Novel Zwitterionic Inorganic−Organic Hybrids: Kinetic and Equilibrium Model Studies on Pb2+ Removal from Aqueous Solution

• Published in: Journal of chemical and engineering data Vol. 56; no. 5; pp. 2119 - 2127
• Main Authors: Liu, Junsheng, Song, Long, Shao, Guoquan
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.05.2011
• Subjects: Applied sciences; Chemistry; Exact sciences and technology; General and physical chemistry; General purification processes; General, apparatus; Pollution; Surface physical chemistry; Wastewaters; Water treatment and pollution; Removal; Ring opening polymerization; Hybrid material; Adsorption isotherm; Temperature effect; Model study; Zwitterion; Operating conditions; Heavy metal; Pyromellitimide polymer; Sol gel process; Kinetics; Aqueous solution; Betaines; Lead II Compounds
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je1011949

Pb2+ removal from aqueous solution using zwitterionic hybrid polymers as adsorbents was studied. Influence factors such as solution temperature, initial pH, adsorption time, and solution concentration on Pb2+ adsorption were investigated. Adsorption kinetics data were modeled using four two-parameter kinetic equations (i.e., Lagergren first-order and second-order, Ritchie modified second-order, and intraparticle diffusion models). It was indicated that Pb2+ adsorption on these zwitterionic hybrid polymers followed the Lagergren second-order kinetic model. Meanwhile, the equilibrium adsorption data were analyzed using four two-parameter isotherm equations (i.e., Langmuir, Freundlich, Dubinin−Radushkevich, and Temkin isotherm models). The results reveal that the adsorption of Pb2+ ions followed the Langmuir isotherm model. The thermodynamic parameters ΔG, ΔH, and ΔS for Pb2+ removal from aqueous solution were also calculated. The negative values of ΔG and the positive values of ΔH are evidence that Pb2+ adsorption on these zwitterionic hybrid polymers is spontaneous and an endothermic process in nature. Moreover, the zwitterionic hybrid polymers produced reveal relatively high desorption efficiency in 1.0 mol·dm−3 aqueous HNO3 solution, indicating that they can be recycled in industrial processes. These findings suggest that the zwitterionic hybrid polymers are promising adsorbents for Pb2+ removal from contaminated water.