Abstract
ABSTRACTOrganophosphorus pollution and heavy metal pollution are prominent in China and have caused increasingly severe environmental pollution. This research used Pseudomonas putida to degrade dimethoate so as to induce the formation of calcium carbonate (CaCO3) and calcium phosphate (Ca3(PO4)2) in beef extract peptone medium. In addition, the mineral immobilizing function of the generated Ca3(PO4)2 and CaCO3 for Cd2+ was studied by adding different concentrations of Cd2+ to the culture solution. Meanwhile, transmission electron microscopy (TEM), scanning electronic microscopy (SEM), X-ray diffraction, gas chromatography and atomic absorption spectrophotometry were used to investigate the biodegradation of dimethoate, the concentration variation of Ca2+ and Cd2+, the mineral and chemical compositions of the precipitates. The results showed that the growth of P. Putida could increase the pH value of the culture solution and effectively degrade the organophosphorus pesticide dimethoate. Besides, the concentration of Ca2+ in the culture solution decreased significantly in the first four days and then tended to be stable. Moreover, the TEM and SEM results presented that there were large amounts of biogenic sedimentary CaCO3 and a little Ca3(PO4)2 in the precipitates. Furthermore, in the employed culture system, the removal rates of Cd2+, when added at two different concentrations (6 ppm and 15 ppm), reached 100%. Therefore, this study provided a new idea for treating wastewater polluted with organophosphorus pesticide and heavy metals by using microorganisms.
Published Version
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