Abstract Activated carbon (AC) is a widely used adsorbent with a limited selectivity for chromium species. In this study, polysulfide rubber (PSR) polymer was synthesized, characterized by FTIR, and coated on F400 granular AC to obtain AC-PSR. The material properties of this composite adsorbent were investigated using SEM, TEM, EDS, TGA, BET isotherm, and XPS. The effectiveness of AC-PSR for aqueous Cr(VI) removal was investigated, and compared against virgin AC. The results showed that despite a 23% decrease in the surface area of AC after PSR coating, AC-PSR had a higher capacity for Cr(VI) adsorption. Adsorption followed a pseudo-second-order biphasic diffusion model for both AC and AC-PSR. The reaction rate constants showed that despite faster initial kinetics between AC and Cr(VI) during the film diffusion step, AC-PSR exhibited faster kinetics during the intraparticle diffusion step. The Langmuir isotherm model was found to be the best model to describe the experimental data, which showed a higher adsorption capacity for AC-PSR (QM,AC = 3.472 mg/g vs. QM,AC-PSR = 8.929 mg/g) and a stronger binding between Cr(VI) and AC-PSR (bA,AC = 0.391 L/mg vs. bA,AC-PSR = 0.696 L/mg). Regenerated AC-PSR showed an 8% increase in Cr(VI) removal efficiency after the first cycle, and then maintained a ∼98% Cr(VI) removal for three additional successive cycles.

中文翻译：

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聚硫橡胶涂层改性活性炭除水六价铬的合成、表征及动力学研究

摘要 活性炭 (AC) 是一种广泛使用的吸附剂，但对铬种类的选择性有限。在本研究中，合成了聚硫橡胶 (PSR) 聚合物，通过 FTIR 表征，并涂覆在 F400 颗粒 AC 上获得 AC-PSR。使用 SEM、TEM、EDS、TGA、BET 等温线和 XPS 研究了这种复合吸附剂的材料特性。研究了 AC-PSR 去除水性 Cr(VI) 的有效性，并与原始 AC 进行了比较。结果表明，尽管 PSR 涂层后 AC 的表面积减少了 23%，但 AC-PSR 具有更高的 Cr(VI) 吸附能力。吸附遵循 AC 和 AC-PSR 的伪二阶双相扩散模型。反应速率常数表明，尽管在薄膜扩散步骤中 AC 和 Cr(VI) 之间的初始动力学更快，AC-PSR 在颗粒内扩散步骤中表现出更快的动力学。发现 Langmuir 等温线模型是描述实验数据的最佳模型，它显示出对 AC-PSR 的更高吸附容量（QM,AC = 3.472 mg/g vs. QM,AC-PSR = 8.929 mg/g）和Cr(VI) 和 AC-PSR 之间的结合更强（bA,AC = 0.391 L/mg vs. bA,AC-PSR = 0.696 L/mg）。再生的 AC-PSR 在第一个循环后表现出 8% 的 Cr(VI) 去除效率增加，然后在另外三个连续循环中保持 98% 的 Cr(VI) 去除率。AC-PSR = 0.696 L/mg)。再生的 AC-PSR 在第一个循环后显示出 8% 的 Cr(VI) 去除效率增加，然后在另外三个连续循环中保持约 98% 的 Cr(VI) 去除率。AC-PSR = 0.696 L/mg)。再生的 AC-PSR 在第一个循环后表现出 8% 的 Cr(VI) 去除效率增加，然后在另外三个连续循环中保持 98% 的 Cr(VI) 去除率。