铁铝柱撑膨润土组成特征及其磷吸附性能研究

Removal of Phosphate from Aqueous Solutions by Iron-and Aluminum-pillared Bentonites

利用天然膨润土合成了铁柱撑膨润土(Fe1-Mt、Fe10-M)t、羟基铁膨润土(FeOx-M)t、羟基铝膨润土(AlOx-M)t和羟基铝铁膨润土复合体(AlFe-M)t,对其化学组成和矿物组成等特征进行分析,比较了5种不同铁铝柱撑膨润土对磷污染水体的吸附净化性能,并通过等温吸附试验探讨了柱撑膨润土对磷的吸附机制。结果发现,不同铁铝柱撑均可以增加天然膨润土的层间距,其中以羟基铝铁膨润土复合体的层间距增加最明显,与原土相比增加约为2倍。5种不同铁铝柱撑均能显著增强膨润土对磷污染水体的吸附净化能力,其中以FeOx-Mt的理论磷吸附容量最大,为12.03mg.g-1,其次为Fe10-Mt、AlFe-Mt和AlOx-Mt,吸附等温曲线同时符合Freundlich方程和Langmuir方程,均达显著水平。结果表明,除膨润土层间距外,不同铁铝柱撑膨润土的磷吸附能力主要与铁铝氧化物的含量及铁的存在形态相关。

In this study,several iron-and aluminum-pillared bentonites were synthesized and characterized,and their potentials for removing phosphate from aqueous solutions were evaluated using adsorption isotherms.The five Fe-/Al-pillared bentonites were：（1）iron-pillared bentonites with two different iron contents（Fe1-Mt and Fe10-M）t（,2）hydroxyl-iron pillared bentonite（FeOx-M）t（,3）hydroxyl-aluminum pillared bentonite（AlOx-M）tand（4）hydroxyl-iron/aluminum pillared bentonite（AlFe-M）t,respectively.Results showed that both iron-and aluminum-pillaring could increase the inter-lamellar spacing,of which the hydroxyl-iron/aluminum pillared bentonite had the highest inter lamellar spacing,approximately twice as much as that of the untreated bentonite.Phosphate adsorption isotherms by pillared bentonites could be well described by either Freundlich or Langmuir equations.Adsorption results indicated that pillared bentonites exhibited greatly enhanced capabilities for removing phosphate than that of the untreated bentonite（qm=1.05 mg.g-1）,with the FeOx-Mt having the highest maximum adsorption capacity（～12.03 mg.g-1）,followed by Fe10-M（t8.14 mg.g-1）,AlFe-M（t8.01 mg.g-1）,AlOx-M（t7.92 mg.g-1）,Fe1-M（t4.83 mg.g-1）,respectively.The results suggested that the phosphate adsorption capacities of the pillared bentonites were related to the content of iron and aluminum oxides and the existing form of iron,as well as to their interlayer spacings.