To explore the adsorption removal mechanism of Mg–Al layered double oxides (LDOs) for low-concentration (≤ 5 mg L⁻¹) Cr(VI), the adsorption kinetics, adsorption isotherms and its influencing factors were studied by batch experiments. Cr(VI) adsorption reached equilibrium after 6, 11 and 15 h for initial Cr(VI) concentrations of 1, 3 and 5 mg L⁻¹, respectively, and the final adsorption efficiency exceeded 99.0%. The residual concentration of Cr(VI) was within the allowable limit of Drinking Water Quality Standard of World Health Organization (0.05 mg L⁻¹). The experimental data fitted the pseudo-second-order and Freundlich models well. Mg–Al LDOs showed effective adsorption efficiency in the range of pH 3–9, and the adsorption efficiency was influenced by anions competition (HPO₄²⁻ > SO₄²⁻ > CO₃²⁻ > NO₃⁻ > Cl⁻). The analyses of XRD, SEM and FT-IR spectra suggested adsorption Cr(VI) on Mg–Al LDOs was caused by capturing dichromate ions to reconstruct its structure. Therefore, Mg–Al LDOs is promising adsorbents for the low-concentration Cr(VI) treatment in polluted surface water and groundwater.

为了探索低浓度（≤5 mg L ^-1）Cr（VI）的Mg-Al层状双氧化物（LDOs）的吸附去除机理，通过分批实验研究了其吸附动力学，吸附等温线及其影响因素。Cr（VI）的初始吸附浓度分别为1、3和5 mg L ^-1时，分别在6、11和15 h时达到Cr（VI）吸附平衡，最终吸附效率超过99.0％。Cr（VI）的残留浓度在世界卫生组织饮用水质量标准的允许范围内（0.05 mg L ^-1）。实验数据很好地拟合了伪二阶模型和Freundlich模型。镁铝LDO的显示有效的吸附效率在pH为3-9的范围内，和吸附效率通过阴离子竞争的影响（HPO ₄ ^2- > SO ₄ ^2- > CO ₃ ^2- > NO ₃ ^- >氯^- ）。XRD，SEM和FT-IR光谱分析表明，Mg-Al LDOs吸附Cr（VI）是由于捕获重铬酸根离子以重建其结构而引起的。因此，Mg-Al LDOs是被污染地表水和地下水中低浓度Cr（VI）处理的有前途的吸附剂。