title: Recycling of indium from CIGS photovoltaic cells: potential of combining acid-resistant nanofiltration with liquid-liquid extraction.
abstract: Electronic consumer products such as smartphones, TV, computers, light-emitting diodes, and photovoltaic cells crucially depend on metals and metalloids. So-called "urban mining" considers them as secondary resources since they may contain precious elements at concentrations many times higher than their primary ores. Indium is of foremost interest being widely used, expensive, scarce and prone to supply risk. This study first investigated the capability of different nanofiltration membranes of extracting indium from copper-indium-gallium- selenide photovoltaic cell (CIGS) leachates under low pH conditions and low transmembrane pressure differences (<3 bar). Retentates were then subjected to a further selective liquid-liquid extraction (LLE). Even at very acidic pH indium was retained to >98% by nanofiltration, separating it from parts of the Ag, Sb, Se, and Zn present. LLE using di-(2-ethylhexyl)phosphoric acid (D2EHPA) extracted 97% of the indium from the retentates, separating it from all other elements except for Mo, Al, and Sn. Overall, 95% (2.4 g m(-2) CIGS) of the indium could be extracted to the D2EHPA phase. Simultaneously, by nanofiltration the consumption of D2EHPA was reduced by >60% due to the metal concentration in the reduced retentate volume. These results show clearly the potential for efficient scarce metal recovery from secondary resources. Furthermore, since nanofiltration was applicable at very low pH (≥ 0.6), it may be applied in hydrometallurgy typically using acidic conditions.
authors.affiliation: Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland , Gründenstrasse 40, CH-4132 Muttenz, Switzerland.
authors.forename: Yannick-Serge
authors.initials: YS
authors.lastname: Zimmermann
authors.forename: Claudia
authors.initials: C
authors.lastname: Niewersch
authors.forename: Markus
authors.initials: M
authors.lastname: Lenz
authors.forename: Zöhre Zohra
authors.initials: ZZ
authors.lastname: Kül
authors.forename: Philippe F-X
authors.initials: PF
authors.lastname: Corvini
authors.forename: Andreas
authors.initials: A
authors.lastname: Schäffer
authors.forename: Thomas
authors.initials: T
authors.lastname: Wintgens
mesh_terms: D000143:Acids / Q000737:chemistry*; D005374:Filtration / Q000379:methods*; D005708:Gallium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007204:Indium / Q000737:chemistry*; D007221:Industry / Q000191:economics; D007477:Ions; D059625:Liquid-Liquid Extraction / Q000379:methods*; D008567:Membranes, Artificial; D058955:Metalloids / Q000032:analysis / Q000191:economics; D036103:Nanotechnology / Q000379:methods*; D010777:Photochemistry; D011312:Pressure; D059027:Recycling; D012643:Selenium / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D000143:Acids; D007477:Ions; D008567:Membranes, Artificial; D058955:Metalloids; D012997:Solvents; C517764:gallium selenide; D007204:Indium; D005708:Gallium; D012643:Selenium