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Reagents for Water Treatment
Published in Willy J. Masschelein, Unit Processes in Drinking Water Treatment, 2020
Sodium thiosulfate is used to eliminate residual oxidants, particularly residual chlorine. Its use is frequent in laboratory investigations up to pilot scale. The product is normally not applied full-scale on drinking water that is distributed.
Carbon, Nitrogen, and Sulfur Chemistry
Published in Jerome Greyson, Carbon, Nitrogen, and Sulfur Pollutants and Their Determination in Air and Water, 2020
By boiling sodium sulfite with sulfur, one obtains sodium thiosulfate Na2SO3+S=Na2S2O3
Environmental Sampling
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
Organic species can also undergo changes due to chemical reactions. Photooxidation of polynuclear aromatic hydrocarbons, for example, is prevented by storing the sample in amber glass bottles. Organics can also react with free chlorine to form chlorinated organics. This type of problem is common for samples collected in treatment plants after the water has been chlorinated. Sodium thiosulfate, added to the sample, will remove chlorine.
Investigation of photo-catalytic removal of arsenic from aqueous solutions using UV/H2O2 in the presence of ZnO nanoparticles
Published in Chemical Engineering Communications, 2020
Mohamadreza Massoudinejad, Hassan Keramati, Mansour Ghaderpoori
A view of the used pilot is shown in Figure 1. As shown in Figure 1, the reactor was a double-glazed glass cylinder equipped with a magnetic stirrer with a quartz-coated UV lamp (11 W, Philips TUVG8T5). The lamp emits ultraviolet radiation (UV) at 254 nm and for the maximum use of UV rays. The intensity of the output light was equivalent to 600 mJ cm−2. The outer surface of the cylinder was covered with aluminum foil. The pilot contains a water tank at ambient temperature which does not allow the sample temperature to change due to the heat produced by the lamp. The tank has a tap connection at the bottom part and an outlet at the top where the water flows continuously in the tank. This study was performed in batch conditions. The studied variables including hydrogen peroxide (5, 10, and 15 mg L−1), initial arsenic concentration (1, 5, and 10 mg/L), ZnO nanoparticles dosage (0.25, 0.5, 1, and 1.5 g L−1), contact time (30, 60, and 90 min), and pH (5, 7, and 9) were considered. The samples were added to the solution before turning on UV light. The pH was adjusted immediately before turning on UV light using H2SO4 and NaOH (0.1 N). It should be noted that the UV lamp was heated at the start of operation outside the reactor for at least 15 min to provide a relatively stable outlet. At the end of the reaction before the measurement of the residual arsenic, the residual H2O2 (or quenching H2O2 residuals) in the solution should be removed. To neutralize the residual H2O2, sodium thiosulfate (Na2S2O3) as a scavenger was used (Ghaderpoori and Dehghani 2016; Liu et al. 2003). After the reaction was completed and neutralize the residual H2O2, ZnO nanoparticles must be separated. Centrifuges (3000 rpm, 10 min) were used for separation of nanoparticles after contact time.