Ind. Eng. Chem. Res. 1988,27, 1797-1802 narrow range of acid strength from -9 to -13. Nomenclature G(Ho) = cumulative amount of acid sites from Ho,~i, to Ho, mol/m2 g(Ho) = density distribution function of acid strength, mol/m2 Ho= Hammett acidity function = strongest acid strength K , = dissociation constant of conjugate acid of indicator KO = constant in eq 1, m3/mol pKa = -(log Ka) QP = amount of indicator adsorbed on nonacidic surface of catalyst, mol/m2 QT = amount of indicator adsorbed on acid sites and nonacidic surface of catalyst, mol/m2 q(C) = amount of indicator chemisorbed on acid sites at equilibrium concentration C, mol/m2 q m = maximum value of q(C), mol/m2 T = absolute temperature, K u = initial reaction rate of isomerization of 1-butene,mol/(kg 9)
Greek Symbols /3 = constant in eq 1 K = ratio of reaction rate producing cis-2-butene to that
producing trans-%butene Subscripts B = Brcansted acid site L = Lewis acid site
1797
Registry No. AZO3,1344-281;SiOz,7631-86-9;NH3,7664-41-7; 2,6-dimethylpyridine,108-48-5.
Literature Cited Benesi, H. A. J. Catal. 1973, 28, 176. Benesi, H. A.; Winquist, B. H. C. Adv. Catal. 1978, 27, 97. Hashimoto, K.; Masuda, T. J . Chem. Eng. Jpn. 1985, 18, 71. Hashimoto, K.; Masuda, T.; Isobe, K. J. Chem. Eng. Jpn. 1988,21, 249. Hashimoto, K.; Masuda, T.; Motoyama, H.; Yakushiji, H.; Ono, M. Ind. Eng. Chem. Prod. Res. Deu. 1986, 25, 243. Hightower, J. W.; Hall, W. K. J. Am. Chem. SOC.1967, 89, 778. Jacobs, P. A.; Heylen, C. P. J. Catal. 1974, 34, 267. James, A. S. J. Vac. Sci. Technol. 1975, 12, 321. Laidler, K. J. Chemical Kinetics, 2nd ed.; McGraw-Hill: New Delhi, 1978, pp 246-249. Matsubara, T.; Imokawa, T.; Take, J.; Yoneda, Y. Shokubai 1978, 20, 202. Parry, E. P. J. Catal. 1963,2, 371. Seiyama, T. Kinzoku Sankabutsu to sono Shokubai Sayou; Kodansha: Tokyo, 1978. Shephard, F. E.; Rooney, J. J.; Kemball, C. J. Catal. 1962, 1, 379. Tanabe, K. Solid Acids and Bases; Kodansha Academic: Tokyo, 1970; pp 5-33, 58-66, 73-80. Tanabe, K.; Sumiyoshi, T.; Kiyoura, T.; Kitagawa, J. Bull. Chem. SOC. Jpn. 1974, 47, 1064. Ward, J. W. J. Catal. 1967, 6, 225.
Received for reuiew September 16, 1987 Accepted June 6, 1988
MATERIALS AND INTERFACES Polymers for Removal of Free and Combined Active Chlorine and Active Bromine from Water. Sulfonamides Derived from Styrene-Divinylbenzene Copolymers. Polymer Supported Reagents. 4 David W. Emerson Department of Chemistry, The University of Nevada, Las Vegas, Las Vegas, Nevada 89154 Sulfonamides and N-alkylsulfonamides derived from styrene-divinylbenzene copolymers were prepared by reaction of sulfochlorinated styrene-divinylbenzene copolymers with ammonia or aminoalkanes and alkanediamines such as methylamine, ethylamine, isobutylamine, 1,2-ethanediamine, 1,3-propanediamine, and 1,6-hexanediamine. When solutions containing sodium hypochlorite, hypochlorous acid, chloramine, dichloramine, trichloramine, or hypobomous acid or sodium hypobromite were pumped through a column containing one of the polymeric sulfonamides, the active halogen content of the water was greatly reduced, often by 99% or more. After saturation of the resins with chlorine or bromine is approached, their ability to remove active halogen compounds diminishes. The ability of the resins to react with active halogen can be restored by removing the active halogen with suitable reducing agents such as hydrazine or sodium sulfite. This enables use of the resins for cycles of halogen loading followed by regeneration. Active chlorine compounds, such as hypochlorites, hypochlorous acid, chloramine, dichloramine, and trichloramine, have found widespread use in water disinfection (White, 1972,1978). It is sometimes undesirable, however, to have these disinfectants present when the water is put to its end use or discharged into a natural waterway (Brungs, 1973). Dechlorination may be accomplished by
