Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface regio...Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface region plays a critical role in bioPd(0)synthesis process.However,the mechanisms for its role remains elusive.Results:The experimental results indicated that 1)diffusion resistance existed around the microorganism's cell in reaction vessel and 2)fluid shear stress affected the mass transfer rates differently according to its strength and thus had varying effects on the bioPd(0)synthesis.More than 97.9±1.5%Chromium(VI)(Cr(VI))(384μM)was reduced to Cr(III)within 20 min with 5%Pd/bioPd(0)as catalyst,which was generated by the K.Pneumoniae ECU-15,and the catalytic performance of Pd/bioPd(0)was stable over 6 months.The optimal condition of bioreduction of Pd(II)to Pd(0)was determined at the Kolmogorov eddy length of 7.33±0.5μm and lasted for 1 h in the extended reduction process after the usual adsorption and reduction process.Conclusions:It is concluded that a high bioPd(0)catalytic activity can be achieved by controlling the fluid shear stress intensity in an extended reduction process in the bioreactor.展开更多
基金financially supported by the open Project Funding of State Key Laboratory of Bioreactor Engineering of China and the National High Technology Research and Development Program of China(No.2007AA060904 and No.2012AA061503).
文摘Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface region plays a critical role in bioPd(0)synthesis process.However,the mechanisms for its role remains elusive.Results:The experimental results indicated that 1)diffusion resistance existed around the microorganism's cell in reaction vessel and 2)fluid shear stress affected the mass transfer rates differently according to its strength and thus had varying effects on the bioPd(0)synthesis.More than 97.9±1.5%Chromium(VI)(Cr(VI))(384μM)was reduced to Cr(III)within 20 min with 5%Pd/bioPd(0)as catalyst,which was generated by the K.Pneumoniae ECU-15,and the catalytic performance of Pd/bioPd(0)was stable over 6 months.The optimal condition of bioreduction of Pd(II)to Pd(0)was determined at the Kolmogorov eddy length of 7.33±0.5μm and lasted for 1 h in the extended reduction process after the usual adsorption and reduction process.Conclusions:It is concluded that a high bioPd(0)catalytic activity can be achieved by controlling the fluid shear stress intensity in an extended reduction process in the bioreactor.
