News and Views

Sil ica pervap m e m b r a n e Thin porous silica m e m b r a n e s have been deposited on a porous a lumlrm sube t ra te by the sol-gel technique b y re sea rche r s a t Hl rosh tma University. The very well controlled part icle size of the silica sol resu l t s in a relatively sha rp pore size dis tr ibut ion in the membrane , less t h a n a few n m as m e a s u r e d by humid alr permeat ion. The J a p a n e s e group is investigating the pervapora t ion pe r fo rmance of the m e m b r a n e with non-aqueous organic solvent mix tu res and is achieving high pe rmea t ion flux with good separa t ion factors.

Further lnformatlon frorrv Dr M. As aeda or Dr IL Okazakl, Department of Chemical Engineering, Hlroshima University, Higashl.Hlroshima 724, Japan. Tel +81 824 22 7111 (ext3614). Fax +81 824 22 7191.

Metal interca lated c lays Intercalat ion c o m p o u n d s are a type of compound in which a toms , ions, or molecules are t rapped between layers in a crysta l lattice. There Is no formal chemical bonding between the hos t crysta l and the t r apped molecules. Mlcroporous meta l intercalated clays have been sugges ted a s possible mater ia l s for appl icat ions in catalysis, adsorp t ion and molecular selecttvtty, and work on these mater ia l s is being u n d e r t a k e n a t the Pennsylvania Sta te University, USA.

Sr idhar Komarnen l h a s intercalated s w e l l i n g - ~ layer silicates, such as montmoril lonlte, with 4-5 A clusters of copper and nickel meta l us ing a n in-si tu reduct ion process . The meta l c luster intercalates p rop the silicate layers apar t , Jus t as ceramic oxides do in pln~red clays, leading to microporous mater ials .

Although the me ta l intercalated clay nanocompos i tes are not as s table as pillared clays, intercalated meta l c lus ters of these d imens ions are expected to behave very differently f rom the bu lk meta l and m~y prove to be versati le catalysts . The mlcropore surface a reas es t imated from BET monolayer capaci ty of water a n d ni trogen are

2 2 approxlm~tely 200 m /g and 120 m /g, respectively. Although these surface a reas are smaller than those of pillared clays (200-400 m2/g), Komarneni expects tha t fur ther optlmlzat ion in process ing should lead to higher surface areas .

Further Informatlon from: Dr Srldhar KomarnenL Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA. Tel +1 814 865 1542. Fax +1 814 865 2326.

Templates for ceramics High-per formance ceramic m e m b r a n e s are being m a n u f a c t u r e d us ing hybrid orgAnic-ceramic templates b y Cape Cod Research Inc, of E a s t F~lmouth, Massachuse t t s , USA. The c o m p a n y s ta r t s with a hybr id template s t ruc tu re tha t consis ts of a propr ie tary organic p h a s e a n d a n inorganic component , usua l ly a lumina or silica.

The organic phase h a s an u n u s u a l l y regular s t ruc tu re m more organized th~n m o s t templa tes it Is cl~tmed - - which fixes the pa t t e rn of the ceramic phase s on the template . When the templa te is fired to drive off the organics the res idue is a ceramic m e m b r a n e set in the pa t t e rn of the o ~ orgamc molecule. By changing the rat io of the p recursors and t inkering with the organic phA~qe's molecular s t ructure , r e sea rche r s can tailor m e m b r a n e s t ruc ture and performance . Cape Cod Research is current ly p lanning to file for a pa ten t and is looking for pa r tne r s to p u r s u e Joint appl icat ion developments .

Further lnformatlon frorrc Brian G. Dixon, Cape Cod Research Inc, 19 Research Road, Eas t Falmouth, MA 02536, USA. Tel +I 508 540 4400. Fax +1 508 540 4428.

Membrane Techno logy Seminar Osmonics is to sponsor a seminar on Membrane Technology on April 21 a n d 22 in Minnetor~kA~ Minnesota, USA.

The seminar entit led 'Crossflow Membrane Filtration' will be oriented toward m a n a g e r s or pe r sons responsible for water t rea tment , pollution control or p rocess engineering. Topics c o v ~ e d include the u se of crossflow RO, UF, NF and MF m e m b r a n e s for industr ial water t rea tment , medica l / pha rmaceu t i ca l water t rea tment , was te water reclAmAtion a n d the recovery of meta l salts, oils and other organics f rom was te or p rocess s t reams. The seminar will cover the fundamen ta l s of reverse osmosis , ultraflltration, nanofi l t rat ion a n d microWtration, total sys tem design considerat ions, s torage a n d distr ibution of water, and the 'zero-discharge ' app roach to pollution control. Hands -on equ ipment operat ion, main tenance , s t a r t -up a n d repai r a re included.

Further Informatlon fron~" Bet te Nelson, Travel & Seminar Coordinator, Osmon~cs Inc, 5951 Clearwater Drive, Minnetonka, MN55343-8990, U S ~ Tel: +1 612 933 2277.

M e m b r a n e T e c h n o l o g y No. 2 9 5