《Chemical Engineering Journal》杂志刊登“利用水合铁(III)–锡(IV)氧化物去除水体中的氟化物”

作者：Krishna Biswas, Kaushik Gupta, Uday Chand Ghosh

刊物：《Chemical Engineering Journal》，2009年，149卷第1–3期，196–206页

关键词：吸附法；氟化物；动力学；水合铁(III)–锡(IV)氧化物；热力学

摘要：本文采用红外光谱、x射线衍射、扫描电镜图像分析对新型吸附材料铁(III)与锡(IV)混合氧化物(HITMO)进行表征。结果表明：铁锡水合氧化物非晶体表面呈现不规则状态。通过实验探究pH值、接触时间和吸附平衡等参数对铁(III)与锡(IV)混合氧化物(HITMO)除氟效果的影响。实验结果表明吸附材料HITMO在pH值为5.0-7.5之间，均能达到良好的吸附效果。HITMO的吸附动力学可采用多级控制的伪二级动力学方程进行拟合。吸附等温线符合Langmuir等温线模型，最大Langmuir吸附容量为10.50 mgg⁻¹。由Dubinin–Redushkevich等温方程计算出HITMO的平均吸附能为9.05 kJ mol⁻¹，表明HITMO除氟机理主要为离子交换。通过计算焓（△H⁰）、熵(△S⁰)和自由能（△G⁰）等的变化，表明HITMO吸附氟的反应是吸热过程，并且是非自发进行。竞争离子影响研究结果表明，仅碳酸氢根对HITMO除氟效果有影响。吸附饱和（吸附容量达到10. 0 mgg−1）后的HITMO，采用pH值为13.0的碱溶液进行再生，其吸附能力可还原75%。原水氟化物浓度为2.94mg/L，HITMO投加量2g/L情况下，可将原水氟化物浓度降至1.5mg/L以下。

Adsorption of fluoride by hydrous iron(III)–tin(IV) bimetal mixed oxide from the aqueous solutions

Authors: Krishna Biswas, Kaushik Gupta, Uday Chand Ghosh

Journal: Chemical Engineering Journal, Volume 149, Number 1–3 (2009), 196–206

Key words: Adsorption; Fluoride; Kinetics;Iron(III)–tin(IV) mixed oxide; Thermodynamics

Abstract:The synthetic iron(III)–tin(IV) mixed oxide (HITMO) has been characterized by the FTIR, XRD and SEMimage analyses. The mixed oxide is found hydrated and amorphous with irregular surface morphology.The relevant parameters studied for fluoride removal by using HITMO are the effects of pH, contact time,and equilibrium. The fluoride adsorption capacity is nearly constant in the pH range 5.0–7.5. The pseudosecondorder equation explains the kinetic data well and, the overall rate is multi-stage controlled. TheLangmuir isotherm describes the equilibrium datawell and gives high Langmuir capacity (∼10.50mgg⁻¹)value. The mean adsorption energy (9.05 kJ mol⁻¹) computed from the Dubinin–Redushkevich isothermsuggests the ion exchange mechanism for fluoride adsorption. The evaluated change of enthalpy (△H⁰),entropy (△S⁰) and free energy (△G⁰) of adsorption values indicates the endothermic and non-spontaneousnature of the present reaction. Excepting bicarbonate, other common ions show no adverse effect onfluoride removal. The regeneration (∼75%) of fluoride-rich (10.0mgg⁻¹) material is possible by a solutionof pH 13.0. Two gram HITMO per litre of the fluoride-doped (2.97mgL⁻¹) natural water reduces fluoridelevel below 1.5mgL⁻¹.

原文链接：http://www.sciencedirect.com/science/article/pii/S1385894708006992