 80 min. Addition of S2O82- to Mn-0 promoted removal efficiency of CIP from 63 to 95% at a reaction time of 80 min using the conditions of [CIP](0)= 10 mg/L, [Mn-0](0)= 1.0 g/L, and [S2O82-](0)= 50 mg/L. The presence of (OH)-O-center dot and SO4 center dot- %-scavengers inhibited the degradation of CIP by Mn-0/S2O82-. The comparable second-order rate constants of CIP with (OH)-O-center dot and SO4 center dot- %-were calculated to be 2.35x10(9) and 2.10x10(9)M(-1) s(-1), respectively. High S2O82- and Mn-0 concentrations and low pH accelerated the degradation of CIP. However, removal efficiency of CIP by Mn-0 with the added S2O82- was inhibited using high CIP concentration, high pH, inorganic anions, and NOM. Degradation pathways from % OH and SO4 %-based degradation of CIP were developed. Acute and chronic toxicities of CIP and its products were estimated, showing the final product to be non-toxic. The as-synthesized Mn-0 was found to be stable as well as environmentally friendly for treating CIP. This study suggests that Mn-0 with the added S2O82- is a promising alternative for potential remediation and detoxification of CIP and other emerging water pollutants.