Adsorption of Pb(II) from glucose solution on thiol-functionalized cellulosic biomass.

Absorbent cotton, wood sawdust, buckwheat hull were thiol-functionalized to facilitate selective adsorption of Pb(II) from glucose solution. Fourier transform infrared (FTIR) spectroscopic analysis confirmed the formation of S-H modifications. While unmodified absorbent cotton had a Pb(II) adsorption capacity of 10.78 mg/g, thiol-modified absorbent cotton was able to adsorb 28.67 mg/g at optimum pH 6.0. The Pb(II) adsorption capacity increased as the concentration of Pb(II) or glucose increased without loss of glucose during the adsorption process. Wood sawdust and buckwheat hull exhibited greater Pb(II) uptake both before and after modification (wood sawdust: 17.03 mg/g and 43.14 mg/g, buckwheat hull: 34.06 mg/g and 44.84 mg/g), because these cellulosic biomass contained more helpful functional groups for metal binding. The results suggested that modified cellulosic biomass might be a promising adsorbent for heavy metal ion uptake in beverage industry.

Adsorption kinetic character of copper ions onto a modified chitosan transparent thin membrane from aqueous solution.

A modified chitosan transparent thin membrane (MCTTM) was prepared and used as the adsorbent to investigate the adsorption kinetics due to excellent capacity of removing copper ions in water solution. The structure and morphology of MCTTM were characterized by SEM analysis and FTIR analysis. External mass transfer, intra particle diffusion, and pseudo-first and pseudo-second order models were used to describe the adsorption process. The results obtained from the study illustrated that the adsorption process could be described by the pseudo-second order model, which indicated adsorption process was a chemical adsorption behavior of chelation ion exchange proved by the FTIR and adsorption free energy analysis. External mass transfer and intra particle diffusion processes were the rate-controlling steps.