Sorção do corante ácido azul 260 em sistema particulado de quitosana

Abstract

The sorption of Acid Blue 260 (AB260) was studied in three different isotherms: 25, 35 and 45 ° C in a particulate chitosan system. The sorption of AB260 was disadvantaged by the increase of the temperature. The maximum amount of dye removed from the solution was quantified by the Uv-Vis absorption spectroscopy technique at λ_Max=608 nm, after construction of an AB260 calibration curve. The results showed that the adsorption of the dye AB260 followed the Langmuir and Sips models, because they showed a higher correlation. Thermodynamic parameters, ΔH, ΔS and ΔG were calculated using the Langmuir K_L constant at different temperatures using the Van't Hoff equation. After calculating the parameters, it was obtained: 〖∆H〗_ads=-59.62 KJ/mol, 〖∆S〗_ads=-94.28 J/molK, 〖∆G〗_(ads25°C)=-31.82 KJ/mol. The thermodynamic parameters allowed to identify that the sorption has a physical interaction and spontaneous behavior. Fourier transform infrared spectroscopy (FTIR) spectra were performed from samples of chitosan, dye and chitosan + dye. The results of the spectra showed that the bands of the chitosan and dye + chitosan samples appeared in the same wavenumber, evidencing that there was no formation of chemical bonding.