Removal of Erioglaucine (Acid Blue 9) with a new coagulant agent from Acacia mearnsii tannin extract.

A new coagulant obtained through the polymerisation of Acacia mearnsii de Wild. tannin extract has been characterised in the removal of a dangerous dye pollutant: Erioglaucine (also called Acid Blue 9 or FD&C Blue 1). This coagulant was laboratory synthesised according to the etherification of tannins using glycidyltrimethylammonium chloride and formaldehyde and its performance in dye removal in terms of efficiency was high. Reasonably low coagulant dosages ( ca. 50 mg l⁻¹) reach high capacity levels (approximately 0.7 mg dye mg⁻¹ of coagulant) and pH and temperature are not extremely affecting variables. A design of experiments using response surface methodology led to the evaluation of the influence of parameters such as coagulant dosage and initial dye concentration, and reliable data were collected in order to maximise the removal capacity. The whole coagulant-dye system was successfully modelled by applying the Langmuir hypothesis. Parameters q_max and b were obtained with an adjusted correlation factor ( r²) above 0.8. [ABSTRACT FROM AUTHOR]