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Fabrication of charge-mosaic membranes
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Low-pressure reverse osmosis membrane Nitto Denko Corporation h a s developed an improved thin-film composite low pressure reverse osmosis membrane. Spiral w o u n d modules containing the NTR-759 HR m e m b r a n e have been tested in the production of ultrapure water. Published results (Membrane, 16 (4), 1991, 223-232) indicate that the NTR-759 HR exhibits up to 99.5% NaCI rejection, 99.9% Na2SO4 rejection and 96% isopropanol rejection when tested at 1.5 MPa and 25°C on 1500 ppm solution. High permeate flux combined with good chloramine resistance were obtained at low operating pressures. Kenichi Ikeda, Nitto Denko Corporation, 61-7, Aza-sasatani, Yamadera-cho, Kusatsu-city, Shiga 525, Japan.
F a b r i c a t i o n of charge- mosaic membranes Practical applications of charge-mosaic m e m b r a n e s are predicted soon by J a p a n e s e researchers (Membrane, 16 (4), 1991, 233-238). In these studies m e m b r a n e s were fabricated from pentablock copolymers of the BABCB type w polyflsopr ene-b-styrene-b-butadiene-b-(4-vlnylbenzyl) dimethylamine-b-isoprene) J by selectively introducing anion- a n d catlon-exchange groups into the micro-separated phases. The three layer lamellar structure of the pentablock copolymer films was not disturbed by the modification. Membranes showed negative osmosis for aqueous solutions of salts and highly selective transport for sodium chloride in mixed solutions of low molecular weight organic non-electrolytes and sodium chloride when the m e m b r a n e s were applied to a dialysis process. Selectivity was reported to be m u c h higher t h a n with conventional porous, reverse osmosis and dialysis m e m b r a n e s .
Exxon buys stake in Z e n o n Continuing its series of investments in companies developing m e m b r a n e technology, Exxon Chemical Co
2
has acquired a 20% interest in Zenon Environmental Systems Inc, a Canadian c o m p a n y specializing in treatment and recycling of industrial pollutants. Zenon Environmental Systems is a subsidiary of Zenon Environmental Inc of Burlington, Ontario.
Groundwater aromatics removed Crossflow filtration m e m b r a n e s are to be used to treat groundwater contaminated wlth polycyclic aromatic compounds, including n a p h t h a l e n e - - claimed by m e m b r a n e producer X-Flow of Vriezenveen, NL, to be the first application of its kind. The X-Flow system is based on the use of PES, with the m e m b r a n e s m o u n t e d on stainless steel a n d with PVC housings. Filtration surfaces generally range from 0. I m 2 up to i0 m 2. The order, placed by ESD in Delfzfl, is for 500 m 2 of m e m b r a n e area to treat 30 m 3 / h o u r of drinking water. The scheme should come on-line in March 1992.
Software predicts molecule / surface interactions Researchers at the University of Pennsylvania have found that for the prediction of the interactions between newly-developed molecules and water as few as 90 water molecules will do what billions of molecules will do when they encounter an oily or a water-absorbing surface. They claim t h a t a software program developed for a table top workstation can now remove the need for involved a n d expensive supercomputer analysis - - the work can be done in a few days by one person. J o s e p h H a u t m a n a n d Michael Klein found that a cluster of 90 water molecules ~ l l form into a droplet when coming in contact with a neutral surface b u t will spread on a surface containing charges. Scientists could not a s s u m e t h a t this was going to be the case because in a small group of molecules a larger proportion of necessity sit on the surface rather t h a n in the interior. Molecules on surfaces have different properties to their inner counterparts: they can be more reactive because they have an exposed side, while interior molecules are completely s u r r o u n d e d by other molecules. Speaking at the Fall meeting of the Materials Research Society, Professor Klein found it: "strange that nobody had done this before. Everything was
Membrane Technology
Low-pressure reverse osmosis membrane Nitto Denko Corporation h a s developed an improved thin-film composite low pressure reverse osmosis membrane. Spiral w o u n d modules containing the NTR-759 HR m e m b r a n e have been tested in the production of ultrapure water. Published results (Membrane, 16 (4), 1991, 223-232) indicate that the NTR-759 HR exhibits up to 99.5% NaCI rejection, 99.9% Na2SO4 rejection and 96% isopropanol rejection when tested at 1.5 MPa and 25°C on 1500 ppm solution. High permeate flux combined with good chloramine resistance were obtained at low operating pressures. Kenichi Ikeda, Nitto Denko Corporation, 61-7, Aza-sasatani, Yamadera-cho, Kusatsu-city, Shiga 525, Japan.
F a b r i c a t i o n of charge- mosaic membranes Practical applications of charge-mosaic m e m b r a n e s are predicted soon by J a p a n e s e researchers (Membrane, 16 (4), 1991, 233-238). In these studies m e m b r a n e s were fabricated from pentablock copolymers of the BABCB type w polyflsopr ene-b-styrene-b-butadiene-b-(4-vlnylbenzyl) dimethylamine-b-isoprene) J by selectively introducing anion- a n d catlon-exchange groups into the micro-separated phases. The three layer lamellar structure of the pentablock copolymer films was not disturbed by the modification. Membranes showed negative osmosis for aqueous solutions of salts and highly selective transport for sodium chloride in mixed solutions of low molecular weight organic non-electrolytes and sodium chloride when the m e m b r a n e s were applied to a dialysis process. Selectivity was reported to be m u c h higher t h a n with conventional porous, reverse osmosis and dialysis m e m b r a n e s .
Exxon buys stake in Z e n o n Continuing its series of investments in companies developing m e m b r a n e technology, Exxon Chemical Co
2
has acquired a 20% interest in Zenon Environmental Systems Inc, a Canadian c o m p a n y specializing in treatment and recycling of industrial pollutants. Zenon Environmental Systems is a subsidiary of Zenon Environmental Inc of Burlington, Ontario.
Groundwater aromatics removed Crossflow filtration m e m b r a n e s are to be used to treat groundwater contaminated wlth polycyclic aromatic compounds, including n a p h t h a l e n e - - claimed by m e m b r a n e producer X-Flow of Vriezenveen, NL, to be the first application of its kind. The X-Flow system is based on the use of PES, with the m e m b r a n e s m o u n t e d on stainless steel a n d with PVC housings. Filtration surfaces generally range from 0. I m 2 up to i0 m 2. The order, placed by ESD in Delfzfl, is for 500 m 2 of m e m b r a n e area to treat 30 m 3 / h o u r of drinking water. The scheme should come on-line in March 1992.
Software predicts molecule / surface interactions Researchers at the University of Pennsylvania have found that for the prediction of the interactions between newly-developed molecules and water as few as 90 water molecules will do what billions of molecules will do when they encounter an oily or a water-absorbing surface. They claim t h a t a software program developed for a table top workstation can now remove the need for involved a n d expensive supercomputer analysis - - the work can be done in a few days by one person. J o s e p h H a u t m a n a n d Michael Klein found that a cluster of 90 water molecules ~ l l form into a droplet when coming in contact with a neutral surface b u t will spread on a surface containing charges. Scientists could not a s s u m e t h a t this was going to be the case because in a small group of molecules a larger proportion of necessity sit on the surface rather t h a n in the interior. Molecules on surfaces have different properties to their inner counterparts: they can be more reactive because they have an exposed side, while interior molecules are completely s u r r o u n d e d by other molecules. Speaking at the Fall meeting of the Materials Research Society, Professor Klein found it: "strange that nobody had done this before. Everything was
Membrane Technology