Comparison of Fenton and Photo-Fenton Processes for Removal of Organic Pollutants from Tanneries, Department of Quindío, Colombia

Abstract

The wastewater produced by tanneries has many recalcitrant and toxic organic pollutants that do not meet the current environmental standard and are very dangerous for humans and biota. Therefore, there is an urgent challenge in developing robust oxidation processes guaranteeing their organic elimination to preserve water quality. Fenton and photo-Fenton techniques, which are part of advanced oxidation processes, are currently very innovative and effective for the decontamination of polluting organic agents and recalcitrant compounds in industrial wastewater. In this context, this research aimed to apply the reagents Fenton (Fe+2/H2O2) and photo-Fenton (Fe+2/H2O2 + uv) in contaminated waters from tanneries in the Department of Quindío, Colombia. For this, solutions of 1L of raw water extracted from the tanneries were prepared by adjusting the pH to 4.0. Then, Fenton’s reagent was added and stirred for 2 hours at 150 rpm. Later these same solutions were exposed to ultraviolet light at 269 nm for 2 hours to perform the photo-Fenton process. The results indicated that better decontamination of these effluents was obtained with the photo-Fenton process, although the differences between the two reagents were not statistically significant (p > 0.05). However, we found a decrease in water turbidity, chemical oxygen demand (COD), total organic carbon (TOC), and color, in a higher percentage with photo-Fenton (92%), which makes these techniques sustainable to improve the environment and the quality of life of people who live around these industries. In addition, the advanced oxidation processes are very economical when implemented since, in the photo-Fenton case, solar energy, a type of renewable energy, is used. It should also be noted that they are very efficient techniques when removing organic contaminants for the tannery industries since these have been reported as one of the most polluting industries in the world. Therefore, these processes are recommended for the effective decontamination of organic residues in the effluents produced by the tanning processes.