We evaluated the performance of a resorcinol–formaldehyde (RF) hydrogel as an adsorbent for removing aqueous cesium ions (Cs⁺), by synthesizing cylindrical pellets of RF gels under different molar ratios (R/C) between resorcinol (R) and sodium carbonate (C) as the catalyst for the sol–gel polycondensation in the range from 2.5 to 400. The RF gel prepared at R/C = 2.5, containing the greatest amount of sodium ion (Na⁺), had the greatest Cs⁺ adsorption amount (0.660 mmol g⁻¹), because Cs⁺ could be adsorbed on the network structure in the gel through exchange with Na⁺ at an equal molar ratio, but with the smallest effective diffusion coefficient of Cs⁺ (1.45 × 10^–12 m² s⁻¹). Kinetic analyses based on the Dryden–Kay and intra-particle diffusion models revealed that the diffusivity of Cs⁺ in the RF gel depended strongly on the density of the network structure, which can be controlled by varying the R/C ratio.

Graphic abstract

中文翻译：

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间苯二酚-甲醛水凝胶作为铯离子吸附剂的表征

我们通过合成间苯二酚（R）和碳酸钠之间不同摩尔比（R / C）的RF凝胶圆柱形小球，评估了间苯二酚-甲醛（RF）水凝胶作为吸附剂去除含水铯离子（Cs ⁺）的性能。 （C）作为溶胶-凝胶缩聚反应的催化剂，范围从2.5到400。以R / C = 2.5制备的RF凝胶，其钠离子（Na ⁺）量最大，Cs ⁺吸附量最大。（0.660 mmol g ^-1），因为Cs ⁺可以通过以相同摩尔比与Na ⁺交换而吸附在凝胶的网络结构上，但Cs ^+的有效扩散系数最小（1.45×10 ^–12 m ²  s ^-1）。基于Dryden-Kay和粒子内扩散模型的动力学分析表明，RF凝胶中Cs ⁺的扩散性很大程度上取决于网络结构的密度，可以通过改变R / C比率来控制其密度。

图形摘要