the use of sulfites, thiosulfate, or activated carbon (White, 1972),but the sulfites and thiosulfates add to the mineral burden of the water and are toxic (Shaw and Snodgrass, 1983). Activated carbon is consumed. The classical studies of Chattaway (1905) and Dakin et al. (1916) reported methods for chlorinating primary arenesulfonamides (11)to N-chloroarenesulfonamides(111)and
0888-5885/88/2627-1797$01.50/0 0 1988 American Chemical Society
1798 Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 N,N-dichloroarenesulfonamides(IV) (Scheme I). Scheme I ArSOzNHz + NaOCl I1 I11 + HOC1
-
-
ArS02NC1.Na I11
+ HzO
ArSOzNClz+ NaOH IV
Studies have demonstrated that these techniques also chlorinate polystyrene or styrene-divinylbenzene copolymers bearing a primary sulfonamide group V (Nakamura, 1954; Emerson et al., 1978), and styrene-divinylbenzene copolymers bearing N-alkylsulfonamide groups, VI (Emerson et al., 1982). An objective in all of these studies was to chlorinate the sulfonamides groups to the greatest extent possible. Our attention turned to the possibility of using polymer-supported arenesulfonamides for dechlorination of water. A useful intermediate, chlorosulfonated styrenedivinylbenzene copolymer, IA, prepared from a commercially available macroreticular ion-exchange resin, Amberlyst-15, has been reported (Emerson et al., 1978,1979). The sulfonyl chloride functional group reacted readily with ammonia (Emerson et al., 1978) or hydrazine (Emerson et al., 1979). It reacted with a,w-alkanediamines in aqueous solutions (Emerson et al., 1982) to make polymeric arenesulfonamides which react with hypochlorous acid or hypochlorites to form N-chloro derivatives. Three questions remain. Will polymeric arenesulfonamides, V and VI, remove from water hypochlorous acid and hypochlorite ion in the parts per million range? Will the sulfonamides, V and VI, remove chlorinated derivatives of ammonia? Will the sulfonamides remove active bromine (hypobromous acid and hypobromite) from aqueous solution? The answers to all of these questions are affirmative, as is described below. Naming the polymeric products is awkward. For the purpose of this discussion, the word “Haloscrub”has been coined as a generic name for the materials employed. The code letter A or D follows Haloscrub to indicate whether the starting material was the macroreticular Amberlyst-15 or gel type Dowex 50-X-8. Two numbers follow “ A or “D”, the first indicating the number of carbon atoms in the amine used to make the polymer and the second indicating the number of nitrogen atoms in the amine. Thus, the substance,
Table I. Materials Used in This Studs IA chlorosulfonated poly(dietheny1benzene-co-ethenylbenzene) from Amberlyst-15a ID chlorosulfonated poly(dietheny1benzene-co-ethenylbenzene) from Dowex 50-X-8* V Haloscrub-A-0,l from IA and NH3 VIa Haloscrub-A-l,l from IA and CH3NHz VIb Haloscrub-A-2,l from IA and CH3CH2NHz VIC Haloscrub-A-2,2 from IA and HzN(CHz)zNH2 VId Haloscrub-A-3,P from IA and HzN(CHz)3NHz VIe Haloscrub-D-3,2 from ID and H2N(CHz)3NH2 VIP Haloscrub-A-6,2 from IA and HzN(CH3)6NHz VIg Haloscrub-A-iso-4,l from IA and CH3CH(CH3)CHzNH2 “Amberlyst-15 is a registered trademark of Rohm and Haas. *Dowex 50-X-8 is a registered trademark of the Dow Chemical Co.
groups on the polymer, thus attaching the diamine at both ends. This contrasts with a report that 1,6-hexanediamine reacts mainly on one amino group with I in the absence of water (Tschang et al., 1980). It has been demonstrated in the present study that the washing of crude I with organic solvents can be eliminated if I is to be used immediately to make VI.
