Química Moderna e Aplicações

Abstrato

Modeling of Tartrazine Dye Adsorption onto Treated and Untreated Cocoa Shell by Non-Linear Regression Methods

Michele Nana Nemgne, Alain Paul Nanssou Kouteu, Donald Raoul Tchuifon Tchuifon2, Christian Sadeu Ngakou, Ndifor-Angwafor George Nche, Anagho Solomon Gabche

Tartrazine is a toxic industrial dye, and it is reported to affect water quality and is harmful to human health. The objective of this study is to contribute to elaborate less expensive adsorbents from cocoa shell for the elimination of tartrazine from aqueous solution. The effects of initial pH (2-8), contact time (0-90 min), mass of adsorbent (10-70 mg) and the nature of treatment were evaluated on the adsorption of tartrazine. The optimal conditions for the adsorption of tartrazine on all the substrates are pH=2, contact time=60 min, amount of adsorbent=40 mg. Nonlinear regression analysis showed the best fit for pseudo second order kinetics regardless of material with Chi-square (χ²) test values of 0.1672, 0.0811 and 0.0366 respectively for CC-H₂O, CC-HNO₃ and CC-H₃PO₄. Equilibrium data were fitted to two-parameter mono-solute models and mono-solute three-parameter models. Adsorption isotherm data were best described by Jovanovic model for water washed substrate, Langmuir model for phosphoric acid treated substrate and Dubinin-Radushkevich model for treated substrate to nitric acid for the 2-parameter isotherms. As for the three-parameter isotherms, it is the Khan model that better describes the data for the substrate washed with water and the substrate treated with phosphoric acid, whereas the Redlich-Peterson model was found for the substrate treated with nitric acid.