Sixteenth International Conference on Environmental, Cultural, Economic & Social Sustainability

Abstract

Cyanide has been widely used as an essential raw material in several industries including mining/metallurgy, agriculture, plastics, textile, paints, and medicine. Cyanides and cyanides compounds in wastewater streams are regulated. The present work had the objective of studying the treatment of effluents containing free cyanide through the systems: H2O2, SO2/O2 e H2O2. All the systems are in the presence and absence of copper catalyst ions. For that, it synthetic solutions of KCN with characteristics of pH and concentration similar to those of a real effluent were employed. The evaluated variables were initial pH of the solution, molar ratio [Cu2+]/[CN-], and molar ratio [oxidant]/[CN-]. For a solution containing an initial concentration of cyanide equal to 100 mg/L, it was possible to reach a removal efficiency of 99% in 2 minutes for SO2 systems in pH equal to 9, with a molar ratio of [Cu2+]/[CN-] = 0,16 and with a molar ratio [SO2 + O2]/[CN-] =2. Similar efficiency in the oxidation of free cyanide was achieved in 10 minutes for SO2/H2O2 and H2O2 systems, also with molar ratio [Cu2+]/[CN-] = 0,16 in pH equal to 9 and molar ratio [SO2 + 2H2O2]/[CN-] = 2 for the SO2/O2 systems and molar ratio [2H2O2]/[CN-] for the H2O2 process.