Uporaba ligandov na osnovi tiosečnine pri raztapljanju zlata v organskih topilih

Cizerl, Ana (author), Kljun, Jakob (mentor)

Razvila sem enostaven, cenovno ugoden in okolju prijazen postopek recikliranja zlata iz odpadnih elektronskih naprav, ki temelji na načelih katalize. Kot ligand za raztapljanje zlata sem preizkusila različne komercialno dostopne in, v sklopu tega dela, sintetizirane ligande z žveplovimi funkcionalnimi skupinami na osnovi tiosečnine ter spojine na osnovi selena, ki bi delovale kot katalizator. Kot ligand je bil najprimernejši 2-merkaptobenzimidazol, ki se je v te namene že uporabljal, kot katalizator pa organski diselenidi. Kot topilo sem uporabila etanol, kot »zelen« oksidant pa vodikov peroksid. Po raztapljanju, sem izvedla redukcijo zlata do elementarnega stanja z natrijevim tiosulfatom, ter reciklirala del liganda, 2-merkaptobenzimidazola. Postopek sem izvedla na realnih vzorcih, t.i. »zlatih prstih« na tiskanih vezjih. Raztopine, oborine in izolirane produkte celotnega procesa sem analizirala z različnimi metodami karakterizacije (NMR, HRMS, CHN elementna analiza, IR, AES, SEM-EDS).

• Language: Slovenian
• Keywords: zlato, recikliranje, kataliza, diselenid, raztapljanje
• Work type: Master's thesis/paper
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2026
• PID: 20.500.12556/RUL-188864
• Publication date in RUL: 29.09.2026

Secondary language

• Language: English
• Title: Use of thiourea-based ligands in the dissolution of gold in organic solvents

Abstract

I developed a simple, cost-effective, and environmentally friendly procedure for recycling gold from waste electrical and electronic equipment, based on the principles of catalysis. As a ligand for dissolving gold, I evaluated various commercially available ligands and, as part of this work, synthesized ligands with sulfur functional groups based on thiourea, as well as selenium-based compounds that could act as catalysts. The most suitable ligand was 2-mercaptobenzimidazole, which has been previously used for this purpose, while diselenides served as the catalyst. I used ethanol as the solvent and hydrogen peroxide as a green oxidant. After dissolution, I conducted the reduction of gold to its elemental state using sodium thiosulfate and recycled part of the ligand, 2-mercaptobenzimidazole. I performed the process on real samples, namely gold fingers from printed circuit boards. The solutions, precipitates, and isolated products of the entire process were analyzed using various characterization methods (NMR, HRMS, CHN elemental analysis, IR, AES, SEM-EDS).

• Keywords: gold, recycling, catalysis, diselenide, dissolution