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Membrane Water Treatment Volume 9, Number 2, March 2018 , pages 95-104 DOI: https://doi.org/10.12989/mwt.2018.9.2.095 |
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Heavy metal adsorption of a novel membrane material derived from senescent leaves: Kinetics, equilibrium and thermodynamic studies |
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Yu Zhang, Qiang Tang, Su Chen, Fan Gu and Zhenze Li
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| Abstract | ||
| Copper pollution around the world has caused serious public health problems recently. The heavy metal adsorption on traditional membranes from wastewater is limited by material properties. Different adsorptive materials are embedded in the membrane matrix and act as the adsorbent for the heavy metal. The carbonized leaf powder has been proven as an effective adsorbent material in removing aqueous Cu(II) because of its relative high specific surface area and inherent beneficial groups such as amine, carboxyl and phosphate after carbonization process. Factors affecting the adsorption of Cu(II) include: adsorbent dosage, initial Cu(II) concentration, solution pH, temperature and duration. The kinetics data fit well with the pseudo-first order kinetics and the pseudo-second order kinetics model. The thermodynamic behavior reveals the endothermic and spontaneous nature of the adsorption. The adsorption isotherm curve fits Sips model well, and the adsorption capacity was determined at 61.77 mg/g. Based on D-R model, the adsorption was predominated by the form of physical adsorption under lower temperatures, while the increased temperature motivated the form of chemical adsorption such as ion-exchange reaction. According to the analysis towards the mechanism, the chemical adsorption process occurs mainly among amine, carbonate, phosphate and copper ions or other surface adsorption. This hypothesis is confirmed by FT-IR test and XRD spectra as well as the predicted parameters calculated based on D-R model. | ||
| Key Words | ||
| carbonized leaf powder; membrane; Cu(II); adsorption; benefit groups; mechanism | ||
| Address | ||
| Yu Zhang and Su Chen: School of Urban Rail Transportation, Soochow University, China Qiang Tang: 1.) School of Urban Rail Transportation, Soochow University, China 2.) Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, China 3.) Jiangsu Research Center for Geotechnical Engineering Technology, Hohai University, China Fan Gu: National Center for Asphalt Technology, Auburn University, U.S.A. Zhenze Li: Canadian Nuclear Safety Commission, Canada | ||
