Sonoelectrochemical degradation of 2,4-dihydroxybenzoic acid in water

摘要

Aromatic pollutants in waste waters are difficult to eliminate by chemical treatment. These chemical species are frequently recalcitrant to biologic treatment and harmful to aquatic life even at low concentrations. Dihydroxybenzoic acids (DHBA) have been used as intermediate chemical reactants in industrial synthetic processes. Trihalomethane compounds, can be produced during water disinfection by chlorinating techniques. So, an alternative depollution technique is of interest. Electrooxidation methods are a possible way for organics elimination from liquid wastes. Unfortunately, electrooxidation processes show often some limitations: mass transfer in the liquid near the electrodes or passivating films frequently formed at the anode surface, inhibiting the oxidation of organic compounds. Ultrasound can then be powerful to enhance mass transfer and to clean solid surfaces. But, ultrasonic waves alone can also degrade organic molecuels by formation of HO radicals through the cavitation phenomenon.