Facile preparation of dual functions zeolite-carbon composite for zinc ion removal from aqueous solutions

Abstract

The cost-effective dual functions zeolite-carbon composite (DFZCC) was prepared using an eco-friendly substrate prepared from bio-waste and an organic adhesive at intermediate conditions. The green synthesis method used in this study ensures that chemically harmless compounds are used to obtain a homogeneous distribution of zeolite over porous carbon. The greenly prepared dual-function composite was extensively characterized using Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, N2 adsorption/desorption isotherms, field emission scanning electron microscope, dispersive analysis by X-ray, and point of zero charges. DFZCC had a surface area of 248.84 m2/g and a pore volume of 0.141 cm3/g. DFZCC was used in the sorption process of Zn2+ ions from aqueous solutions, and it achieved higher removal (98%) at normal pH of 6.4 and temperature of 40°C. The Langmuir model was the best model for representing equilibrium data with a maximum sorption capacity of 6.711 mg/g. The kinetic studies showed that the pseudo-second-order model was the most appropriate model for representing experimental data. The intra-particle diffusion kinetics demonstrated that the boundary film is the rate-determining step in the sorption process. The sorption process of Zn2+ ions by DFZCC was spontaneous and endothermic. Moreover, solidification of the spent DFZCC by kaolin successfully reduced the leaching ions to the solution after 12 weeks from exposure to a salty solution.