A new adsorbent for heavy metal ions, sulfhydryl chitosan (S chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by e...A new adsorbent for heavy metal ions, sulfhydryl chitosan (S chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FT IR spectra analysis. The adsorption properties of sulfhydryl chitosan for Cu(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ)and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.展开更多
Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1H NMR and FT-IR. The...Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1H NMR and FT-IR. These results suggested the for- mation of an amide linkage between the amino groups of chitosan and the carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase became larger as the DS increased. All of the O-chitosans could reduce surface tension slightly. The critical aggregation concentration (CAC) of O-chitosans with DS 5%, 11%, and 27% were 79.43 mgL-1, 31.6 mgL-1, and 10 mgL-1, respectively. Nanoparticles were prepared using an O/W emulsification method. The mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5% and 11% were around 327.4 nm and 275.3 nm, respectively.展开更多
This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting mate...This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting materials and treated with or without various concentrations of glucose and/or δ-aminolevulinic acid (ALA) in the dark. Leaves harvested at the indicated time were determined for their contents of Chl, protoporphyrin Ⅸ (Proto), Mg-protoporphyrin Ⅸ (Mg-Proto) and protochlorophyllide (Pchlide). The mole percentage of porphyrin was calculated. The Chl content in the etiolated rice seedlings slightly increased from about 2.5 μg/g to 7.5 μg/g within 12 d in the dark, but the total Chl of dark-grown rice increased from 0.36 μg/g to 3.6 μg/g. While the mole percentages of Proto, Mg-Proto and Pchlide in the dark-grown seedlings without any treatment were about 65%, 27.5% and 7.5% at the beginning, respectively, those in the light-grown seedlings were about 42.5%, 35% and 22.5%, respectively. The mole percentage of porphyrin of etiolated seedlings resumed its normal ratio within 2 d after treatment with glucose. While the Chl content of etiolated seedlings grown in culture solution with 3% and 6% glucose increased 2.5 and 4.0 folds, respectively, those with 3% and 6% glucose and 1 mmol/L ALA increased 22 and 24 folds, respectively. It is concluded that angiosperm might be able to synthesize a small amount of Chl in complete darkness, that either glucose or ALA could stimulate dark Chl synthesis in angiosperm, and that a combination of glucose and ALA exhibited an additional effect. It is still unknown and remains to be further explored what is the mechanism of the effect of glucose and ALA on the Chl synthesis of rice in the dark.展开更多
文摘A new adsorbent for heavy metal ions, sulfhydryl chitosan (S chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FT IR spectra analysis. The adsorption properties of sulfhydryl chitosan for Cu(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ)and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.
基金financial support from the National Natural Science Foundation of China(No.30370344)the Scientist Encouragement Foundation of Shandong Province(2004BS7001).
文摘Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1H NMR and FT-IR. These results suggested the for- mation of an amide linkage between the amino groups of chitosan and the carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase became larger as the DS increased. All of the O-chitosans could reduce surface tension slightly. The critical aggregation concentration (CAC) of O-chitosans with DS 5%, 11%, and 27% were 79.43 mgL-1, 31.6 mgL-1, and 10 mgL-1, respectively. Nanoparticles were prepared using an O/W emulsification method. The mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5% and 11% were around 327.4 nm and 275.3 nm, respectively.
文摘This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting materials and treated with or without various concentrations of glucose and/or δ-aminolevulinic acid (ALA) in the dark. Leaves harvested at the indicated time were determined for their contents of Chl, protoporphyrin Ⅸ (Proto), Mg-protoporphyrin Ⅸ (Mg-Proto) and protochlorophyllide (Pchlide). The mole percentage of porphyrin was calculated. The Chl content in the etiolated rice seedlings slightly increased from about 2.5 μg/g to 7.5 μg/g within 12 d in the dark, but the total Chl of dark-grown rice increased from 0.36 μg/g to 3.6 μg/g. While the mole percentages of Proto, Mg-Proto and Pchlide in the dark-grown seedlings without any treatment were about 65%, 27.5% and 7.5% at the beginning, respectively, those in the light-grown seedlings were about 42.5%, 35% and 22.5%, respectively. The mole percentage of porphyrin of etiolated seedlings resumed its normal ratio within 2 d after treatment with glucose. While the Chl content of etiolated seedlings grown in culture solution with 3% and 6% glucose increased 2.5 and 4.0 folds, respectively, those with 3% and 6% glucose and 1 mmol/L ALA increased 22 and 24 folds, respectively. It is concluded that angiosperm might be able to synthesize a small amount of Chl in complete darkness, that either glucose or ALA could stimulate dark Chl synthesis in angiosperm, and that a combination of glucose and ALA exhibited an additional effect. It is still unknown and remains to be further explored what is the mechanism of the effect of glucose and ALA on the Chl synthesis of rice in the dark.
