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| Adsorption of heavy metal ions by loofah sponge-immobilized biogenic manganese oxides |
| Received:September 07, 2020 |
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| KeyWord:loofah sponge;heavy metals;adsorption;Bacillus;biogenic manganese oxides |
| Author Name | Affiliation | | MENG You-ting | Beijing Radiation Center, Beijing Academy of Science and Technology, Beijing 100875, China
Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China |
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| Abstract: |
| The biosorption capacities of loofah sponge-immobilized biogenic manganese oxides(LIBMOs) for heavy metal ions were investigated. The manganese-oxidizing bacterium Bacillus cereus CP133 was immobilized onto NaOH-treated loofah sponge to produce biogenic manganese oxides(BMOs). Fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM) analyses showed that the hydrophilicity and surface properties of the loofah sponge were improved by NaOH pretreatment. After 14 d of culture, the proportion of biogenic manganese oxides(BMOs) immobilized by the NaOH-treated loofah sponge(79.66%) was higher than that of untreated natural loofah sponge(49.39%). The Langmuir and Freundlich isotherm models were used to simulate the adsorption behaviors. On the basis of the experimental data, the adsorption behaviors of Cd2+ and Pb2+ well fitted both isotherms(R2 > 0.98), while those of Cu2+ and Zn2+ better fitted the Langmuir isotherm(R2 > 0.98) than the Freundlich isotherm. The adsorption capacities of the LIBMOs(2.0 g·L-1, pH of 6.0, and 25℃) for Pb2+, Cd2+, Cu2+, and Zn2+ were 0.81, 0.68, 0.51, and 0.41 mmol·g-1, respectively. The pseudo-first-order and pseudo-second-order models were used to simulate the adsorption kinetics. The adsorption kinetics of Pb2+, Cd2+, Cu2+, and Zn2+ by the LIBMOs could be better fitted by the pseudo-first-order model than the pseudo-second-order model, although the adsorption kinetics of Pb2+, Cd2+, and Zn2+ could be well fitted by both models(R2 > 0.95). These findings suggest that LIBMOs have a considerable potential for the removal of heavy metal ions from aqueous solutions. |
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