Contribution of the electrocoagulation method in the removal of fluorine ions from aqueous solutions

Abstract

Photovoltaic technology has experienced a huge global economic boom in recent decades and a growing trend is expected in the future. This technology consists of the application of a number

of processes including growth, oxidation, doping, metallization, etc. In order to reduce the fluo- ride content in the water below a threshold value that complies with the standards of industrial

discharges or water intended for human consumption, various treatment techniques have been implemented. In this respect, electrocoagulation (EC) has been chosen in this study because of its performance compared to other methods. Wastewaters from surface treatment of silicon wafers are rich in fluoride and the lime precipitation is insufficient to comply with environmental standards. In this work, the EC technique, with Fe anodes, was used as an alternative for water purification. By coupling electroflotation to the electrocoagulation in the same cell, the separation of solid/liquid was significantly improved. To study the process performance, tests on the effect of the operational

parameters such as current intensity, initial pH, nature of supporting electrolyte and its concentra- tion were carried out on synthetic solutions. The optimal values are: pHo = 4; current = 1.4 A and

[NaCl] = 2 g/L. The removal efficiency of 62% was reached starting from an initial concentration of 35 mg/L. A total clarification of the synthetic solution was also obtained