Novel N-Halamine Biocidal Polymers for Water Purification.

Novel heterocyclic biocidal polymers (N-halamines and poly Quat's) were prepared for disinfection purposes. They were designed to increase bioactive sites and to stabilize the attached halogen ions to the N-halamine polymers. Two methods were used in their preparation; reacting linear polymers (polyacrylonitrile and polyethylacrylate) with uramil and co-polymerizing novel azo monomers (based on uramil) with diisocyanates (toluene-2,4-diisocyanate and tolylene-2,6-diisocyanate). The resulting polymers were halogenated to form N-halamine polymers and acidified to form poly Quat's. The biological activity of the prepared monomers and polymers was evaluated. The optimum halogenation conditions for N-halamine polymers preparation were determined to improve the biological activity. The particle size of the N-halamines was modified as follows; loading uramil to modified silica gels, 2-Cyano-functionalized and 3-(Isocyanato)propyl-functionalized silica gels, and by blending N-halamine polymers with sodium alginate followed by cross-linking with calcium chloride. Optimum preparation conditions and recycling possibilities of the alginate beads were determined. The biological activity of both modified silica and beads was evaluated. A low cost version of the N-halamine polymers was prepared by cross linking polyepichlorohydrin with m-phenylenediamine followed by a reaction with cyanuric acid. A multi-filtration system based on this polymer and its halogenated form was designed to produce halogen-free water. The system is formed from three columns; sand, halogenated polymer and non-halogenated polymer columns. The system regenerability and life-time was determined. A new design for a water purification system (multi-filtration), based on this polymer, was suggested and has potential for development at pilot scale. Some questions have been raised regarding the practicality of the main aim of this project - the potential for using halogenated polymers in water disinfection for water supply. However, a range of other applications have been suggested during the course of the thesis. A new theory about the mode of action of N-halamine polymers has been created based on a combination of factors; contact, release and changing the nature of the bacterial medium. The theory was supported with microbiological and metabolomics evidence