Development of a γ-Al[sub.2]O[sub.3]-Based Heterogeneous Fenton-like Catalyst and Its Application in the Advanced Treatment of Maotai-Flavored Baijiu Wastewater

Heterogeneous Fenton technology was employed for the advanced treatment of Maotai-flavored Baijiu wastewater. Novel catalysts were prepared by loading different active ingredients (Mn, Fe, and Cu) on γ-Al[sub.2]O[sub.3] using an impregnation method. The effects of active ingredient, reaction time, initial pH, H[sub.2]O[sub.2] dosage, catalyst dosage, and other factors on the reaction were examined. The properties of the new catalysts were analyzed using BET analysis, XPS, and SEM. Moreover, the mechanisms of Fenton-like oxidation and its reaction kinetics were explored through experiments and analyses including GC–MS and intermediate active species scavenging by tertiary butyl alcohol (TBA) and/or para-benzoquinone. The results revealed that the most effective removal of organic matter was achieved with a Mn-Fe/Al (2:1 wt%) catalyst dosage of 30 g/100 g water, pH of 5.0, H[sub.2]O[sub.2] dosage of 0.3 g/L, and reaction time of 60 min; the effluent COD value was 12 ± 1 mg/L, and the degradation rate was 65.7 ± 3%, approximately 14% higher than that of the conventional Fenton catalyst under similar conditions; moreover, the catalytic efficacy remained high after seven cycles. Kinetic analysis indicated that the heterogeneous Fenton oxidation reaction followed a third-order kinetics model, with R[sup.2] = 0.9923 and K = 0.0006 min[sup.−1].