an
IWEEI Unit
ODeratwns Review
Ion Exchange by Robert Kunin, Rohm & Haas Co., Philadelphia, Pa. Water pollution, conservation, and quality problems have increased utilization of ion exchange
-
>
THE
YEAR 1960 has witnessed continued progress in the devclopment of ion exchange as a unit operation throughout the chemical industry. New technical advances in the synthesis of ion exchange resins and in the design and construction of ion exchange equipment have contributed to this progress. Concern over stream and river pollution, water conservation programs, demand for higher quality sugars a t low cost, and the necessity for ultra-high-quality water for supercritical steam power generating stations have increased the utilization of ion exchange operations. Again, the Franklin Institute has recognized the importance of ion exchange by awarding Walter Juda the John Price Wetherill Medal for the development of the ion exchdnge membrane electrodialysis process for the desalinization of brackish waters. This review covers the pertinent literature published during the period June 1, 1959, to Nov. 1, 1960.
Reviews
*
T h e literature of the past year is replete with many general reviews and reviews covering specific areas of application in the field of ion exchange. A recent book ( 7 A ) published in the U.S.S.R. covers much of the progress of the Russians. Two books on ion exchange by Salmon and Hale (77.4) and Kunin ( 7 A ) have been written as primers for students and technicians. T h e status of ion exchange technology in Red China has been summarized by Ping-Lin H o (5A). Helfferich (4A) has reviewed recent developments from a theoretical viewpoint. Reviews of engineering interest have been prepared by Poole (70A) and Seamster and Wheaton ( 7 2 4 . From a n application point of view, summaries and reviews have been prepared by Kressman ( 6 A ) , Hale ( 3 A ) , Genge (ZA), and Millett and others ( 8 A ) . A review of the progress in the field of ion exchange during the past two decades has been analyzed by Morrison and Thompson ( Q A ) .
Theory Much of the recent theoretical work in the field of ion exchange has revolved
around the relationship between the physical structure of ion exchange resins and the stability and kinetics of the exchange phenomenon. Tager (25B), of the U.S.S.R., suggested that ion exchange resins are devoid of the pores associated with the solid rigid adsorbents. Grubhofer (70B) has also considered physical models for the internal structure of ion exchange resins. Some difficulties inherent in the study of the physical chemistry of ion exchange resins center about the heterogeneity in batches of resins. Hogfeldt (77B) has found major differences in selectivity among the various beads within single batches of resins. However, density gradient measurements by Suryaraman and Walton (24B) do not confirm this conclusion. A selectivity table was compiled by Strelow (23B) for 43 cations in H C l of varying concentration for a standard sulfonic acid cation exchanger. Kennedy and Wheeler (73B) have attempted to explain the sequence of absorption or selectivity of cation exchange resins by means of induced dipoles. Bonner and Pruett (2B) and Kraus and Raridon (75B) have studied the effect of temperature on the selectivity of sulfonic and phosphoric acid cation exchangers. A mechanism involving the exchange of large organic cations in carboxylic cation exchange resins was proposed by Savitskaya and others (27B). Kraus and others (74B) have found that the adsorbability of negatively charged complexes by cation exchange resins increases with ionic strength and is greater from salt solutions than from acid solutions. Attempts to relate the selectivity of both cation and anion exchange resins with capacity and swelling have been made by Lindenbaum and others (77B) and Blasius and Pittack (7B). Nelson and others (2OB) have examined the selectivity of strongly basic resins for 19 elements in mixed HF-HC1 solutions. T h e temperature dependency of anion exchange equilibria (Cl--Br-) for strongly basic anion exchangers was studied by Kraus in the 5' to 150' C. temperature range. Marcus (79B) has studied the metal chloride (Cd, Zn, Ag, and Fe) equilibria in similar resins.
T h e adsorption of LiCl, CuC12, CoC12, a c d Ni(N03)z from organic solvents by weak base resins has been investigated Gartner by Kennedy and Davies (72%). and Penndorf (6B) have found that weakly basic resins can adsorb traces of metals from concentrated solutions of electrolytes. A review of the general characteristics of Soviet anion exchangers was given (4B). I n the realm of ion exchange kinetics, solid diffusion constants for cation exchangers were measured by Tien (26B) and Fedoseyeva and others ( 5 B ) . The former proposes a method for a nonlinear isotherm, whereas the latter present the results of a n elaborate study on the measurement of self-diffusion constants. Tien and Thodos (27B) have developed mathematical relationships based on a material balance and rate equations for a fixed bed involving a Freundlich-type isotherm. Other theoretical fixed bed studies have been described by Goldstein and Murray (8B) and Wevers (28B). Some kinetic studies on the adsorption of HCl by a weak base resin in a n alcohol medium have been described by Shukla and Bhatnagar (22B). Since the theory of chromatography is as applicable to large scale column performance as it is to analytical chemistry, the study of Glueckauf 1723) on extension of chromatography theory to the separation of isotopes is of prime interest The strong interaction between anion and cation exchange resin particles was demonstrated by Grubhofer (QB).A most interesting study on the transformation of chemical into mechanical energy in ion exchange fibers has been described by K u h n and others 176B).
