Through a facile impregnation–precipitation strategy, chitosan was dispersed on bentonite to prepare an organic/inorganic hybrid composite for Pb²⁺ adsorption. The strong promotion effect of a small amount of highly dispersed chitosan on the Pb²⁺ adsorption capacity of clay minerals was unveiled. With a chitosan loading of 0.4 wt%, the experimental adsorption capacity reached 261.3 mg/g. The good dispersion of chitosan played a crucial role in the high capacity. The large proportion of mesopores in the adsorbent facilitated mass transfer, and thereby adsorption equilibrium states could be achieved within 15 s. The adsorption isotherms were consistent with the Freundlich expression. The Pb²⁺ adsorption capacity was suppressed with the addition of 150 ppm Ca²⁺ and almost eliminated in the presence of 150 ppm Mg²⁺. The adsorption enthalpy change was measured to be − 28.6 kJ/mol and Gibbs free energy change was in the range of − 18.4 to − 16.7 kJ/mol, indicating that this adsorption process was exothermic and spontaneous. The FTIR and XPS results demonstrated that the amino groups on chitosan could bond with Pb²⁺, and contributed to the high adsorption capacity. DFT calculation results showed that the amino and hydroxyl groups in adjacent chitosan units could be tri-coordinated with Pb²⁺, and the energy of system was greatly decreased due to the coordination interaction.

通过一种简便的浸渍-沉淀策略，将脱乙酰壳多糖分散在膨润土上，以制备用于Pb ²⁺吸附的有机/无机杂化复合材料。揭示了少量高度分散的壳聚糖对粘土矿物对Pb ²⁺吸附能力的强促进作用。壳聚糖负载量为0.4 wt％时，实验吸附容量达到261.3 mg / g。壳聚糖的良好分散性对高容量起着至关重要的作用。吸附剂中大量的中孔促进了质量传递，因此可以在15 s内达到吸附平衡状态。吸附等温线与Freundlich表达一致。添加150 ppm Ca抑制了Pb ^2+的吸附能力²⁺并在150 ppm Mg ²⁺的存在下几乎消除。测得的吸附焓变化为-28.6 kJ / mol，吉布斯自由能变化为-18.4至-16.7 kJ / mol，表明该吸附过程是放热的，是自发的。FTIR和XPS结果表明，壳聚糖上的氨基可以与Pb ^2+结合，并具有较高的吸附能力。DFT计算结果表明，相邻的壳聚糖单元中的氨基和羟基可以与Pb ²⁺三配位，并且由于配位相互作用，系统的能量大大降低。