High-Quality and Easy-to-Regenerate Personal Filter

Proper respiratory tract protection is the key factor to limiting the rate of COVID-19 spread and providing a safe environment for health care workers. Traditional N95 (FFP2) respirators are not easy to regenerate and thus create certain financial and ecological burdens; moreover, their quality may vary significantly. A solution that would overcome these disadvantages is desirable. In this study a commercially available knit polyester fleece fabric was selected as the filter material, and a total of 25 filters of different areas and thicknesses were prepared. Then, the size-resolved filtration efficiency (40-400 nm) and pressure drop were evaluated at a volumetric flow rate of 95 L/min. We showed the excellent synergistic effect of expanding the filtration area and increasing the number of filtering layers on the filtration efficiency; a filter cartridge with 8 layers of knit polyester fabric with a surface area of 900 cm2 and sized 25 x 14 x 8 cm achieved filtration efficiencies of 98 % at 95 L/min and 99.5 % at 30 L/min. The assembled filter kit consists of a filter cartridge (14 Pa) carried in a small backpack connected to a half mask with a total pressure drop of 84 Pa at 95 L/min. In addition, it is reusable, and the filter material can be regenerated at least ten times by simple methods, such as boiling. We have demonstrated a novel approach for creating high-quality and easy-to-breathe-through respiratory protective equipment that reduces operating costs and is a green solution because it is easy to regenerate.

DEVELOPMENT OF A CALCULATION METHODFOR TWO-STAGE NATURAL GAS PURIFICATION PLANTS FROM MECHANICAL IMPURITIES

Statement of the problem. Currently, there is no methodology for calculating the degree of clogging of a multilayer filter cartridge taking into account the prevention of deposition of mechanical impurities in the gap between the coarse and fine filter cylindrical filter cartridges. In this regard, the development of such a technique is an urgent task. Results. In this paper, we propose a calculation method for determining the average integral degree of clogging of multilayer cylindrical filter cartridges with mechanical impurities and pressure loss on them which take into account the prevention of sedimentation of mechanical impurities in the gap between the coarse and fine filter cartridges.Conclusions. The results obtained make it possible to determine the pressure loss and the average integral degree of clogging of the multilayer filter cartridge depending on the decrease in the living cross-section of all filter meshes in the process of clogging and to prevent the deposition of solids in the gap between the coarse and fine filter cartridges.

Fabrication of Metal Oxide-Biopolymer Nanocomposite for Water Defluoridation

Fluoride contamination in groundwater affects about 150 million people worldwide. In this study, the authors focused on synthesizing biopolymer metal oxide nanocomposite for fluoride removal. Nanocomposite material was done using SEM. As(V), Al, Ti, Zr, and Fe water samples were analysed by ICP-MS (inductively coupled plasma-mass spectrometry). Fluoride level was determined using the standard method – Ion-Selective Electrode method. Preliminary results indicate arsenic (V) removal was below the 10 ppb and fluoride less than 1.5 ppm as prescribed by WHO. The removal efficiency was after 60-70 minutes with recyclability of 11 cycles. The nanocomposite worked well in all pH ranges 6.5-8.5. A filter cartridge biopolymer metal oxide nanocomposite constituting of template aluminium homogenized in the aggregated network of chitosan was developed as an adsorbent for fluoride from the water with better adsorption limit.