The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-poly...The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.展开更多
Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas t...Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas temperature, feeding rate of activated carbon, polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs) concentration at the inlet of the air pollution control device (APCD), filter materials, pressure drop on PCDDs/Fs removal efficiency are reviewed and commented upon in this paper. Evaluation on the various mechanistic models for entrained flow adsorption is carried out based on the computational simulation in terms of the actual operating condition and theoretical analysis. Finally, an advancement of en- trained flow adsorption in combination of dual bag filter is introduced.展开更多
Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were mea...Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.展开更多
In this paper, the thermodynamic parameters are calculated for all gaseous Poly Chlorinat Dibenzo-p-dioxins （PCDDs） using the Density Functional Theory （DFF） method and both the enthalpy of formation （ΔfH^0） an...In this paper, the thermodynamic parameters are calculated for all gaseous Poly Chlorinat Dibenzo-p-dioxins （PCDDs） using the Density Functional Theory （DFF） method and both the enthalpy of formation （ΔfH^0） and Gibbs free energy of formation （Δf G^0） are derived, from which the order of stability of individual congeners is then predicted. All these properties, together with the calculated entropies （ S^0） and heat capacities （ Cp）, are presented as a function of the number of chlorine atoms in the various PCDD molecules. The accuracy of the method used here, is evaluated by comparing the thermodynamic parameters of gaseous chlorobenzenes with experimental values collected from literature.展开更多
For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the...For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the Ya-Er Lake area . Total concentrations of PCDDs from 70 to 1.6 ×105 ng/kg dw ,median 7.9×104 ng/kg dw and of PCDFs from 1.8 to 1.8 ×104ng/kg dw ,median 9.2 ×103 ng/kg dw were measured . The internaional toxic equivalents (I-TEQ) varied from 0.14 to 8.1×10 2 ng/kg dw,median 4.1×102 ng/kg dw The PCDDs pattern showed that the concentration of OCDD was significantly higher than that of the low chlorinated congeners . The results indicated that parts of Ya-Er Lake are heavily pollutad by there chiorinated compounds. Comparison of our results with the pattern of sediments showed significant differences . The asults are of special importance bocause the pollution that affected Ya-Er Lake may spread to agricultural land and the Changjiang River.展开更多
Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO...Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO_(x)-FeO_(x)/TiO_(2) catalyst prepared via mechanochemically method was investigated for the catalytic removal of PCDD/Fs.The removal efficiency of 1,2-DCBz,pure PCDD/Fs gas generated in the lab,PCDD/Fs from actual fue gas,long-term were studied,and the degradation mechanism was explored using FTIR and TOFMS.The degradation efficiency of 1,2-DCBz and PCDD/Fs on VO_(x)-FeO_(x)/TiO_(2) were higher than that of VO_(x)/TiO_(2)catalyst,and the optimal FeOx addition ratio was 3 wt.%.The characterization results show that the addition of FeOx can effectively improve the pore structure,surface acidity,and VOx dispersion of the catalyst,thus contributing to increasing the V^(5+)content and surface-active oxygen,which is conducive to the improvement of adsorption and redox performance of the catalyst.Under the actual MSWI (municipal solid waste incineration)fue gas,the PCDD/Fs removal efficiency over VTi-3Fe-MC maintained long-term stability,higher than 85%for 240 min.This result was not significantly reduced compared with the data obtained in the laboratory.According to the analysis results of intermediate products by FTIR and GC-TOFMS,it can be inferred that the epoxidation fracture of benzene ring is the rate-limiting step of dioxin catalytic degradation reaction.This work gives an in-depth view into the PCDD/Fs removal over VO_(x)-FeO_(x)/TiO_(2) catalysts and could provide guidelines for the rational design of reliable catalysts for industrial applications.展开更多
基金TheNationalKeyBasicResearchFoundationofChina (No .G1 9990 4 571 1 )
文摘The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.
