摘要
利用共沉淀法成功制备出绿色、高效且具有较强重复利用性和抗氧化性能的介孔磁性材料氧化石墨烯负载纳米零价铁(GO-nFe0).通过场发射扫描电镜(FESEM)、透射电子显微镜(TEM)、傅立叶红外光谱仪(FTIR)、比表面积测试仪(BET)、X射线衍射仪(XRD)以及X射线光电子能谱分析(XPS)等表征手段对GO-nFe0的形貌、结构以及元素价态进行分析.研究了弱磁场(WMF)协同GO-nFe0体系(GO-nFe0/WMF)处理水体中Cr(Ⅵ)的特性和机制,并且考察了不同反应条件对体系去除Cr(Ⅵ)的影响.结果表明,当氧化石墨烯(GO)与纳米零价铁(nFe0)的负载质量比为1∶10且在20 mT弱磁感应强度的最佳条件下,GO-nFe0/WMF能够在30 min内完全去除浓度为10mg·L-1的Cr(Ⅵ).随着体系初始pH值的降低和材料投加量的增加,Cr(Ⅵ)的去除效率显著提高.无机阴离子(Cl-,SO42-)对Cr(Ⅵ)的去除表现出促进作用,而ClO-4和CO32-则分别表现出无明显影响和抑制效果.GO-nFe0在循环利用5次以及暴露空气中30 d仍能保持较高的反应活性.通过XRD、XPS以及邻菲啰啉掩蔽实验证明:GO-nFe0/WMF体系具有潜在的协同作用,GO可以提高WMF促进nFe0的腐蚀速率并提高电子转移速率,从而释放更多的Fe2+.
A green,high-efficiency mesoporous magnetic material with strong reusability and oxidation resistance,named graphene oxide immobilized nanoscale zero-valent iron(GO-nFe0),was prepared by a co-precipitation method.The structure,appearance,surface elements,and valence of GO-nFe0 were characterized via FESEM,TEM,FTIR,BET,XRD,and XPS.The characteristics and mechanism of Cr(Ⅵ)treatment in water using a weak magnetic field(WMF)coupled with GO-nFe0(GO-nFe0/WMF)were studied.Batch experiments established that when the load mass ratio of GO to nFe0 was 1:10 under 20 mT weak magnetic field strength,the GO-nFe0/WMF system could completely remove the 10 mg·L-1 of Cr(Ⅵ)solution in 30 min,consistent with first-order dynamics.With a decrease in initial pH value and an increase in material dosage,the removal efficiency of Cr(Ⅵ)increased significantly by enhancing the release rate of Fe2+.ClO4-had no effect on the reaction,Cl-could encourage corrosion and promote the corrosion of nFe0 to release Fe2+,CO32-restrained the reaction through an increase in initial pH of the solution,and SO42-could promote the dissolution of the nFe0 surface passivation film to accelerate the reaction process.The GO-nFe0/WMF system can maintain high activity after five reuses and 30 days of exposure to air.XRD,XPS,and 1,10-phenanthroline shielding experiments proved that its great conductivity allowed GO to provide electron transfer sites to accelerate the transfer of electrons,and nFe0 could quickly release Fe2+.WMF generated a magnetic gradient force(FΔB)that pushed the paramagnetic Fe2+ions in the diffusion boundary layer concentrated on the two poles of GO-nFe0,where the most magnetic intensity was present,to exposed active sites on both sides.The high removal rate ability of GO-nFe0 to release Fe2+continuously was maintained.
作者
计盟
鲍建国
朱晓伟
杜江坤
郑汉
JI Meng;BAO Jian-guo;ZHU Xiao-wei;DU Jiang-kun;ZHENG Han(Hubei Laboratory of Special Wastewater Treatment,School of Environmental Studies,China University of Geosciences,Wuhan 430074,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2020年第7期3326-3336,共11页
Environmental Science
基金
国家自然科学基金项目(41907153)
湖北省自然科学基金项目(2018CFB262)。
