A novel nanocomposite based zeolite for efficient remediation of Cd- contaminated industrial wastewater

Abstract

The nanostructured water treatment residuals (nWTR) were obtained through ball milling of bulk water treatment residuals (WTR) and then coated with zeolite (Ze). The prepared nanocomposite (Ze-nWTR) was characterized before and after Cd adsorption using SEM-EDX, XRD and FTIR analyses. Cadmium adsorption study was conducted in batch system at various conditions of solution pH, coexist competing ions, sorbent dose, temperature and contact time. Langmuir and power function models well fitted to Cd adsorption equilibrium and kinetic data respectively. The maximum adsorption capacity (qmax) value of the nanocomposite (147.9 mgg-1) was 3 and 5.9 times higher than those of nWTR and Zeolite sorbents, respectively. Increasing temperature from 287K to 307K caused increasing in qmax value from 147.9 mgg-1 to 270 mgg-1. The pH of point of zero charge (pHzpc) for nanocomposite was 7.2. Thermodynamic Parameters of Cd adsorption by nanocomposite were calculated at different initial Cd concentration and pH values. The high value range of ΔH° (123292 − 18600 J mol− 1) for Cd adsorption on nanocomposite reflects different forces governing the adsorption reaction. Furthermore, FTIR, XRD, and EDX analysis confirmed that combination reactions (nonspecific/specific interaction) are responsible for Cd adsorption on the nanocomposite. The reusability study revealed that (Ze-nWTR) nanocomposite could be reused effectively for up to 6 consecutive cycles. The results from this study confirmed the nanocomposite excellent removal ability (98%) of Cd from industrial wastewater.