Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants （HOCs）. The major factors limiting phytoremediation are the mass transfer, ra...Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants （HOCs）. The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. This article discusses the potential of surfactants to enhance desorption, plant uptake, and biodegradation of HOCs in the contaminated sites. Positive effects of surfactants on phytoremediation have been recently observed in greenhouse studies. The presence of some nonionic surfactants including polyoxyethylene sorbltan monooleate （Tween 80） and polyoxyethylene（23）dodecanol （Brij35） at relatively low concentrations resulted in significant positive effects on phytoremediation for pyrene-contaminated soil. However, the anionic surfactant （sodium dodecyl sulfate, SDS） and the cationic surfactant （cetyltrimethylammonium bromide, CTMAB） were not useful because of their phytotoxicity or low efficiency for surfactant-enhanced phytoremediation （SEPR）. The mechanisms of SEPR for HOC-contaminated sites were evaluated by considering experimental observations. In view of concerns about the cost effectiveness and toxicity of surfactants to plants, more research is needed to enhance the use of SEPR technology.展开更多
A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehal...A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehalogenation of organic halides,such as 4'-bromoacetophenone,polyfluoroarenes,cholorobenzene,and 2,2',4,4'-tetrabromodiphenyl ether(a resistant and persistent organic pollu-tant).The strongly reducing singlet excited states of the amines enabled diffusion-controlled disso-ciative electron transfer to effectively cleave carbon-halogen bonds,followed by radical hydrogena-tion.Diisopropylethylamine served as the terminal electron/proton donor and regenerated theamine sensitizers.展开更多
In Kazakhstan, there are obsolete pesticides which should be buried in special dedicated and prepared burial sites or neutralized for minimization of dangerous genetic and ecological risks. The work in two years was i...In Kazakhstan, there are obsolete pesticides which should be buried in special dedicated and prepared burial sites or neutralized for minimization of dangerous genetic and ecological risks. The work in two years was identifying the obsolete pesticides in 91 the former warehouses of chemical plant protection products. In two regions （Almaty and Akmola regions） of Kazakhstan, the total amount of 388.6 tones of obsolete pesticides and unidentified stockpile material was observed, along with 513 pesticide containers. Results of the study have shown that soil around storehouses polluted by organochlorine pesticides residues in soil included metabolites of DDT （p, p＇-dichlorodiphenyltrichloroethane） and HCH （hexachlorocyclohexane）. The strategy was to identify pesticide-tolerant plant genotypes which can be used for phytoremediation of pesticide-contaminated soils in Almaty regions of Kazakhstan. The results have shown that selected wild species plants demonstrated ability to phytoaccumulation of organochlorine metabolites and reduce pesticide concentrations in soil （control without plant）. It was shown that accumulation of pesticides depended on the species of plants, plant biomass and pesticide concentrations in soil. The use of mineral fertilizers resulted in stimulation of growth and biomass accumulation followed by an increasing phytoextraction.展开更多
Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of ...Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of serious pathogens or insects injury. This grass is suitable for multipurpose use, providing forage, bioethanol feedstock and phytoremediation of cadmium （Cd） contaminated soil in Kyushu, Japan. When two cultivars of Napier grass （Wruk wona, WK and Merkeron, ME） were grown in Cd-contaminated soils, dry matter yield and the concentration and uptake of herbage Cd were higher in WK than in ME, and soil Cd concentration was reduced by 14% in a single season of cultivation. A dwarf variety of late-heading type （DL）, Napier grass had superior sustainability for more than 5 years in Miyazaki, Japan, and has gradually increased in cultivation areas for both cut-and-carry and grazing herbage production in cooperation with regional communities. Through the extension in several Kyushu areas, DL Napier grass required temperatures above -6.2 ~C for sustainability in winter, based on its threshold response to the lethal minimum temperature. DL Napier grass pasture can be utilized by grazing beef cattle even in early spring with temperate Italian ryegrass inter-sown into its inter-row spaces. Organic digested animal manure or sun-dried leguminous leaves as green manure can replace chemical fertilizers to reduce energy consumption and allow comparable productivity.展开更多
基金the National Natural Science Foundation of China (No.20507009)the Program for New Century Excellent Talents in University (NCET) of the Ministry of Education of China,the Natural Science Foundation of Jiangsu Province for Outstanding Young Scientist (No.BK2006518)and the International Foundation for Science (No.C/3958-1).
