Remoción de cefalexina en solución acuosa empleando ozono y radiación UV

Drugs such as cephalexin are emerging micro-pollutants because they are present in minimal amounts in the environment and their effects are unknown. In this project, an advanced oxidation process (AOP) was evaluated in order to examine the transformation of cephalexin in an aqueous solution utilizing ozone as an oxidizing agent and UV radiation (254 nm, 5 W). The process was compared with tests in which only ozone was used in the absence of UV radiation. An experimental design of the Box-Behnken type was used, for which the process factors were the initial pH of the aqueous solution (6.5, 7.5, and 8.5), reaction time (30, 45, and 60 minutes), and initial concentration of cephalexin (7.5, 10 and 12.5 mg / L). The response variables were the percentage reduction in the concentration of cephalexin and TOC. The results indicate that the greatest concentration reductions were 48.85% using ozone, and 62.53% with ozone and UV radiation, these values ​​were reached for an initial pH of 8.5, 60 minutes of reaction, and 12.5 mg/L of initial concentration of cephalexin. Statistical comparison of the results indicates that the effectiveness of the UV radiation intensified ozonation process is greater than the ozonation process alone. The analysis of variance carried out on the results indicates that at alkaline pH the effectiveness of the process is greater, which is explained through the decomposition reactions of ozone and the formation of OH● and ozone radicals due to the effect of UV radiation.