ZnFe_2O_4/石墨烯纳米片复合材料光催化染料废水脱色研究

Study on photocatalytic decolorization of dye wastewater by ZnFe_2O_4/graphene nanoplates composites

采用改进的水热-共沉淀法将ZnFe2O4负载在石墨烯纳米片表面,制备ZnFe2O4/石墨烯纳米片复合光催化剂,采用XRD和SEM等对该复合材料的结晶和微观形貌进行表征,考察了ZnFe2O4/石墨烯纳米片复合光催化剂对水中刚果红的去除效果,探究了复合材料对刚果红光催化脱色的机理.结果表明:复合材料中铁酸锌为尖晶石结构,与石墨烯能够均匀复合.在模拟太阳光照射下,经过4 h处理后,复合材料对刚果红染料的去除率可达92%,且4次循环使用后去除率仍保持在88%以上,表明ZnFe2O4/石墨烯纳米片是一种对印染废水稳定有效的光催化剂.自由基清除剂的试验表明,·OH自由基、光生电子和h+,特别是光生h+,共同支配了ZnFe2O4/石墨烯纳米片对刚果红的光催化降解过程.

ZnFe2O4/graphene nanoplates composite catalyst was prepared using modified hydrother-mal-coprecipitation method by loading ZnFe2O4 on the surface of graphene nanoplates. The crystal shape and morphological structure of the composites were characterized by XRD and SEM. The removal efficiency of composite catalyst on Congo Red solution and mechanism of photocatalytic decolorization were investigated. The results indicated that ZnFe2O4 with a spinel structure was dispersed uniformly on the surface of graphene nanoplates. The removal rate of Congo Red dye was up to 92% in 4 h under simulated solar light irradiation. An 88% of decolorization could be maintained after 4 cycles, indicating that ZnFe2O4/graphene nanocomposite was a stable and effective photocatalyst for the decolorization of dye wastewater under simulated solar light ir-radiation. Free radicals scavenging experiments showed that ·OH radicals, photoproduced e-and h＋, especial y h＋, commonly dominated the photocatalytic decolorization process of Congo Red dye by ZnFe2O4/graphene nanocomposite.