Synthesis of β-cyclodextrin-glycine-modified TiO2 nanoparticles for adsorption of dyes from aqueous solutions

In this paper, beta-cyclodextrin-glycine-modified TiO2 nanoparticles (TiO2/Gly/βCD NPs) as anefficient adsorbent were prepared and employed for the removal of some commercial organic dyes fromaqueous solutions. The structure and morphology of adsorbent were fully characterized by Fouriertransform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and X-raydiffractometer (XRD). TiO2/Gly/βCD NPs showed excellent adsorption ability toward different classes oforganic dyes, including Acid Blue 113 (AB 113) and Disperse Red 1 (DR 1). The effects of environmentalfactors including pH, contact time, adsorbent dosage, temperature, initial dye concentration on theadsorption capacity of the TiO2/Gly/βCD NPs were investigated in details. The results of this study showedthat the TiO2/Gly/βCD NPs has a high adsorption efficiency toward organic dyes especially DR 1, and wascomparable with other adsorbents. In addition, the adsorbent presented can be used in several adsorptiondesorptioncycles. This property is very important for further applications in other processes. The dyeadsorption kinetics, thermodynamic and isotherms were also investigated. The results indicated thatpseudo-second-order kinetics model and Freundlich isotherm model well describe the adsorption of AB113 and DR1 on the TiO2/Gly/βCD NPs. The maximum adsorption capacity of AB 113 and DR 1 dyes were76.92 and 138.89 mg/g, respectively. Moreover, the thermodynamic parameters indicated that theadsorption process for AB 113 and DR 1 was exothermic. The proposed adsorbent has been successfullyapplied to remove model dyes from aqueous solutions with satisfactory results.

Keywords:

Titanium dioxide nanoparticles , Dye removal , Surface-modification , βeta-Cyclodextrin , Glycine