Experimental Section Microanalyses were performed by Spang Microanalytical Laboratory, Eagle Harbor, MI. Sulfochlorinated Poly(dietheny1benzene-co ethenylbenzene). IA and ID. Either Amberlyst-15 or Dowex 50-X-8 was allowed to react with excess chlorosulfonic acid at 80 “C (Emerson et al., 1978,1979) to form chlorosulfonated poly(dietheny1benzene-co-ethenylbenzene). If the product was to be used immediately, the excess chlorosulfonic acid was removed by filtration and the chlorosulfonatedresin was washed quickly with ice-cold water and then added to a mixture of the amine, water, and ice. Washing of crude I with 50% sulfuric acid has been reported (Min et al., 1985). Haloscrub-A-O,l, V. The polymeric arenesulfonyl chloride, IA, was allowed to react with ice-cold excess aqueous ammonia (Emerson et al., 1978). Bulk density: 0.64 kg/L (dry), 0.46 kg/L (wet). Haloscrub-A-l,l, VIa. Method A. To 50 mL of cold, aqueous 40% methanamine was added gradually, with shaking, 14.1 g of IA. After 50 min, the resin was washed by decantation and then by filtration and was washed with distilled water. A cation total exchange capacity measurement was performed (Kunin, 1958). The resin was rinsed thoroughly with distilled water after the total exI L - C H ~ C H C ~ H ~ S O ~)nN H Z change capacity measurement and dried in vacuo: yield, V 14.1 g; cation total exchange capacity, 0.57 mequiv/g. For the halogen removal experiments, several batches were made from Amberlyst-15 is Haloscrub-A-0,l; combined. This mixture had a cation total exchange capacity of 0.86 mequiv/g. Microanalysis for S and N gave I 14.2% S and 5.6% N for a S / N mole ratio of 1.1. The ( - CH2CHCs H4S02 NHCH3 )n nitrogen content was 4.0 mmol/g. V Ia Method B. Crude IA was placed in a mixture of water is Haloscrub-A-1,l; and the product and ice, stirred for 30 s, filtered, and then added to a mixture of ice and 32.4 g of 40% methanamine in water I I mol). The mixture was allowed to warm to room ( - C H ~ C H C B H ~ S ~ ~ N H ( C H ~ ) ~ N H S O ~ C ~ H ~ C H C H ~ -(0.42 )~ temperature and stand for 42 h. The resin was filtered off, V I washed with dilute hydrochloric acid, and then subjected made from Dowex 50-X-8, is Haloscrub-D-3,2,and so on. to a cation total exchange capacity measurement, 0.99 The polymers used in this study are listed in Table I. mequiv/g. The dry product, with the sulfonic acid groups It was reported earlier (Emerson et al., 1978, 1982) that in the Na+ form, weighed 29.1 g. Bulk density: 0.57 kg/L the polymers possess both sulfonamide groups and sulfonic (dry), 0.46 kg/L (wet). Haloscrub-A-2,1, VIb. To a mixture of ice and 14.7 acid groups, the latter of which can be determined by g of 70% ethanamine (210 mmol) was added, in portions cation total exchange capacity measurements. When alkanediamines in water are used to make VI, both amino with shaking, 30.1 g of IA and 15 g of 50% sodium hygroups, for the most part, react with sulfonyl chloride droxide (188 mmol). The reaction mixture was allowed
Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 1799
to stand for 2 h, after which it was allowed to warm to room temperature. The resin was subjected to a cation total exchange capacity measurement: 0.34 mequiv/g; yield, 28.9 g of resin in the vacuum-dried Na+ form. Analysis for S and N gave 14.2% S and 5.2% N for a S / N mole ratio of 1.18. N content: 3.7 mol/g. Bulk density: 0.54 kg/L (dry), 0.49 kg/L (wet). Haloscrub-A-2,2, VIc. The material was prepared as previously described (Emerson et al., 1982). Analysis: 14.94% S 6.36% N; S/N mole ratio, 1.03; cation total exchange capacity, 0.09 mequiv/g; N content, 4.54 mmol/g; bulk density, 0.58 kg/L (dry), 0.43 kg/L (wet). Haloscrub-A-3,2, VId. The material was prepared as previously described (Emerson et al., 1982). Analysis: 14.62% S; 6.23% N; S/N ratio, 1.03; cation total exchange capacity, 0.06 mequiv/g; N content, 