聚合羟基铁改性蒙脱石的制备、表征及吸附Se(Ⅵ)的特性（英文）  

Hydroxyiron Polymers-Modified Montmorillonite: Preparation, Characterization and Adsorption Characteristics for Selenate

作　　者：杨小洪[1] 魏世勇[1] 方敦[1] 但悠梦[1] 

机构地区：[1]生物资源保护与利用湖北省重点实验室、湖北民族学院化学与环境工程学院,恩施445000

出　　处：《无机化学学报》2014年第12期2863-2871,共9页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.41261060);生物资源保护与利用湖北省重点实验室开放基金(No.PKLHB1315)资助项目

摘　　要：采用共沉淀法制备了3种聚合羟基铁改性蒙脱石（Mt-Fex,x=1,2,3）,对比研究了纯蒙脱石（Mt）和Mt-Fex（x=1,2,3）的表面性质及吸附Se（Ⅵ）的特性.结果表明,Mt样品的d（001）层间距为1.296 nm,在Mt-Fex中升高至1.430 nm以上;与Mt样品比较,Mt-Fex的孔体积、表面积、表面分形度均随含铁量的增加而升高,其中微孔体积和微孔表面积的变化尤为明显;Mt样品的等电点（IEP）低于3,而Mt-Fe3的IEP升高至6.8;初始pH=5.0时,Mt和Mt-Fex（x=1,2,3）的表面ζ电位分别为-33.5,-11.7,9.9和33.2mV.单吸附位Langmuir模型能够很好地拟合Mt样品对Se（Ⅵ）的等温吸附数据（R2=0.993）,4种样品吸附数据的单吸附位Langmuir拟合判断系数（R2）随样品含铁量的增加而降低;3种Mt-Fex样品的吸附数据更适合用双吸附位Langmuir模型拟合（R2=0.993～0.997）;Freundlich模型对4种样品的吸附数据拟合度较低（R2=0.849～0.970）,其判断系数（R2）随样品含铁量的增加而升高.初始pH=5.0时,Mt和Mt-Fex（x=1,2,3）对Se（Ⅵ）的吸附容量分别为4.23,7.83,10.38和14.34 mg·g^-1.可见,聚合羟基铁含量较高的Mt-Fex样品对土-水体系中Se（Ⅵ）的固定能力明显高于Mt.Hydroxyiron polymers-modified montmorillonite （Mt-Fe, x=1, 2, 3） was prepared by a coprecipitation procedure. The surface properties and selenate （Se（Ⅵ）） adsorption of Mt-Fex were investigated and compared with those of pure montmorillonite （Mt）. Results show that the d（001） spacing of Mt-Fe, montmorillonite increases to more than 1.430 nm from 1.296 nm of the Mt. Compared to Mr, the pore volume, surface area and surface fractal dimension of Mt-Fe, increase with increasing the Fe content. The increased quantities of the micropore volume and micropore surface area are very significantly. The isoelectric point （IEP） varies from the value of 〈 3 of the Mt to 6.8 of the Mt- Fe3, and the surface ζ potential at pH value of 5.0 is -33.5, -11.7, 9.9, and 33.2 mV for Mt, Mt-Fe1, Mt-Fe2, and Mt- Fe3, respectively. The Se（Ⅵ） adsorption data of Mt can be well fitted by one-site Langmuir model （R^2=0.993） and the R^2 of the four samples shows the order of Mt〉Mt-Fe1〉Mt-Fe2〉Mt-Fe3. As for Mt-Fex, two-site Langmuir model fits the adsorption data better than the one-site model. The coefficients of deternination （R^2） obtained from Freundlich model of the samples are relatively low （R^2=0.849-0.970） and increase slightly with increasing the Fe content in Mt-Fex. This indicates that the surface of Mt-Fe, possesses different types of reactive sites for Se（Ⅵ） adsorption. At pH=5.0, the adsorption capacities （qmax） of Mt, Mt-Fe1, Mt-Fe2, and Mt-Fe3 are 4.23, 7.83, 10.38, and 14.34 mg .g^-1,respectively. Mt-Fex with a high content of hydroxyiron polymers has a high adsorption capacity for the Se（Ⅵ） in soil and sediment solutions.

关 键 词：蒙脱石 聚合羟基铁改性蒙脱石 表面性质 吸附 硒(Ⅵ) 

分 类 号：O614.81[理学—无机化学] S153.6[理学—化学]