ZnO, Al/ZnO and W/Ag/ZnO nanocomposite and their comparative photocatalytic and adsorptive removal for Turquoise Blue Dye

Abstract

In the present investigation, ZnO, Al/ZnO, and W/Ag/ZnO nanocomposites were prepared and employed as an adsorbent and photocatalyst for the removal of Turquoise Blue Dye (TBD) as a function of various process variables. The dye removal (maximum) was observed at pH range 2–3, adsorbent dose of 0.05–0.1 g, contact time 60 min, 170–200 mg/L initial TBD dye concentration at 30 0C. The adsorption of dye on to nanocomposite followed pseudo second order kinetics and Langmuir equilibrium model. The thermodynamics study revealed the spontaneous and exothermic dye adoption nature on to nanocomposites. On the other hand, the TBD dye photocatalytic removal was efficient in pH range 2–3, catalyst dose 0.05 g, 5 mg/L dye initial concentration within 60 min of visible light exposure. The TBD dye degradation followed first-order kinetics model. The SEM and FTIR analysis were also performed of dye loaded and unloaded ZnO, Al/ZnO, and W/Ag/ZnO along with desorption study of using NaOH as eluting agent. The W/Ag/ZnO showed higher efficiency (adsorption and photocatalysis) versus ZnO and Al/ZnO and results revealed that the nanocomposites are efficient, which could be applied for the adsorptive and photocatalytic remediation of dyes from industrial effluents.