Kinetic modelling of TOC removal by H2O2/UV, photo-Fenton and heterogeneous photocatalysis processes to treat dye-containing wastewater

Wastewater from textile manufacturing introduces recalcitrant organic compounds, such as dyes and toxic by-products into the environment, where advanced oxidation processes are used to treat toxic and non-biodegradable organic pollutants which cannot be removed by traditional methods. H2O2/UV, photo-Fenton and heterogeneous photocatalysis (TiO2/H2O2/UV) processes were used, and the effect of the hydraulic retention time on total organic carbon (TOC) removal was evaluated by fitting the analytical data for the three processes to different kinetic models. The high correlation between empirical and modelled data was accomplished with a pseudo-first-order model for the three processes (R (2) = 0.9823 +/- A 0.017). Mineralisation, decolourisation and disinfection of textile wastewater were investigated with laboratory-scale experiments for each process. Data showed that when 5 g/L H2O2 was used, heterogeneous photocatalysis was the most effective method for the removal of TOC (94.55 %). With respect to colour, all three processes achieved nearly 100 % removal (99.6, 99.3 and 99.9 % at 120 min for the H2O2/UV, photo-Fenton and TiO2/H2O2/UV processes, respectively).