4.45 mmol/g; bulk density, 0.55 kg/L (dry), 0.46 kg/L (wet). Haloscrub-D-3,2,VIe. To a mixture of 200 g of water and ice were added 15.5 g (210 mol) of 1,3-propanediamine (Aldrich), 22.5 g of 50% sodium hydroxide (281 mmol), and, in portions with stirring 52 g of ID made from Dowex 50-X-8. The flask was cooled externally with ice. The ice was allowed to melt and the reaction mixture warmed to room temperature over a 24-h period. The resin was rinsed thoroughly with water and subjected to a cation total exchange capacity measurement, 0.40 mequiv/g. The yield of resin in Na+ form was 39.8 g. After the resin was used in several experiments, the cation total exchange capacity was 2.77 mequiv/g. Analysis: 12.58% S; 2.12% N; S / N ratio, 2.59; N content, 1.51mmol/g; bulk density, 0.67 kg/L (dry), 0.37 kg/L (wet). Haloscrub-A-6,2,VIf. To a mixture of 24.4 g of 1,6hexanediamine (210 mmol) and 13.6 g of 50% sodium hydroxide (170 mmol) in 400 mL of water and ice was added, in portions, 32.6 g of IA. After 48 h, the reaction mixture was worked up as described for VIe. The cation total exchange capacity was 0.45 mequiv/g, and the polymer was 12.83% S and 4.70% N for a S / N mol ratio of 1.20. N content, 3.36 mmol/g; bulk density, 0.60 kg/L (dry), 0.47 kg/L (wet). Haloscrub-A-iso-4,1,VIg. To 20.3 g of I were added 25 mL of THF and 16.4 g of 2-methyl-1-propanamine.The mixture was cooled and shaken for 10 min and then allowed to stand. After 3 days, water was added and the resin was filtered off. The cation total exchange capacity of the resin was 0.10 f 0.01 mequiv/g: yield of vaccumdried resin in the H+ form, 21.7 g; bulk density, 0.50 kg/L (dry), 0.46 kg/L (wet). Method for Determining Uptake of Active Halogen. The resin to be tested was placed in either of two glass reactor tubes, 22 mm i.d. by 310 mm, 118 cm3; or 20 mm by 220 mm, 69 cm3. The resin rested on a foundation of glass wool and 3-mm and 4-mm glass beads. A thermometer was placed in the reactor. Feed solution was prepared from either tap water or distilled or deionized water and sodium hypochlorite with the pH adjusted using hydrochloric acid. The feed solution was placed in a reservoir consisting of a 4-L Erlenmeyer flask and was pumped upward through the reactor by means of a peristaltic pump (Cole-Parmer Masterflex, Model 7014 20) driven by a variable-speed motor and controlled by a timer switch. The feed line components were glass, Tygon tubing, and a section of silicone tubing in the pump. A “tee” with a section of Tygon tubing aimed upward with a valve on the end was placed between the pump and the reactor tube to serve the dual purpose of diverting gas bubbles away from the reactor and of catching feed samples. Reactor effluent was allowed to drip into a sink or into a sample
collector. Flow rates were varied beween 5.4 f 0.1 and 15.0 f 1 mL/min. Some fluidization of the resin fed occurred in the 20-mm-i.d. column at the higher flow rate. Resin beds in the 22-mm-i.d. column were stable up to flow rates of about 10 mL/min. The amounts of resin placed in the reactions were between 15 and 32 g, dry weight. Fluidization of the resin resulted in classification of the polymer beads, with the smaller beads accumulating at the top and larger beads at the bottom of the reactor. Active Bromine Solutions. Solutions containing active bromine were prepared by adding 1.0 g (4.9 mmol) of sodium bromide to a solution of 10.0 mL of 5.25% sodium hypochlorite in 2.00 L of tap water. The pH was adjusted by adding 4.0 mL of 1 N hydrochloric acid. Analysis for Active Halogen. The N,N-diethyl-pphenylenediamine (DPD) methods were employed (Palin, 1967), as described in standard sources (American Public Health Association, American Water Works Association, and Water Pollution Control Federation, 1981,1985; Palin, 1967,1975). Both the spectrophotometric and the ferrous ammonium sulfate (FAS) titrimetric