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| Performance of live and dead cells of Klebsiella sp. in removing Pb (Ⅱ)from aqueous solution |
| Received:January 09, 2018 |
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| KeyWord:Klebsiella sp.;live cells;dead cells;adsorption;Pb (Ⅱ) |
| Author Name | Affiliation | E-mail | | LIU Shu-li | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | | | DUAN Zheng-yang | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | | | XU Long-qian | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | | | XU Xiao-jun | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | xuxiaojun88@sina.com | | SONG Shu-min | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | | | ZHANG Meng-jiao | Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China | |
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| Abstract: |
| Live cells (LC) and dead cells (DC) of Klebsiella sp. were used as adsorbents to remove Pb (Ⅱ) from aqueous solutions. The dead cells were generated by sterilizing the cell cultures. The ability of LC and DC to remove Pb (Ⅱ) was compared and differences in adsorption capacity of above adsorbents were investigated in this work, through systematically studying factors influencing the adsorption and removal, including solution pH, adsorbent dosage, contact time, and initial Pb (Ⅱ) concentration. In addition, scanning electron microscopy (SEM), specific surface area determination, zeta potential analysis, fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were performed to further illustrate the difference in adsorption performances. The results revealed that Pb (Ⅱ) adsorption by DC and LC fits well with pseudo-second-order kinetics and the Langmuir isotherm model according to adsorption kinetic and isotherm analyses, respectively. The maximum adsorption capacity of Pb (Ⅱ) was 134.92 mg·g-1 for DC and 116.18 mg·g-1 for LC at 30℃, determined by the Langmuir isotherm model. The thermodynamic parameters, such as △G, △H, and △S, showed that the adsorption of Pb (Ⅱ) by DC was spontaneous and exothermic, whereas it was spontaneous and endothermic for LC. Our results indicated that DC had a larger specific surface area and more negative charges than LC, possibly because the DC cell wall structure was no longer intact following high temperature treatment, increasing the permeability of the cell wall, thereby exposing more amino groups to the surface. The above difference resulted in DC presenting greater adsorption capacity for Pb (Ⅱ) than LC under the described experimental conditions. |
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