Legrouri A, Lakraimi M, Barroug A, De Roy A, Besse J P
School of Science and Engineering, Al Akhawayn University, P.O. Box 1871, Ifrane 53000, Morocco.
Water Res. 2005 Sep;39(15):3441-8. doi: 10.1016/j.watres.2005.03.036.
Batch sorption studies were conducted to investigate the potential of [Zn-Al-Cl] layered double hydroxides (LDHs) for the removal of the herbicide 2,4-dichlorophenoxyacetate (2,4-D) from contaminated aqueous solutions. Experiments were performed at different pH values, initial pesticide concentration, solid/pesticide ratio and anion exchange capacity of LDHs. The LDH samples evaluated had very high retention capacity for 2,4-D whose removal was a rapid process, as a quasi-equilibrium state was reached after 1-h reaction time. The adsorption can be described by Langmuir-type isotherms, with an average affinity constant of 12.5 L mmol(-1). At initial 2,4-D concentrations between 0.08 and 4 m molL(-1), the solids removed up to 98% of the pesticide. Physicochemical characterization of the LDH solids, both fresh and after removal of 2,4-D, by X-ray diffraction, infrared spectroscopy and thermogravimetry, indicates that the retention of 2,4-D is done by adsorption on the surface of the solid for low 2,4-D concentrations. However, a combination of surface adsorption and interlayer ion exchange takes place when the 2,4-D concentration is high.
进行了批量吸附研究，以探究[Zn-Al-Cl]层状双氢氧化物（LDHs）从受污染水溶液中去除除草剂2,4-二氯苯氧基乙酸酯（2,4-D）的潜力。实验在不同的pH值、初始农药浓度、固/药比和LDHs的阴离子交换容量条件下进行。所评估的LDH样品对2,4-D具有非常高的保留容量，其去除过程迅速，在1小时反应时间后达到准平衡状态。吸附可用朗缪尔型等温线描述，平均亲和常数为12.5 L mmol⁻¹。在初始2,4-D浓度为0.08至4 mmol L⁻¹之间时，固体可去除高达98%的农药。通过X射线衍射、红外光谱和热重分析对新鲜的以及去除2,4-D后的LDH固体进行物理化学表征，结果表明，对于低浓度的2,4-D，其保留是通过吸附在固体表面实现的。然而，当2,4-D浓度较高时，会发生表面吸附和层间离子交换的结合。