methods were used, with preference for the latter. The lower limit of detection for the titrimetric method has been reported as 0,011 mg/L (Nicolson, 1965). Regeneration (Dehalogenation) of Resins. A. Hydrazine Method. The resin was removed from the reactor and placed in an Erlenmeyer flask. A mixture of water, 5 g of sodium carbonate, and 3-5 mL of hydrazine hydrate was added to the flask, and it was allowed to stand for several hours. Vigorous gas evolution occurred during the first few minutes. The mixture was then filtered and washed with water, with dilute acetic acid, with dilute sodium hydrogen carbonate, and finally with water. A variation of this method was earlier reported as an analytical method for polymer-bound active chlorine (Emerson et al., 1978). B. Sodium Sulfite Method. A solution of approximately 25 g of sodium sulfite in 50 mL of water was pumped intermittently upward through the reactor, with pauses to allow cooling. This was followed by pumping with distilled water. C. Sodium Chloride/Sodium Sulfite Method. A solution of 250 mL of 5% sodium chloride solution was pumped upward through the reactor followed by the introduction of 500 mL of 5% sodium sulfite solution, with pauses for cooling. D. Sodium Sulfate/Sodium Hydroxide/Sodium Sulfite Method. The solution, 300 mL, of 8% sodium sulfate solution was pumped upward through the reactor followed by the intermittent introduction of 2 L of a solution of 0.1 M sodium hydroxide and 0.1 M sodium sulfite. E. Sodium Chloride/Sodium Sulfite/Sodium Carbonate Method. A solution of 2% sodium chloride solution was pumped upward through the reactor followed by the intermittent introduction of a solution of 0.2 M sodium sulfite and 0.2 M sodium carbonate. F. Sodium Chloride/Sodium Hydrogen Sulfite. A solution, 200 mL, of 5% sodium chloride was pumped upward through the reactor followed by the intermittent introduction of a solution of 0.2 M sodium hydrogen sulfite. The data from all runs were plotted in Figure 1, and the curves were computer generated by double regression using SIGMAPLOT (Jandel Scientific). In Figure 1, the x axis, ”percentage of capacity,” is computed by calculating the cumulative active chlorine deposited on the resin using [(liters of feed)(concentration of active Clz in grams/liter)(fraction of active chlorine retained)]/n[(formula weight of Clz)(weightof dry resin in grams)(millimoles of N in
1800 Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 Table 11. Removal of Free vo1,o L regeneration* SV,‘ m3/kg/s feed 41.0 1.8 1.7 0.0 44.5
Cl2 NHpCl NHClp NC13 total free combined total C1 on resine PH
and Combined Active Chlorine by Haloscrub2,Zf 4 14 24 25 A 7.7 x 10” 7.7 x 10“ 7.7 x 10” 2.8 ppm as Clz eff.d feed eff. feed eff. feed 0.00 201 201 2.23 0.00 39.4 11 0.49 0.8 0.14 11 0.00 0.38 0.07 22 22 0.00 2.0 0.02 0 0.00 0 0.00 0.0 234 3.10 234 0.00 42.2 0.14 7’ C1 Removed 98.9 97.4 98.7 1.3 7.7
100 99.7 99.7 0.51
100 100 100 0.07
8.7
8.7
37 X
10” eff. 0.04 0.48 0.28 0.04 0.84
2.8
X
10“
feed 191
eff. 0.06 0.57 0.38 0.04 1.05
2
27 0 220
100 97.6 99.6 1.4 7.0
43
100 96.6 99.5 2.6
2.8 X 10” feed 190 4 19 16 229
eff. 1.90 0.58 0.49 0.10 3.07 99.0 97.0 98.7 3.0
7.7
Volume of feed passed through reactor. See Experimental Section. Space velocity, volume of feed per weight of dry resin. Samples of approximately 0.5 L were collected for analysis. eMillimoles/gram of chlorine added after regeneration of resins. ’Run 87P-8; Haloscrub-2,2, VIc, 32.3 g.
0
To’ol CI I
3
chlorine is feasible using either hydrazine or sodium sulfite (Scheme 11).
Scheme I1 2(PolSOZNClR) + NzH4 ~ ( P O ~ S O ~ N+ H Nz R ) + 2HC1 (1) +
0
75-
0
x
“Pol” = polymer 5
C
P
-
20
~
40
60
80
100
% OF CAPACITY
Figure 1. Total C1 removed, free and combined.
resin per gram)] and converting the result to a percentage. The integer n is unity for N-alkylsulfonamides and 2 for unsubstituted sulfonamides.
