Combined electrocoagulation and TiO2 photoassisted treatment applied to wastewater effluents from pharmaceutical and cosmetic industries

The treated wastewater consists of refractory materials and high organic content of hydrolyzed peptone residues from pharmaceutical factory. The combination of electrocoagulation (EC) followed by heterogeneous photocatalysis (TiO2) conditions was maximized. The EC: iron cathode/anode (12.50 cm × 2.50 cm × 0.10 cm), current density 763 A m−2, 90 min and initial pH 6.0. As EC consequence, the majority of the dissolved organic and suspended material was removed (about 91% and 86% of the turbidity and chemical oxygen demand (COD), respectively). After EC, refractory residues still remained in the effluent. The subsequent photocatalysis: UV/TiO2/H2O2 (mercury lamps), pH 3.0, 4 h irradiation, 0.25 g L−1 TiO2 and 10 mmol L−1 H2O2 shows high levels of inorganic and organic compounds eliminations. The obtained COD values: 1753 mg L−1 for the sample from the factory, 160 mg L−1 after EC and 50 mg L−1 after EC/photocatalyzed effluents pointed out that the combined treatment stresses this water purification.