In this work, an effective nanocomposite-based adsorbent directed to adsorb cobalt (Co²⁺) ion was successfully synthesized from graphene oxide (GO), polyvinyl alcohol (PVA), and magnetite (Fe₃O₄) nanoparticles via a coprecipitation technique. The synthesized GO/PVA/Fe₃O₄ nanocomposite was applied for Co²⁺ ion removal with the optimized working conditions including 100 min of contact time, 0.01 g of adsorbent dosage, pH of 5.2, and 50°C of temperature. The investigation of adsorption kinetics showed that the adsorption of Co²⁺ ion onto the GO/PVA/Fe₃O₄ nanocomposite followed the pseudo-second-order kinetic model with the rate constant k₂ being 0.0026 (g mg⁻¹·min⁻¹). The Langmuir model is suitable to describe the adsorption of Co²⁺ ion onto the GO/PVA/Fe₃O₄ nanocomposite with the maximum sorption capacity (q_max) reaching 373.37 mg·g⁻¹. The obtained results also indicated that the GO/PVA/Fe₃O₄ nanocomposite can adsorb/regenerate for at least 5 cycles with a little reduction in removal efficiency. Therefore, we believe that the GO/PVA/Fe₃O₄ nanocomposite could be used as a potential adsorbent for heavy metal treatment in terms of high adsorption capacity, fast adsorption rate, and recyclability.

中文翻译：

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氧化石墨烯/聚乙烯醇/ Fe3O4纳米复合材料：高效去除Co（II）离子的吸附剂

在这项工作中，通过共沉淀技术成功地从氧化石墨烯（GO），聚乙烯醇（PVA）和磁铁矿（Fe ₃ O ₄）纳米颗粒成功地合成了一种有效的基于纳米复合材料的吸附钴（Co ²⁺）离子的吸附剂。将合成的GO / PVA / Fe ₃ O ₄纳米复合材料用于优化的工作条件，包括100分钟的接触时间，0.01 g的吸附剂用量，5.2的pH值和50°C的温度，以去除Co ²⁺离子。吸附动力学研究表明，Co ²⁺离子在GO / PVA / Fe ₃ O ₄上的吸附纳米复合材料遵循伪二级动力学模型，速率常数k ₂为0.0026（g mg ^-1 ·min ^-1）。Langmuir模型适用于描述Co ²⁺离子在GO / PVA / Fe ₃ O ₄纳米复合材料上的吸附，最大吸附容量（q _max）达到373.37 mg·g ^-1。所得结果还表明，GO / PVA / Fe ₃ O ₄纳米复合材料可吸附/再生至少5个循环，去除效率略有降低。因此，我们认为GO / PVA / Fe ₃ O ₄ 从高吸附能力，快速吸附速率和可回收性方面考虑，纳米复合材料可以用作重金属处理的潜在吸附剂。