This work presents a study of sorption of heavy metals (HMs)—Cu(II), Co(II) and Cd(II)—from water media by carbonated and calcined forms of layered-double hydroxides (LDH) with various Mg(II)/Fe(III) molar ratios, which are obtained by precipitation. It is ascertained that the maximum sorption (99.9%) of the HM ions stated is observed with the use of calcined forms of LDH at pH>2.8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{pH}\,{>}\,2.8$$\end{document} (pH after sorption ≥8.3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\ge 8.3$$\end{document}). Such an increase in the pH of the aqueous suspension causes sorption of the HM ions by the mechanism of their precipitation in the form of hydroxides or hydroxocarbonates (for Cu(II)). Sufficiently high degrees of sorption of HMs, even at low pH of the aqueous medium, are apparently caused not only by the precipitation of their hydroxide forms, but also due to the complex formation with ferrinol groups of brucite sorbent layers. An increase in the Mg/Fe ratio from 2 to 4 and a corresponding decrease in the positive charge of the layers, which determines the size of the interlayer space in the LDH, have virtually no effect on the degree of extraction of HMs. The presented results suggest that the use of the studied-LDH in practice might be promising.

中文翻译：

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通过具有不同 [Mg(II)]/[Fe(III)] 摩尔比的层状双氢氧化物从水溶液中去除 Cu(II)、Co(II) 和 Cd(II)

这项工作介绍了通过碳酸化和煅烧形式的层状双氢氧化物 (LDH) 和各种 Mg(II) 从水介质中吸附重金属 (HMs)——Cu(II)、Co(II) 和 Cd(II)。 )/Fe(III) 摩尔比，通过沉淀获得。确定使用煅烧形式的 LDH 在 pH>2.8\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage 下观察到所述 HM 离子的最大吸附（99.9%） {amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{pH}\,{>} \,2.8$$\end{document}（吸附后的 pH ≥8。3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin} {-69pt} \begin{document}$$\ge 8.3$$\end{document}）。水性悬浮液的 pH 值的这种增加通过它们以氢氧化物或碳酸氢盐形式（对于 Cu(II)）沉淀的机制引起 HM 离子的吸附。HMs 的足够高的吸附度，即使在水介质的低 pH 值下，显然不仅是由于它们的氢氧化物形式的沉淀，而且还由于与水镁石吸附剂层的铁醇基团形成复合物。Mg/Fe 比从 2 增加到 4，层的正电荷相应减少，这决定了 LDH 中层间空间的大小，对 HM 的提取程度几乎没有影响。所呈现的结果表明，在实践中使用所研究的 LDH 可能是有希望的。