Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recen...Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.展开更多
The novel microwave catalyst MgFe204-SiC was synthesized via sol-gel method, to remove azo dye Direct Black BN （DB BN） through adsorption and microwave-induced catalytic reaction. Microwave- induced catalytic degrad...The novel microwave catalyst MgFe204-SiC was synthesized via sol-gel method, to remove azo dye Direct Black BN （DB BN） through adsorption and microwave-induced catalytic reaction. Microwave- induced catalytic degradation of DB BN, including adsorption behavior and its influencing Factors of DB BN on MgFc204-SiC were investigated. According to the obtained results, il indicated thai the pseudo-second-order kinetics model was suitable fbr the adsorption of DB BN onto MgFc204-SiC. Besides, the consequence of adsorption isotherm depicted that the adsorption of DB BN was in accordance with the Langmuir isotherm, which verified that the singer layer adsorption of MgF%O4- SiC was dominant than the multi-layer one. The excellent adsorption capacities of MgFe204-SiC were kept in the range of initial pH from 3 to 7. In addition, it could be concluded that the degradation rate of DB BN decreased over ten percent after the adsorption equilibrium had been attained, and thc results from the result of comparative experiments manitbsted that the adsorption process was not conducive to the process of microwave-induced catalytic degradation. The degradation intermediates and products of DB BN were identified and determined by GC-MS and LC-MS. Furthermore, combined with the catalytic mechanism of MgFe204-SiC, the proposed degradation pathways of DB BN were the involution of microwave-induced OH and holes in this catalytic system the breakage of azo bond, hydroxyl substitution, hydroxyl addition, nitration reaction, dcamination reaction, dcsorbate reaction, dehydroxy group and ring-opening reaction.展开更多
基金supported by the National Natural Science Foundation of China(No.41671493)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF17030)the National Major Project of the Science and Technology Ministry of China(No.2017ZX07202-004 and 2017X07301002-3)。
文摘Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.
文摘The novel microwave catalyst MgFe204-SiC was synthesized via sol-gel method, to remove azo dye Direct Black BN （DB BN） through adsorption and microwave-induced catalytic reaction. Microwave- induced catalytic degradation of DB BN, including adsorption behavior and its influencing Factors of DB BN on MgFc204-SiC were investigated. According to the obtained results, il indicated thai the pseudo-second-order kinetics model was suitable fbr the adsorption of DB BN onto MgFc204-SiC. Besides, the consequence of adsorption isotherm depicted that the adsorption of DB BN was in accordance with the Langmuir isotherm, which verified that the singer layer adsorption of MgF%O4- SiC was dominant than the multi-layer one. The excellent adsorption capacities of MgFe204-SiC were kept in the range of initial pH from 3 to 7. In addition, it could be concluded that the degradation rate of DB BN decreased over ten percent after the adsorption equilibrium had been attained, and thc results from the result of comparative experiments manitbsted that the adsorption process was not conducive to the process of microwave-induced catalytic degradation. The degradation intermediates and products of DB BN were identified and determined by GC-MS and LC-MS. Furthermore, combined with the catalytic mechanism of MgFe204-SiC, the proposed degradation pathways of DB BN were the involution of microwave-induced OH and holes in this catalytic system the breakage of azo bond, hydroxyl substitution, hydroxyl addition, nitration reaction, dcamination reaction, dcsorbate reaction, dehydroxy group and ring-opening reaction.
