Acid mine drainage (AMD) treatment using galvanic electrochemical system Al-Cu

Acid mine drainage was evaluated using a galvanic (GV) electrochemical system, Al-Cu (anode/cathode), based on a 3² factorial design. The factors analyzed were anodic area/volume ratios (A/V) of 0.037, 0.072, and 0.112 cm²/cm³, and treatment time from 0.25-8 h, and analyses were performed in duplicate with 11 degrees of freedom. The response variables were the total dissolved solids and concentrations of As, Cu, Co, Cr, Pb, Fe, Ni, and $$. The pH, electrical conductivity, and temperature were monitored during the process. Significant differences between treatments were determined by analysis of variance with Tukey's test (p < 0.05) using Statgraphics Centurion XVI.I software. The results showed that a greater electrode surface, A/V ratio, and treatment time improved pollutant removal. The spontaneous reactions generated by the galvanic cell, through the current that flows owing to the potential difference between the Al and Cu electrodes, allows the removal of heavy metals, arsenic, and $$ by coagulation and precipitation mechanisms. The removal efficiencies achieved were Cu (99.1%), As (76.6%), Ni (80.2%), Pb (83.6%), Cr (100%), Fe (93.71%), and 92.9% for sulfates. The X-ray diffraction and Raman analyses of the solid fraction indicated that cuprite was formed with a purity of 96%, and the recovery of Cu by the GV system may be a viable option for mining companies.