Removal of 4-chlorophenol from aqueous solution by pillared clays: combined action of Catalytic hydrodechlorination and Catalytic wet peroxide oxidation

Abstract

Two important techniques for removal of 4-chlorophenol from industrial effluents are the Catalytic Hydrodechlorination (HDC) and Catalytic wet peroxide oxidation (CWPO). However, when conducted individually, these techniques can present serious problems. Thus, the present work aimed to provide a greater scientific contribution about the possibility of coupling of these two processes, to improve the final removal of organic pollutants, obtaining products with low toxicity. The catalysts used were pillared clays. Three experiments were performed with aqueous solutions containing 4-chlorophenol: CWPO in series with HDC, HDC in series with CWPO and HDC simultaneously with CWPO. The reactions were performed in a batch reactor at 25 ° C and 1 atm. The samples collected during the reactions were analyzed by HPLC, TOC, Ionic Chromatography and Colorimetry / UV-VIS Spectrophotometry. The results showed that the experiments had considerable success with regard to the total elimination of 4-chlorophenol. The most effective combination was CWPO in series with HDC, mainly because it presented low iron leaching and require a small amount of hydrogen peroxide to the process. This combination represents an important alternative in optimizing the treatment of industrial wastewater containing 4-chlorophenol.