Adsorbimento di coloranti e tensioattivi su ceneri volanti di carbone. [Adsorption of dyes and surfactants on coal fly ash]

Adsorption of dyes and surfactants from aqueous solutions on coal fly ash has been studied in batch tests. The dyes were chosen as representative of three classes: basic, acid and direct; the surfactants used were anionic and nonionic. The adsorption efficiency was determined by varying the initial concentration of the dye (100-1000 mg/l) or surfactant (150-1500 mg/l) and the ash dosage (2-20 g/l); dosages up to 100 g/l were used in dyeworks waste treatment. In some cases the results can be plotted according to Freundlich type isotherms. Ash basicity seems to be the key factor in the adsorption.