Results and Discussion The detailed data on a typical product are displayed in Table 11. The data for bromine removal are shown in Table 111. Scrutiny of Table I1 and Figure 1 reveals that the polymers all remove 99+% of the active chlorine from water in the temperature range 17-32 OC and pH range 6.3-10.2 until a substantial fraction of the chlorine holding capacity of the resin is used up. An experiment using Amberlyst-15 as the reactor packing demonstrates that the starting material for most of the polymers does not account for the removal of active chlorine. The ability to remove active chlorine occurs over a wide range of feed concentrations from as low as 9 ppm to over 250 ppm. There is no evidence to suggest that the polymers would fail to operate similarly at lower or higher concentrations of free and combined chlorine. The residence times of the feed in the reactor bed were 3-10 min under the conditions studied. One striking observation is that combined chlorine in the form of chloramines is removed about as effectively as so-called free chlorine (Table 11). The equilibria involving water, hypochlorous acid, hypochlorite ion, monochloramine, dichloramine, nitrogen trichloride, sulfonamide, and N-chlorosulfonamidesare unquestionably very complex. An inherent advantage of polymer-supported reagents is that the high concentration of functional groups which are confined to a small volume sometimes results in favorable mass action effects. Regeneration of the polymers by removal of the active
-
HzO + PolSOzNCIR + S032S042-+ C1- + H+ + PolSOzNMR (2) Hydrazine removes all of the active chlorine and has been used to determine the active chlorine content of chlorinated sulfonamideresins (Emerson et al., 1978). The exothermic reaction produces nitrogen gas, so regeneration of the polymers in small reactors is a nuisance. Regeneration with sulfite ion is exothermic and attended by two difficulties. The first difficulty is that the regeneration is not as complete as with hydrazine, as shown by runs on resins regenerated by that method (Table 11). One possible reason is that some of the active sites of the polymer are sterically hindered. This was dramatically demonstrated by observing the differing extents of reaction of the sulfonic acid hydrazide of poly(dietheny1benzene-co-ethenylbenzene) with aldehydes and ketones of differing bulk (Emerson et al., 1979). The second indication of steric hindrance is that only 4% of the potential sites on Amberlyst-15 and its various salts is occupied by crown ethers (Kyba et al., 1972). A second possible reason is that when hard water is used, calcium ions accumulate on the sulfonic acid groups by a normal ion-exchange process. Sparingly soluble calcium carbonate or sulfite can form when the regenerating reagent is introduced, possibly occluding some of the pores of the macroreticular resin. A white, insoluble substance was observed during some of the regenerations. Some observations on the resins are in order. The use of sulfonamides made from alkanediamines conveys some advantages. It has been reported (Emerson et al., 1982) that the diamines, for the most part, react at both ends with sulfonyl chloride groups on the polymer, I. Whether this results in loops on the same polystyrene chain or cross-linking between polystyrene chains is not known, but either can result in increased mechanical strength. N Alkylsulfonamidesare quite stable toward hydrolysis, but through prolonged use, particularly in strongly acidic environments, slow hydrolysis can occur. In the doubly connected sulfonamides resulting from the use of alkane-
Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 1801
t
ah t
7
h
t
2
h
t
2
h
t
2
h
~
Bd d
B2 ~
a,
3
diamines, hydrolysis at both functional groups has to occur before the diamine can detach from the polymer. The monoalkaneamines tend to decrease the density of the polymer beads if the alkyl group is fairly large. Thus, the product prepared from 2-methyl-l-propanamine, VIg, had a tendency to float on water. The dry resin had a lower bulk density than the others, and it swelled less in water. The resins generally functioned best after being conditioned by one or more chlorination-dechlorination cycles. The unsubstituted sulfonamide, V, had a high capacity for chlorine uptake but is less stable than the others (Emerson et al., 1978). Haloscrub-D-3,2,VIe, which is a gel-type resin, displayed a much greater tendency to swell when wet than the others, but its performance in chlorine removal tests was not markedly different from the other materials. Washing the crude chlorosulfonated polymer, IA, with ice water and using it immediately to prepare VI worked very well and did not result in a product having a high concentration of sulfonic acids groups. This technique simplifies the synthesis of VI. Modest space velocity effects were observed (Table 11) when the products V and VI were partly chlorinated, indicating that residence times on the order of at least 3-10 min are required. The lower limit needed to be raised as saturation of the resin approached to ensure extensive removal of active halogen.
