TY - JOUR
T1 - Palladium recovery by immobilized cells of Desulfovibrio desulfuricans using hydrogen as the electron donor in a novel electrobioreactor
AU - Yong, Ping
AU - Farr, John
AU - Harris, Ivor
AU - Macaskie, Lynne
PY - 2002/1/1
Y1 - 2002/1/1
N2 - Desulfovibrio desulfuricans reduces Pd(II) to Pd(0) at the expense of H-2. Mass transfer limits the rate under hydrogen in a static solution, while a bubble reactor was inefficient due to loss of H-2. A novel approach to the transfer of H-2 to the biomass utilized a biofilm on the surface of a Pd-Ag membrane that traps and transports atomic hydrogen (H-circle), formed at the back-side electrochemically, for delivery to the immobilized biofilm to form a biocatalytic surface for reduction of Pd(II) and deposition of Pd(0). Separation of the primary electrolysis chamber from the biocatalytic chamber permits the use of different solutions and pH in each, and use of a low voltage for H-2 generation. Pd(0) recovery was efficient and fed by H-2 on demand to give a clean, economic system with no generation of secondary wastes. The system was tested against a precious metal processing waste where the continuous removal of Pd, Pt and Rh was up to 88%, 99% and 75%, respectively, at a flow residence time of 10-20 min at an input pH of 2.5 and a total metals concentration of approx. 5 mM. Biorecovered Pd(0) was a better chemical catalyst than its chemical counterpart in a test reaction which liberated H-2 from hypophosphite.
AB - Desulfovibrio desulfuricans reduces Pd(II) to Pd(0) at the expense of H-2. Mass transfer limits the rate under hydrogen in a static solution, while a bubble reactor was inefficient due to loss of H-2. A novel approach to the transfer of H-2 to the biomass utilized a biofilm on the surface of a Pd-Ag membrane that traps and transports atomic hydrogen (H-circle), formed at the back-side electrochemically, for delivery to the immobilized biofilm to form a biocatalytic surface for reduction of Pd(II) and deposition of Pd(0). Separation of the primary electrolysis chamber from the biocatalytic chamber permits the use of different solutions and pH in each, and use of a low voltage for H-2 generation. Pd(0) recovery was efficient and fed by H-2 on demand to give a clean, economic system with no generation of secondary wastes. The system was tested against a precious metal processing waste where the continuous removal of Pd, Pt and Rh was up to 88%, 99% and 75%, respectively, at a flow residence time of 10-20 min at an input pH of 2.5 and a total metals concentration of approx. 5 mM. Biorecovered Pd(0) was a better chemical catalyst than its chemical counterpart in a test reaction which liberated H-2 from hypophosphite.
KW - biofilm
KW - palladium recovery
KW - Desulfovibrio desulfuricans
KW - electrobioreactor
UR - http://www.scopus.com/inward/record.url?scp=0036163093&partnerID=8YFLogxK
U2 - 10.1023/A:1014141610562
DO - 10.1023/A:1014141610562
M3 - Article
SN - 0141-5492
VL - 24
SP - 205
EP - 212
JO - Biotechnology Letters
JF - Biotechnology Letters
ER -