Synthesis of copper with sodium ascorbate and its application in malachite green discoloration

The discoloration of malachite green (MG) was investigated by heterogeneous Fenton-like process using copper as catalyst. Copper was synthesized with a simple and ecofriendly method using sodium ascorbate as green reducing agent. The synthesized product formed by Cu-Cu2O was characterized by SEM, XRD and EDX analyses and was applied in the in situ production of H2O2/OH. Different parameters were investigated in order to optimize the discoloration process of MG by copper such as catalyst loading, temperature and initial pH of dye solution. Total discoloration was achieved after 60 min with 0.03 g of copper at pH 3 and 60 degrees C. In order to decrease the discoloration time, ultrasounds at 40 kHz and H2O2 at 0.001 M were associated to copper. Total discoloration was attained after 6 min. The kinetic of the reaction followed first order in all cases and the activation energy of MG discoloration by copper was 90.51 kJ/mol.