Antibacterial Filter Research Articles

Reusability and regeneration of antibacterial filter immobilized zinc oxide nanoparticles on white silica gel beads coated with chitosan

Most antibacterial air filters show good performance for single-use. However, reusable ones are also essential for reducing cost, emergency use, and environmental reduction waste, which are still less attention by researchers. This study investigated the reusability and regeneration capabilities of air filters containing zinc oxide nanoparticles immobilized on white silica gel beads coated with chitosan (ZnOChSi). TEM confirmed nanoparticle size of 11.5 ± 2 nm and dispersed particles. Bacteria-containing spore (Bacillus subtilis) was used to investigate the antibacterial properties of the air filter. The reusable ZnOChSi air filter showed antibacterial properties up to the fourth cycle (4 × 48 h) with >20% efficacy and was no longer practical for the fifth cycle. The regenerated ZnOChSi air filter still performed relatively high antibacterial properties until the third cycle (3 × 48 h) with >50% efficacy and was slowly decreased for continued use. This regeneration test confirmed that the cleansing (heating) method carried out once after 2 × 48 h re-activated the antibacterial properties of the filter. The zinc content release was 1.186 mg/L (0.012% from 10.245 g of the zinc oxide filter).

STUDY OF ANTIBACTERIAL PROPERTIES OF A TiO2-SiO2-Ag COMPOSITE FILTER ON A GLASS FABRIC BASE

Composite films based on catalytically active forms of titanium dioxide synthesized on the fibrous structure of glass fabric are a promising solution for the creation of antibacterial filters for photocatalytic oxidation of microorganism cells under the influence of light radiation of the visible region of the spectrum. The filter obtained in the present work is a multilayer TiO2-SiO2-Ag composite film bonded to fibres of glass fibre carrier. This material has photocatalytic activity due to the presence of titanium dioxide in the anatase phase, which under the influence of light radiation is able to decompose organic compounds and microorganisms sorbed on the filter surface. Special attention was paid to thermal analysis, as a result of which the optimal mode of step-by-step heat treatment of materials was determined to obtain the required phase composition. The selected heat treatment regime allowed to increase the crystallinity of the anatase phase of TiO2, which significantly affected its optical characteristics such as refractive index and forbidden band width energy. The antimicrobial effect of TiO2-SiO2-Ag/glass material tested as a filter in the air purification process was demonstrated in this work. After applying this material as a filter, it was possible significantly reduce the number of E. coli colonies detected in the filter washes, reaching a level of 125 CFU m-3. This indicates the high oxidative capacity of the filter in relation to microorganisms and confirms its potential for use in the field of photocatalytic air purification. The authors note the possibility of application of the developed material in the field of water purification and surface treatment, which determines the prospects for further research. For citation: Buzaev A.A., Tkachuk V.A., Lyutova E.S., Borilo L.P. Study of antibacterial properties of A TiO2-SiO2-Ag composite filter on a glass fabric base. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 63-71. DOI: 10.6060/ivkkt.20246707.7001.

Transparent and antibacterial air filters based on nanofiber/nets membrane

Air pollution is a serious human health issue worldwide, especially the pollution of particulate matter (PM) and the spread of airborne bacteria. However, most existing filters are opaque, have limited filtration efficiency and no antimicrobial properties. We report an electrospinning/netting technology to prepare high-performance and transparent air filters with antibacterial properties. By regulating the ejection and phase separation of charged droplets, nanofiber/nets (NFN) membrane is created. The resulting NFN filter has integrated properties of low packing density (0.32 g cm−3), high porosity (85 %), desirable pore size (280 nm), robust tensile strength (12.8 MPa) and high PM0.3 removal efficiency (99.996 %). Furthermore, the NFN filter also exhibits ideal transparency (90 %) and excellent bactericidal rate (99.99 %). This work should be a positive attempt to develop efficient, transparent and antibacterial filtration materials.

A High Efficiency, Low Resistance Antibacterial Filter Formed by Dopamine-Mediated In Situ Deposition of Silver onto Glass Fibers.

