Znd. Eng. Chem. Res. 1991,30,2426-2430
2426
MATERIALS AND INTERFACES Slow Release of Active Chlorine and Bromine from Styrene-Divinylbenzene Copolymers Bearing N,N-Dichlorosulfonamide, N - Chloro- N -alkylsulfonamide, and N -Bromo-N-alkylsulfonamide Functional Groups. Polymer-Supported Reagents. 6 David W. Emerson Department of Chemistry, The University of Nevada, Las Vegas, Las Vegas, Nevada 89154-4003
Macroporous styrene-divinylbenzene (>15% divinylbenzene) copolymer (Pol) substituted with N-halosulfonamide groups, Pol-S02NX2 (1, X = Cl); N-halo-N-alkylsulfonamidegroups, PolS02NXR (2a-c, R = Me, Et, 2-Me-l-Pr, X = C1, Br); or NJV'-allranediylbis(hal~~onamide) groups, Pol-S02NX-(CH2),-NCXSO?-Pol (3a-c, n = 2, 3, 6, X = C1, Br), release active halogen at concentrations high enough for dismfection of water flowing at 0.1 mL/ [ (mL of resin)-min] or of standing water. Halogen in effluent decreased with the volume of water treated and decreased faster a t p H 5.6 than at p H 7.3. Data [ppm C12 equivalent in effluent per L of water treated per g of resin (dry, before halogenation)] follow, ppm (L/g): 3a[C1], pH 6, 2.3 (0.18), 0.26 (3.21), 25.8 "C; 3a[Br], p H 5.6, 3.08 (0.35),0.33 (5.67), 24.4 "C; La[Br], pH 7.3, 2.88 (0.27), 0.34 (14.4). Aqueous bromide ion converts N-chlorinated resins to N-brominated resins in situ. Passing water with 1-5 ppm NaBr through 3b[C1] resulted in a sustained output of active halogen-O.48 f 0.09 ppm from 3.4 to 18.53 L/g. Sodium hypochlorite regenerates the resins.
Introduction In earlier studies it was shown that polystyrene, ring substituted with sulfonamide groups (Nakamura, 1954; Okawara et al., 1962), and (Table I) sytrene-divinylbenzene copolymers ring substituted with sulfonamide groups 1 (Hagge et al., l958,1959a,b; Emerson et al., 1978; Bogoczek and Kociolek-Balawejder, 1986, 1987, 1989), N-alkylsulfonamide groups 2, or N,N'-a,o-alkanediylbis(su1fonamide) groups 3 (Emerson et al., 1982; Emerson, 1988, 1990) react with hypochlorous acid, hypochlorite ion, or hypobromite ion to form the N-chloro or N-bromo derivatives as do their nonpolymeric counterparts (Chattaway, 1905). These substances exhibited bactericidal properties on bacteria growing in Petri dishes (Nakamura, 1954). In the cross-linked bead form, these N-halo derivatives disinfect polluted water in flow systems (Emerson et al., 1978 Emerson, 1990) or by allowing protracted contact of the chlorinated resin with standing water (Bogoczek and Kociolek-Balawejder, 1986, 1987, 1989). It is of considerable interest, therefore, to measure the release of active halogen from these substances in flow and static systems. It has already been shown that all of the active halogen can be quickly and completely removed from the N-chlorinated sulfonamides 1[C1], 2[C1], and 3[C1] by hydrazine (Emerson et al., 1978,1982; Emerson, 1988) and partially removed by sullites (Emerson, 1988). (The element symbol in brackets shows the active halogen which replaces H in the starting sulfonamides.) Halogenating proclivities and oxidizing ability have also been demonstrated (Bogoczek and Kociolek-Balawejder, 1986,1987,1989;Emerson, 1978 and unpublished; Okawara et al., 1962). It is also of interest to measure the sustained, gradual release of active halogen from the halogenated polymers to water in flow or static systems because this should indicate the disin-
Table I. Haloscrub Resins Used in the Study (Pol = Styrene-DVB Copolymer) POI-SO~NH~ Haloscrub-A-O,l 1
Pol-SO2NHR 2 a, R = CH3
Haloscrub-A-l,l
b, R = CHzCH3 Haloscrub-A-2,l R CH2CH(CH3)2 Haloscrub-A-4,1
C,
Pol-SO,NH-( CH2),-HNO&Pol 3
a,n=2 Haloscrub-A-P,P b,n=3 Haloscrub-A-3,P c,n=6 Haloecrub-A-6,P
fection potential of of the materials more easily than can be accomplished by performing bacteriological studies.
Experimental Section Resins Employed. The resins employed in the project (Table I) were prepared from partly chlorosulfonated (ethenylbenzene-diethenylbenzene) copolymers, both macroporous and gel type, by reaction with aqueous solutions of ammonia, alkanamines, and a,@-alkanediamines. The preparation and characterization of the resins have been described previously (Emerson et al., 1978; 1982; Emerson, 1988). A rudimentary nomenclature has been devised (Emerson, 1988). "Haloscrub" is the generic name followed by "A" indicating that the starting material was
0888-5885/91/2630-2426$O2.5O/O0 1991 American Chemical Society
Ind. Eng. Chem. Res., Vol. 30, No. 11, 1991 2427 Amberlyst-15. The first number indicates the number of C atoms in the N-alkyl group, and the second indicates the number of N atoms. Resin 1 is thus Haloscrub-A-O,l, 2a is Haloscrub-A-l,l, 3a is Haloscrub-A-2,2and so on. Amberlyst-15 is a registered trademark of the Rohm and Haas Chemical Company. The Flow System. The resins being tested were placed in a 22 mm i.d. X 310 mm glass tube (118 cm3) which served as the reactor, and water was pumped upward through the resin bed by a peristaltic pump (Cole-Parmer Masterflex Model 7014 20) connected to a variable-speed motor with a timer switch. The output line from the pump was fitted with a "T" connected to a piece of rubber tubing clamped at the open end. When held vertically, the side tube trapped any gas bubbles accompanying the feed. The Static System. Approximately 1g of resin 2b was placed in a 2-L volumetric flask. The resin was chlorinated by adding 5.25% sodium hypochlorite solution (bleach), water, and 0.05 mL of glacial acetic acid per milliliter of bleach. The mixture was allowed to stand for 1-3 days, the solution was decanted, the resin was washed in situ with two 100-mL portions of deionized (DI) water, and the flask was filled to the mark with DI water containing 67 mg/L sodium hydrogen carbonate, pH 7.7. After being allowed to stand in a dark cabinet for 2-3 days, the flask was inverted several times to mix the contents and a sample was obtained for active halogen analysis. The water was then replaced with fresh buffer and the process was repeated. The resin was brominated by adding 3-4 mmol of sodium bromide after the active halogen of the supernatant water was
