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Abstract:
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An apparatus was constructed and used to investigate the separation of copper (II) from very dilute solutions of cupric sulfate by foam fractionation. Two agents, SARKOSYL NL-30 and AEROSOL 22 were used, with emphasis on the latter. Both are commercial purity amides: SARKOSYL NL-30 is lauroyl-N-methyl, N-acetic acid, sodium salt while AEROSOL 22 is tetrasodium N-octadecyl, N-(l,2-dicarboxyethyl) sulfosuccinamate.
Spectrophotometric methods using ^-quinolinol-5-sulfonic, acid (HQSA) and cyclohexene-l, 2-dinitrilotetraacetic acid (CDTA) were investigated and used to analyze for one to two hundred mg/l Cu(II). HQSA is sensitive to an excess of AEROSOL 22, while CDTA is not, due to the much larger instability constant of CuCDTA (pK « 21.30 compared to 11.53 for the HQSA complex). A reasonably large instability constant for Cu-AEROSOL 22 is indicated.
Good recoveries of copper were obtained. It was found that SARKOSYL NL-30 precipitates copper from solutions containing as little as 5 mg/l, while cupric AEROSOL 22 was almost completely miscible with water. The latter was precipitated from 1.0 M KCl containing 12 mg/l copper, however. |