Removal of chloramphenicol by direct current and pulse current electrocoagula-tion: implications for energy consumption and sludge reduction

The discharge of antibiotics in wastewater endangers human health. Electrocoagulation (EC) technology can effectively treat chloramphenicol (CAP) in wastewater, but its practical application is limited by issues such as plate passivation, high energy consumption, and a large sludge volume. This study compared the CAP removal performances of positive single pulse current electrocoagulation (PSPC-EC), alternating pulse current electrocoagulation (APC-EC), and conventional direct current electrocoagulation (DC-EC). Under optimal operating conditions, all three methods achieved similar CAP removal rates of >98%, although DC-EC was significantly faster. However, PSPC-EC and APC-EC reduced the sludge quality by 34.95% and 87.48%, respectively, compared with DC-EC and the energy consumption by 57.74% and 39.62%, respectively. PSPC-EC produced a slightly larger floc size than the other methods, which weakened the adsorption capacity. Energy-dispersive spectrometry demonstrated that APC-EC produced flocs with a higher carbon content, which indicates greater adsorption capacity. Fourier transform infrared spectroscopy showed that the flocs produced by the three methods had absorption peaks with similar intensities at the same characteristic wavelengths. The results confirmed that pulse current EC may be a better choice than DC-EC for CAP removal and can effectively reduce operating costs and sludge production in actual wastewater treatment.