Xu Jiali, Chen Yi, Zhou Junpeng
School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China.
School of Geological Survey, China University of Geosciences, Wuhan, 430074, China.
Environ Monit Assess. 2025 Sep 9;197(10):1096. doi: 10.1007/s10661-025-14547-9.
Cadmium (Cd) contamination in water poses a critical global challenge. A novel nanocomposite, montmorillonite (Mt)-supported nanoscale zero-valent iron (Mt-nZVI), synthesized by liquid phase reduction, offers a promising method for effectively removing Cd. The material underwent characterization through various techniques, including X-ray diffraction (XRD) and Scanning Electron Microscope(SEM). The effects of initial pH, Cd concentration, solid-to-liquid ratio, temperature, solid dosage, and reaction time on the performance of Mt-nZVI in removing Cd were investigated. Remarkably, a notable 93.12% removal rate was achieved for Cd concentration of 10 mg·L under a 2-h reaction time, pH 7, and 0.5 g·L Mt-nZVI dosage. The adsorption process exhibited an excellent fit with both the pseudo-second-order kinetic model and the intra-particle diffusion model, suggesting that the adsorption mechanisms involve both the chemical adsorption and intra-particle diffusion. Dynamic adsorption experiments were conducted using Mt-nZVI. Under optimized conditions (adsorbent-to-quartz sand mass ratio of 1:250 and flow rate of 2 mL·min), Mt-nZVI achieved optimal Cd removal efficiency, demonstrating its potential for continuous wastewater treatment applications. The removal mechanism of Cd, as inferred from a series of characterization analyses, likely involves processes including rapid adsorption facilitated by electrostatic interactions, hydrolysis of Fe leading to the formation of precipitates with Cd, and surface corrosion of nZVI resulting in the formation of surface complexes with Cd. Overall, these findings highlight the excellent potential of Mt-nZVI for treating Cd-containing wastewater.
水中镉（Cd）污染是一项严峻的全球性挑战。一种通过液相还原法合成的新型纳米复合材料——蒙脱石（Mt）负载纳米零价铁（Mt-nZVI），为有效去除镉提供了一种很有前景的方法。该材料通过多种技术进行了表征，包括X射线衍射（XRD）和扫描电子显微镜（SEM）。研究了初始pH值、镉浓度、固液比、温度、固体投加量和反应时间对Mt-nZVI去除镉性能的影响。值得注意的是，在反应时间2小时、pH值为7、Mt-nZVI投加量为0.5 g·L的条件下，对于10 mg·L的镉浓度，去除率达到了显著的93.12%。吸附过程与准二级动力学模型和颗粒内扩散模型都具有良好的拟合度，这表明吸附机制涉及化学吸附和颗粒内扩散。使用Mt-nZVI进行了动态吸附实验。在优化条件下（吸附剂与石英砂质量比为1:250，流速为2 mL·min），Mt-nZVI实现了最佳的镉去除效率，证明了其在连续废水处理应用中的潜力。通过一系列表征分析推断，镉的去除机制可能涉及静电相互作用促进的快速吸附、铁水解导致与镉形成沉淀以及nZVI表面腐蚀导致与镉形成表面络合物等过程。总体而言，这些发现突出了Mt-nZVI在处理含镉废水方面的优异潜力。
