Abstract:

CoW-LDH/ATP composites with notable micro- and nanocluster sheet structures were created by employing a one-step hydrothermal process to fix the sheet CoW-LDH on the attapulgite (ATP) rod-shape structure. The microscopic morphology and the physical phases composition were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). A systematic study was conducted to explore the adsorption properties and the mechanism of Pb²⁺ adsorption in lead-containing wastewater under laboratory conditions. The experimental results of Pb²⁺ adsorption treatment in wastewater showed that at the initial Pb²⁺ concentration of 5.0mg/L and solution pH of 6, the Pb²⁺ removal efficiency reached approximately 99% after 20min adsorption. The Pb²⁺ adsorption selectivity of CoW-LDH/ATP composites was significant, with a partition coefficient K_d value of 938.51L/g, and nearly no interference from coexisting anions. CoW-LDH/ATP composite had a saturation adsorption capacity for Pb²⁺ of 872.07mg/g, which was significantly greater than the concave clay-based materials that had been described in the literature. Furthermore, following eight cycles of adsorption-desorption, the Pb²⁺ removal efficiency held steady at over 94%, suggesting the CoW-LDH/ATP composites had strong cyclic stability. The study on the adsorption mechanism of Pb²⁺ showed that the removal of Pb²⁺ by CoW-LDH/ATP composites was predominantly through the metal-oxygen bonding complexation and ligand retention between oxygen-containing groups and Pb²⁺. The prepared CoW-LDH/ATP composites had the advantages of quick adsorption rate, high adsorption capacity and strong selectivity. The results of this work might offer a theoretical foundation and technical assistance for the extensive treatment of Pb²⁺ contamination wastewater.

Key words: cobalt-tungsten hydrotalcite, attapulgite, Pb²⁺, adsorbents, adsorption mechanism

摘要：

采用一步水热法将片状CoW-LDH锚定在凹凸棒石（ATP）表面，制备了具有微纳米花簇片状结构的CoW-LDH/ATP复合材料，采用扫描电子显微镜（SEM）、X射线衍射（XRD）和X射线光电子能谱（XPS）等表征其微观形貌与物相组成，并对实验室条件下模拟含铅废水中Pb²⁺的吸附性能与机理进行了系统研究。废水中Pb²⁺吸附处理实验结果表明，Pb²⁺初始浓度为5.0mg/L、pH=6条件下，经20min吸附处理，Pb²⁺去除效率达约99%；CoW-LDH/ATP复合材料对Pb²⁺表现出显著的吸附选择性，分配系数K_d为938.51L/g，且水体共存阴离子对Pb²⁺吸附干扰小。CoW-LDH/ATP复合材料Pb²⁺饱和吸附容量为872.07mg/g，显著高于文献报道的凹凸棒石基材料。除此之外，经8次吸附-解吸后，Pb²⁺去除效率仍保持在94%以上，表明CoW-LDH/ATP复合材料具有较好的循环稳定性。Pb²⁺吸附机理研究表明，CoW-LDH/ATP复合材料对Pb²⁺的去除主要通过含氧基团与Pb²⁺之间的金属-氧键络合作用和配位截留作用。本研究制备的CoW-LDH/ATP复合材料，具有吸附速率快、选择性好、吸附容量高的优势，研究结果可为废水Pb²⁺污染规模化治理提供理论依据和技术支撑。

关键词: 钴钨水滑石, 凹凸棒石, 铅离子, 吸附剂, 吸附机理