The coating of filter media with silver is typically achieved by chemical deposition and aerosol processes. Whilst useful, such approaches struggle to provide uniform coating and are prone to blockage. To address these issues, an in situ method for coating glass fibers is presented via the dopamine-mediated electroless metallization method, yielding filters with low air resistance and excellent antibacterial performance. It is found that the filtration efficiency of the filters is between 94 and 97% and much higher than that of silver-coated filters produced using conventional dipping methods (85%). Additionally, measured pressure drops ranged between 100 and 150Pa, which are lower than those associated with dipped filters (171.1Pa). Survival rates of Escherichia coli and Bacillus subtilis bacteria exposed to the filters decreased to 0 and 15.7%±1.49, respectively after 2h, with no bacteria surviving after 6 h. In contrast, survival rates of E. coli and B. subtilis bacteria on the uncoated filters are 92.5% and 89.5% after 6 h. Taken together, these results confirm that the in situ deposition of silver onto fiber surfaces effectively reduces pore clogging, yielding low air resistance filters that can be applied for microbial filtration and inhibition in a range of environments.

Получение и применение иодированного бактерицида для дезинфекции воды в локальных системах очистки

The paper presents the results of studies on obtaining a bactericide based on iodized anion exchange resin АВ-17-8. The obtained compound bactericidal efficiency was assessed on Escherichia сoli culture suspensions at 103–109 CFU/mL. All experiments gave positive results and demonstrated the possibility of their use for natural water treatment in local water treatment systems. The obtained bactericidal filter can be used for quantitative determination of bacteriological contamination of the studied waters. Water samples contaminated with E. coli at 500, 1000, 5000 and 10000 CFU/mL were prepared to quantify the bactericidal activity of the iodine-containing compound obtained on an anion-exchange resin. Then samples were sequentially passed through a 100 cm3 bactericidal filter. By the amount of iodine released, the degree of microbial contamination can be determined. There were no microbial cells in the filtrate at zero concentrations of released iodine in the solution. The degree of microbiological contamination of water Q was 10,000 CFU/mL at 0.00391 g/L of iodine. A linear dependence between bactericidal activity and iodine release from the anion-exchange resin was established. This allows us to assume that the positive iodine radical is released “on a signal” – at the appearance of living microorganisms carrying excessive electrostatic charge. The released by the bactericide positive iodine radical (I*+) interacts only with the electrostatic charge of microorganisms, and not with the functional groups of their shells. The found quantitative dependence makes it possible to determine microbiological contamination based on the iodine concentration in the treated solution. Based on the test results, a flowchart of the technological process of surface water treatment was proposed. The presence of a bactericidal filter allows the use of a reverse osmosis filter, sensitive to biological water contaminants, as part of the installation.

Low-Cost Antibacterial Ceramic Water Filters for Decentralized Water Treatment: Advances and Practical Applications.

Access to clean water remains challenging for people living in underdeveloped regions, rural areas, and remote locations. In the absence of centralized water treatment systems, point-of-use (POU) solutions are necessary. Ceramic water filters (CWFs) have emerged as a practical and affordable option for decentralized water treatment. This review focuses on recent advances in antibacterial CWFs, including preparation methods, filtration performance, and applications. The review highlights the significance of preparation techniques, material choices, and additives in determining CWF properties and performance. Despite virus and chemical contaminant removal limitations, ongoing research on nanofillers and antibacterial additives shows promise for enhancing the CWF performance. The cost-effectiveness, ease of production, and low operational requirements of CWF make it a viable solution for decentralized drinking water systems, particularly in resource-limited areas. Studies have demonstrated the efficacy of CWFs in reducing water contaminants, but proper maintenance and user training are crucial to optimal performance.

Constructing green, smart wettability-switchable and antibacterial Caragana cellulose filter by cooperative regulation of texture and surface for on-demand purification of emulsions

The efficient on-demand purification of complex oily emulsions containing multiple pollutants and bacteria by a green filter has always been desired, but also extremely challenging. The abundant and renewable natural cellulose biomass is the best choice for developing green separation materials, but the limited separation capability of raw biomass restricts its application. To resolve this problem, this paper proposed a synergetic texture-surface regulation strategy to improve the liquid-locking ability and amphiphilicity of Caragana cellulose fiber, and thus prepared an intelligent multifunctional filter with an arbitrarily switchable underoil superhydrophobic (WCA = 152.1°) and underwater superoleophobic (OCA = 151.6°) surface. The surface wettability of the filter can be switched randomly by changing the wetting liquid, thus achieving efficient separation of different types of emulsions. As expected, both simulated different oils-in-water and different actual waters-in-oil emulsions, and all types of practical industrial oily complex emulsion sewage were purified by the filter at a high level (separation efficiency: 99.9 %). In addition, the filter can simultaneously remove 99.1 % of the Methylene blue and 98.6 % of the Oil red O in emulsions and has excellent antibacterial activity against E. coli (efficiency: 99.87 %) and S. aureus (efficiency: 99.43 %). The spent filter can be regenerated as an adsorbent capable of dynamically adsorbing 99.9 % of Orange II and 99.8 % of Methylene blue. This study provides a new method to modulate natural renewable cellulose and thus produce a multifunctional separation material for on-demand purification of complex and stubborn emulsions.

