No abstract

The use of food additives (such as dyes, which improve the appearance of the products) has become more prominent, due to the rapid population growth and the increase in demand for beverages and processed foods. The dyes are usually found in effluents that are discharged into the environment without previous treatment; this promotes mass contamination and alters the aquatic environment. In recent years, advanced oxidation processes (AOPs) have proven to be effective technologies used for wastewater treatment through the destruction of the total organic content of toxic contaminants, including food dyes. Studies have shown that the introduction of catalysts in AOPs improve treatment efficiency (i.e., complete decomposition without secondary contamination). The present review offers a quick reference for researchers, regarding the treatment of wastewater containing food dyes and the different types of AOPs, with different catalyst and nanocatalyst materials obtained from traditional and green chemical syntheses.

groups and reduction of the chemical oxygen demand. The post-treatment samples were tested for toxicity on lettuce Lactuca sativa germination to verify the effect of the advanced oxidation process employed. The most efficient treatment determined in the preliminary study was photo-Fenton assisted by sunlight radiation. Under the best conditions developed and analyzed with the experimental designs, a 99% degradation of the chromophore groups was achieved, and a 98.72% decrease in chemical oxygen demand, in 120 min. The experimental data were well represented by the nonlinear kinetic model proposed by Chan and Chu with values of R 2 > 0.95. The toxicity test results demonstrated a decrease in the root growth of the species Lactuca sativa. The results demonstrate that the photo-Fenton system assisted by sunlight Abstract Effluents from the food industry regularly contain synthetic dyes that cause damage to ecosystems and water bodies. The present work aimed to evaluate homogeneous advanced oxidation processes for the mixed degradation of food dyes blue 1 and yellow 6. Through preliminary studies of advanced oxidation processes by photolysis, UV/H 2 O 2 , Fenton, and photo-Fenton, applying UV-C, artificial solar (sunlight), and natural solar radiation, the system with the best performance for the integral optimization of the treatment was determined. Based on the treatment with the best results, the multilevel factorial design 2 2 × 3 1 and central composite design 2^2 + star were created to optimize the variables [H 2 O 2 ], [Fe], and pH. The kinetics of the process was evaluated based on the percentages of degradation of the chromophore