The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform
Ted S Oyama - One of the best experts on this subject based on the ideXlab platform.
-
supported Perfluorotributylamine liquid membrane for h2 o2 separation
Journal of Membrane Science, 2013Co-Authors: Bernardo Castrodominguez, Pornravee Leelachaikul, Atsushi Takagaki, Takashi Sugawara, Ryuji Kikuchi, Ted S OyamaAbstract:Abstract Photocatalytic water splitting is the cleanest method to produce H2, but often requires the removal of O2, which is simultaneously generated. To achieve this separation, use was made of supported liquid membranes formed from Perfluorotributylamine (PFTBA) imbued in porous alumina supports. The PFTBA membranes were subject to single and mixed H2/O2 gas permeance tests at room temperature and showed a sieving transport behavior. The membranes had an average H2/O2 selectivity of 140 with a H2 permeability of 4500 barrers. The performance of the membrane showed only a slight dependence with increases of temperature and gas flow rate, but these increases reduced the lifetime of the membranes because of enhanced volatilization of the Perfluoro Compound. Studies showed that at small support pore sizes, the membrane displayed longer lifetime because of reduced vapor pressure of the liquid inside the porous support. A partial pressure analysis revealed that the selectivity improved when the partial pressure of the gases was reduced. Additionally, it was shown that separation at humid conditions reduced the stability of the membrane, but did not affect its permeance. The diffusivity and solubility of the gases across the membrane were obtained by the time-lag technique. It was found that H2 has higher solubility and diffusivity than O2 giving rise to a higher overall permeance for the smaller sized gas.
Wassenaar Pnh - One of the best experts on this subject based on the ideXlab platform.
-
Water quality standards for PFOA : A proposal in accordance with the methodology of the Water Framework Directive
Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2017Co-Authors: Verbruggen Emj, Wassenaar PnhAbstract:RIVM proposes water quality standards for PFOA. This Perfluoro Compound has been used for the production of teflon and is found in many surface waters around the world. The quality standard for chronic exposure accounts for the accumulation of PFOA in fish. Using this information, RIVM calculated a safe concentration in water of 48 nanograms per liter, which is protective for lifetime consumption of fish by humans and wildlife. For this research an extensive overview was made of the scientific data on effects of PFOA on aquatic organisms and the accumulation in biota. Based on the oral risk limit for humans as derived recently by RIVM, a maximum allowable concentration in fish was calculated assuming a lifetime daily consumption. This biota standard is converted to an equivalent safe concentration in water using information on the uptake of PFOA from water by fish. Data on bioaccumulation are needed because the water quality standard for ecological effects on aquatic organisms is not sufficiently protective for food chain effects. PFOA has a relatively low toxicity for water organisms, but may pose a problem when entering the food chain via fish. The use of PFOA is restricted by European law, but it can still reach the environment from PFOA-containing products that were produced in the past. Because of its high persistence, emissions will lead to long term presence in the environment. An initial comparison with monitoring data indicates that the safe concentration derived in this research is not exceeded in Dutch surface waters
-
Waterkwaliteitsnormen voor PFOA : Een voorstel volgens de methodiek van de Kaderrichtlijn Water
'Journal of Wildlife Management', 2017Co-Authors: Verbruggen Emj, Wassenaar PnhAbstract:RIVM proposes water quality standards for PFOA. This Perfluoro Compound has been used for the production of teflon and is found in many surface waters around the world. The quality standard for chronic exposure accounts for the accumulation of PFOA in fish. Using this information, RIVM calculated a safe concentration in water of 48 nanograms per liter, which is protective for lifetime consumption of fish by humans and wildlife. For this research an extensive overview was made of the scientific data on effects of PFOA on aquatic organisms and the accumulation in biota. Based on the oral risk limit for humans as derived recently by RIVM, a maximum allowable concentration in fish was calculated assuming a lifetime daily consumption. This biota standard is converted to an equivalent safe concentration in water using information on the uptake of PFOA from water by fish. Data on bioaccumulation are needed because the water quality standard for ecological effects on aquatic organisms is not sufficiently protective for food chain effects. PFOA has a relatively low toxicity for water organisms, but may pose a problem when entering the food chain via fish. The use of PFOA is restricted by European law, but it can still reach the environment from PFOA-containing products that were produced in the past. Because of its high persistence, emissions will lead to long term presence in the environment. An initial comparison with monitoring data indicates that the safe concentration derived in this research is not