Electrochemically enhanced simultaneous degradation of sulfamethoxazole, ciprofloxacin and amoxicillin from aqueous solution by multi-walled carbon nanotube filter

Abstract

Electrochemical filters exhibited excellent properties of time saving and energy conservation and were widely used in water purification. In this work, an efficient method was proposed for degrading antibiotics including sulfamethoxazole (SMZ), ciprofloxacin (CIP) and amoxicillin (AMO) in both single system and mixed system by utilizing multi-walled carbon nanotube (MWCNT)-based electrochemical membrane. The effect of experimental parameters was investigated with respect to voltage, pH, temperature, initial pollutant concentration and sodium dodecyl benzene sulfonate (SDBS). The recycling experiments of MWCNT-based electrochemical filter were also performed. Results revealed that the degradation efficiency could be enhanced by increasing the voltage and temperature, while it decreased with the increased initial pollutant concentration and the addition of SDBS. Degradation of SMZ and AMO was weakly affected by solution pH. However, the degradation efficiency of CIP in acidic or alkaline solution was much higher than that in neutral solution. Furthermore, the MWCNT-based electrochemical membrane still exhibited high efficiency for antibiotic degradation after reuse of four times, which could facilitate the development of reproducible and low-cost pollutant-processing method. Noticeably, this membrane filter also presented high performance on simultaneously removing the multiple antibiotics with the efficiency order of AMO (98%) > SMZ (95%) > CIP (20%). The degradation mechanism of antibiotics by the MWCNT-based membrane was analyzed and a clear explanation on the antibiotics-removed pathway was provided. These results indicated that the MWCNT-based electrochemical membrane filtration may have potential to effectively treat multiple antibiotics in real wastewater.