Surface modification of halloysite nanohybrid for the enhanced reduction and immobilization of Cr(Ⅵ)in groundwater
Halloysite nanotubes(HNTs),a typical nanoporous geomaterial,were used to remove Cr(VI)from aqueous solution by surface modification.Due to the limited capacity of natural HNTs towards the removal of heavy metal cations,it was functionalized by polyethyleneimine(PEI)or oxygen-containing organic group grafting to increase the surface positive charge and the removal efficiency for Cr(VI).The results indicated that the modified halloysite(PEI-HNTs and HNTs@C)had an excellent performance for Cr(VI)removal from aqueous solution with the maximum adsorption capacity of 81.5 mg/g and 137.5 mg/g,which was about 64 and 100 times higher than that of the original HNTs.Cr(VI)adsorption was fitted to Langmuir model and the kinetics of uptake could be described by a pseudo-second-order rate model very well.By X-ray photoelectron spectroscopic analysis,the interaction of functional groups with Cr(VI)was investigated,in which the reduction of Cr(VI)to low toxicity Cr(III)and then adsorbed on the surface of adsorbent were proposed.The appreciable magnetization via the deposition of Fe3O4 further made the adsorbent easily separated from aqueous solutions after Cr pollution adsorption.The surface modified nano-geomaterial then provided a promising candidate of low cost for highly efficient Cr(VI)removal.
Halloysite Modification Cr (Ⅵ) removal Adsorption Recovery
Xike Tian Yulun Nie Weiwei Wang
Faculty of Material Science and Chemistry,China University of Geosciences,Wuhan 430074,PR China
国际会议
The 11th International Symposium on Geochemistry of the Earths Surface(GES-11)(第十一届地球表层地球化学国际研讨会)
贵阳
英文
1-2
2017-06-11（万方平台首次上网日期，不代表论文的发表时间）