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Review Papers | Chemical Sciences | India | Volume 12 Issue 5, May 2023
Silver Recovery from used X-Rays and Other Silver-Rich Diagnostic Radiography Films: A Review
Abstract: Silver is a precious metal and is used in electronics, industrial catalysis and biomedical sector because of its physiochemical properties. The present work focuses on techniques that are used in recovering silver from waste X-ray films, radiographic films and photographic films. Due to decrease in natural resources, there is increase in prices of pure silver. Direct decomposition of these films causes several environmental concerns therefore it becomes important to recover and regenerate silver. Toxiferous nature of silver depends on its redox potential, salinity and chemical form. The soluble salts of silver cause a serious effect to humans as well as ecosystem. Hydrometallurgical processes provide silver with highest purity. Approaches that must be adopted towards recovering silver should be economical and less harmful to the environment.SEM and XRD techniques confirm that silver recovered in metallic form. Hydrometallurgical techniques are the best route to recover silver that needs strong acid solution. Alternative method for recovering solution is through leaching solution. Silver recovered through UV-visible light driven process involves photolytic deposition of pure metallic silver over ZnO photolytic. This is the novel green process for silver recovery. ZnO photolytic is dissolved through acidic solutions and pure silver is recovered with very low cost and no harm to the environment. It needs mild operating conditions and is economically viable. Thiosulphate solutions are now widely used to recover silver from photovoltaic cells and electric vehicles through precipitation using TriMercapto-s-Triazine (TMT).TMT is a nontoxic organo-sulphide reagent. Researchers have shown that concentration of TMT has highest impact on silver precipitation.
Keywords: Silver recovery, Semipermeable membrane, dimethyl formamide, hydroquinone, Thiosulphate solutions, Trimercapto-S-triazine, Hydrogen Peroxide
Edition: Volume 12 Issue 5, May 2023,
Pages: 526 - 530