Disinfection of Water by N-Halamine Biocidal Polymers

Abstract

Two novel polymers have been tested in a filter application for biocidal efficacy for flowing aqueous solutions of microorganisms. A laboratory water pump was employed in the experiments to provide contact times on the order of 1-2 s/mL. The two polymers are N-chlorinated and N-brominated derivatives of a polystyrene hydantoin. The variables of pH, temperature, flow rate, and dilution with inert sand have been examined. The N-bromamine polymer (Poly-IB) was generally more effective than the N-chloramine polymer (Poly-I), probably because N-bromamines and free bromine are more biocidal under a given set of conditions than are their N-chloramine and free chlorine analogs. Once the biocidal efficacies of the polymers were exhausted due to chemical reaction with microorganisms or organic load, they could be regenerated by exposure to circulated free chlorine or bromine. This demonstrated that the polymer. materials were not permanently damaged by the exhaustion process. @ Abstract published in Advance ACS Abstracts, September 15, 1995.

Biocidal polymers (II): Determination of biological activity of novel N-halamine biocidal polymers and evaluation for use in water filters

“…However, some biocidal activity is retained in the presence of the quenching agent which suggests some biocidal effect depends on the action of the halogenated polymer itself and proceeds through contact between bacteria and polymer particles. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This dual mechanism of killing (contact + release of halogen species) is currently under investigation and will be reported in due course. In addition to these two expected modes of action there is another possibility: killing the bacteria by changing the nature of the environment around the bacterial cells by exchanging the halogen between the halogenated polymer and proteins in medium.…”

A novel N-halamine monomer for preparing biocidal polyurethane coatings

“…It was observed that the filters inactivated numerous species of bacteria, fungi, and even rotavirus in only seconds of contact time in flowing water. [11][12][13][14][15] Also, it was observed that the columns did not leach out decomposition products into the water, 14 and that the free chlorine and bromine concentrations leached into the flowing water were less than 0.1 mg/L and less than 2.0 mg/L, respectively. Furthermore, once the halogen supply was exhausted through various loss processes, it could be replenished on the polymers by simply exposing them to flowing aqueous free halogen (e.g., sodium hypochlorite bleach for the chlorinated derivative).…”

“…These include cellulose, 5 , 6 nylon, 6 , 7 PET, 6 , 8 Kraton rubber, 9 various surface coatings, 10 and the N-halogenated poly(styrene) hydantoins. [11][12][13][14][15] The latter polymers are granular solids which are insoluble in water and which were packed into glass columns which functioned as a cartridge filters. It was observed that the filters inactivated numerous species of bacteria, fungi, and even rotavirus in only seconds of contact time in flowing water.…”

Biocidal polymers (I): Preparation and biological activity of some novel biocidal polymers based on uramil and its azo-dyes

“…The N-Halamine biocidal polymers described in the literature are water-insoluble; therefore they can be used safely in sterilizing drinking water and many other applications, such as disinfecting water supplies, swimming pools, hot-tubs, industrial water systems, and other applications where a sanitized water supply is required [15][16][17][18][19][20][21][22][23][24][25]. N-Halamine biocidal polymers have been prepared previously by introducing five or six membered heterocyclic rings containing amide or imide functional groups to be halogenated (Scheme 1, d) [15][16][17][18][19][20][21][22][23][24][25].…”