Methylene blue dye adsorption on sulphide minerals — relevance to surface area measurement
| Autor: | N.W. Barker, H.G. Linge |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Aqueous solution
Chemistry Chalcopyrite Inorganic chemistry Metals and Alloys Langmuir adsorption model engineering.material Industrial and Manufacturing Engineering Bismuthinite symbols.namesake chemistry.chemical_compound Adsorption visual_art Materials Chemistry symbols visual_art.visual_art_medium Surface roughness engineering Methylene blue BET theory |
| Zdroj: | Hydrometallurgy. 6:311-326 |
| ISSN: | 0304-386X |
| DOI: | 10.1016/0304-386x(81)90048-7 |
| Popis: | Methylene blue dye adsorbs on chalcopyrite (CuFeS 2 ) powder slurried in aqueous solution. The rate of adsorption is quite low, and at least two days of contact is required to reach a steady state. Adsorption isotherms rise sharply for dye equilibrium concentrations less than 10 −5 M but an adsorption plateau is reached at higher solution concentrations (measured to 10 −4 M ). These data can be fitted to a Langmuir isotherm. The saturation adsorption of the chalcopyrite samples is proportional to their BET surface area, with 2.18 ± 0.07 μ mol of dye being adsorbed per m 2 of surface. This value is compatible with “flat” physical adsorption of methylene blue cations associated as dimers, and also gives good agreement with the surface area calculated from the average particle radius for several closely-sized chalcopyrite samples, using reasonable values for the surface roughness. The same model applies to methylene blue adsorption on chalcopyrites concentrates and on pure pyrite (FeS 2 ) surfaces, but not to more reactive sulphide minerals such as galena (PbS) and bismuthinite (Bl 2 S 3 ). For the latter sulphides, the dye surface coverage is lower than for chalcopyrite, unless chalcopyrite is also present in the sample, e.g. as in chalcopyrite concentrates. This difference has been interpreted using a galvanic mechanism. |
| Databáze: | OpenAIRE |
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