关键词: 酸镍（NiFe₂O₄）, 表面活性剂, 十二烷基硫酸钠, 类芬顿, 废水, 亚甲基蓝, 降解

Abstract:

In this work, modified nano-NiFe₂O₄ (marked as NiFe₂O₄-S) which was modified by sodium dodecyl sulfate was prepared by coprecipitation and characterized by XRD, FTIR，EDS, TEM, BET techniques. The heterogeneous Fenton reaction process on the degradation of methylene blue was studied by SDS modified NiFe₂O₄. The effect of SDS modification, initial pH of methylene blue solution and catalyst recycling times on Fenton-like catalytic activity were investigated. The results showed NiFe₂O₄-S prepared with SDS exhibited much higher catalytic activity for the degradation of methylene blue (MB) in acidic (pH 3.5), near-neutral (pH 6.5) and alkaline (pH 9.5) solutions conditions than pure NiFe₂O₄. NiFe₂O₄ had good catalytic stability and reusability. Mechanism of action was discussed and we considered that could be attributed to its higher electron transfer ability. The adsorbed SDS accelerated the reduction of surface Fe³⁺ to Fe²⁺ by H₂O₂ and \text{?} {\mathrm{O}}_{\mathrm{2}}^{\text{-}} . The high concentration of Fe²⁺ on NiFe₂O₄-S surface during the reaction promoted the decomposition of H₂O₂ into ·OH, which was the main active specie for the degradation of MB. Furthermore, SDS increased the adsorption capacity of the catalyst toward MB, thus facilitating the reaction between adsorbed MB and ·OH generated on the catalyst surface.

Key words: nickel ferrite （NiFe₂O₄）, surfactants, sodium dodecyl sulfate, fenton-like, waste water, methylene blue, degradation