exceeded in Dutch surface waters.Het RIVM doet een voorstel voor waterkwaliteitsnormen voor PFOA. Deze perfluorverbinding is jarenlang gebruikt bij de productie van teflon en wordt overal ter wereld in het oppervlaktewater aangetroffen. De norm voor de langetermijn-blootstelling houdt rekening met de mate waarin PFOA zich ophoopt in vis. Met die informatie heeft het RIVM berekend dat een concentratie van 48 nanogram per liter veilig is als mensen, vogels en zoogdieren hun leven lang vis uit dat water zouden eten. Voor dit onderzoek is een uitgebreid overzicht gemaakt van wat er in de wetenschappelijke literatuur bekend is over de effecten van PFOA op waterorganismen en in welke mate ze deze stof opnemen. In eerder onderzoek heeft het RIVM bepaald hoeveel een mens van de stof zou mogen binnenkrijgen zonder daar schadelijke gevolgen van te ondervinden. Vervolgens is berekend wat er maximaal in vis zou mogen zitten als mensen elke dag gedurende hun hele leven vis zouden eten. Deze waarde in vis is vertaald naar een veilige concentratie in water. Dit is gedaan met behulp van gegevens over de mate waarin vissen PFOA opnemen vanuit het water. Deze werkwijze is gevolgd omdat de voedselketen onvoldoende wordt beschermd door de ecologische norm voor waterorganismen. PFOA is relatief weinig giftig voor waterorganismen zelf, maar kan een probleem vormen als de stof via vis in de voedselketen terechtkomt. Het gebruik van PFOA is in Europa inmiddels aan banden gelegd, maar kan nog wel vrijkomen uit producten waarin de stof in het verleden is verwerkt. Omdat PFOA nauwelijks afbreekt, zullen restanten nog lang in het milieu aanwezig blijven. Uit een eerste vergelijking met meetgegevens blijkt echter dat de veilige concentratie momenteel niet wordt overschreden in Nederlands oppervlaktewaterMinisterie van I&
Verbruggen Emj - One of the best experts on this subject based on the ideXlab platform.
-
Water quality standards for PFOA : A proposal in accordance with the methodology of the Water Framework Directive
Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2017Co-Authors: Verbruggen Emj, Wassenaar PnhAbstract:RIVM proposes water quality standards for PFOA. This Perfluoro Compound has been used for the production of teflon and is found in many surface waters around the world. The quality standard for chronic exposure accounts for the accumulation of PFOA in fish. Using this information, RIVM calculated a safe concentration in water of 48 nanograms per liter, which is protective for lifetime consumption of fish by humans and wildlife. For this research an extensive overview was made of the scientific data on effects of PFOA on aquatic organisms and the accumulation in biota. Based on the oral risk limit for humans as derived recently by RIVM, a maximum allowable concentration in fish was calculated assuming a lifetime daily consumption. This biota standard is converted to an equivalent safe concentration in water using information on the uptake of PFOA from water by fish. Data on bioaccumulation are needed because the water quality standard for ecological effects on aquatic organisms is not sufficiently protective for food chain effects. PFOA has a relatively low toxicity for water organisms, but may pose a problem when entering the food chain via fish. The use of PFOA is restricted by European law, but it can still reach the environment from PFOA-containing products that were produced in the past. Because of its high persistence, emissions will lead to long term presence in the environment. An initial comparison with monitoring data indicates that the safe concentration derived in this research is not exceeded in Dutch surface waters
-
Waterkwaliteitsnormen voor PFOA : Een voorstel volgens de methodiek van de Kaderrichtlijn Water
'Journal of Wildlife Management', 2017Co-Authors: Verbruggen Emj, Wassenaar PnhAbstract:RIVM proposes water quality standards for PFOA. This Perfluoro Compound has been used for the production of teflon and is found in many surface waters around the world. The quality standard for chronic exposure accounts for the accumulation of PFOA in fish. Using this information, RIVM calculated a safe concentration in water of 48 nanograms per liter, which is protective for lifetime consumption of fish by humans and wildlife. For this research an extensive overview was made of the scientific data on effects of PFOA on aquatic organisms and the accumulation in biota. Based on the oral risk limit for humans as derived recently by RIVM, a maximum allowable concentration in fish was calculated assuming a lifetime daily consumption. This biota standard is converted to an equivalent safe concentration in water using information on the uptake of PFOA from water by fish. Data on bioaccumulation are needed because the water quality standard for ecological effects on aquatic organisms is not sufficiently protective for food chain effects. PFOA has a relatively low toxicity for water organisms, but may pose a problem when entering the food chain via fish. The use of PFOA is restricted by European law, but it can still reach the environment from PFOA-containing products that were produced in the past. Because of its high persistence, emissions will lead to long term presence in the environment. An initial comparison with monitoring data indicates that the safe concentration derived in this research