Activated carbon (AC) was produced from date seeds by a calcination process at 700 °C for 2 h and then its surface was improved with CaO and magnetic nanoparticles. AC/CaO/Fe₃O₄ nanocomposite was then employed to remove formaldehyde ions from aqueous media. The structural characteristics of the materials were completely studied through FT-IR, XRD, SEM, EDX, Map, VSM, BET and TEM analyses. The results showed that the nanocomposite has a mesoporous structure (average pore diameter∼13 nm) with great sorption capability. Also, the utmost removal efficiency of formaldehyde using AC, AC/Fe₃O₄, CaO/Fe₃O₄ and AC/Fe₃O₄/CaO nanocomposite was 94.73, 95.67, 95.14 and 98.22%, respectively, indicating that the removal efficiency increases by improving the surface properties of the AC. Moreover, the uptake of formaldehyde using AC/Fe₃O₄/CaO nanocomposite follows the Freundlich isotherm and pseudo-2^nd-order kinetic models. Furthermore, the highest sorption capacity of AC, AC/Fe₃O₄, CaO/Fe₃O₄ and AC/Fe₃O₄/CaO nanocomposite using the Langmuir model was obtained 19.86, 24.21, 21.28 and 24.01 mg/g, respectively. The thermodynamic study showed that formaldehyde sorption using all four adsorbents is exothermic and spontaneous. The reusability of the adsorbents was also evaluated after ten reuse cycles and the outcomes indicated that these four adsorbents have significant reusability. Moreover, the impact of interfering ions (e.g., carbonate, sulfate, phosphate, nitrate and chloride) showed that all of these compounds, except nitrate, had little competition with formaldehyde ions for adsorption on the nanocomposite surface.

活性炭 (AC) 是从枣子中通过在 700°C 下煅烧 2 小时的过程生产的，然后用 CaO 和磁性纳米粒子改进其表面。然后采用AC/CaO/Fe ₃ O ₄纳米复合材料从水性介质中去除甲醛离子。通过FT-IR、XRD、SEM、EDX、Map、VSM、BET和TEM分析，对材料的结构特性进行了全面研究。结果表明，该纳米复合材料具有介孔结构（平均孔径~13 nm），具有很好的吸附能力。此外，使用AC、AC/Fe ₃ O ₄、CaO/Fe ₃ O ₄和AC/Fe ₃ O ₄的甲醛去除效率最高/CaO 纳米复合材料分别为 94.73、95.67、95.14 和 98.22%，表明通过改善活性炭的表面性能提高了去除效率。此外，甲醛的使用AC /铁摄取₃ ö ₄ / CaO的纳米复合材料如下所述Freundlich等温和伪2^次阶动力学模型。此外，AC、AC/Fe ₃ O ₄、CaO/Fe ₃ O ₄和AC/Fe ₃ O _{4 的}吸附能力最高使用朗缪尔模型的 /CaO 纳米复合材料分别为 19.86、24.21、21.28 和 24.01 毫克/克。热力学研究表明，使用所有四种吸附剂的甲醛吸附都是放热和自发的。在十次重复使用循环后还评估了吸附剂的可重复使用性，结果表明这四种吸附剂具有显着的可重复使用性。此外，干扰离子（例如，碳酸盐、硫酸盐、磷酸盐、硝酸盐和氯化物）的影响表明，除硝酸盐外，所有这些化合物与甲醛离子在纳米复合材料表面上的吸附几乎没有竞争。