Fabrication and properties of biocidal fibre materials

Abstract

The conditions Jbr fabricating biocidal material based on strongly basic VION AS-1 fibre containing iodine were elaborated. The elevated biocidal activi O, of the material allows using it as the filtering component in .filters for pur(17cation of drinking water with a high concentration of miclvorganisms which cause dangerous gastrointestinal diseases.Sorbents containing iodine are recommended for destroying bacteria that cause infectious intestinal diseases in aqueous medium. Type AV-17 granulated ion-exchangers [ 1 ] in which quaternary ammonium bases absorb a large amount of iodine [2] are primarily used as the sorbents. It was noted that iodine is not only molecularly sorbed in the polymer, but also participates in the formation ofpolyiodide complexes.We fabricated bactericidal material using VION AN-1 chemisorption fibre manufactured on the pilot-industrial scale and based on the copolymer of acrylonitrile and 5-vinyl-2-methylpyridine and epichlorohydrin-alkylated VION AS-1 fibre and investigated the biocidal properties.The solubility of iodine in water is approximately 0.34 g/liter. For this reason, iodine was incorporated in these chemisorbents from aqueous solutions of potassium iodide in which formation of the triiodide ion 13-is not accompanied by electron transfer and is due to attraction of the 12 molecule to the I ion.I 2 was dissolved in an aqueous solution of KI with a concentration of 58 wt. % in the ratio of 1.4:1. The solution was then diluted to a 0.64% concentration of iodine. The VION AN-1 and VION AS-1 fibre chemisorbents were treated with this solution. The concentration of iodine in the fibre was estimated with the static exchange capacity (SEC) determined with sodium thiosulfate (Na2S203). The fibres were subsequently processed into nonwoven cloth with a weight of 1 kg/m 2.The biocidal properties of the fibre materials were evaluated by filtering suspensions of the microorganisms Versinia pestis (vaccine strain EV) and Escherichia coli. Before filtration, disks ofnonwoven cloth with an area of 15.57 cm 2 prepared for the study were held in tap water for different times: 0.1, 1.0, 4.0, 24, and 48 h. After conducting the preparative operations, suspensions of the microorganisms were filtered through the disks of the nonwoven material. The volume of the filtered suspension of viable microorganisms in each experiment was 100 cm 3.The concentration of viable microorganisms was monitored by inoculating samples in solid nutrient medium in the amount of 0.1 cm 3 of suspension in each of three dishes by successive dilution in accordance with generally accepted microbiological methods.The biocidal power of the materials was estimated quantitatively by calculating the number of colony-fomaing units (CFU) in 1 cm 3 of liquid and comparing this index for samples collected before and after filtration of the suspension. This estimation was performed with consideration of the proportion of microorganisms on the filtering materials. For this purpose, after the experiment the disks were immersed in 100 ...