Conclusions Polystyrene-divinylbenzene copolymers ring substituted with sulfonamide or N-alkylsulfonamide groups readily remove active chlorine and active bromine compounds from water in the parts per million range. Removal of the active halogens can exceed 99% with residence times of 3-10 min at ambient temperatures. When the polymers approach saturation with active halogen, the active halogen can be removed using reducing agents. The resins are then capable again of combining with active halogens. The polymers, particularly those with N-alkylsulfonamide functional groups, show good chemical stability. Acknowledgment
i (
i 1
B 3
i i
I thank Prof. E. I. Smith for plotting the data in Figure 1.
Registry No. Cl,, 7782-50-5; NH,Cl, 10599-90-3; NHCl,, 3400-09-7; NC13, 10025-85-1; Brz, 7726-95-6; HzNNHz,302-01-2; Na2S03,7757-83-7; NaHS03, 7631-90-5. Supplementary Material Available: Data for all runs
CI
on the halogen removal by sulfonamides of poly(dietheny1benzene-co-ethenylbenzene)(12 pages). Ordering information is given on any masthead page.
a
Literature Cited
p i 1
p I
American Public Health Association, American Water Works Association, and Water Pollution Control Federation 'Chlorine (residual) DPD Ferrous Titrimetric Method, DPD Colorimetric Method". In Standard Methods for the Examination of Water and Wastewater, 15th and 16th eds; Wiley: New York, 1981, 1985; pp 290-293 (1981), pp 306-310 (1985). Brungs, W. A. "Effect of Residual Chlorine on Aquatic Life". J . Water Pollut. Control Fed. 1973, 45, 2181. Chattaway, F. D. "Nitrogen Halogen Derivatives of the Sulfonamides". J . Chem. SOC.1905, 87, 145. Dakin, H. D.; Cohen, J. B.; Daufresne, M.; Kenyon, J. "Antiseptic Action of Substances of the Chloramine Group". PFOC. R. SOC. London, Ser. B. 1916, 89, 232. Emerson, D. W.; Shea, D. T.; Sorensen, E. M. "Functionally Modified Poly(styrene-divinylbenzene). Preparation, Characterization, and Bactericidal Action". Znd. Eng. Chem. Prod. Res. Deu. 1978, 17. 269.
1802
Ind. Eng. Chem. Res. 1988,27, 1802-1806
Emerson, D. W.; Emerson, R. R.; Joshi, S. C.; Sorensen, E. M.; Turek, J. E. “Polymer-Bound Sulfonylhydrazine Functionality. Preparation, Characterization, and Reactions of Copoly(styrenedivinylbenzensulfonylhydrazine)”. J . Org. Chem. 1979,44,4634. Emerson, D. W.; Gaj, D.; Grigorian, C.; Turek, J. E. “Intraresin reactions of a,w-Alkanediamines with Sulfochlorinated Copoly(styrene-divinylbenzene)”. Polym. Prepr., Am. Chem. SOC.,Div. Polym. Chem. 1982,23, 289. Kunin, R. Ion Exchange Resins, 2nd ed.; Wiley: New York, 1958, p 341ff. Kyba, E. B.; Koga, K.; Sousa, L. R.; Siegel, M. G.; Cram, D. J. “Chiral, Hinged, and Functionalized Multiheterocycles”. J. Am. Chem. SOC.1972, 95, 2691. Min, K.-e.; Lee, H.-k.; Klee, D.-h. “Synthesis of Amphoteric Ion Exchange Resins and Their Physicochemical Properties”. Polymer (Korea) 1985, 9, 68. Nakamura, Y. “High Polymers Containing Free Functional Groups. VII. Resins Containing Sulfoamide, Sulfochloramide, or SulfoJpn, Znd. Chem. Sect. 1954, dichloramide Group”. J. Chem. SOC. 57, 818. Nicolson, N. J. “An Evaluation of the Methods for Determining the Residual Chlorine in Water”. Analyst 1965, 90, 187.