Multifunctional Polymer Nanocomposite Coated Antibacterial Filters for Air-Purification

Air and environmental pollution require products used and produced in industrial areas to have natural ingredients and low energy consumption. It is impossible for standard used filters to clean bacteria in homes, workplaces and areas working with biological creatures. Therefore, the production of multifunctional composite and hybrid filter papers is necessary. In the study, filter papers coated with nanocomposite solutions prepared from green synthesized nanosilver (AgNPs) with plant extracts and Polyvinyl Alcohol (PVA). Scanning Electron Microscope (SEM) analyses showed that silver nanoparticles and PVA homogeneously coat the filter paper fibers, thereby reducing the average pore diameters by only 3% compared to commercial standards of filter paper. Using nanosilver, plant extracts, and PVA, a filter with 36% higher burst pressure resistance was produced. The antibacterial effect is provided to the filters with a high effect of up to 100,000 times, by coating them with nanosilver and plant extracts. This study enabled the production of antibacterial and high mechanical strength filter paper with natural ingredients, low energy and raw material consumption, and low cost. In this way, bacteria and pollutants in the air environment will be cleaned without harming the environment and also human health.

Quaternary ammonium salt coated air filter for bioaerosol removal from building indoor air

Developing air filters with biocidal ability is important to protect the public from infectious respiratory diseases. A simple spray-coating approach was devised to fabricate antimicrobial air filters to remove bioaerosols. The commercial antimicrobial agent Goldshield 75 was coated on the air filters through covalent immobilization, endowing the fabricated filter with long-lasting biocidal ability. All coated filters significantly inhibited both Gram-positive bacteria (Micrococcus luteus) and Gram-negative bacteria (Escherichia coli). The antibacterial ability of the coated filters is similar to the commercial AeraSafe antibacterial filter. The coated filter showed over 99.9 % antibacterial efficiency 3 months after the application of the coating. Both bacterial and virus filtration efficiencies of coated charged polypropylene filter were higher than 99.9 %. The coating did not have much effect on the NaCl aerosol filtration efficiency of the filters. This simple spray-coating strategy is a practical method for producing antimicrobial air filters for the prevention of infectious respiratory diseases.

Antivirus and antibacterial filters for face masks based on silver quantum dots

Background/Aim. Available face masks, used to protect the respiratory system from various types of pathogens, show unsatisfactory efficiency because the size of viruses like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is much smaller than the void spaces in these masks. Difficult breathing through some masks quickly tires out, which makes ordinary people avoid wearing them. These facts suggest that a new strategy is desirable for designing protective face masks. The aim of the study was to present new filters for face masks to protect people exposed to high concentrations of bacteria and viruses, particularly SARS-CoV-2. Methods. Filters for these masks were manufactured of dense cotton fabric impregnated with silver quantum dots. The filters were characterized by scanning electron microscopy and ioncoupled plasma mass spectrometry. Wettability properties were determined by measuring contact angles with water, and a color fastness test was performed. Antibacterial assay was performed using Staphylococcus (S.) aureus. Viability quantitative polymerase chain reaction (qPCR) for virus integrity assay and reverse transcription qPCR (RT-qPCR) assay were used for antiviral activity assessment. Results. In vitro assays showed extremely high efficiency of these filters in destroying S. aureus and SARS-CoV-2 virus. The filters also showed high safety and easy breathing possibilities. Conclusion. The high efficiency of these masks against SARS-CoV-2 has been demonstrated through numerous tests, and they have been approved as anti-SARS-CoV-2 masks for the first time in the world. In the meantime, this solution has been applied in practice, and the data obtained about that are very encouraging.

Nanocellulose-reinforced air filter with gradient hierarchical structure for highly effective and reuseable antibacterial air filtration

Since the outbreak of COVID-19, microbial pollutants in the air have attracted people's attention. Existing air filters can only intercept microorganisms but cannot inactivate them. Thus, there is an urgent need to design air filters with antibacterial properties. In this study, we used vacuum-assisted filtration to adjust the pore structure of the traditional glass fiber air filter with cellulose nanofiber (CNF) and tempo-oxidized nanocellulose (TNF), and constructed a graded air filter (GCT) with gradient pore structure and Janus structure. At the same time, the addition of nanofibers increased the mechanical properties of the glass fiber air filter. Finally, the filters were endowed with good photothermal properties and stable antibacterial properties by adding antibacterial agents from previous studies (GCT/Ag-3). GCT/Ag-3 responded under near-infrared light, achieving a 99.9 % antibacterial rate against E. coli and S. aureus within 90s, and maintaining this high efficiency after 6 cycles, which provides a feasibility for the design of antibacterial air filter.

