Polyepoxysuccinic acid (PESA), as an environmental benign biodegradable chelant, was used to remove heavy metals from the sewage sludge of Shanghai Taopu Wastewater Treatment Plant. The extraction of cadmium (Cd) from...Polyepoxysuccinic acid (PESA), as an environmental benign biodegradable chelant, was used to remove heavy metals from the sewage sludge of Shanghai Taopu Wastewater Treatment Plant. The extraction of cadmium (Cd) from sewage sludge using aqueous solution of PESA was studied. It was found that PESA was capable of extracting Cd from the sludge, and the extraction effciency was dependent on both pH and the concentration of the chelating reagent. The extraction effciency decreased gradually with increasing of pH, whereas the dependency on pH decreased as the concentration of PESA increased. In the case of the high PESA to total metal ratio, e.g., 10:1, the extraction effciency reached above 70% within the pH range from 1 to 7. The highest extraction effciency obtained in the experiment was 78%. By comparing the contents of the heavy metals in sewage sludge before and after the extraction, it was found that the extracted Cd came mainly from the four fractions: acid-soluble, reducible, oxidizable, and water-soluble fractions.展开更多
The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the c...The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.展开更多
基金Project supported by the National High Technology Research and Development Program (863 Program) of China(No.2006AA06Z384)the National Natural Science Foundation of China (No. 50478103)
文摘Polyepoxysuccinic acid (PESA), as an environmental benign biodegradable chelant, was used to remove heavy metals from the sewage sludge of Shanghai Taopu Wastewater Treatment Plant. The extraction of cadmium (Cd) from sewage sludge using aqueous solution of PESA was studied. It was found that PESA was capable of extracting Cd from the sludge, and the extraction effciency was dependent on both pH and the concentration of the chelating reagent. The extraction effciency decreased gradually with increasing of pH, whereas the dependency on pH decreased as the concentration of PESA increased. In the case of the high PESA to total metal ratio, e.g., 10:1, the extraction effciency reached above 70% within the pH range from 1 to 7. The highest extraction effciency obtained in the experiment was 78%. By comparing the contents of the heavy metals in sewage sludge before and after the extraction, it was found that the extracted Cd came mainly from the four fractions: acid-soluble, reducible, oxidizable, and water-soluble fractions.
基金This work was supported by the Key Technologies Research and Development Program of the Eleventh-Five Year Plan of China(Grant No.2006BAJ08B02)the Innovation Project of Talented Scientific Youth of Fujian Province in 2008 Year(No.2008F3096).
文摘The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.
