凹凸棒石黏土-腐植酸复合吸附剂吸附Cr(Ⅵ)的性能研究  

Adsorption of Cr(Ⅵ) on Attapulgite Clay-Humic Acid Composite Adsorbent

作　　者：柏文博 张立威[1] 薛田田 李静萍[1] BAI Wen-bo;ZHANG Li - wei;XUE Tian-tian;LI Jing-ping(School of Chemical and Biological Engineering,Lanzhou Jiaotong University,Langzhou 730070,China)

机构地区：[1]兰州交通大学化学与生物工程学院

出　　处：《材料保护》2019年第5期131-136,156,共7页Materials Protection

基　　金：甘肃省自然科学基金(3ZX062-B25-002);甘肃省建设科技攻关项目(JK2010-31);金川公司预研基金(JCYY2013002)资助

摘　　要：为促进凹凸棒石黏土-腐植酸复合吸附剂在水处理中的应用,用酸改性的甘肃靖远凹凸棒石黏土和天祝褐煤提取的腐植酸制备出凹凸棒石黏土-腐植酸复合吸附剂,通过SEM、XRD、FT-IR等分析方法对复合吸附剂的结构进行了表征,考察了物料配比及吸附时间、pH值、温度、投加量和初始浓度对Cr(Ⅵ)吸附率的影响。结果表明:靖远凹凸棒石黏土最佳酸改性条件为盐酸5 mol/L,酸化时间120 min,酸用量固液比为1∶10。当Cr(Ⅵ)的起始浓度为0.1 g/L,体积为50 m L,复合吸附剂用量为1.2 g,吸附时间为6 h,p H值为6,温度25℃,酸改性的凹凸棒石黏土与腐植酸的最佳复合比为1∶3时,复合吸附剂对Cr(Ⅵ)的吸附率达到91.7%。复合吸附剂对Cr(Ⅵ)的吸附满足Freundlich模型。在25~45℃条件下,吸附过程ΔG <0、ΔS=87.46 J/(mol·K)、ΔH=-21.2 kJ/mol,表明该吸附是一个自发、熵增、放热的过程。The attapulgite clay-humic acid composite adsorbent was prepared by acid-modified Ganjing Jingyuan attapulgite clay and humic acid extracted from Tianzhu brown coal. The composite adsorbent was analyzed by SEM,XRD and FT-IR to character the structure. The effects of material ratio,adsorption time,pH value,temperature,dosage and initial concentration on the adsorption rate of Cr( Ⅵ) were investigated.Results showed that the optimum acid modification condition of Jingyuan attapulgite clay was hydrochloric acid concentration of 5 mol/L,acidification time of 120 min,and acid-to-liquid ratio of 1 ∶ 10. The adsorption efficiency of Cr( Ⅵ) by the composite adsorbent reached91.7% when the conditions were as follows: the initial concentration of Cr(Ⅵ) of 0.1 g/L,the amount of composite adsorbent of 1.2 g,the adsorption time of 6 h,the p H value of 6,the temperature of 25 ℃,and the ratio of acid-modified attapulgite clay and humic acid complex of 1 ∶ 3. The adsorption of Cr(Ⅵ) ions by the composite adsorbent met the Freundlich model. At 25-45 ℃,the adsorption process ΔG<0,ΔS =87.46 J/( mol·K),ΔH =-21.2 k J/mol,indicating that the adsorption was a spontaneous,entropic-increasing and exothermic process.

关 键 词：凹凸棒石黏土 腐植酸 吸附剂 吸附率 Cr(Ⅵ) 

分 类 号：TM277[一般工业技术—材料科学与工程]