尖晶石型c-CuFe2O4催化过硫酸盐降解偶氮染料

Degradation of azo dyes by catalyzed persulfate with spinel c-CuFe2O4

摘要:

以三水合硝酸铜、九水合硝酸铁为原料，在柠檬酸辅助下通过溶胶凝胶-自蔓延燃烧法制备了尖晶石型纳米铁酸铜（CuFe2O4），采用SEM、EDX、XRD、VSM对材料进行了表征。利用CuFe2O4/过硫酸盐（PDS）体系对偶氮染料活性黑5（RB5）进行催化氧化处理，考察了CuFe2O4投加量、初始PDS浓度、反应温度、初始pH、常见无机阴离子和腐殖酸对催化体系的影响。结果表明，300℃煅烧制备得到的c-CuFe2O4催化性能最好，当温度为25℃，RB5初始质量浓度为100 mg/L，CuFe2O4-300投加量为1 g/L，初始PDS浓度为8 mmol（1.9 g）/L，初始pH为9.00时，RB5的去除率可以达到92.9%，其降解过程遵循准一级动力学模型。猝灭实验发现，催化位点在材料表面和孔隙部位，反应依赖材料表面二价铜/三价铜循环以及游离Cu2+的均相催化，SO4-•和•OH是主要活性产物。CuFe2O4具有超顺磁性，可以通过磁分离回收，5次循环实验后能够保持80%以上的去除率。

Abstract:

Using Cu(NO3)2•3H2O and Fe(NO3)3•9H2O as raw materials, spinel nano-copper ferrite(CuFe2O4) was prepared by the sol-gel-self-propagating combustion method with the aid of citric acid, and the material was characterized by SEM, EDX, XRD and VSM.The CuFe2O4/persulfate (PDS) system was used to catalytic oxidation treatment of azo dye reactive black 5 (RB5). With the aim to study the effects on catalytic system by the CuFe2O4 dosage, initial PDS concentration, reaction temperature, initial pH, common inorganic anions and humic acid. The results show that the catalytic performance of c-CuFe2O4 prepared by calcination at 300℃ is at the best level. When the temperature at 25℃, the initial concentration of RB5 is 100 mg/L, the dosage of CuFe2O4-300 1 g/L, the initial PDS concentration 8 mmol（1.9 g）/L, and the incipient pH 9.00, the removal rate of RB5 can reach 92.9%. the degradation process follows a quasi-first-order kinetic model. Quenching experiments found that the catalytic sites are on the surface of the material and the pores. The reaction depends on the bivalent/trivalent copper cycle on the surface of the material and the homogeneous catalysis of free Cu2+. SO4-•and •OH are the main active products. CuFe2O4 is super paramagnetic and can be recycled through magnetic separation. After 5 cycles of experiment, it can maintain a removal rate of more than 80%.