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Urban Mining of Precious Metals with Thiosulfate and Thiourea as Lixiviant
Published in Sadia Ilyas, Hyunjung Kim, Rajiv Ranjan Srivastava, Sustainable Urban Mining of Precious Metals, 2021
Sadia Ilyas, Huma Munir, Hyunjung Kim, Rajiv Ranjan Srivastava
Thiosulfate, with the chemical symbol, S2O32− and tetrahedral molecular shape, is an oxyanion of sulphur and can be derived by replacing one oxygen atom with a sulphur atom in a sulphate anion (Schmidt, 1962) as indicated in Figure 5.1.
Biotransformation of Toxic Thiosulfate into Merchandisable Elemental Sulfur by Indigenous SOB Consortium
Published in Ederio Dino Bidoia, Renato Nallin Montagnolli, Biodegradation, Pollutants and Bioremediation Principles, 2021
Panteha Pirieh, Fereshteh Naeimpoor
Reduced sulfur compounds (RSC), such as thiosulfate in wastewater or gaseous streams, can have adverse effects on human health and the environment. Thiosulfate (S203−), an oxyanion of sulfur is discharged as an effluent by many chemical process industries. In most cases, thiosulfate comes to industrial wastewater as a result of sulfide oxidation (Baquerizo et al. 2013, Xu et al. 2017). The sulfur present in the natural gas from offshore gas production installations is oxidized, and the generated wastewater contains a predominant amount of thiosulfate at concentrations as high as 3000 mg/L. Thio sulfate is also used as a photographic fixer in photographic processing laboratories, and is consumed for extraction of gold at 0 to 220 g-thiosulfate L−1 (Abdel-Monaem Zytoon et al. 2014, Ahmad et al. 2014, Xu et al. 2017).
Environmental Biomonitoring, Sampling, and Testing
Published in Frank R. Spellman, The Science of Water, 2020
Chlorine can also affect BOD measurement by inhibiting or killing the microorganisms that decompose the organic and inorganic matter in a sample. If sampling in chlorinated waters (such as those below the effluent from a sewage treatment plant), neutralizing the chlorine with sodium thiosulfate is necessary (see Standard Methods).
Valorization of resources from end-of-life lithium-ion batteries: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Francine Duarte Castro, Mentore Vaccari, Laura Cutaia
Li leaching is usually faster than Co leaching due to the weaker bonds and smaller atomic radius of Li. Cobalt ions in cathodes are more stable than lithium ions (Takacova et al., 2016). In the leaching process, Co+3 is converted to Co+2, which has a higher solubility in aqueous media (Zhang, Li, et al., 2018). H2O2, represented in Eq. (16), as well as sodium thiosulfate (Na2S2O3), sodium bisulfite (NaHSO3) (Liu, Lin, et al., 2019) and ascorbic acid may be used as reducing agents (Aaltonen et al., 2017). When HCl is used, no other reductants need to be added to the media due to its high reducibility, leading to a high leaching efficiency of Co (Liu, Lin, et al., 2019). Takacova et al. (2016) did not use reducing agents and proved that at 20 °C, L:S ratio of 50, and an acid concentration of 2 M, H2SO4 and HCl present similar Co leaching efficiencies of approximately 25% after 60 min. When the temperature was increased to 80 °C, however, HCl became much more effective in Co extraction than H2SO4. While 60% of Co extraction was achieved by H2SO4 after 60 min at 80 °C, HCl was capable of leaching 100% of the Co from LiCoO2 cathodes under the same operational conditions. Regarding Li extraction, Takacova et al. (2016) showed that there is no significant difference between the leaching efficiencies achieved using HCl and H2SO4. In both cases, almost 100% of Li was extracted after 20 min at 80 °C for acid concentrations of 1 M. The authors reported that 2 M HCl at 60–80 °C is the optimal condition for leaching. The process, however, results in the formation of Cl2, as shown by Eq. (14).