Resumo

LOZANO-ALVAREZ, Juan Antonio et al. Removal of Azo dyes with Xanthan. J. Mex. Chem. Soc [online]. 2019, vol.63, n.4, pp.176-198.  Epub 14-Set-2020. ISSN 1870-249X.  https://doi.org/10.29356/jmcs.v63i4.699.

The interaction among Xanthan (XANT) and three azo dyes: Direct blue 1 (DB1), Direct red 81 (DR81), and Direct black 22 (DB22) was studied. The Xanthan-dye-Al product was formed after the addition of AlCl3 to a Xanthan-Dye adduct containing solution. It was proposed that polyhydroxyoxoaluminum clusters named CAL-13 and CAL-30 react with this adduct producing a Xanthanate aluminum network, XANT-Al, and as a consequence a decrease in dye concentration in an aqueous medium was observed. The removal efficiencies obtained were the following: DB1 (99 %), DB22 (99 %) and DR81 (94 %), demonstrating that this dye removal method is very efficient. The Zimm-Bragg model adequately described the experimental data and the order observed in the Ku (nucleation) and U (aggregation) parameters from this model was the following: DB1>DB22> DR81. Evidence suggests that physicochemical properties of dyes such as charge, molecular weight, aggregation ability and the capacity of XANT-Al to trap dye molecules are involved in the high removal values. Moreover, the dye binding mechanisms include electrostatic, hydrogen bonding and hydrophobic interactions that determine the magnitude of the parameters Ku and U. These findings suggest that the XANT polymer is a good option to remove azo dyes from an aqueous medium.

Palavras-chave : Xanthan; azo dyes; removal efficiency; polyhydroxyoxoaluminum cations; aggregation.

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