The presence of SO2 display significant effect on the mercury (Hg) adsorption ability of carbon-based sorbent. Yet the adsorption and oxidation of SO2 on carbon with oxygen group, as well as the roles of different sulfur oxide groups in Hg adsorption have heretofore been unclear. The formation of sulfur oxide groups by SO2 and their effects on Hg adsorption on carbon was detailed examined by the density functional theory. The results show that SO2 can be oxidized into SO3 by oxygen group on carbon surface. Both C-SO2 and C-SO3 can improve Hg adsorption on carbon site, while the promotive effect of C-SO2 is stronger than C-SO3. Electron density difference analyses reveal that sulfur oxide groups enhance the charge transfer ability of surface unsaturated carbon atom, thereby improving Hg adsorption. The experimental results confirm that surface active groups formed by SO2 adsorption is more active for Hg adsorption than the groups generated by SO3. 相似文献
The pollutants in urban storm runoff,which lead to an non-point source contamination of water environment around cities,are of great concerns.The distributions of typical contaminants and the variations of their species in short term storm runoff from different land surfaces in Xiamen City were investigated.The concentrations of various contaminants,including organic matter,nutrients(i.e.,N and P) and heavy metals,were significantly higher in parking lot and road runoff than those in roof and lawn runoff.The early runoff samples from traffic road and parking lot contained much high total nitrogen(TN 6-19 mg/L) and total phosphorus(TP 1-3 mg/L).A large proportion(around 60%) of TN existed as total dissolved nitrogen(TDN) species in most runoff.The percentage of TDN and the percentage of total dissolved phosphorus remained relatively stable during the rain events and did not decrease as dramatically as TN and TP.In addition,only parking lot and road runoff were contaminated by heavy metals,and both Pb(25-120 μg/L) and Zn(0.1-1.2 mg/L) were major heavy metals contaminating both runoff.Soluble Pb and Zn were predominantly existed as labile complex species(50%-99%),which may be adsorbed onto the surfaces of suspended particles and could be easily released out when pH decreased.This would have the great impact to the environment. 相似文献
Converting the NO from gaseous pollutant into NH4+ through electrocatalytical reduction using cost-effective materials holds great promise for pollutant purifying and resources recycling. In this work, we developed a highly selective and stable catalyst CoSe2 nanoparticle hybridized with carbon nanotubes (CoSe2@CNTs). The CoSe2@CNTs hybrid catalysts performed an extraordinary high selectivity for NH4+ formation in NO electroreduction with minimal N2O production and H2 evolution. The specific spatial structure of CoSe2 is conductive to the predominant formation of N-H bond between the N from adsorbed NO and H and inhibition of N-N formation from adjacent adsorbed NO. It was also the first time to convert the coordinated NO into NH4+ using non-noble metal catalysis. Moreover, the original concept of employing CoSe2 as eletrocatalyst for NO hydrogenation presented in this work can broaden horizons and provide new dimensions in the design of new highly efficient catalysts for NH4+ synthesis in aqueous solution.