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Calcium sulphate scaling in membrane distillation process
Gryta, Marek Calcium sulphate scaling in membrane distillation process Chemical Papers, Vol.63, No. 2, 2009, 146-151
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Document type:
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Článok z časopisu / Journal Article |
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Collection:
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Chemical papers
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| Author(s) |
Gryta, Marek
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| Title |
Calcium sulphate scaling in membrane distillation process
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| Journal name |
Chemical Papers
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| Publication date |
2009
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| Year available |
2009
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| Volume number |
63
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| Issue number |
2
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| ISSN |
0366-6352
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| Start page |
146
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| End page |
151
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| Place of publication |
Poland
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| Publisher |
Versita
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| Collection year |
2009
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| Language |
english
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| Subject |
290000 Engineering and Technology
291100 Environmental Engineering
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| Abstract/Summary |
Formation of precipitates containing CaSO4 during membrane distillation, applied to the concentration of aqueous salt solutions, is discussed in this paper. It was found that the concentration of SO42− ions in such solutions should not exceed 600 mg L−1 when they are subjected to concentration. However, concentration of sulphates at the level of 800 mg L−1 in the feed is permissible provided that the excess of CaSO4 is removed in a crystallizer. Crystallisation of salts, mainly CaSO4 · 2H2O, on the surface and inside the membrane was observed at higher feed concentrations, causing damage of the module. Precipitation of calcium sulphate was also observed during the production of demineralised water when high values of the water recovery coefficient (above 90 %) were used. In this case, the formed precipitate also contained CaCO3, the co-precipitation of which significantly changed the properties of the scaling layer. The precipitate containing both CaSO4 and CaCO3 was formed mainly on the membrane surface and it could easily be removed by rinsing the module with a HCl solution.
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