New aspects of application of ion exchangers in water purification

320 been found that Pt can suitably be recovered from TDA solution on an anion exchange bed. This finding indicates that Pt is present in TDA solution as an anionic complex. Platinum sorption is preferably carried out on a Wofatit AD-41 bed; 1 1 of Wofatit AD-41 retained up to 1 g of Pt. Concentrated Pt was recovered by combustion of the anion exchanger. The ashes contained up to 40% wt of Pt. An industrial-scale plant according to the above process was started up. It permits retention of 80-90% of the Pt dissolved in the aqueous TDA. W. R a t a j c z a k a n d K. Zi~borak, R e s e a r c h I n s t i t u t e of I n d u s t r i a l C h e m i s t r y , W a r s a w , P o l a n d : I o n E x c h a n g e Resins in T r e a t m e n t o f Effluents f r o m C u m e n e Synthesis It has been found that macroporous sulphonic acid cation exchangers can completely remove A1Cl3 catalyst from a cumene synthesis mixture. The sorption efficiency increases with reduction of temperature and depends on the water content of the cation exchanger. This finding shows that the process is based not merely on ion exchange but is a result of aluminium salt extraction from the organic phase to the aqueous ion exchanger phase. The crude synthesis mixture containing 0.1 to 0.2% wt A1C13 passed at 50 ° C through a Wofatit KS-10 bed at a space velocity 6-12 h 1 reduces its ion content to less than 2 ppm CI- and less than 1 ppm A13+. One litre of wet cation exchanger retains up to 100 g of AIC13 at 50 ° C. The method presented here makes it possible to reduce the cumene synthesis wastewater volume to 0.1 m3 per 1 ton of cumene product. The wastewater containing more than 5% wt of A1C13 can be utilized in raw water treatment. • I. Haklits, B. Keszler a n d G. Kovfics, R e s e a r c h Institute for the Plastics I n d u s t r y , Budapest, H u n g a r y : A p p l i c a t i o n o f I o n E x c h a n g e R e s i n for P r e p a r a t i o n o f / 3 - C y c l o d e x t r i n O l i g o m e r s Conventional methods for preparation of water-soluble/3-cyclodextrin oligomers yield aqueous solutions with high salt content, which must be removed in a subsequent separation step. A new, sing-step method is suggested in which the polymerization is carried out in the presence of an anion exchange resin. Varion AD, AT, or ATM anion exchangers were used for this purpose at 333 K. In contrast to the bimodal mass distribution of oligomers prepared by conventional methods, that of oligomers from the new process is unimodal. F. Vinczi a n d J. Bfilint, B I O G A L P h a r m a c e u t i c a l W o r k s , D e b r e c e n , H u n g a r y : E x p e r i m e n t s on R e a c t i v e E x t r a c t i o n o f Penicillin G F r o m F e r m e n t a t i o n B r o t h Reactive extraction allows penecillin to be recovered at higher pH under more favorable stability conditions. Penicillin G was extracted from filtered fermentation broth with liquid anion exchanger Amberlite LA-2 in isobutylacetate solution at pH 4.5. This was compared with control extraction at pH 2.5 without anion exchanger. The lesser decomposition loss at higher pH resulted in a higher yield. K l a r a Salacz-Morelli, N a t i o n a l I n s t i t u t e o f Hygiene, Budapest, H u n g a r y : Use o f I o n E x c h a n g e R e s i n s in W a t e r T r e a t m e n t In Hungary, ion exchange resins are used for nitrate removal from drinking water and for production of deionized water for hemodialysis. Based on our studies, the operations must conform with the following specifications: for nitrate removal, (1) continuous measurement of the nitrate level or utilization of no more than 80% of capacity, and (2) continuous disinfection and occasional prechlorination; for hemodialysis, (1) monitoring of release of organic compounds, (2) regeneration every third day, and (3) discharge of two bed volumes of water before start of procedure. V.D. G r e b e n j u k , A.V. D u m a n s k y I n s t i t u t e of C o l l o i d a n d W a t e r C h e m i s t r y , U k r a i n i a n A c a d e m y o f Sciences, Kiev, U S S R : N e w A s p e c t s of A p p l i c a t i o n of I o n E x c h a n g e r s in W a t e r P u r i f i c a t i o n Electrofiltration with an MEF-500 industrial filter of 500 1/h capacity was used as a new method of production of ultrapure water with a specific resistance of 15-20 Mohm/cm and microparticle concentration below 20 units/ml.

321 Electricity consumption is 30 W h / m 3. Newly developed, modified ion exchange membranes were used to provide an entirely new technology of purification of saline waters to produce fresh water and valuable mineral substances.

I. Haklits, A. Nagy, L. Kiss, P. Simon and O. Nagy, Research Institute of the Plastics Industry, North Hungarian Chemical Works, and Technical University of Budapest, Budapest, Hungary: Cadmium Removal From Waste Water by Ion Exchange An ion exchange system was developed for treating cadmium-containing waste water from plants manufacturing accumulators. Two typical streams with different contents of cadmium and accompanying aluminum and magnesium were examined. The competition from aluminum and magnesium can be eliminated by sorption of cadmium as chloro-complex on an anion exchanger in chloride form. The stream with low cadmium content is first preconcentrated by sorption of all metal cations on a cation exchanger in H form and subsequent elution with hydrochloric acid. Process details are provided.

1~. Horv~tovfi, Water Research Institute, Bratislava, Czechoslovakia: Ammonia Removal by Slovak Natural Clinoptilolite Static and dynamic experiments were carried out for removal of ammonia from water by natural Slovakian zeolite. Untreated and Na-form clinoptilolite were used in the experiments. In the static experiments the initial ammonia concentration ranged between 10 and 2740 m g / d m 3. Equilibrium data and selectivity coefficients were calculated. It is concluded that the Na-form clinoptilolite is selective for ammonia over the entire range of zeolite composition. In the dynamic experiments three different model solution (56, 106 and 134 mg NH~--N/dm ~) were used and the breakthrough capacity was measured. Finally, ammonia was removed from industrial waste water and the Na-form clinoptilolite proved far superior to the untreated material.

Gfibor Sinka and Mih~ly Vigvfiri, HUNGALU Engineering and Development Centre, Budapest, Hungary: Removal of Iron from Iron-rich Solutions of Nickel and Cadmium Sulphate The Aluterv-FKl method for hydrometallurgical processing of scrap alkaline batteries involves the generation of iron-rich solutions of Ni and Cd sulphates. Iron removal in the form of hydroxide precipitate is not suitable: separation as well as mixing of the slurry is almost impossible and its filtration can only be performed at a considerable loss of metallic values. An anion exchange method was applied for the removal of iron from leach liquors, utilizing the selectivity of anionic iron sulphate complex formation over Ni and Cd sulphates. Adsorption rate, adsorption isotherms, distribution coefficients were measured as functions of the iron and sulphuric acid concentrations. Varion AT 660 strong-base synthetic anion exchange resin was used. A two-stage counter-current batch-type ion exchange operation performed at pH 2 resulted in a considerable decrease of the iron content: from 30-50 g / d m 3 to below 5 g / d m 3.