is not exceeded in Dutch surface waters.Het RIVM doet een voorstel voor waterkwaliteitsnormen voor PFOA. Deze perfluorverbinding is jarenlang gebruikt bij de productie van teflon en wordt overal ter wereld in het oppervlaktewater aangetroffen. De norm voor de langetermijn-blootstelling houdt rekening met de mate waarin PFOA zich ophoopt in vis. Met die informatie heeft het RIVM berekend dat een concentratie van 48 nanogram per liter veilig is als mensen, vogels en zoogdieren hun leven lang vis uit dat water zouden eten. Voor dit onderzoek is een uitgebreid overzicht gemaakt van wat er in de wetenschappelijke literatuur bekend is over de effecten van PFOA op waterorganismen en in welke mate ze deze stof opnemen. In eerder onderzoek heeft het RIVM bepaald hoeveel een mens van de stof zou mogen binnenkrijgen zonder daar schadelijke gevolgen van te ondervinden. Vervolgens is berekend wat er maximaal in vis zou mogen zitten als mensen elke dag gedurende hun hele leven vis zouden eten. Deze waarde in vis is vertaald naar een veilige concentratie in water. Dit is gedaan met behulp van gegevens over de mate waarin vissen PFOA opnemen vanuit het water. Deze werkwijze is gevolgd omdat de voedselketen onvoldoende wordt beschermd door de ecologische norm voor waterorganismen. PFOA is relatief weinig giftig voor waterorganismen zelf, maar kan een probleem vormen als de stof via vis in de voedselketen terechtkomt. Het gebruik van PFOA is in Europa inmiddels aan banden gelegd, maar kan nog wel vrijkomen uit producten waarin de stof in het verleden is verwerkt. Omdat PFOA nauwelijks afbreekt, zullen restanten nog lang in het milieu aanwezig blijven. Uit een eerste vergelijking met meetgegevens blijkt echter dat de veilige concentratie momenteel niet wordt overschreden in Nederlands oppervlaktewaterMinisterie van I&
Bernardo Castrodominguez - One of the best experts on this subject based on the ideXlab platform.
-
supported Perfluorotributylamine liquid membrane for h2 o2 separation
Journal of Membrane Science, 2013Co-Authors: Bernardo Castrodominguez, Pornravee Leelachaikul, Atsushi Takagaki, Takashi Sugawara, Ryuji Kikuchi, Ted S OyamaAbstract:Abstract Photocatalytic water splitting is the cleanest method to produce H2, but often requires the removal of O2, which is simultaneously generated. To achieve this separation, use was made of supported liquid membranes formed from Perfluorotributylamine (PFTBA) imbued in porous alumina supports. The PFTBA membranes were subject to single and mixed H2/O2 gas permeance tests at room temperature and showed a sieving transport behavior. The membranes had an average H2/O2 selectivity of 140 with a H2 permeability of 4500 barrers. The performance of the membrane showed only a slight dependence with increases of temperature and gas flow rate, but these increases reduced the lifetime of the membranes because of enhanced volatilization of the Perfluoro Compound. Studies showed that at small support pore sizes, the membrane displayed longer lifetime because of reduced vapor pressure of the liquid inside the porous support. A partial pressure analysis revealed that the selectivity improved when the partial pressure of the gases was reduced. Additionally, it was shown that separation at humid conditions reduced the stability of the membrane, but did not affect its permeance. The diffusivity and solubility of the gases across the membrane were obtained by the time-lag technique. It was found that H2 has higher solubility and diffusivity than O2 giving rise to a higher overall permeance for the smaller sized gas.
C. E. Smit - One of the best experts on this subject based on the ideXlab platform.
-
water quality standards for melamine a proposal in accordance with the methodology of the water framework directive
2018Co-Authors: C. E. SmitAbstract:RIVM proposes water quality standards for PFOA. This Perfluoro Compound has been used for the production of teflon and is found in many surface waters around the world. The quality standard for chronic exposure accounts for the accumulation of PFOA in fish. Using this information, RIVM calculated a safe concentration in water of 48 nanograms per liter, which is protective for lifetime consumption of fish by humans and wildlife. For this research an extensive overview was made of the scientific data on effects of PFOA on aquatic organisms and the accumulation in biota. Based on the oral risk limit for humans as derived recently by RIVM, a maximum allowable concentration in fish was calculated assuming a lifetime daily consumption. This biota standard is converted to an equivalent safe concentration in water using information on the uptake of PFOA from water by fish. Data on bioaccumulation are needed because the water quality standard for ecological effects on aquatic organisms is not sufficiently protective for food chain effects. PFOA has a relatively low toxicity for water organisms, but may pose a problem when entering the food chain via fish. The use of PFOA is restricted by European law, but it can still reach the environment from PFOA-containing products that were produced in the past. Because of its high persistence, emissions will lead to long term presence in the environment. An initial comparison with monitoring data indicates that the safe concentration derived in this research is not exceeded in Dutch surface waters.