| 聚合羟基铁改性蒙脱石的制备、表征及吸附Se(Ⅵ)的特性 | |
| Hydroxyiron Polymers-Modified Montmorillonite: Preparation, Characterization and Adsorption Characteristics for Selenate | |
| 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33.2 mV.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. | |
| 关键词: 蒙脱石 聚合羟基铁改性蒙脱石 表面性质 吸附 硒(Ⅵ) | |
| 基金项目: 国家自然科学基金(No.41261060)和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. | |
| Abstract: Hydroxyiron polymers-modified montmorillonite (Mt-Fex, 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-Fex montmorillonite increases to more than 1.430 nm from 1.296 nm of the Mt. Compared to Mt, the pore volume, surface area and surface fractal dimension of Mt-Fex 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 (R2=0.993) and the R2 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 (R2) obtained from Freundlich model of the samples are relatively low (R2=0.849~0.970) and increase slightly with increasing the Fe content in Mt-Fex. This indicates that the surface of Mt-Fex 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. | |
| Keywords: montmorillonite hydroxyiron polymers-modified montmorillonite surface properties adsorption selenate | |
| 投稿时间：2014-07-22 修订日期：2014-09-11 | |
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| 杨小洪,魏世勇,方敦,但悠梦.聚合羟基铁改性蒙脱石的制备、表征及吸附Se(Ⅵ)的特性[J].无机化学学报,2014,30(12):2863-2871. | |
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