文摘Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants （HOCs）. The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. This article discusses the potential of surfactants to enhance desorption, plant uptake, and biodegradation of HOCs in the contaminated sites. Positive effects of surfactants on phytoremediation have been recently observed in greenhouse studies. The presence of some nonionic surfactants including polyoxyethylene sorbltan monooleate （Tween 80） and polyoxyethylene（23）dodecanol （Brij35） at relatively low concentrations resulted in significant positive effects on phytoremediation for pyrene-contaminated soil. However, the anionic surfactant （sodium dodecyl sulfate, SDS） and the cationic surfactant （cetyltrimethylammonium bromide, CTMAB） were not useful because of their phytotoxicity or low efficiency for surfactant-enhanced phytoremediation （SEPR）. The mechanisms of SEPR for HOC-contaminated sites were evaluated by considering experimental observations. In view of concerns about the cost effectiveness and toxicity of surfactants to plants, more research is needed to enhance the use of SEPR technology.
文摘A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehalogenation of organic halides,such as 4'-bromoacetophenone,polyfluoroarenes,cholorobenzene,and 2,2',4,4'-tetrabromodiphenyl ether(a resistant and persistent organic pollu-tant).The strongly reducing singlet excited states of the amines enabled diffusion-controlled disso-ciative electron transfer to effectively cleave carbon-halogen bonds,followed by radical hydrogena-tion.Diisopropylethylamine served as the terminal electron/proton donor and regenerated theamine sensitizers.
文摘In Kazakhstan, there are obsolete pesticides which should be buried in special dedicated and prepared burial sites or neutralized for minimization of dangerous genetic and ecological risks. The work in two years was identifying the obsolete pesticides in 91 the former warehouses of chemical plant protection products. In two regions （Almaty and Akmola regions） of Kazakhstan, the total amount of 388.6 tones of obsolete pesticides and unidentified stockpile material was observed, along with 513 pesticide containers. Results of the study have shown that soil around storehouses polluted by organochlorine pesticides residues in soil included metabolites of DDT （p, p＇-dichlorodiphenyltrichloroethane） and HCH （hexachlorocyclohexane）. The strategy was to identify pesticide-tolerant plant genotypes which can be used for phytoremediation of pesticide-contaminated soils in Almaty regions of Kazakhstan. The results have shown that selected wild species plants demonstrated ability to phytoaccumulation of organochlorine metabolites and reduce pesticide concentrations in soil （control without plant）. It was shown that accumulation of pesticides depended on the species of plants, plant biomass and pesticide concentrations in soil. The use of mineral fertilizers resulted in stimulation of growth and biomass accumulation followed by an increasing phytoextraction.
文摘Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of serious pathogens or insects injury. This grass is suitable for multipurpose use, providing forage, bioethanol feedstock and phytoremediation of cadmium （Cd） contaminated soil in Kyushu, Japan. When two cultivars of Napier grass （Wruk wona, WK and Merkeron, ME） were grown in Cd-contaminated soils, dry matter yield and the concentration and uptake of herbage Cd were higher in WK than in ME, and soil Cd concentration was reduced by 14% in a single season of cultivation. A dwarf variety of late-heading type （DL）, Napier grass had superior sustainability for more than 5 years in Miyazaki, Japan, and has gradually increased in cultivation areas for both cut-and-carry and grazing herbage production in cooperation with regional communities. Through the extension in several Kyushu areas, DL Napier grass required temperatures above -6.2 ~C for sustainability in winter, based on its threshold response to the lethal minimum temperature. DL Napier grass pasture can be utilized by grazing beef cattle even in early spring with temperate Italian ryegrass inter-sown into its inter-row spaces. Organic digested animal manure or sun-dried leguminous leaves as green manure can replace chemical fertilizers to reduce energy consumption and allow comparable productivity.
