Batch adsorption techniques were used to study the biosorption of Lead and Nickel from aqueous solutions by Flame of the forest pods. The effects of optimum pH, contact time, metal ion concentration, biosorbent dose, ...Batch adsorption techniques were used to study the biosorption of Lead and Nickel from aqueous solutions by Flame of the forest pods. The effects of optimum pH, contact time, metal ion concentration, biosorbent dose, biosorbent particle size and the presence of sodium, calcium and magnesium interfering ions on the sorption were investigated. Experimental results showed that Delonix regia biomass was effective in removing these metals from aqueous solutions as the equilibrium biosorption of both metals was attained within 60 minutes of interaction with 98% of the metals removed within this period. Sorption of these metals was dependent on pH as maximum removal was attained at pH 4 and pH 5 for Lead and Nickel ions respectively. Adsorption experiments showed that the process followed the pseudo second order kinetic model with high r2 (0.9999) and the equilibrium data fitted well with Langmuir and Freundlich isotherm models. The presence of competing ions impacted negatively on the sorption process irrespective of the type used. 27% and 36% of lead (II) were recovered from the spent biosorbents with 1 MHCl and disodium salt of EDTA solutions respectively.展开更多
By examining the second leading mode （EOF2） of the summer rainfall in China during 1958 2001 and associated circulations, the authors found that this prominent mode was a dipole pattern with rainfall decreasing to t...By examining the second leading mode （EOF2） of the summer rainfall in China during 1958 2001 and associated circulations, the authors found that this prominent mode was a dipole pattern with rainfall decreasing to the north of the Yangtze River and increasing to the south. This reverse relationship of the rainfalls to the north and to the south of the Yangtze River was related with the meridional circulations within East Asia and the neighboring region, excited by SST in the South China Sea-northwestern Pacific. When the SST was warmer, the geopotential heights at 500 hPa were positive in the low and high latitudes and negative in the middle latitudes. The anticyclone in the low latitudes favored the subtropical high over the northwestern Pacific （SHNP） shifting southwestward, leading to additional moisture transport over southern China. The anomalous atmospheric circulations along the East Asian coast tends to enhance upward movement over the region. Subsequently, rainfall in southern China is enhanced.展开更多
文摘Batch adsorption techniques were used to study the biosorption of Lead and Nickel from aqueous solutions by Flame of the forest pods. The effects of optimum pH, contact time, metal ion concentration, biosorbent dose, biosorbent particle size and the presence of sodium, calcium and magnesium interfering ions on the sorption were investigated. Experimental results showed that Delonix regia biomass was effective in removing these metals from aqueous solutions as the equilibrium biosorption of both metals was attained within 60 minutes of interaction with 98% of the metals removed within this period. Sorption of these metals was dependent on pH as maximum removal was attained at pH 4 and pH 5 for Lead and Nickel ions respectively. Adsorption experiments showed that the process followed the pseudo second order kinetic model with high r2 (0.9999) and the equilibrium data fitted well with Langmuir and Freundlich isotherm models. The presence of competing ions impacted negatively on the sorption process irrespective of the type used. 27% and 36% of lead (II) were recovered from the spent biosorbents with 1 MHCl and disodium salt of EDTA solutions respectively.
基金supported by the National Basic Research Program of China(Grant Nos 2004CB418302 and 2009CB421404)Na-tional Natural Science Foundation of China (Grant No40675058)
文摘By examining the second leading mode （EOF2） of the summer rainfall in China during 1958 2001 and associated circulations, the authors found that this prominent mode was a dipole pattern with rainfall decreasing to the north of the Yangtze River and increasing to the south. This reverse relationship of the rainfalls to the north and to the south of the Yangtze River was related with the meridional circulations within East Asia and the neighboring region, excited by SST in the South China Sea-northwestern Pacific. When the SST was warmer, the geopotential heights at 500 hPa were positive in the low and high latitudes and negative in the middle latitudes. The anticyclone in the low latitudes favored the subtropical high over the northwestern Pacific （SHNP） shifting southwestward, leading to additional moisture transport over southern China. The anomalous atmospheric circulations along the East Asian coast tends to enhance upward movement over the region. Subsequently, rainfall in southern China is enhanced.
