改性硅藻土的制备及其对氟的吸附机理。
Preparation of aluminium-hydroxide-modified diatomite and its fluoride adsorption mechanism.
机构信息
College of Environmental Science and Engineering, Liaoning Technical University, Fuxin, 123000, China.
出版信息
Sci Rep. 2023 Mar 8;13(1):3871. doi: 10.1038/s41598-023-30901-8.
As the current excessive accumulation of fluoride (F) in the environment can be hazardous to human health, it is essential to remove fluoride from wastewater. In this study, diatomite (DA) was used as a raw material and modified using aluminum hydroxide (Al-DA) for use in the adsorption of F from water bodies. SEM, EDS, XRD, FTIR, and Zeta potential characterization analyses were carried out; adsorption tests and kinetic fitting were performed, and the effects of pH, dosing quantity, and presence of interfering ions on the adsorption of F by the materials were investigated. The results show that the Freundlich model effectively describes the adsorption process of F on DA, which therefore involves adsorption-complexation interactions; however, the Langmuir model effectively describes the adsorption process of F on Al-DA, corresponding to unimolecular layer adsorption mainly via ion-exchange interactions, that is, adsorption is dominated by chemisorption. Aluminum hydroxide was shown to be the main species involved in F adsorption. The efficiency of F removal by DA and Al-DA was over 91% and 97% for 2 h, and the adsorption kinetics were effectively fit by the quasi-secondary model, suggesting that chemical interactions between the absorbents and F control the adsorption process. The adsorption of F was highly dependent on the pH of the system, and the maximum adsorption performance was obtained at pH 6 and 4. The optimal dosage of DA and Al-DA was 4 g/L. Even in the presence of interfering ions, the removal of F on Al-DA reached 89%, showing good selectivity. XRD and FTIR studies showed that the mechanism of F adsorption on Al-DA involved ion exchange and the formation of F-Al bonds.
由于当前环境中氟（F）的过度积累可能对人类健康造成危害，因此必须从废水中去除氟。在本研究中，以硅藻土（DA）为原料，用氢氧化铝（Al-DA）进行改性，用于水体中氟的吸附。进行了 SEM、EDS、XRD、FTIR 和 Zeta 电位特征分析；进行了吸附试验和动力学拟合，并考察了 pH、投加量和共存干扰离子对材料吸附 F 的影响。结果表明，F 在 DA 上的吸附过程可用 Freundlich 模型有效描述，涉及吸附-络合相互作用；而 F 在 Al-DA 上的吸附过程可用 Langmuir 模型有效描述，对应于主要通过离子交换相互作用的单分子层吸附，即吸附主要由化学吸附控制。结果表明，氢氧化铝是吸附 F 的主要物质。DA 和 Al-DA 对 2 h 内 F 的去除效率均超过 91%和 97%，准二级模型能有效地拟合吸附动力学，表明吸附剂与 F 之间的化学相互作用控制着吸附过程。F 的吸附高度依赖于体系的 pH 值，在 pH 6 和 4 时达到最大吸附性能。DA 和 Al-DA 的最佳投加量为 4 g/L。即使存在干扰离子，Al-DA 对 F 的去除率仍达到 89%，显示出良好的选择性。XRD 和 FTIR 研究表明，Al-DA 吸附 F 的机制涉及离子交换和 F-Al 键的形成。
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