Reduction of Cr(VI) by “palladized” biomass of Desulfovibrio desulfuricans ATCC 29577

Abstract

A novel catalytic activity of palladium [Pd(0)]-coated cells of Desulfovibrio desulfuricans ATCC 29577 ["bio-Pd(0)"] is demonstrated. Reduction of 700 microM Cr(VI) occurred within 24 h using formate (25 mM) or hydrogen (1 atm) as the electron donor, under conditions whereby cells lacking bound Pd(0), or palladium metal manufactured via chemical reduction of soluble Pd(II), did not reduce Cr(VI). The biomass-bound Pd(0) also functioned in the continuous removal of 400 microM Cr(VI) from a 1 mM solution under H(2) (flow residence time approximately 5 h), where chemically prepared Pd(0) was ineffective. This demonstrates a new type of active bioinorganic catalysis, whereby the presence of biomass bound to Pd(0) confers a novel catalytic capability not seen with Pd base metal or biomass alone.

Concomitant Microbial Generation of Palladium Nanoparticles and Hydrogen To Immobilize Chromate

“…Its reduced form, Cr(III), is not known to be carcinogenic (14) and can readily precipitate as Cr(OH) 3 under neutral to slightly basic pH. Therefore, the reduction of Cr(VI) to Cr(III) is a key step in the removal of Cr(VI) from aqueous solution (15).…”

Biorecycling of Precious Metals and Rare Earth Elements

“…Yong et al (2002bYong et al ( , 2007Yong et al ( , 2010, Mabbett et al ( , 2004Mabbett et al ( , 2006, , , Humphries et et al (2006), Deplanche et al ( , 2008Deplanche et al ( , 2009), Harrad et al (2007), Redwood et al (2008). Bennett et al (2010), Harrad et al (2007) Cr ( Biosorption of precious metals onto biomass has been considered as an attractive alternative to traditional recovery techniques.…”

Using non‐invasive magnetic resonance imaging (MRI) to assess the reduction of Cr(VI) using a biofilm–palladium catalyst

“…The two most common Cr oxidation states are Cr(III), which is relatively benign, and the more-oxidized form Cr(VI), which is toxic and carcinogenic. After bioremediation of Cr(VI) to produce Cr(III) it may be necessary to isolate the Cr(III); this may be achieved by precipitation of Cr(III) as Cr(OH) 3 (Mabbett et al 2004) followed by filtration or sedimentation.…”

“…A number of methodologies have been applied to the reduction of Cr(VI) to Cr(III), including electroreduction (Diaz and Schermer, 1985), reduction by bacterial suspensions (Mabbett et al, 2004), and catalyzed or uncatalyzed redox reactions. Electrochemical reduction may not be appropriate for mixed waste streams, may have high energy requirements, and can be difficult to scale up (Pletcher and Walsh, 1990).…”