Adsorption kinetics of Pb and Cd by two plant growth promoting rhizobacteria |
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Authors: | S.C. Wu X.L. Peng K.C. Cheung S.L. Liu M.H. Wong |
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Affiliation: | 1. Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Hong Kong, PR China;2. Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China;3. Joint Laboratory of Soil and Environment, HKBU and ISSCAS, PR China |
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Abstract: | A bench study was carried out to characterize the kinetics of two plant growth promoting rhizobacteria (PGPR) Azotobacter chroococcum and Bacillus megaterium to adsorb heavy metals from solution. Adsorption of Pb2+ and Cd2+ by bacterial cells was processed quickly with an equilibration achieved within 5 min. The adsorptions were fitted well with Freundlich and Langmuir isotherm models. The comparison of isotherm parameters indicated that A. chroococcum had a stronger capacity to bind metal ions than B. megaterium, with an average increase of 59.8% for Pb2+ and 75.6% for Cd2+, respectively. Both bacteria had a stronger affinity to Pb2+ than Cd2+ since Pb2+ was more easily bound with the phosphoryl groups on the cell surface than Cd2+. This demonstrated that the presence of bacteria in the rhizosphere may result in the reduction of mobile ions in soil solution. |
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Keywords: | Adsorption Bacteria Heavy metals ion Medal binding capacity |
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