Degradation of Cefixime from Wastewater Using Photo-Activated Sodium Persulfate and Optimization by Response Surface Methodology

Present work investigates degradation of aqueous cefixime (CFX) using visible light activated sodium persulphate (SPS). The effect of five major parameters viz. pH (3–11), initial concentration of CFX (1–10 mg/L), SPS concentration (10–100 mg/L), time (1–90 min), and temperature (25–70 °C) studied. The degradation process was monitored based on CFX removal efficiency and results were further analyzed using Response Surface Methodology (RSM). The maximum efficiency of CFX removal was found to be 87% with desirability 1, pH = 11, CFX initial concentration = 1 mg/L, SPS dose 55 mg /L, time 45.5 min, and temperature 47.5 °C specified as the optimum conditions. The proposed model was found to be valid and adequate as confirmed by the plots and corresponding statistics (i.e., F-values of 26.80 and p-values of 0.0001 and 0.0132 for the own model and its lack of fit, respectively, R² = 0.9554, R² adj. = 0.9198, R² pred. = 0.8217, AP = 18.1300, CV% = 13.28). Additionally, at the optimum conditions the microbial analysis showed that treated water was found to be less toxic and cost evaluation revealed the economic feasibility of the treatment method as 5.26$ per litre.