不同修饰模式高岭土的表征及对CrO<sub>4</sub><sup>2-</sup>的吸附

李文斌; 孟昭福; 吴琼; 赵云飞; 任爽; 余璐; 郭惠; 周春艳

文章摘要

李文斌,孟昭福,吴琼,赵云飞,任爽,余璐,郭惠,周春艳.不同修饰模式高岭土的表征及对CrO₄^2-的吸附[J].农业环境科学学报,2016,35(4):677-683.

不同修饰模式高岭土的表征及对CrO₄^2-的吸附

Surface characteristics and CrO₄^2- adsorption of kaolin with different modification

投稿时间：2015-11-15

DOI：10.11654/jaes.2016.04.010

中文关键词: 修饰模式高岭土表征 CrO₄^2- 吸附量

英文关键词: modified mode kaolin surface characteristics CrO₄^2- adsorption capacity

基金项目:国家自然科学基金项目(41271244);陕西省社会发展攻关项目(2013K13-01-05)

作者	单位	E-mail
李文斌	西北农林科技大学资源环境学院, 陕西杨凌 712100
孟昭福	西北农林科技大学资源环境学院, 陕西杨凌 712100 农业部西北植物营养与农业环境重点实验室, 陕西杨凌 712100	zfmeng@hotmail.com
吴琼	西北农林科技大学资源环境学院, 陕西杨凌 712100
赵云飞	西北农林科技大学资源环境学院, 陕西杨凌 712100
任爽	西北农林科技大学资源环境学院, 陕西杨凌 712100
余璐	西北农林科技大学资源环境学院, 陕西杨凌 712100
郭惠	西北农林科技大学资源环境学院, 陕西杨凌 712100
周春艳	西北农林科技大学资源环境学院, 陕西杨凌 712100

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中文摘要:

为了研究不同修饰模式高岭土对CrO₄^2-的吸附效果,并分析外界条件对CrO₄^2-吸附效果的影响,采用DTAB(十二烷基三甲基溴化铵,简写为DT)分别对15%、30%和60%BS-12(十二烷基二甲基甜菜碱,简写为BS)高岭土进行复配修饰,探索不同BS-12和BS+DT复配修饰模式高岭土的表面特征及其对CrO₄^2-的吸附特征,并对比不同pH值和温度条件下的吸附差别。结果表明:高岭土经BS-12和BS+DT修饰后,TOC含量均表现为疏水修饰模式 >疏水修饰和离子交换共存模式 >离子交换模式;不同修饰模式高岭土层间距d₀₀₁无显著变化,但相比原土(CK)均增大;不同修饰模式高岭土的比表面积S_BET随疏水修饰的增强而减小。BS+DT修饰高岭土对CrO₄^2-的吸附量均比CK和BS-12修饰的土高,Henry模型拟合证明疏水修饰模式高岭土对CrO₄^2-保持着良好的吸附能力,且随着疏水修饰比例的增强,土样对于CrO₄^2-的结合能力增强。温度范围10~30℃内,CK对CrO₄^2-吸附量增加5%以上,不同BS-12修饰土的吸附量增加了1.4%~3.7%。15%、30%和60% BS+DT复配修饰土对CrO₄^2-吸附量降低了5.4%~7.2%。pH值在4~10范围内,随着pH值增大,各修饰土样对CrO₄^2-的吸附量均逐渐减小。

英文摘要:

Modified minerals have enhanced surface and thus adsorption. In this study, surface characteristics and CrO₄^2- adsorption of kaolin under different modification were examined at various pH and temperature. Dodecyl trimethyl ammonium bromide(DTAB) was used to modify 15%, 30% and 60% BS-12(Dodecyl dimethyl betaine) pre-modified kaolin. Results showed that:TOC content was hydrophobic >hydrophobic and ion exchange >ion exchange modifications for BS-12 and BS+DTAB modified samples. The interlayer spacing in different modified kaolin had no significant variation, but was all greater to different extent than that of the original(CK). The specific surface area of different modified kaolin decreased with increasing hydrophobic modification. Adsorption of CrO₄^2- on BS-12 kaolin was greatly improved after co-modification with DTAB. Henry model fitting proved that kaolin modified with hydrophobic substance had enhanced adsorption capacity for CrO₄^2-, which increased with increasing hydrophobic ratios. When temperature increased from 10 to 30℃, the adsorption capacity for CrO₄^2- was increased by more than 5% on CK and by 1.4%~3.7% on BS-12 modified kaolin, but was reduced by 5.4%~7.2% on 15%, 30% and 60% BS+DTAB modified kaolin. Increasing pH from 4 to 10 decreased the adsorption capacity for CrO₄^2- on all modified kaolin.

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