Synthesis of antibacterial polymers reducing biofilm formation and their application on hollow fiber membranes

Conventional water filtration systems become insufficient to fulfill the standards. Therefore, the demand to advanced filtration processes increases dramatically. Membrane processes are preferred the most, especially the ultrafiltration (UF) membranes. Among the cross-flow and static (dead-end) ultrafiltration methods, static filtration is advantageous by using less energy; however, relatively fast fouling compared to the cross-flow method is one of the main drawbacks of this system. One of the major reasons for fouling is the biofouling caused by the colonization of microorganisms on the surface of membranes. In general, to remove the formed biofilms on the membrane surfaces, chemical backwashings are periodically applied to membranes and these washings decrease the membranes mechanic performances. If the halogens (occur during the backwashing cycles) can be hold for a longer period of time on the surface of membranes, the use-life of membranes can be increased by reducing the number of harmful washing cycles. This assumption can be achieved by using halogen storing N-halamine compounds. In this regard, the prepared membranes will be reactivated in each washing-cycle and antibacterial surfaces will be provided without the necessity of various chemicals. In this study, in order to increase the biodegradability resistance of the ultrafiltration membranes used in water treatments, polymers having high chlorine loading capacity, good solubility in matrix systems, high chlorine stability and not leaching from the material by water were synthesized and added to matrix polymers being used in the production of flat sheet and hollow fiber membranes (HFM). A dry-jet-wet spin line and spinneret was designed and produced. HFMs were successfully manufactured in the established spinning system and packed in module form. The effects of antibacterial polymers on the membrane structures were determined by investigation of ternary phase diagrams, morphological and surface properties of flat sheet and HFMs. The permeability tests and SEM analyzes were used to obtain information about the porosity of the membranes and the improvement of the water flux and protein rejection values of the membranes according to the unmodified membranes. In addition, the produced flat-sheet membranes permeability values were compared with a commercial PVDF membrane and it was found that some of the produced membranes showed higher protein rejection performance than the commercial membrane. Likewise, the water flux of HFMs were very close to the commercial membranes. Finally, the speed and duration of the produced membranes biocidal performances were proven with different test methods.