摘要
为了研究两性-阴离子复配修饰膨润土对Cr(VI)和Cd2+的吸附性能差异及其机理,并为两性复配修饰黏土矿物治理重金属污染水体提供依据,采用阴离子型有机修饰剂1-癸烷磺酸钠(DAS)复配修饰两性修饰剂十二烷基二甲基甜菜碱(BS-12或BS)修饰膨润土,研究各供试土样对Cr(VI)和Cd2+的等温吸附曲线及不同温度、pH值和离子强度条件对吸附的影响.结果表明,Langmuir模型能较好地拟合各修饰土样对不同类型重金属离子(Cr(VI)和Cd2+)的吸附曲线,其对Cr(VI)和Cd2+的平衡吸附量均呈现BS+150DAS(150%CEC DAS复配修饰膨润土)>BS+100DAS>BS+50DAS>BS+25DAS>BS>CK(膨润土)的趋势,且对Cr(VI)、Cd2+的最大吸附量(qm)分别为85.92 mmol·kg-1(100BS+150DAS)和321.89 mmol·kg-1(100BS+150DAS).各供试土样对Cr(VI)和Cd2+的吸附均表现为自发、焓增和熵增的特征,升温可增加其对Cr(VI)和Cd2+的最大吸附量.酸性环境有利于各修饰土样对Cr(VI)的吸附,而不利于对Cd2+的吸附.离子强度增加均降低了各修饰土样对Cr(VI)和Cd2+的吸附.
In order to reveal the mechanism and difference of Cr（ VI） and Cd2＋adsorption on amphoteric-anionic-modified bentonite（ AAMB）,and to provide evidences for applying amphoteric complex modified clay minerals on treatment of heavy metal contaminated water. After complex modifying bentonite with both amphoteric surfactant,dodecyl dimethyl betaine（ BS-12 or BS）,and anionic surfactant,Sodium 1-decanesulfonate（ DAS）,the studies on adsorption isotherms of Cr（ VI） and Cd2＋under the different modification proportion,temperature,pH and ionic strength were carried out.Results showed that the Langmuir equation was a best model to describe the adsorption of both Cr（ VI） and Cd2＋,and the equilibrium adsorption capacity of Cr（ VI） and Cd2＋were ordered by BS＋150 DAS（ DAS modification with 150% CEC proportion） BS＋100 DAS BS＋50 DAS BS＋ 25 DAS BS CK（ bentonite）. The maximum adsorption capacity（ qm） of Cr（Ⅵ） and Cd2＋were 85.92 mmol·kg-1（100 BS＋150 DAS） and 321.89 mmol·kg-1（100 BS＋150 DAS）,respectively. The adsorption of Cr（ VI） and Cd2＋was a spontaneous process with an enthalpy increase and an entropy increase,and increased with an increase of temperature and a decrease of ionic strength. The pH at acidic region in favored of adsorption of Cr（ VI） on AAMB,but was unfavorable for the adsorption of Cd2＋on AAMB.
作者
谢婷
孟昭福
路浩源
刘伟
李文斌
白丹
田凯
XIE Ting;MENG Zhaofu;LU Haoyuan;LIU Wei;LI Wenbin;BAI Dan;TIAN Kai(College of Natural Resources and Environment, Northwest A＆F University, Yangling 712100;Key Lab of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Yangling 712100;Department of Chemical and Environmental Engineering, Xinjiang Institute of Engineering, Urumqi 830091;College of Environmental Science and Engineering, China West Normal University, Nanchong 637009)
出处
《环境科学学报》
CAS
CSCD
北大核心
2018年第7期2833-2841,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.41271244)
陕西省重点研发计划(No.2017SF-385)~~
