| Heavy metal ions pollution caused great harm to human health and ecosystems. A large number of domestic and foreign research and application have proved that traditional physical and chemical methods of remediation of heavy metal pollution usually need high cost and can lead to secondary pollution and other defects. But biological adsorption method is a approach with significant application potential. Variety of microbial cells and biomass has been proven to have good adsorption of heavy metal performance. However, in order to adsorbing and recovering metal ions in mobile phase, bioreactors or large water contamination, we need to make the microbial cells and biomass immobilized. Therefore, research and exploration is an efficient, economical and usefull biological adsorption method become a hot research areas.This study compared modified polycarbonate,polyamide, Polyethylene and polyethylene terephthalate, four kinds of organic polymeric material’s performance of immobilizing the; results show that the recombinant efficiency of modified polycarbonate immobilized Pseudomonas putida Cells is 91%, Then, the recombiant strain Pseudomonas putida and four kinds of amination modified materials were carried out for scanning electron microscopy (SEM). The results showed that the amination modified polycarbonate fixed a large amount of recombiant strains on its surface, while the other three kinds of modified materals was short.The optimum adsorption conditions were obtained by studying the effects of pH, temperature, initial concentration of metal ions and adsorption revolution on the adsorption of Copper (Ⅱ), chromium (Ⅲ), cadmium (Ⅱ). The datas indicated that the best conditions(pH, adsorption revolution and initial concentration of metal ions) for the adsorption of Copper (Ⅱ), chromium (Ⅲ) and cadmium (Ⅱ) were 6.0,210rpm,50mg/L, 6.0,180rpm,50mg/L and 6.0,180rpm,50mg/L, respectively. Through the analysis towards kinetics and isotherm equations of adsorption, the adsroption process of material to the three kinds of metal ions compled with the pseudo-second order kinetics equation. By contrast, the Langmuir adsorption isotherm can better describe the adsorption process of composite material for Copper (Ⅱ), chromium (Ⅲ) and cadmium (Ⅱ) than that of Freundlich. In the adsorption/desorption cycle test, the composite material still retained 60% of adsorption capacity after being used for six times. This finding indicated that the material can be used over and over again and keep relative high ability of adsorption in application cycles of treatment for water polluted by heavy metal ions.The composite material could absorb maximum adsorption efficiency 5.4mg/g copper ion under the cadmium ion concentration of 100mg/L, the composite material could absorb maximum adsorption efficiency 3.378mg/g cadmium ion under the cadmium ion concentration of 150mg/L, the composite material could absorb maximum adsorption efficiency up to 2.833mg/g under the chromium ion concentration of 150mg /L.In the adsorption/desorption cycle test, the composite material 6 times repeated use, can maintain the adsorption capacity of more than 90%, indicating that the composite material handling heavy metal ions in wastewater recycling applications, can be repeatedly used and to ensure its higher metal ion adsorption capacity.Infrared spectroscopy experiments showed that polycarbonate add a 2335cm-1 peak after the polycarbonate modified amino, the peak should be the amide bond C-N bond, and 1403 cm-1 is C-N stretching vibration. That the carboxyl and amino groups hexamethylenediamine amide bond forming reaction, that is, on the polycarbonate surface modification group. Biological adsorbents in the adsorption of metal ions, C-H group, a carbonyl group, N-H fundamental peaks have occurred in some mobile. Description of the recombinant amino, carboxy and metallothionein may binding heavy metal ions are involved. |
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