Adsorption of heavy metal ions using hierarchical CaCO₃-maltose meso/macroporous hybrid materials: Adsorption isotherms and kinetic studies

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• 作者：Xiaoming Ma ; ^{sunshinyma@hotmail.com} ; Liping Li ; Lin Yang ; Caiyun Su ; Kui Wang ; Shibao Yuan ; Jianguo Zhou
• 关键词：Hierarchical meso/macroporous structure ; Hybrid materials ; Heavy metal ions ; Calcium carbonate&ndash ; maltose ; Adsorption isotherm ; Kinetics
• 刊名：Journal of Hazardous Materials
• 出版年：2012
• 期刊代码：50_03043894
• 类别：ce
• 出版时间：30 March, 2012
• 卷：209-210
• 期：Complete
• 页码：467-477
• 文件大小：1608 K

摘要

Highly ordered hierarchical calcium carbonate is an important phase and has technological interest in the development of functional materials. The work describes hierarchical CaCO₃-maltose meso/macroporous hybrid materials were synthesized using a simple gas-diffusion method. The uniform hexagonal-shaped CaCO₃-maltose hybrid materials are formed by the hierarchical assembly of nanoparticles. The pore structure analysis indicates that the sample possesses the macroporous structure of mesoporous framework. The distinguishing features of the hierarchical CaCO₃-maltose materials in water treatment involve not only high removal capacities, but also decontamination of trace metal ions. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The maximum removal capacity of the CaCO₃-maltose hybrid materials for Pb²⁺, Cd²⁺, Cu²⁺, Co²⁺, Mn²⁺ and Ni²⁺ ions was 3242.48, 487.80, 628.93, 393.70, 558.66 and 769.23 mg/g, respectively. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that pseudo-second-order kinetic equation and intra-particle diffusion model can better describe the adsorption kinetics. The adsorption and precipitation transformation mechanism can be considered due to hierarchical meso/macroporous structure, rich organic ligands of the CaCO₃-maltose hybrid materials and the larger solubility product of CaCO₃.