纤维素水凝胶包覆Fe_3O_4类Fenton纳米催化剂的制备及其催化降解性能

Preparation of Fe_3O_4-Cellulose Hydrogels Core-shell Fenton Nano-catalyst for Degrading of Azo Dyes

采用纤维素水凝胶包覆Fe_3O_4颗粒,制备得到核壳结构的羧甲基纤维素聚丙烯包覆Fe_3O_4类Fenton纳米催化剂(CMC-co-AA/Fe_3O_4),并应用于降解偶氮染料酸性大红GR。考察了体系pH值、催化剂用量、染料初始浓度等参数对降解效果的影响。SEM和FT-IR分析结果表明水凝胶成功地包覆在Fe_3O_4颗粒表面,且壳层厚度为20~30nm。XRD分析显示,包覆层不影响纳米Fe_3O_4的晶型结构,纳米催化剂在使用过程中仍保持Fe_3O_4磁响应性能,能够有效地分离回收。相比传统的Fe_3O_4纳米催化剂,包覆型CMC-co-AA/Fe_3O_4纳米催化剂水溶液显示出了较好的均一分散性。且当pH>3直至中性条件下,此时传统未包覆的Fe_3O_4纳米催化剂对酸性大红GR的降解率为0,而CMC-co-AA/Fe_3O_4纳米催化剂的降解率仍能维持36%,说明了水凝胶壳层结构赋予CMC-co-AA/Fe_3O_4纳米催化剂较宽的pH适用范围。重复试验表明,该纳米催化剂在循环使用四次后,对染料的降解率仍能保持98%左右。

Inorganic/organic core-shell Fenton nano-catalyst was prepared by introducing cellulose hydrogel networks to the surface of Fe3O4 nanoparticles,and the obtained nano-catalyst was named as CMC-coAA/Fe3O4.CMC-co-AA/Fe3O4nano-catalyst was applied to activate the catalytic degradation of acid brilliant scarlet GR.Results show that the CMC-co-AA/Fe3O4 nano-catalyst exhibits higher degradation rate than traditional Fe3O4 catalyst as the solution pH value ranges from 3to 7.Especially when the solution is neutral（pH value is 7）,the degradation rate still remain 36% for CMC-co-AA/Fe3O4 catalyst,illustrating that the new inorganic/organic core-shell nano-catalyst can be used in a wide pH range for degradation of acid brilliant Scarlet GR.The properties and structure of nano-catalyst were characterized by XRD,FT-IR and SEM techniques.The XRD studies reveal that the cellulose hydrogel shell doesn＇t change the crystalline structure of Fe3O4,the resultant CMC-co-AA/Fe3O4nano-catalyst still have magnetic response properties,which can lead to convenient recovery of nano-catalyst in a magnetic field.