1. Preparation of Negatively Charged Hybrid Adsorbents and Their Applications for Pb2䗩ꢽ.
- Author
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Liu, Junsheng, Si, Jingyu, Zhang, Quan, Zheng, Jiuhan, Han, Chengliang, and Shao, Guoquan
- Subjects
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ADSORPTION (Chemistry) , *LEAD compounds , *FOURIER transform infrared spectroscopy , *THERMODYNAMICS , *CHEMICAL kinetics , *CHEMICAL processes , *SCANNING electron microscopy , *WATER pollution , *SEPARATION (Technology) , *THERMOGRAVIMETRY - Abstract
A novel approach to the negatively charged hybrid adsorbents was proposed. These hybrid adsorbents were prepared via the ring opening of pyromellitic acid dianhydride (PMDA) and N-[3-(trimethoxysilyl)propyl]ethylenediamine and a subsequent solâgel process. Fourier transform infrared spectra confirmed the step products. Their adsorption kinetics, isotherm, and thermodynamic parameters ÎG, ÎH, and ÎSfor Pb2귩ꢽ from aqueous solution were examined. Differential scanning calorimetry and thermogravimetric analysis thermal amylases showed that these samples had high thermal stability and the crystallization temperature increased with an increase in the PMDA content because of cross-linking between organic and inorganic moieties and the further formation of a hybrid matrix. Adsorption experiments indicated that Pb2槛⢮魢 on these hybrid adsorbents followed the Lagergren second-order kinetic and Langmuir isotherm models. The negative values of ÎGand the positive values of ÎHshowed that Pb2槛⢮魢 on these hybrid adsorbents was spontaneous and an endothermic process in nature. Scanning electron microscopy and energy-dispersive spectrometry images further confirmed Pb2誉 on the surfaces of samples AâD. Moreover, a desorption experiment indicated that they can be regenerated. These findings suggest that the prepared hybrid adsorbents are promising in the separation and recovery of Pb2誉 from contaminated water. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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