Remoção de fosfato dissolvido em solução aquosa através do processo de eletrocoagulação com eletrodos de cobre

Abstract

The growing concern with the phosphate pollutant in water bodies has generated an endless search for technologies and efficient methods for its treatment. The aim of the present work was to evaluate the efficiency of electrocoagulation (EC) with copper electrodes in the removal of phosphate from aqueous effluent, as well as the recovery of this nutrient through the sludge generated in the process. For this purpose, the impact of the amount of support electrolyte (NaCl), initial amount of phosphate (PO₄- 3), applied current density, and the initial pH of the solution were evaluated through laboratory analysis. A reactor constructed with transparent acrylic and electrolytic copper electrodes connected to a direct current source was used to generate coagulating agents. In order to evaluate the possibility of recovering the phosphate present in the solution, the generated sludge was characterized by the technique of Xray diffraction. From preliminary tests, concentrations of 500 mg/L of NaCl and 50 mg/L of PO₄-3 were defined for the subsequent tests. In conducting the experiment, optimal operating conditions of current density = 4.11 mA/cm² and pH = 4.00 were obtained. The phosphate removal predicted by statistical modeling was 94.6%, while the removal obtained experimentally in these parameters resulted in 100%. Regarding the sludge, in the XRD analysis, the minerals copper oxide (CuO) and sodium chloride (NaCl) were identified, a result that did not corroborate the hypothesis of phosphorus recovery through the formation of phosphate crystals. It was concluded that the EC process proved to be efficient for removing phosphate from the aqueous solution, and resulted in final parameters amable of disposal according to current regulations.