CNTs改性及水体中Cr(VI)离子的吸附性能研究  

Study on the Surface Modification of CNTs and Their Adsorption of Cr( VI) from Aqueous Solution

作　　者：杨汉培[1,2,3] 宋双双[2,3] 俞咪虹 傅小飞 吴俊明[2,3] 

机构地区：[1]河海大学浅水湖泊综合治理与资源开发教育部重点实验室,江苏南京210098 [2]河海大学环境学院,江苏南京210098 [3]河海大学淮安研究院,江苏淮安223001

出　　处：《安徽理工大学学报（自然科学版）》2014年第2期38-45,共8页Journal of Anhui University of Science and Technology:Natural Science

基　　金：河海大学淮安研究院开放基金资助项目

摘　　要：为了脱除水体Cr(VI),600℃下于Fe2Ni/γ-Al2O3上苯催化化学气相分解(catalytic chemical vapor decomposition)制备碳纳米管(carbon nanotubes,CNTs),粗CNTs经混酸(H2SO4/HNO3,3∶1,volume ratio,体积比),超声氧化纯化,纯化的同时赋予其表面功能基团,进一步地,表面包覆功能分子聚乙烯醇(polyvinyl alcohol,PVA)。系统探讨了改性CNTs对高浓度水体Cr(VI)离子的吸附脱除,结果表明,CNTs的氧化纯化使其表面植入-COOH、-OH等功能基团,进一步地,富含羟基功能基团的PVA分子在CNTs表面包覆,赋予CNTs表面活性的同时,显著提高CNTs的亲水性能。观察到了随氧化纯化和PVA修饰的CNTs上高浓度Cr(VI)离子吸附的逐步和明显提升,吸附热力学和动力学研究表明,CNTs表面Cr(VI)的吸附符合Freundlich热力学和准二级动力学特征。随氧化纯化和PVA修饰,CNTs对水体Cr(VI)吸附性能的提高可能与CNTs亲水性能的提升以及表面功能化基团对Cr(VI)的化学吸附的促进相关联。Carbon nanotubes （ CNTs ） were prepared by catalytic chemical vapor decomposition of benzene on Fe2Ni/γ-Al2 O3 at 600℃, the as-prepared CNTs were ultrasonically purified by oxidation with mixed acid of H2SO4 and HNO3（H2SO4/HNO3, 3∶1, volume ratio）, embedding the active -COOH and -OH groups onto the surface of CNTs , and consecutively , the acid-treated CNTs were further modified by surface wrapping of PVA with abundant functional groups of -OH.The batch removal of hexavalent chromium （ Cr （ VI） ） from a-queous solution by using modified CNTs was studied under ambient conditions and the effect of pH , initial con-centration of Cr （ VI） , CNTs content , contact time on the removal of Cr （ VI） was also investigated .The steady enhancement of adsorption of Cr （ VI） onto CNTs along with the treatment of CNTs by mixed acid and PVA was observed .Equilibrium data were well described by the typical Freundlich adsorption isotherm and the pseudo -second-order kinetics model was well suitable to model the kinetic adsorption of Cr （ VI） .It is proposed that the enhanced adsorption capacity of Cr （ VI） onto CNTs is correlated with the grafting of functional active groups onto the surface of CNTs and the improvement in the hydrophilic ability of modified CNTs .

关 键 词：碳纳米管 表面修饰 Cr( VI) 吸附 废水 

分 类 号：O644[理学—物理化学]