This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy d...This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved the successful synthesis of the adsorbent. The adsorption of Cr(III) on the SDS material was investigated by varying experimental conditions such as pH, contact time and adsorbent dosage. The maximum adsorption capacity of SDS-chitosan for Cr(III) was estimated to be 3.42 mg?g<sup>-1</sup>. The results of adsorption kinetics and isothermal models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating that the adsorption is single-layer chemical adsorption. Thermodynamic analyses indicate that the adsorption of Cr(III) is an endothermic reaction. These results show that the new adsorbent has obvious application prospect to eliminate Cr(III).展开更多
Cr2O3 nanotubes with diameters of 80 nm and lengths of 550 nm were synthesized in a solvothermal reduction system at 180 ℃. The acetyl acetone (AcAc) and ethylene glycol (EG) were used as the chelate agent and the re...Cr2O3 nanotubes with diameters of 80 nm and lengths of 550 nm were synthesized in a solvothermal reduction system at 180 ℃. The acetyl acetone (AcAc) and ethylene glycol (EG) were used as the chelate agent and the reductant respectively in the system. An intermediate compound-Cr(C5H7O2)3 was formed to force Cr2O3 to crystallize along one direction.展开更多
The sol/gel phase diagrams were studied for two systems: polyacrylamide/Cr (III) and polyacrylamide/glyoxal. Sol or gel phase could be distinguished according to the concentrations of polymer and crosslinker. The boun...The sol/gel phase diagrams were studied for two systems: polyacrylamide/Cr (III) and polyacrylamide/glyoxal. Sol or gel phase could be distinguished according to the concentrations of polymer and crosslinker. The boundary polymer concentration did not depend on the types of gelation and decreased with increasing polymer dimension (molecular weight and conformation). The gelation, which is basically interchain bonding, requires the occurrence of entanglement. The overlap concentration is thus considered as the minimum polymer concentration required for gelation.展开更多
The method for the sepration and determination of trace Cr(VI) exiting in mass Cr(III) has been researched. The method is highly sensitive and less interference, but is simple and useful for analysis trace Cr(VI).
The removal of Cr(III) from aqueous Cr(III) using Arthrobacter nicotianae cells was examined. Cr(III) removal was strongly affected by the pH of the solution and the amounts of Cr(III) removed increased as the pH (1 -...The removal of Cr(III) from aqueous Cr(III) using Arthrobacter nicotianae cells was examined. Cr(III) removal was strongly affected by the pH of the solution and the amounts of Cr(III) removed increased as the pH (1 - 5) of the solution increased. The removal of Cr(III) using the cells was also strongly affected by the Cr(III) concentration of the solution, and obeyed the Langmuir isotherm. The percentage of Cr increased as the cell quantity increased, whereas the amount of Cr (μmol/g dry wt. cells) decreased. The removal of Cr(III) using the cells was very fast, and reached an equilibrium within 6 h from the supply of Cr(III) in the solution. A small amount of Cr(III) absorbed by immobilized cells was desorbed at 30oC;however, most was desorbed at reflux temperature using diluted HCl. Cr(III) adsorption-desorption cycles can be repeated 5 times using immobilized cells. These results have practical implications for industrial wastewater management.展开更多
This study herein was investigated the removal of chromium(VI) from an aqueous solution using persimmon tannin gel and its subsequent recovery as chromium(III). At pH 2, Cr(VI) was effectively adsorbed (~80% adsorptio...This study herein was investigated the removal of chromium(VI) from an aqueous solution using persimmon tannin gel and its subsequent recovery as chromium(III). At pH 2, Cr(VI) was effectively adsorbed (~80% adsorption) and ppm solution was reduced to Cr(III) on the persimmon gel within 10 min. Although desorption of the Cr(III) species was challenging at 30°, it was increased upon increasing the temperature and was quantitatively desorbed in the presence of 1 M hydrochloric acid under reflux. In addition, although the quantity of retained Cr(VI) on the tannin gel increased upon increasing the chromium concentration of the original aqueous solution, all the desorbed chromium was successfully reduced to Cr(III). Finally, Cr(VI) removal and recovery as Cr(III) was repeated effectively 8 times using the same persimmon tannin gel sample, thus demonstrating the recyclability of this system.展开更多
文摘This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved the successful synthesis of the adsorbent. The adsorption of Cr(III) on the SDS material was investigated by varying experimental conditions such as pH, contact time and adsorbent dosage. The maximum adsorption capacity of SDS-chitosan for Cr(III) was estimated to be 3.42 mg?g<sup>-1</sup>. The results of adsorption kinetics and isothermal models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating that the adsorption is single-layer chemical adsorption. Thermodynamic analyses indicate that the adsorption of Cr(III) is an endothermic reaction. These results show that the new adsorbent has obvious application prospect to eliminate Cr(III).
