Treatment of wastewater, especially of industrial origin, is a major challenge. Although wastewater treatment methods have already been established, active efforts are being made to develop more efficient and economical methods. In recent years, the attention has been focused on electrochemical methods, most of which are focused on electrocoagulation. This paper gives a detailed description of the mechanism of the electrocoagulation process, as well as the application of this method in wastewater treatment of different origins.

The effectivness of UV/H2O2 process, Fenton and photo-Fenton process at decolorization of commercially important textile dyes Reactive Orange 4 (RO4) and Reactive Blue 19 (RB19) was evaluated. The effect of operational condition such as initial pH, initial H2O2 concentration, initial Fe2+ concentration and initial dye concentration on decolorization of RO4 and RB19 was studied. The photo-Fenton process is found to be more efficient than UV/H2O2 and Fenton process for decolorization of simulated dye bath effluent and solutions of the dyes in water alone under optimum conditions. In simulated dye bath the removal efficiency was slightly lower than for the solutions of the dyes in water alone for both dyes types. The results revealed that the tested advanced oxidation processes were very effective for decolorization of RO4 and RB19 in aqueous solution.

Lagenaria vulgaris activated carbon (LVAC) was synthesized from Lagenaria vulgaris biomass by treatment with diluted H2SO4 followed by thermo-chemical carbonization and overheated steam activation process and used for removal of the herbicide 2,4-dichlo-rophenoxyacetic acid (2,4-D). Fourier transform infrared spectroscopy (FTIR) indicated that 2,4-D is adsorbed in micropores of the very porous LVAC (665 m2 g-1). LVAC showed high sorption capacity as compared to many previously used sorbents at optimal conditions: the stirring rate of 300 rpm, the sorbent dose of 1.0 g dm-3 and pH from 2 to 7. The experimental maximum sorption capacity of LVAC was 333.3 mg g-1. The pseudo-second-order model and Chrastil model described the 2,4-D sorption kinetics by LVAC. Thermodynamic studies have indicated that the sorption process was endothermic, spontaneous and physical in nature. LVAC was shown to be an ultrahighly efficient sorbent for removal of 2,4-D from groundwater, which could be also recycled and reused.