基金Project supported by the National Basic Research Program (973) of China (No. G1999022211) and the National Natural Science Founda-tion of China (No. N59836210)
文摘Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas temperature, feeding rate of activated carbon, polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs) concentration at the inlet of the air pollution control device (APCD), filter materials, pressure drop on PCDDs/Fs removal efficiency are reviewed and commented upon in this paper. Evaluation on the various mechanistic models for entrained flow adsorption is carried out based on the computational simulation in terms of the actual operating condition and theoretical analysis. Finally, an advancement of en- trained flow adsorption in combination of dual bag filter is introduced.
基金supported by National Research Program (No. 2003CB415005)"Youth Chen-Guang Project" of Wuhan Bureau of Science and Technology (No. 200750731259).
文摘Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.
文摘In this paper, the thermodynamic parameters are calculated for all gaseous Poly Chlorinat Dibenzo-p-dioxins （PCDDs） using the Density Functional Theory （DFF） method and both the enthalpy of formation （ΔfH^0） and Gibbs free energy of formation （Δf G^0） are derived, from which the order of stability of individual congeners is then predicted. All these properties, together with the calculated entropies （ S^0） and heat capacities （ Cp）, are presented as a function of the number of chlorine atoms in the various PCDD molecules. The accuracy of the method used here, is evaluated by comparing the thermodynamic parameters of gaseous chlorobenzenes with experimental values collected from literature.
文摘For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the Ya-Er Lake area . Total concentrations of PCDDs from 70 to 1.6 ×105 ng/kg dw ,median 7.9×104 ng/kg dw and of PCDFs from 1.8 to 1.8 ×104ng/kg dw ,median 9.2 ×103 ng/kg dw were measured . The internaional toxic equivalents (I-TEQ) varied from 0.14 to 8.1×10 2 ng/kg dw,median 4.1×102 ng/kg dw The PCDDs pattern showed that the concentration of OCDD was significantly higher than that of the low chlorinated congeners . The results indicated that parts of Ya-Er Lake are heavily pollutad by there chiorinated compounds. Comparison of our results with the pattern of sediments showed significant differences . The asults are of special importance bocause the pollution that affected Ya-Er Lake may spread to agricultural land and the Changjiang River.
基金supported by the Natural Science Foundation of Zhejiang Province (No. LY21E060007)the National Natural Science Foundation of China (No. 52006191)。
文摘Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO_(x)-FeO_(x)/TiO_(2) catalyst prepared via mechanochemically method was investigated for the catalytic removal of PCDD/Fs.The removal efficiency of 1,2-DCBz,pure PCDD/Fs gas generated in the lab,PCDD/Fs from actual fue gas,long-term were studied,and the degradation mechanism was explored using FTIR and TOFMS.The degradation efficiency of 1,2-DCBz and PCDD/Fs on VO_(x)-FeO_(x)/TiO_(2) were higher than that of VO_(x)/TiO_(2)catalyst,and the optimal FeOx addition ratio was 3 wt.%.The characterization results show that the addition of FeOx can effectively improve the pore structure,surface acidity,and VOx dispersion of the catalyst,thus contributing to increasing the V^(5+)content and surface-active oxygen,which is conducive to the improvement of adsorption and redox performance of the catalyst.Under the actual MSWI (municipal solid waste incineration)fue gas,the PCDD/Fs removal efficiency over VTi-3Fe-MC maintained long-term stability,higher than 85%for 240 min.This result was not significantly reduced compared with the data obtained in the laboratory.According to the analysis results of intermediate products by FTIR and GC-TOFMS,it can be inferred that the epoxidation fracture of benzene ring is the rate-limiting step of dioxin catalytic degradation reaction.This work gives an in-depth view into the PCDD/Fs removal over VO_(x)-FeO_(x)/TiO_(2) catalysts and could provide guidelines for the rational design of reliable catalysts for industrial applications.
