Adsorption and photocatalytic degradation behaviours of cationic dye BV16 in ZnO-Ghezeljeh nanoclay composite/UV-C system: Equilibrium, kinetic and thermodynamic studies

Abstract

Ghezeljeh montmorillonite nanoclay or “Geleh-Sar-Shoor” (means head-washing clay) has been used as a natural adsorbent to photocatalytic decolorization of BV16 dye under UV radiation. The results of XRD, FT-IR, CEC, Specific surface area and Zeta potential of the Ghezeljeh clay confirm that montmorillonite is the dominant mineral phase. Based on SEM images, it can be understood that the distance between the plates is in nm level. Adsorption of BV16 on to different clays might inhibit its photodegradation has been investigated. The photocatalytic decolorization of BV16 dye under UV radiation in aqueous ZnO-natural Ghezeljeh nanoclay composite suspension compared to the behavior of the dye on Ghezeljeh nanoclay, ZnO-Ghezeljeh nanoclay (shell-core), Cloisite Na+ nanoclay, ZnO-Cloisite Na+nanoclay composite, ZnO-Cloisite Na+nanoclay (shell-core). The linearity of the plots (R2) demonstrates that pseudo-second order kinetic model play a significant role in the uptake of the dye. The R2 values show that the dye removal isotherm using ZnO-natural Ghezeljeh nanoclay composite follows the Langmuir isotherm at natural temperature and Dubinin–Radushkevich isotherm at upper temperature. Calculation of ΔG0, ΔH0 and ΔS0 showed that the procedure is feasible, spontaneous and endothermic.