Development of bamboo-derived sorbents for mercury removal in gas phase.

Activated carbon sorbents were synthesized from bamboo precursors by carbonization in an inert atmosphere followed by physiochemical activation with carbon dioxide and finally acidulation in hydrochloric acid. Bamboo strips with and without the epidermal tissue (bark) were used. The morphology and specific surface area changes due to the treatment were analysed. The adsorption characteristics of these sorbents after each stage of treatment were also analysed and the data were correlated to the changes in the physical characteristics of the sorbents. Kinetic studies were conducted on these samples. The adsorption equilibrium and kinetics of elemental mercury adsorption on these carbons were evaluated at room temperature. Elemental mercury uptake at different sorbent loading and initial elemental mercury concentrations were examined. The adsorption rate constants and the mass transfer constants were estimated for the sorbents prepared under different conditions. Adsorption isotherms of the elemental mercury on these activated carbons were determined and correlated with Langmuir and Freundlich adsorption isotherm equations. It was found that the overall process was mass transfer controlled and that the adsorption equilibrium could be described by a linear isotherm for the concentrations used in this study.