College of Resources and Environment, South-Central Minzu University, Wuhan, 430074, China.
Environ Sci Pollut Res Int. 2024 Mar;31(14):21279-21290. doi: 10.1007/s11356-024-32526-4. Epub 2024 Feb 22.
A novel adsorbent, deposited PPy on the DMI (PPy/DMI) composite, was successfully synthesized for Cr(VI) removal from aqueous solution. PPy/DMI composite was characterized by BET, SEM, TEM, XRD, and XPS. The SEM and TEM analyses revealed that DMI can greatly reduce the aggregation of PPy and significantly enhance its adsorption performance. The Cr(VI) removal was highly pH dependent. The high selectivity of PPy/DMI composite for Cr(VI) removal was found even in the presence of co-existing ions. The adsorption kinetic process followed the pseudo-second-order equation, demonstrating that the Cr(VI) adsorption behavior onto PPy/DMI is chemisorption. Furthermore, the intra-particle diffusion model implied that the adsorption was controlled by both liquid membrane diffusion and internal diffusion. The adsorption isotherm data fitted well with the Langmuir model with the maximum adsorption capacity (406.50 mg/g at 323 K) which was considerably higher than that of other PPy-based adsorbents. The Cr(VI) adsorption onto PPy/DMI composite was endothermic. The main mechanisms of Cr(VI) removal are involved in adsorption through electrostatic attractions, ion exchange, and in situ reduction. The results suggested that PPy/DMI composite could be a promising candidate for efficient Cr(VI) removal from aqueous solution.
一种新型吸附剂，即在 DMI 上沉积 PPy（PPy/DMI）复合材料，成功合成用于从水溶液中去除 Cr(VI)。通过 BET、SEM、TEM、XRD 和 XPS 对 PPy/DMI 复合材料进行了表征。SEM 和 TEM 分析表明，DMI 可以大大减少 PPy 的聚集，并显著提高其吸附性能。Cr(VI) 的去除高度依赖于 pH 值。即使存在共存离子，PPy/DMI 复合材料对 Cr(VI)去除也具有很高的选择性。吸附动力学过程符合准二级方程，表明 Cr(VI)在 PPy/DMI 上的吸附行为是化学吸附。此外，内扩散模型表明吸附受液膜扩散和内部扩散的共同控制。吸附等温线数据与 Langmuir 模型拟合良好，最大吸附容量（323 K 时为 406.50 mg/g）明显高于其他基于 PPy 的吸附剂。Cr(VI)在 PPy/DMI 复合材料上的吸附是吸热的。Cr(VI)去除的主要机制涉及静电吸引、离子交换和原位还原。结果表明，PPy/DMI 复合材料可能是一种从水溶液中高效去除 Cr(VI)的有前途的候选材料。
