Platinum group metals (PGMs), including platinum, palladium, rhodium, ruthenium, and iridium, are critical for catalytic, electronic, and clean energy applications. However, mining is highly resource- and carbon-intensive, with supply concentrated in South Africa and Russia. Secondary recovery through chemical recycling of end-of-life products can reduce global warming potential by up to 98% compared with mining, but still relies on intensive chemical use. An emerging alternative is biological recovery using the metal-reducing bacterium Shewanella oneidensis (S. oneidensis) which converts soluble PGMs into catalytically active nanoparticles, offering a potentially selective and low-energy route for recovery from complex effluents. This study presents a cradle-to-gate life cycle assessment using ReCiPe 2016 to compare three PGM production routes: (1) primary production via conventional mining, (2) secondary recovery through chemical refining of industrial waste streams, and (3) an innovative biological pathway using S.oneidensis for PGM biorecovery and nanoparticle biosynthesis from low-concentration industrial waste effluent. At current laboratory-derived parameters, industrial-scale biorecovery performs worse than mining in 17 of 18 impact categories, exceeding chemical recycling in all cases, though it avoids ore depletion and thus reduces mineral resource scarcity. Sensitivity analysis shows that increasing initial biomass concentration reduces impacts by at least 70% at a five-fold increase. The findings underline that the unfavourable results stem from the very early stage of development and small-scale experimental data. With optimisation of media composition, improved recovery yields, and effluent recycling, biorecovery could progress into a viable complementary route within future circular economy strategies.
Li et al. (Thu,) studied this question.