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Heavy Metals
Published in Abhik Gupta, Heavy Metal and Metalloid Contamination of Surface and Underground Water, 2020
Arsenic (As) has an atomic number of 33, an atomic weight of 74.922, and a density of 5.72 g cm–3. Arsenopyrite or iron-arsenic sulfide (FeAsS2) is the most common ore of arsenic. Realgar (As4S4) and orpiment (As2S3) are important ores of As as well. Arsenic can occur as inorganic arsenic compounds, which in turn can have the trivalent or pentavalent form of the element. Besides, arsenic also occurs as organic arsenic compounds, and as arsine gas and substituted arsines. The addition of elemental arsenic to alloys increases their hardness and heat resistance. Elemental arsenic is also used in some types of glass, and in electrical devices. Arsenic trichloride (AsCl3) is used to make pharmaceuticals, pesticides, and ceramics. Arsenic trioxide (As2O3) is the precursor to other arsenic compounds, and is used as a hide and wood preservative, a mordant, and decolorizing agent in glass manufacture. Some arsenic compounds are also used as insecticides, herbicides, corrosion inhibitors, and dehairing agents in the tanning industry. Pentavalent arsenic compounds are used in glass-making, wood-curing, and as herbicides, insecticides, and wood preservatives. Organic arsenic compounds are also used as herbicides and defoliants (Encyclopaedia of Occupational Health and Safety 2012).
Arsenic Trioxide Leaching and Scorodite Crystallization in Methanesulfonic Acid
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Junmo Ahn, Jiajia Wu, Jaewoo Ahn, Jaeheon Lee
This technology is applicable during the copper refining in industrial scale, especially for arsenic treatment during decopperization. Arsenic in copper refining electrolyte is required to be maintained in a certain level for the quality of copper cathode. Generally, arsenic is reduced and collected from the electrolyte bleed stream during the decopperization process. Arsenic can be removed by precipitation as arsenic trioxide using SO2 gas, and the arsenic-depleted electrolyte can cycle back to the tank house. The precipitated arsenic trioxide by SO2 gas can be treated by leaching in MSA for enhanced dissolution followed by scorodite precipitation. MSA has been proven to be a chemical to dissolve arsenic, and scorodite can be formed in the solution.
Removal of arsenic from contaminated water using radiation-induced grafted chitosan: a critical review
Published in Chemistry and Ecology, 2022
Arsenic is also being introduced into the environment through various anthropogenic activities. These sources release As compounds that differ greatly in chemical nature and bioavailability. Major sources of As approximately discharged onto land originate from commercial wastes (40%), coal ash (22%), mining industry (16%), and the atmospheric fallout from the steel industry (13%) [59,60]. Arsenic trioxide (As2O3) is used extensively in the manufacturing of ceramic and glass, electronics, pigments and antifouling agents, cosmetics, fireworks and Cu-based alloys [4]. Disposal of these materials often leads to As contamination of soil and water [61].