Domestic production and application of protective mask filters against CBRN threats

The term CBRN refers to all dangerous situations caused by chemical, biological, radiological, and nuclear substances for humans and the environment. Chemical warfare agents include all chemicals used to incapacitate living things, injure and kill people, pollute and destroy food sources, and cause chaos and panic. Chemical warfare agents disrupt economically and strategically important targets and force military and civilian personnel to wear protective clothing and use protective equipment. Although whole-body protection against CBRN agents is necessary, respiratory protection is the most important safety measure because the respiratory tract is extremely sensitive. Within the scope of the thesis, CBRN nanofiber filters were produced using the electrospinning technique in three (3) different groups, comprising six(6) pieces. Cellulose acetate (CA) and cellulose acetate + polyvinyl pyrrolidone (CA + PVP) nanofibers were produced by coating on coarse filter paper, medical crepe fabric, and melt-blown fabric. The surface morphology of nanofiber CBRN filters was investigated by SEM and the functional groups in the structure were investigated by the FTIR technique. In SEM images, it was observed that the surface was coated homogeneously with the formation of beadless nanofibers. The average fiber diameters of CA filters were found to be 377 ± 196 nm and the average fiber diameters of CA + PVP filters were 601 ± 209 nm. Characteristic peaks of CA and CA + PVP were seen in the FTIR spectrum. The mechanical properties of the filters such as flexibility, mechanical strength, and elasticity were evaluated in a tensile tester (Shimadzu, AGS-X 10 kN) in accordance with EN ISO 134934–1:2013 standards. Melt-blown fabric increased the tensile strength and unit deformation of nanofibers. The determination of the air permeability properties of the developed CBRN filters was tested with the permeability tester (Prowhite Airtest II) in accordance with TS 391 EN ISO 9237 standards. Filters covered with melt-blown fabric exhibited relatively higher air permeability (29 m3h-1). The filtration efficiency and pressure drop of CBRN filters were measured with an automatic air filter tester (model 8130A, TSI Inc.). A high-efficiency filter accepted as a standard must exhibit a removal efficiency of 90% − 100% PM2.5 (particles less than or equal in size to 2.5 μm). When the meltblown fabric was coated with CA + PVP nanofibers, the particle retention efficiency (PM0.3) increased to 93.19%. The formaldehyde (HCHO) adsorption capacity of CBRN filters was measured using the UV-Vis spectrophotometer (Shimadzu, UV-1900i). The highest adsorption capacity was observed in melt-blown fabric + CA + PVP nanofiber filters. The toxic effects of CBRN filters on healthy bronchial epithelial cells (BEAS-2B) have been investigated. CBRN nanofiber filters have been found to have no toxic effects on BEAS-2B cells. Considering the highest dose of 200 μg/mL in all groups, the viability of the cells did not fall below 50%. However, when CBRN filters were exposed to formaldehyde vapor, their toxic effects increased. When the filters were exposed to formaldehyde vapor, their cell viability decreased due to the inherent toxicity of formaldehyde. Based on the results of other studies on particle retention and adsorption, it can be concluded that the filters that retain formaldehyde. Staphylococcus aureus, Escherichia coli, and Staphylococcus epidermis bacteria were used to determine the antimicrobial activity of CBRN filters. It has been observed that the filters exhibit anti-bacterial properties. As a conclusion, the developed CBRN filters have the potential to be used as filters in face masks, which are personal protective equipment, as well as ambient air filtration, and are open to development as a potential domestic and national filter candidate in the field of CBRN. Keywords: Electro-spinning; Filtration capacity; CBRN; Nanofiber filter