In this work, graphene nanosheet/δ-MnO₂ (GN-MnO₂) was synthesized via a microwave-assisted method. The adsorption behavior of cobalt (Co(II)) and chromium (Cr(III)) ions onto GN-MnO₂ adsorbent was investigated through batch and column experiment under various conditions. GN-MnO₂ was characterized using Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), N₂ adsorption/desorption (BET) and Boehm's titration method. Under static conditions, the effect of parameters like pH level, initial metal ion concentration, temperature, contact time and adsorbent dosage was studied. The optimum batch adsorption capacity of 403.4 mg/g and 491.98 mg/g were obtained at a temperature of 303 K and pH of 6 and 4 for Co(II) and Cr(III), respectively. Additionally, adsorption kinetics, isotherm, and thermodynamic were created. Regarding the column mode operation, the influence of both flow rate and bed height was examined and the data obtained for the total removal for both heavy metals were well described by Thomas and Bed depth service time (BDST) models. The column regeneration experiment was carried out for six cycles of desorption. The graphene nanosheet/δ-MnO₂ was proven to be a highly effective adsorbent and could easily be used for separation purpose.

在这项工作中，石墨烯纳米片/δ-的MnO ₂（GN-的MnO ₂）通过微波辅助的方法合成。通过在不同条件下的分批和柱实验研究了钴（Co（II））和铬（Cr（III））离子在GN-MnO ₂吸附剂上的吸附行为。使用傅立叶变换红外光谱（FTIR），拉曼光谱，扫描电子显微镜（SEM），X射线衍射（XRD），N _2对GN-MnO ₂进行表征吸附/解吸（BET）和Boehm滴定法。在静态条件下，研究了pH值，初始金属离子浓度，温度，接触时间和吸附剂用量等参数的影响。在303 K的温度和pH分别为6和4时，Co（II）和Cr（III）的最佳批吸附容量分别为403.4 mg / g和491.98 mg / g。另外，产生了吸附动力学，等温线和热力学。关于柱模式操作，检查了流速和床层高度的影响，并通过Thomas和床层深度服务时间（BDST）模型很好地描述了两种重金属的总去除量所获得的数据。进行了六个脱附循环的柱再生实验。石墨烯纳米片/δ-的MnO ₂ 被证明是一种高效吸附剂，可轻松用于分离目的。