Advanced oxidation process for the degradation of acid violet 109 from aqueous solution: Influence of the quantity of the catalyst

Wastewater treatment in the textile industry poses a major challenge, particularly due to the residues of chemically stable synthetic dyes resistant to conventional degradation methods. Conventional treatment techniques are often insufficient to effectively remove these pollutants, so the development of more efficient solutions is required. Advanced oxidation processes are successfully used in the textile industry for the degradation of dyes remaining in wastewater. This study focuses on the influence of the catalyst in the degradation of the anthraquinone dye Acid Violet 109 using the Fenton reagent in a microfluidic reactor. The microfluidic reactor system consists of two pump units, a mixer and a polytetrafluoroethylene (PTFE) tube. The catalyst has large influence on this reaction and the influence of the catalyst amount was analysed for different cases of H2O2 concentration, microreactor properties and total flow rate of the reaction mixture. High amounts of catalyst lead to the appearance of sludge, which stops the Fenton reaction, but this was not the case for the amounts used in the experiment. The experiments showed that it is more favorable to use 1 mM than 0.5 mM of catalyst. In some cases, increasing the amount of catalyst leads to a 13 or 15 % increase in efficiency.