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Electrochemical production and use of free chlorine for pollutant removal: an experimental design approach

Antonelli, Raissa, de Araújo, Karla Santos, Pires, Ricardo Francisco, Fornazari, Ana Luiza de Toledo, Granato, Ana Claudia, Malpass, Geoffroy Roger Pointer
Environmental technology 2019 v.40 no.3 pp. 321-328
chlorine, electrochemistry, electrolysis, environmental technology, experimental design, pH, pollution control, sodium chloride, textile mill effluents, total organic carbon, ultraviolet radiation
The present paper presents the study of (1) the optimization of electrochemical-free chlorine production using an experimental design approach, and (2) the application of the optimum conditions obtained for the application in photo-assisted electrochemical degradation of simulated textile effluent. In the experimental design the influence of inter-electrode gap, pH, NaCl concentration and current was considered. It was observed that the four variables studied are significant for the process, with NaCl concentration and current being the most significant variables for free chlorine production. The maximum free chlorine production was obtained at a current of 2.33 A and NaCl concentrations in 0.96 mol dm⁻³. The application of the optimized conditions with simultaneous UV irradiation resulted in up to 83.1% Total Organic Carbon removal and 100% of colour removal over 180 min of electrolysis. The results indicate that a systematic (statistical) approach to the electrochemical treatment of pollutants can save time and reagents.