Gaseous mercury removal using biogenic porous silica modified with potassium bromide

Rice husk, as an abundant agricultural waste and renewable biomass, is adopted to produce porous silica which is used as a potential carbon-free adsorbent for mercury emission control of coal-fired power plants. The rice husk derived porous silica (RHS) exhibits a good Hg-0 adsorption capability with Hg-0 removal efficiency above 80% in the temperature range of 60-140 degrees C, which is plausibly due to the big specific surface area and mesoporous structure. The mercury removal performance of RHS can be evidently reinforced by KBr modification. The optimal KBr loading value and reaction temperature are 2 wt% and 140 degrees C, respectively. Acidic gas components, such as NO and SO2, both show slight inhibitive effects on Hg-0 adsorption process probably owing to the competitive adsorption or the elimination of adsorption sites.

Automated summary

Porous silica derived from rice husk exhibits good Hg-0 adsorption capability in the temperature range of 60-140 degrees C, with Hg-0 removal efficiency above 80%; the mercury removal performance of RHS can be significantly enhanced by KBr modification.