This study explored the fabrication of Polypyrrole (PPy) and Granular Activated Carbon (GAC) composites (PPy-GAC) for effective removal of toxic hexavalent chromium (Cr(VI)) from aqueous solutions. Two synthesis methods are employed: (1) electrostatic deposition of PPy onto pre-charged GAC paper and (2) in-situ chemical polymerization of pyrrole monomer with GAC particles. Batch adsorption experiments investigated the impact of various operational parameters on Cr(VI) removal. Compared to pristine GAC (54.64 mg g⁻¹), the PPy-GAC composite exhibited a remarkable 3-fold increase in equilibrium adsorption capacity, reaching 175.44 mg g⁻¹. Pseudo-second-order kinetic model (R² > 0.999) accurately described the adsorption kinetics, while the Langmuir isotherm model (R² > 0.99) provided a good fit for the equilibrium data. Maximum adsorption capacity (q_max) increased with temperature, reaching 204.08, 243.90, and 270.27 mg g⁻¹ at 298, 308, and 318 K, respectively. Furthermore, a fixed-bed column experiment examined the composite's effectiveness in continuous Cr(VI) removal, demonstrating its suitability for practical applications. Notably, the PPy-GAC composite successfully removed Cr(VI) from a real wastewater sample containing 68 µg L⁻¹ Cr(VI) obtained from a ferrochrome industry, highlighting its potential for real-world remediation.

中文翻译：

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聚吡咯改性颗粒活性炭纳米复合材料处理高毒六价铬废水

本研究探索了聚吡咯 (PPy) 和颗粒活性炭 (GAC) 复合材料 (PPy-GAC) 的制备，以有效去除水溶液中的有毒六价铬 (Cr(VI))。采用两种合成方法：(1) 将 PPy 静电沉积到预充电的 GAC 纸上；(2) 吡咯单体与 GAC 颗粒进行原位化学聚合。批量吸附实验研究了各种操作参数对 Cr(VI) 去除的影响。与原始GAC（54.64 mg g ^-1）相比，PPy-GAC复合材料的平衡吸附容量显着增加了3倍，达到175.44 mg g ^-1。伪二级动力学模型（R ²  > 0.999）准确地描述了吸附动力学，而Langmuir等温线模型（R ²  > 0.99）提供了对平衡数据的良好拟合。最大吸附容量（q _max）随温度增加，在298、308和318 K分别达到204.08、243.90和270.27 mg g ^-1。此外，固定床柱实验检验了复合材料连续去除 Cr(VI) 的有效性，证明了其实际应用的适用性。值得注意的是，PPy-GAC 复合材料成功地从铬铁工业中获得的含有 68 µg L ^{-1 Cr(VI) 的真实废水样品中去除了 Cr(VI)，凸显了其在现实世界修复的潜力。}