Palin, A. T. “Methods for the Determination, in Water, of Free and Combined Available Chlorine, Chlorine Dioxide and Chlorite, Bromine, Iodine and Ozone using Diethyl-p-phenylenediamine (DPD)”. J . Inst. Water Works Eng. Sci. 1967, 21, 537. Palin, A. T. “Current DPD Methods for Residual Halogen Compounds and Ozone in Water”. J . Am. Water. Works Assoc. 1975, 67, 32. Shaw, M. P.; Snodgrass, W. J. “Natural Chlorination Kinetics of Secondary Municipal Effluents”. In Water Chlorination Environmental Impact and Health Effects; Ann Arbor Science: Ann Arbor, MI, 1983; Vol. 4, Book 1, pp 113-123. Tschang, C.-J.; Klefenz, H.; Sauner, A. “Macroporous Polymers as Support Material for Covalent Bonding of Protein”. Ger. Patent 2834539, 1980; Chem. Abstr. 1980,93,3076. White, G. C. Handbook of Chlorination for Potable Water, Wastewater, Cooling Water, Industrial Processes and Swimming Pools; Van Nostrand Reinhold: New York, 1972. White, G . C. Disinfection of Wastewater and Water for Reuse; Van Nostrand Reinhold: New York, 1978.
Received for review January 12, 1988 Accepted May 23, 1988
Rheological Properties of Polysaccharide Solutions and Derived Printing Pastes in Continuous and Oscillatory Flow Conditions Romano Lapasin* and Sabrina Pricl Istituto d i Chimica Applicata ed Industriale, Uniuersitd d i Trieste, 34127 Trieste, Italy
Marco Graziosi and Giuseppe Molteni Fratelli Lamberti S.p.A., 23100 Albizzate ( V A ) ,Italy
The rheological properties of printing pastes and the corresponding polysaccharide solutions were examined under continuous and oscillatory shear conditions. A two-parameter Cross model was used for the fitting of the data obtained with a stepwise procedure for all systems. Data from measurements in oscillatory conditions were expanded in a Fourier series; accordingly, the analysis of the viscoelastic behavior was carried out taking into account the fundamental harmonic alone. The temperature effect was described by an Arrhenius model law and consequently discussed in terms of activation energy. Color pastes employed in the machine printing of textiles are rheologically complex fluids. In general, they are aqueous systems with high viscosity, prepared by mixing a thickening agent solution and a dye solution or dispersion. The role of thickening agents in the formulation of printing pastes is of paramount importance since they must impart adequate rheological properties to the pastes in the different flow conditions encountered in the printing process (Schurz et al., 1975; Abdel-Thalouth et al., 1986; Wielinga, 1986). During this process, the materials are moved by the sequence across the mask and, through the screen openings, to the substrate. Thus, the pastes are subjected to flows with shear or extensional components, or both, at different strain rates. High shear rate conditions are present during the first steps of the application process, while after being forced through the screen openings and deposited on the fabric the paste will continue to flow at very low shear rates. Hence, the thickening agents must ensure at the same time both a homogeneous distribution of the printing paste on the screen and its uniform flow through the screen openings. In other words, the paste must be characterized by a good screenability and a complete and uniform penetrability into the cloth; moreover, the best sharpness of definition must be achieved, and the flushing out must be prevented. I t follows that favorable properties for an easy application and a good performance of a printing paste are generally low viscosity values at high shear rates and high viscosities
at low shear rates (or the presence of a yield stress), respectively. As the elastic properties are concerned, they affect both the flow behavior of the paste through the screen openings to the fabric and the following step (flow through the fibers) by governing the elastic recovery of the applied flow. The selection of a thickening agent, which in most cases is confined to natural or semisynthetic polysaccharides with high molecular weights, is determined by the fabric to be printed, the printing conditions, and, above all, the type of dye used. Depending on their chemical nature, the dyes may interact with the thickening agents (i.e., to form complexes or to give a chemical reaction), causing a variation of the rheological properties of the printing pastes and, as a consequence, of their application characteristics. The present work was undertaken with the view of studying the rheological properties of printing pastes having different polysaccharidic solutions as bases and the effects that may derive from the addition of different dyes, temperature variations, and periods of storage.
Experimental Section Materials. The polysaccharides used as thickening agents in the formulation of the printing pastes analyzed in this work were the following: hydroxyethyl guar gum (HEG), (carboxymethy1)cellulose (CMC), and sodium alginates (ALG). Guar gum is a natural plant polysaccharide, with a chemical structure corresponding to a linear backbone of
0888-5S85/S8/2627-~802$01.50/0 0 1988 American Chemical Society