Water Conditioning T h e importance of process water purity,, water conservation, and water reuse are becoming of considerable importance to the industrial chemist and chemical engineer. T h e ion exchange developments in this area are of importance not only because of water shortages; the data are often of use in chemical processing. Calise and Homer (8C) .have summarized the ion exchange VOL. 53, NO. 6
0
JUNE 1961
495
an
r dUnit Operations Review
water treatment practices in Russia and other Eastern European countries. Wirth and Fradkin (44C) have attempted to summarize recent ion exchange developments in water conditioning. Frazer (77C) has reviewed some of the special operating and regenerating techniques employed in ion exchange plants. Procedures for the field testing of ion exchange resins have been developed b) Kunin and others 129C). A review of water softening practices and economics in Europe has been reviewed by Gadenberger (27C). Ion exchange softening a t high flow rates has been studied by Fynsk ( 7 S C ) . More research and development effort in water conditioning has been devoted to deionization than to the other ion exchange practices. Burns (6C) and Symons (37C) have summarized some of the more b u i c aspects of design and economics. Of considerable importance have been the high f l o i v rate Monobed and mixed bed deionization studies by Dick and Silliman (73C, 74C) and Dickinson and others (76C). These studies are not only of extreme im-
portance in the polishing of condensate in high pressure boiler power plants but also in the pharmaceutical and sugar industries. Miscellaneous deionization studies have been presented by Berlo (5C), and several studies on the regeneration of weak base resins have been presented by Abrams and Donnally (7C) and Applebaum and Fast (2C). T h e latter study illustrates several economic and technical advantages in the use of aqueous ammonia as a regenerant for weak base resins. The use of ion exchange in the treatment of water used in nuclear reactor power stations has been well covered by Muller (32C), Thompson and Reents (39C); Dickert and others (75C), and Michael and Bell (37C). T h e use of single beds of strong base resins in the hydroxyl form for removing silica from soft water is strongly advocated by Stickney and others (7C) and Demchenko and Molchadskii (72C). Progress in the conversion of saline water into potable and irrigation waLer has been reviewed by Howe (26C),
World’s largest ion exchange sugar treatment plant i s in operation at Nippon Beet Sugar Manufacturing Co., Ltd., Hokkaido, Japan. The process, developed in conjunction with the ion exchange engineering firm, Japan Organo Co., Ltd., consists of partial decolorization of defecated beet juice, followed b y two separate Monobed deionization steps. After this treatment, with juice i s colorless, 99.9% purity. Nearly 5000 cu. ft. of resin are employed in 1 2 ion exchange columns
+
Poivell (343,and Strobe1 (36C). T h e use of ion exchange membranes in electrodialytic process plays a n important role throughout this program. T h e literature survey of Bennett (4C) is most valuable. The use of membrane processes in treating the municipal water supply a t Coalinga, Calif., has been summarized by Cary and others (QC). It was shown by Termansen (38C) that a silver plated Berkefeld filter will sterilize deionized water, and the water will contain but 0.01 p g . of silver per liter. T h e quality of deionized water with respect to its use in sensitive systems has been a topic of considerable effort. Jennings and Knight (28C) have found deionized water to be most useful in washing sensitive semiconductors. However, Gaines (ZOC) has found even mixed bed water unsuitable for sensitive experiments in surface chemistry. T h e quality of deionized water has also been discussed by Guizonnier and Besnard
(24C). The problems associated with the quality of deionized water for sensitive surface chemistry probably arises from trace impurities of surface active materials not being adsorbed by the ion exchange resins. The use of porous resins and the use of proper pretreatment techniques have eliminated much of this problem. The problem with these organic traces in deionization has been studied by Frisch and Kunin (78C), Bacon and Lewis (3C), Janssen (27C), de Jong (7OC), Scheffer and cthers (35C),and Wilson (4OC-43C). Although the applications of water softening and deionization are the major ion exchange water conditioning applications, a number of other applications have developed. Griffin (23C) has reviewed the use of ion exchange for removing mangancse, Vol’f and others (46C) have demonstrated the removal of oxygen during a water softening operation, and Pfeil (33C) and Delius (77C) have examined the use of anion exchangers for removing nitrates from potable water sources. T h e use of ion exchange techniques for removing radioactive and other toxic substances from potable water has been studied by Graul and Reinhardt (ZZC), Higgins (25C), and Lafontaine (30C)).
