Heterogeneous Fenton for Removal Rhodamine-B by Iron-bearing Attapulgite Granular Catalysts

Fenton-advanced oxidation process has a good effect on the degradation of toxic and harmful substances in industrial wastewater. However, homogeneous Fenton has the problems of serious iron sludge pollution and high catalyst cost in practical application. To search for a cheap, stable Fe-based catalyst with good performance has become an urgent task in the field of heterogeneous Fenton. Attapulgite is a natural clay mineral with a porous surface and special crystal structure, which is suitable for a catalyst carrier. In this study, the granulation conditions and Fe 3+ loading conditions of attapulgite were investigated, the effects of two preparation sequences on the degradation of Rhodamine-B were compared, and the best heterogeneous Fenton granular catalyst was selected. In the process of granulation, the adsorption and decolorization effects on Rhodamine-B of particles were the best when the additive dosage ratios were AlCl 3 1%, Fe 2 O 3 3%, and SiO 2 3% respectively. When impregnation concentration, temperature, time and ratio of liquid to solid were 1.6 mol/L, 80 ℃, 4 h, and 20:1, respectively, the optimum Fe 3+ loading condition was obtained, and the method of granulating first had a better removal effect on dye. Subsequently, the structural characteristics, phase changes and iron distribution of attapulgite before and after loading Fe 3+ were characterized. In the process of exploring the optimal degradation conditions, the results showed that the degradation of dye remained above 98% after the catalyst was reused for 5 times, indicating that the catalyst can be a promising eco-friendly material for refractory wastewater treatment. Graphical Abstract