Abstract Detonation nanodiamonds (DNDs), for the first time, were utilized to modify chitosan/polyvinyl alcohol (CS/PVA) thin membrane adsorbents. For this purpose, different contents of DNDs, from nil to 1.5 wt%, were embedded in the polymer matrix of the membranes to obtain the optimum content. Static adsorption of Pb(II) on the prepared membrane adsorbents was studied. The fabricated membranes were characterized in terms of morphology and performance using scanning electron microscopy (SEM) micrographs and Fourier transform infrared (FTIR) spectrum analyses. Langmuir and Freundlich isotherms were used to model the equilibrium adsorption. The effects of pH, temperature, and initial metal concentration on the adsorption capacity were investigated. Results showed that adsorption of lead ion is more favorable at pH = 6. Thermodynamic parameters including ΔHo, ΔSo and ΔGo revealed endothermic, entropy-driven and spontaneous nature of the adsorption. Adsorption capacity for Pb(II) increased from 29.5 mg g−1 (for the plain membrane) to 121.3 mg g−1 by the addition of 1.5 wt% DNDs; however, the optimal content was 1 wt% DNDs considering both mechanical stability and adsorption capacity. Results revealed that the ultra-thin CS/PVA membrane adsorbents modified with DNDs are very potential candidates for heavy metal adsorption.

中文翻译：

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用爆炸纳米金刚石改性的新型壳聚糖/聚乙烯醇薄膜吸附剂：制备、表征和吸附性能

摘要 爆炸纳米金刚石（DNDs）首次被用于改性壳聚糖/聚乙烯醇（CS/PVA）薄膜吸附剂。为此，将不同含量的 DND（从 0 到 1.5 wt%）嵌入到膜的聚合物基质中以获得最佳含量。研究了 Pb(II) 在制备的膜吸附剂上的静态吸附。使用扫描电子显微镜 (SEM) 显微照片和傅里叶变换红外 (FTIR) 光谱分析对制造的膜进行形态和性能表征。Langmuir 和 Freundlich 等温线用于模拟平衡吸附。研究了 pH、温度和初始金属浓度对吸附容量的影响。结果表明，pH=6时铅离子的吸附更有利。包括 ΔHo、ΔSo 和 ΔGo 在内的热力学参数揭示了吸附的吸热、熵驱动和自发性质。添加 1.5 wt% DNDs 后，Pb(II) 的吸附能力从 29.5 mg g-1（对于普通膜）增加到 121.3 mg g-1；然而，考虑到机械稳定性和吸附能力，最佳含量为 1 wt% DND。结果表明，DNDs 改性的超薄 CS/PVA 膜吸附剂是非常有潜力的重金属吸附候选物。