The color removal activity of polyphenolic extracts obtained by maceration of coffee pulp with the Coffea arabica species was evaluated in synthetic waters prepared with three commercial dyes: methylene blue, malachite green and crystal violet. The extract was prepared by maceration using milled coffee pulp in a hydroalcoholic solution with a volume ratio of 1:1 and a solid: solvent ratio of 1:20 (g: mL). Additionally, total polyphenols were quantified using the Folin-Ciocalteu method and pH effects were evaluated based on the color removal percentages at fixed doses of 2.5 mg GAE / L (gallic acid equivalent per liter). Maximum removals with the values of 61.74%, 91.65% and 86.47% were obtained for malachite green, crystal violet and methylene blue at a pH of 4.26, 8.40 and 9.22, respectively. The present study confirms the potential use of waste extracts from the coffee industry for the removal of cationic dyes by coagulation.
Keywords- Cationic coagulants, Polyphenols, coffee pulp.