Inorganic Chemistry a n d Hydrometallurgy T h e recovery and purification of uranium from lovv grade sources is still the major ion exchange metallurgical application; however? the urgent demand for this metal has diminished, and liquid extraction techniques have become competitive in certain areas. T h e success of ion exchange in the recovery and purification of uranium for low grade
496
INDUSTRIAL AND ENGINEERING CHEMISTRY
an
Table 1. Metal Ta Ge In
T
Metallurgy Ref. (1 D ) (17 0 )
Mo
(IQD) (11 D)
cu
(180)
ores has stimulated considerable interest in the possible use of this technique in other areas of inorganic chemistry and hydrometallurgy. Read (750),Kremer ( 6 0 ) , and Maltby ( 9 0 ) have developed resin-in-pulp and moving bed ion exchange systems for uranium recovery. Other studies on the recovery of uranium by ion exchange techniques have been presented by Gordievskii and Savel’eva (5D) and Nugent and others ( 7 2 0 ) . Ion exchange still plays an important role in the processing of other fissionable a n d radioactive materials. Wylie (200) has prepared a literature survey on thorium extraction, a n d Arden and others (20) have described the recovery of thorium from sulfate solutions. Ion exchaqge processes for recovering and purifying the transuranium elements such as americium, neptunium, plutonium, and protactinium have been developed by Naito (70D), Ryan and Pringle ( 7 6 0 ) , Parker and others (70), a n d Paulsen (730). Similar developments have been presented by Pressley (740) on rare earth fractionation. Methods for concentrating the noble metals have been investigated by Davankov and Laufer (30, 4 0 ) a n d Lindeman and Rabek ( 8 0 ) . Various inorganic a n d hydrometallurgical ion exchange studies have been presented (Table I).
Organic Chemistry
r
Much of the activity in the area of ion exchange in organic chemistry involves the recovery and purification of pharmaceuticals and chemical processing in nonaqueous solvents. Mikes ( 7 7E) and Hsu (8E) have reviewed the general utility of ion exchange in organic chemistry. T h e behavior and application of ion exchangers in mixed and nonpolar solvents have been studied by Eaves a n d Munday (5E), Chzi-Syan a n d others ( 3 4 4 E ) , Gorshkov and others (GE), Kennedy and Davies (70E), and Anta1 a n d others ( 7 E ) . T h e ion exchange technique for fractimating the amino acids has been further refined by Hamilton and Anderson ( 7 E ) . Ion exchange procedures for separating alkaloids have been developed by Yoshino and Sugihara (78E) and Yoshino and others (77E). Much OC the published ion exchange research on antibiotics has been from
the U.S.S.R. Bresler (ZE), Kaplan (%E), a n d Samsonov and others (74E) have examined the characteristics of various ion exchangers for adsorbing streptomycin. Samsonov and Vedeneyeva (75E) have found cation exchangers to be more useful than anion exchangers for recovering and purifying penicillin. Miscellaneous studies include work by Rabek and Trochimeszuk (73E) on lactic acid, Pallaud (72E) on perfumes, and Stamberg and Dvorak (7GE) on pectin.
Food Technology T h e various applications of ion exchange in food processing have been reviewed by Gryllus and Magyar (73F). Of all the food processing applications, the refining of sugar is by far the most important; Griessbach (72F) has reviewed this field. Considerable effort has been devoted to the use of porous anion exchangers for decolorizing sugar juices a n d sirups (Table 11). Various procedures for purifying sugar sirups and juices have been investigated. Reents and Keller (24F) have applied ion exclusion, Vajna (30F) has employed the ammonium cycle, and Moebes (20F) has used a carbonate cycle. Schiweck (25F) a n d Dubourg (SF) have investigated the Assalini process which involves a modified deionization system consisting of anion and cation exchange columns operating in parallel. The use of an ion exchange membrane electrodialysis system for deionizing sugar juices has been studied by Burianek and Slechtova
(3F, 4F). Miscellaneous ion exchange sugar studies include the works of Emmerich and Schachten (77F) on inversion and Cheng and Bah ( 6 F ) on citric acid recovery. Ion exchange processes for the treatment of fruit juices and alcoholic beverages have been developed by Smith and Percival (27F), a n d Ratushnyi and others (23F). Vioque and others (33F) have been able to stabilize olive oil by ion exchange treatment.
