Characterization, kinetics and thermodynamics of Ag(I) sorption using novel sorbent: Dry wheatgrass

ABSTRACT

In the present study, dried wheatgrass (DWG), an available and renewable biomass, was investigated as a novel Ag(I) sorbent. Sorption data was modeled to 11 different kinetic and diffusion models at different DWG concentration. Pseudo-second-order model fits the data most appropriately among these. Diffusion was not the sole mechanism controlling Ag(I) sorption by DWG. The enthalpy and entropy for Ag(I) sorption by DWG are 10.511 kJ mol⁻¹ and 0.065 kJ mol⁻¹ K⁻¹, respectively. Gibbs free energy decreases with rise in temperature. Ag(I) sorption by DWG is spontaneous, endothermic with increased randomness at the interface. Characterization of DWG suggested the presence of diverse functional groups. Ag(I) sorption by DWG involved mechanisms such as physisorption and chemisorptions. DWG can be efficiently used to remediate and recover Ag(I) from solution in an eco-friendly manner.

KEYWORDS:

• Dry wheatgrass
• silver remediation
• kinetics
• thermodynamics
• green recovery