文摘Cr2O3 nanotubes with diameters of 80 nm and lengths of 550 nm were synthesized in a solvothermal reduction system at 180 ℃. The acetyl acetone (AcAc) and ethylene glycol (EG) were used as the chelate agent and the reductant respectively in the system. An intermediate compound-Cr(C5H7O2)3 was formed to force Cr2O3 to crystallize along one direction.
基金Project(41272287)supported by the National Natural Science Foundation of ChinaProject(13PJD029)supported by Shanghai Pujiang ProgramProject(SKLGDUEK1202)supported by State Key Laboratory for GeoMechanics and Deep Underground Engineering,China
基金This work was supported by Polymer Physics Laboratory
文摘The sol/gel phase diagrams were studied for two systems: polyacrylamide/Cr (III) and polyacrylamide/glyoxal. Sol or gel phase could be distinguished according to the concentrations of polymer and crosslinker. The boundary polymer concentration did not depend on the types of gelation and decreased with increasing polymer dimension (molecular weight and conformation). The gelation, which is basically interchain bonding, requires the occurrence of entanglement. The overlap concentration is thus considered as the minimum polymer concentration required for gelation.
文摘The method for the sepration and determination of trace Cr(VI) exiting in mass Cr(III) has been researched. The method is highly sensitive and less interference, but is simple and useful for analysis trace Cr(VI).
文摘The removal of Cr(III) from aqueous Cr(III) using Arthrobacter nicotianae cells was examined. Cr(III) removal was strongly affected by the pH of the solution and the amounts of Cr(III) removed increased as the pH (1 - 5) of the solution increased. The removal of Cr(III) using the cells was also strongly affected by the Cr(III) concentration of the solution, and obeyed the Langmuir isotherm. The percentage of Cr increased as the cell quantity increased, whereas the amount of Cr (μmol/g dry wt. cells) decreased. The removal of Cr(III) using the cells was very fast, and reached an equilibrium within 6 h from the supply of Cr(III) in the solution. A small amount of Cr(III) absorbed by immobilized cells was desorbed at 30oC;however, most was desorbed at reflux temperature using diluted HCl. Cr(III) adsorption-desorption cycles can be repeated 5 times using immobilized cells. These results have practical implications for industrial wastewater management.
文摘This study herein was investigated the removal of chromium(VI) from an aqueous solution using persimmon tannin gel and its subsequent recovery as chromium(III). At pH 2, Cr(VI) was effectively adsorbed (~80% adsorption) and ppm solution was reduced to Cr(III) on the persimmon gel within 10 min. Although desorption of the Cr(III) species was challenging at 30°, it was increased upon increasing the temperature and was quantitatively desorbed in the presence of 1 M hydrochloric acid under reflux. In addition, although the quantity of retained Cr(VI) on the tannin gel increased upon increasing the chromium concentration of the original aqueous solution, all the desorbed chromium was successfully reduced to Cr(III). Finally, Cr(VI) removal and recovery as Cr(III) was repeated effectively 8 times using the same persimmon tannin gel sample, thus demonstrating the recyclability of this system.
基金financial support from the National Natural Science Foundation of China(No.51979282)the Fundamental Research Funds for the Central Universities of China(No.27RA2108004)。
