Treatment of effluents contaminated by synthetic dyes using heterogeneous photocatalysis

The treatment of industrial effluents represents one of the most significant challenges in contemporary environmental engineering due to the presence of persistent organic compounds, synthetic dyes, pharmaceuticals, and endocrine disruptors that are not removed by conventional methods. Therefore, advanced oxidation processes (AOPs) are effective alternatives for the complete mineralization of recalcitrant pollutants through the generation of highly reactive species capable of degrading complex molecules into carbon dioxide, water, and inorganic salts. The objective of this work is to degrade five dyes using heterogeneous photocatalysis. The AOP study was carried out using DOE 2k and UV-Vis spectroscopic monitoring (Perkin-Elmer, Spectrum 100). The five model pollutants (AM, AT, RB, RM, and VM) (Sigma-Aldrich) were degraded under controlled conditions of pH, H₂O₂, and TiO₂. The response variables included the percentage of pollutant removal (%ERD), the apparent rate constant (kapp), and the final pH.

The optimized AOP achieved degradation efficiencies exceeding 99% for various aromatic organic compounds, demonstrating the high oxidative capacity of the generated radicals. AOPs constitute a versatile and highly efficient environmental technology capable of transforming persistent organic compounds into less toxic byproducts or completely mineralizing them. Their implementation contributes to reducing the pollutant load in effluents, promoting compliance with environmental regulations, and the reuse of treated water.