Evaluation of the reduction of the cephalexin concentration in aqueous solution by electrocoagulation with graphite electrodes at different initial pH values and applied current intensity

Abstract

This researchwas carried out to evaluate the reduction of cephalexin (CEF) concentration in an aqueous solution using electrocoagulation (EC) with graphite electrodes as an alternative to eliminate this pollutant in wastewater. First, the water's electrical conductivity was adjusted with NaCl, that allows the formation of active chlorine species (HOCl and OCl-). Graphite electrodes were used due to their characteristics against anode wear, which occurs with systems in which metallic anodes are used. The effect of the initial pH of the solution (7 and 8) and the intensity of the applied current (1 A and 1,5 A) were analyzed. In order to evaluate the effect of these variables, an experimental design of a central compound type and the response surface methodology were implemented. Additionally, the conditions of the study variables that allow to achieve the greatest effectiveness of the process were determined. It was determined that at pH 7 and an intensity of 1,5 A a removal of 75,5 % is achieved in the cephalexin concentration. For pH 8, a considerable decrease in the percentage of reduction in the concentration of cephalexin is observed, this situation that implies that the variable that has the greatest influence on the response variable is the pH of the aqueous solution.