Effect of Etching Time on the Adsorption Performance of Two-dimensional Ti₃C₂ for Organic Dyes

Abstract

Two-dimensional Ti3C2 was obtained by etching Ti3AlC2 in hydrofluoric acid(HF) for different time. The phase composition and morphology of the as-obtained samples were characterized by X-ray diffraction patterns(XRD), scanning electron microscopy (SEM). The adsorption behaviour for a cationic dye methylene blue(MB) and anionic dye Congo red(CR) was tested by ultraviolet spectrophotometer, and then the adsorption kinetics and thermodynamics were investigated. The results show that with the elongation of the corrosion time in hydrofluoric acid, the spacing of the two-dimensional Ti3C2 material is increased accordingly. The results show that the etched Ti3C2 exhibits good adsorption performance for MB and CR, both fitting well with the quasi secondary adsorption model, whereas the adsorption thermodynamics fits well with Langmuir and Freundlich adsorption isotherm model, respectively, suggesting that the adsorption is an process dominated by chemical adsorption mechanism and the joint action of mono- and multimolecular adsorption modes. Based on the difference of cationic and anionic dye, the mechanism of action is different, and thus exhibiting different adsorption behaviours.

Keywords

• etching time
• Ti₃C₂
• organic dye
• adsorption kinetics
• adsorption isotherm curve