Uptake of Hexavalent Chromium in Electroplating Wastewater by Hydrothermally Treated and Functionalized Sand and Its Sustainable Reutilization for Glass Production

Abstract

Sand used for glass production was first hydrothermally treated in a sodium hydroxide solution followed by silica coating that created nanoporosity in the residual sand particles increasing the surface area by ca. 740 times when compared to parent sand particles. The hydrothermally treated sand was named as reconstructed sand (R-sand) and was further functionalized with 3-aminopropyltriethoxysilane (F-Sand) and both sands were later used as adsorbents to remove toxic chromium from aqueous solutions. The influence of pH, initial ion concentration, contact time, adsorption temperature, and dosage of adsorbent on the adsorption performance of both sands were investigated and compared. The kinetics of Cr6+ adsorption by both sands follows the pseudo-second-order kinetic model, while the adsorption of Cr6+ of R-sand and F-sand fits Langmuir and Freundlich models, respectively. The F-sand has shown improved adsorption performance and was used to adsorb chromium from electroplating wastewater. Since the hydrothe...