Department of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, 58 Yanta Middle Road, Beilin District, Xi'an, China E-mail:
Department of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, 58 Yanta Middle Road, Beilin District, Xi'an, China.
Water Sci Technol. 2023 Dec;88(11):3009-3023. doi: 10.2166/wst.2023.379.
To solve the problem of liquid-liquid extraction of La(III), the oil-in-water Pickering emulsions were prepared by utilizing the aqueous solution of sodium alginate as the continuous phase, kerosene-diluted extractant di-(2-ethylhexyl) phosphate (P204) as the dispersed phase, and modified silica as an emulsifier. Then the emulsions were added to a calcium chloride solution to prepare the Pickering emulsion hydrogels (PEHGs) to better remove La(III). The PEHGs were characterized using Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. The adsorption properties of PEHGs for La(III) in the aqueous solution were investigated using a UV-vis spectrophotometer. The study found that P204 was successfully coated by hydrogels and reached the highest adsorption capacity of 48 mg/g at pH 4. The amount of adsorption increased with the rise in temperature from 298 to 318 K. La(III) adsorption experimental data were more consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model. Thermodynamic parameters showed that the adsorption of La(III) by PEHGs was a spontaneous endothermic process. The internal diffusion model revealed a linear relationship, indicating that internal diffusion played a role in the adsorption process. The encapsulating property of PEHGs indicated its potential usefulness in industrial wastewater for treating La(III).
为了解决镧（III）的液-液萃取问题，利用海藻酸钠水溶液作为连续相，煤油稀释的萃取剂二-(2-乙基己基)磷酸（P204）作为分散相，改性二氧化硅作为乳化剂，制备了水包油型 Pickering 乳液。然后将乳液加入氯化钙溶液中，制备 Pickering 乳液水凝胶（PEHGs），以更好地去除镧（III）。采用傅里叶变换红外光谱、热重分析和扫描电子显微镜对 PEHGs 进行了表征。利用紫外可见分光光度计研究了 PEHGs 在水溶液中对 La(III)的吸附性能。研究发现，P204 被水凝胶成功包覆，在 pH 4 时达到最高吸附容量 48 mg/g。吸附量随温度从 298 K 升高到 318 K 而增加。La(III)吸附实验数据更符合准二级动力学模型和 Langmuir 等温线模型。热力学参数表明，PEHGs 对 La(III)的吸附是自发的吸热过程。内扩散模型呈现线性关系，表明内扩散在吸附过程中起作用。PEHGs 的包封性能表明其在处理 La(III)的工业废水中具有潜在的用途。
