Norfloxacin removal by ultraviolet-activated sodium percarbonate and sodium hypochlorite: process optimization and anion effect

Abstract

The efficiency of UV-activated sodium percarbonate (SPC) and sodium hypochlorite (SHC) in Norfloxacin (Norf) removal from an aqueous solution was assessed. Control experiments were conducted and the synergistic effect of the UV-SHC and UV-SPC processes were 0.61 and 2.89, respectively. According to the first-order reaction rate constants, the process rates were ranked as UV-SPC > SPC > UV and UV-SHC > SHC > UV. Central composite design was applied to determine the optimum operating conditions for maximum Norf removal. Under optimum conditions (UV-SPC: 1 mg/L initial Norf, 4 mM SPC, pH 3, 50 min; UV-SHC: 1 mg/L initial Norf, 1 mM SHC, pH 7, 8 min), the removal yields for the UV-SPC and UV-SHC were 71.8 and 72.1%, respectively. HCO3−, Cl−, NO3−, and SO42− negatively affected both processes. UV-SPC and UV-SHC processes were effective for Norf removal from aqueous solution. Similar removal efficiencies were obtained with both processes; however, this removal efficiency was achieved in a much shorter time and more economically with the UV-SHC process. HIGHLIGHTS The process rates in the UV-SPC and UV-SHC processes were higher than in single processes.; Norfloxacin removal by the UV-SPC and UV-SHC was 71.8 and 72.1%, respectively.; HCO3−, Cl−, NO3−, and SO42− negatively affected both processes.; UV-SHC is more energy efficient.;

Keywords

• advanced oxidation
• antibiotic removal
• sodium hypochlorite
• sodium percarbonate
• water matrix effect