v d Unit Operations Review
Waste Treatment T h e pollution of streams with wastes is becoming critical in many areas, and both federal and state agencies have become quite concerned. I n many instances, ion exchange techniques for recycling water, concentrating wastes, and recovering reagents have helped to solve potential waste problems. Paulson (5G) has presented details for the disposal of acid and alkaline plant efflltents. Winger (9G) has described an ion exchange treatment for metal treating wastes. T h e recovery of zinc from viscose wastes by anion exchange has been suggested by Sorokin and others (6G). Various ion exchange procedures for handling radioactive wastes have been presented (7G-4G, 7G, 8G).
Catalysis Reactions catalyzed by ion exchange materials are continually being studied, and gradually more are being employed commercially. Epoxidation with a sulfonic acid resin catalyst is now being conducted on a commercial-sized scale. Reviews on the use of ion exchange resins as catalysts have been prepared by Rabovskaya (72H), Kressman ( 6 H ) , Naumann (7023, a n d Berlin and others
(3H). Studies on cation ion exchange resincatalyzed esterification reactions have been conducted by Rabovskaya ( 7 7 H ) , Andreas (7H), Lindenman and Trochimeczuk ( 7 H ) , and Vasilescu ( 73H). Various other cation exchange resin studies have been published, including that of Bafna and Bhale ( 2 H ) on the reaction of acetone a n d iodine; Muller and Pleininger ( 9 H ) on the synthesis of and Mastagli and “reductones” ; Lagrange ( 8 H ) on the decomposition of acetals. Several interesting studies on the catalytic behavior of alumino-silicate exchangers have been conducted by Ishiguro and Otsuka ( 4 H ) , Kerr and and Weisz a n d Frilette Johnson (5H), ( 74H).
Membrane Processes Table II.
Food Technology
Subject Decolorizing sugar juices and sirups Cation exchangers for decalcifying sugar juices Removal of radioactive Sr and C s from milk
Ref. (14F, 16F, 17F, 28F, ZQF, S l F , S2F) (dF, 5F, Q F , 16F, ZZF, 3 4 F ) (IF, 7F, I O F , 18F, lQF,21F,
26F)
Considerable progress has been made in the development of the multiple ion exchange membrane electrodialysis method for treating brackish and sea waters. Krishnaswamy ( 9 J ) ,Cooke a n d Mandersloot 13J), and Cowan and Brown ( 4 4 have presented further studies on some of the fundamentals of multiple cell operation. Of considerable importance are the studies of Glueckauf (GJ) on multiple membrane cell deionization systems containing a mixture of anion and cation exchange resins in the chambers. VOL. 53, NO. 6
JUNE 1961
497
an
Unit Operations Review
Table 111.
Membrane Process
Table V.
Applications Subject Treatment of metal pickling
liquors Simultaneous production of acids and bases from salts Concentration of radioactive wastes Separation of rare earths Ion exchange membranes as solid electrolytes for fuel cells
Ref. ( i O J , 25J) ( 1 2 J , 16J)
(24J) USJ) (BJ)
Design and energy requirements for multiple membrane cells used for electrodialysis have been studicd in detail by h e n t s ( 7 7 4 , Wilson ( Z O J ) , Ricci (77J), and Eshaya and Dodge (5.J).Performance data and other practical aspects of this application have been discussed by Cary and others (ZJ), Boby ( 7 5 ) , and Sieveka (785). Gregor and others ( 7 4 have developed a small membrane cell for emergency use, and Tuthill and Weth ( 7 9 4 have developed a unit for treating radioactive waste solutions. Although not reduced to commercial practice, various other membrane process applications have been studied and demonstrated to be of a promising nature (Table 111). New Ion Exchange Materials
Table IV. New Ion Exchange Materials
Synthesis of weak and strong base anion exchangers Synthesis of sulfonic acid cation exchangers Synthesis of carboxylic cation exchangers Synthesis of complexing and chelating resins Preparation and properties Various redox resins Zr compounds Al, Zn, Mg oxides Ferrocyanides Phosphomolybdates Preparation of ion exchange memtranes
Stability of ion exchange materisls
498
Ref (5I1,1 i K , 2 6 K , 2911, SOK, S6K, 37K) (10K, 2711)
(23K, Z G X , 33R, S 9 K ) ( 7 K , 12K, 3810 (iSIC, fir
