Co60 gamma ray radiolysis of aqueous oxalic acid solution （1 × 10-2 M） was investigated within the dose range up to 80 kGy. The value of pH increases from 2.0 to 4.0 and approximately 90% of oxalic acid and its...Co60 gamma ray radiolysis of aqueous oxalic acid solution （1 × 10-2 M） was investigated within the dose range up to 80 kGy. The value of pH increases from 2.0 to 4.0 and approximately 90% of oxalic acid and its derivatives are degraded at the dose of 80 kGy. Dissolved O2 affects to the degradation of oxalic acid at the initial stage due to total consumption of O2 at the dose of 2 kGy. Formation of CO2 occurs at a higher rate at the initial stage until the dissolved 02 is fully consumed. The kinetic model of oxalic acid degradation in aqueous solution under the gamma irradiation was tested. The suggested mechanism complies with the experimental data both of our own and of that reported earlier.展开更多
The electrochemical degradation of reed pulp black liquor containing lignin pretreated by acidification method was investigated using a three-dimensional electrode reactor. Using activated carbon as particle electrode...The electrochemical degradation of reed pulp black liquor containing lignin pretreated by acidification method was investigated using a three-dimensional electrode reactor. Using activated carbon as particle electrode, the effects of p H value, reaction temperature, electrolysis time and current on residual concentration of total organic carbon(TOC) were discussed in detail. The optimal conditions were obtained: pH 2.5, influent flow rate of 200 mL/min, 25 °C, 300 mA and 2h of electrolysis time, and the removal efficiency of TOC maintains at 35.57 %. The results of the electrochemical method indicate that ·OH radicals are produced in activated carbon anode in the electrolysis process and then adsorbed on the activated carbon surface. Microcell consists of ·OH radicals and the absorbed lignin. With the microcell reaction, the lignin is degraded, while the anodic polarized curve illustrates that the lignin is obviously oxidized in the anode. The contributions of direct and indirect electrolyses to the TOC removal ratio are about 50%, respectively.展开更多
A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scann...A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scanning calorimetry）. Rates of thermal and photochemical degradation are determined by measuring the relative changes of absorbance （A/Ao） of selected bands in PLA （polylactic acid） spectra. Comparison of the effect of both degradation on PLA structure showed that nanosilver act as a stabilizer for photodegradation at 254 nm. As oppose, thermal degradation at 80 ~C indicate, that nanosilver accelerates PLA degradation at the temperature. Glass transition and crystallization/melting processes occurring in PLA and PLA/Ag nanocomposites during both degradation processes were also compared.展开更多
文摘Co60 gamma ray radiolysis of aqueous oxalic acid solution （1 × 10-2 M） was investigated within the dose range up to 80 kGy. The value of pH increases from 2.0 to 4.0 and approximately 90% of oxalic acid and its derivatives are degraded at the dose of 80 kGy. Dissolved O2 affects to the degradation of oxalic acid at the initial stage due to total consumption of O2 at the dose of 2 kGy. Formation of CO2 occurs at a higher rate at the initial stage until the dissolved 02 is fully consumed. The kinetic model of oxalic acid degradation in aqueous solution under the gamma irradiation was tested. The suggested mechanism complies with the experimental data both of our own and of that reported earlier.
基金Project(50925417)supported by the National Natureal Science Foundation for Distinguished Young Scholar of ChinaProject(51074191)supported by the National Natural Science Foundation of China
文摘The electrochemical degradation of reed pulp black liquor containing lignin pretreated by acidification method was investigated using a three-dimensional electrode reactor. Using activated carbon as particle electrode, the effects of p H value, reaction temperature, electrolysis time and current on residual concentration of total organic carbon(TOC) were discussed in detail. The optimal conditions were obtained: pH 2.5, influent flow rate of 200 mL/min, 25 °C, 300 mA and 2h of electrolysis time, and the removal efficiency of TOC maintains at 35.57 %. The results of the electrochemical method indicate that ·OH radicals are produced in activated carbon anode in the electrolysis process and then adsorbed on the activated carbon surface. Microcell consists of ·OH radicals and the absorbed lignin. With the microcell reaction, the lignin is degraded, while the anodic polarized curve illustrates that the lignin is obviously oxidized in the anode. The contributions of direct and indirect electrolyses to the TOC removal ratio are about 50%, respectively.
文摘A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scanning calorimetry）. Rates of thermal and photochemical degradation are determined by measuring the relative changes of absorbance （A/Ao） of selected bands in PLA （polylactic acid） spectra. Comparison of the effect of both degradation on PLA structure showed that nanosilver act as a stabilizer for photodegradation at 254 nm. As oppose, thermal degradation at 80 ~C indicate, that nanosilver accelerates PLA degradation at the temperature. Glass transition and crystallization/melting processes occurring in PLA and PLA/Ag nanocomposites during both degradation processes were also compared.
