Jet electro-absorbers for the treatment of gaseous perchloroethylene wastes

Abstract

In this work, a novel jet electro-absorber is presented as an efficient process that combines absorption and electro-oxidation for the treatment of gaseous pollutants. This system, based on the Venturi effect, enhances the absorption of vapor wastes in absence of a mechanical compressor. It has been tested with a model organochlorine compound, perchloroethylene, that it is widely used as solvent and easily promoted to the gas phase because of its high vapor pressure. Results confirmed that the target compound can be absorbed into the electrolytic solutions proposed, being the efficiency highly influenced by the electrolyte/absorbent composition. Opposite to it was expected, it was also confirmed that the electrolysis does not mineralize the compound, but itpromotes mainly the transformation of the raw pollutant into refractory products. Also, it was determined the paramount influence on the perchloroethylene removal pathway of the bubble size produced by jet absorbers with different throat width, even modifying the products distribution. A gaseous intermediate, phosgene and carbon tetrachloride are promoted in the electro-oxidation treatments with the larger bubbles, while jet aerator of fine bubble promotes the synthesis of trichloroacetic acid mainly in the liquid phase. Finally, intermediates and final products generated shed light on the mechanisms of the processes involved: wet decomposition or electrochemical degradation of perchloroethylene.