Control of microbial agents by functionalization of commercial air filters with metal oxide particles

According to the World Health Organization, low-quality air results in 3.2 million premature annual deaths of which 21 % are attributed to respiratory infections. The recent coronavirus (COVID-19) pandemic, responsible for millions of deaths worldwide, has highlighted the issue of airborne pathogens on human health. Air filtration is an established method to ensure good indoor air quality, being effective at capturing airborne particles and dust, as well as pathogens, and preventing diseases such as asthma. Nevertheless, with usage, water from air humidity, dust, and dirt, including fungi and bacteria spores, can accumulate on filters creating ideal conditions for the propagation of microorganisms. Thus, the filter can become a secondary source for airborne pathogens. In this work, antiviral and antibacterial filters were prepared by spray coating Ag2O, CuO, and ZnO particles into commercially available air filters. The reliability of the filters was tested through particle release in air, through a scanning mobility particle sizer, and filtration performance was measured against an aerosol of iron nanoparticles in nitrogen gas produced through a spark discharge generator. Additionally, the biosafety of the filters was measured in vitro through cytotoxicity tests against L-929 mouse fibroblast cells. Antibacterial activity was measured in vitro against two clinically relevant pathogens: Streptococcus pneumoniae and Pseudomonas aeruginosa and the anti-viral performance was measured against human respiratory syncytial virus. In general, the results have shown that spray coating is a reliable solution, with no detectable cytotoxicity effects or particle release in the air. After functionalization, both Ag2O and CuO compounds have been shown to have total antiviral activity (over 99 %), while only Ag2O presented a clear antibacterial action. In conclusion, spray coating as post-manufacturing functionalization of air filters can be an efficient and low-cost solution against airborne pathogens.

Self-Powered, Biodegradable, and Antibacterial Air Filters Based on Piezoelectric Poly(l-Lactic Acid) Nanofibrous Membranes

Self-Powered, Biodegradable, and Antibacterial Air Filters Based on Piezoelectric Poly(<scp>l</scp>-Lactic Acid) Nanofibrous Membranes

Preparation and property of antibacterial filter membrane by coaxial electro‐spraying/electrospinning technology

AbstractHerein, a novel technology named coaxial electro‐spraying/electrospinning was successfully introduced, which can simultaneously prepare nanofibers and nanoparticles. First, the device contains an outer nozzle and an inner nozzle, which combine electrospinning with electro‐spraying technology. Then, the polyamide 6 (PA6) was spun to prepare the nanofibers from the inner nozzle, and the silver nanoparticles (Ag NPs) into the PA6 solution were sprayed to prepare the nanoparticles from the outer nozzle. PA6 nanofibers (NFs)/Ag nanoparticles (NPs) antibacterial composite membranes for the filtration of fine particulate pollutants were successfully prepared using coaxial electro‐spraying/electrospinning. The microstructure, physical properties, and antibacterial properties of the composite membrane were investigated. The results show that Ag NPs are successfully loaded in situ onto PA6 NFs of approximately 100 nm to form a three‐dimensional (3D) structure. The filtration efficiency of the 3D structured filtration membrane reaches 90.98%, compared to only 12.78% for the melt‐blown cloth mask filter material when tested with polystyrene microspheres (PS) of 200 nm. The contact angle of the composite membrane decreased from 145.47° to 44.11°, indicating a significant improvement in the hydrophilicity of the membrane. Furthermore, depositing Ag on the surface fibers resulted in an impressive antibacterial rate of 99.75% against Penicillium.

Effectiveness of Cellulose Acetate Nanofiber from Banana Leaf Waste (Musa paradisiaca L.) as an Antibacterial Filter in Masks

The COVID-19 pandemic requires all people in Indonesia to comply with health protocols, from washing hands to wearing masks. Cloth masks are one of the masks that are widely used by the community. However, the public needs to pay attention to the rules of the cloth masks used. The purposes of this study were to produce an antibacterial filter on masks and to find out the effective and efficient processing of banana stems as an antibacterial filter on masks. Banana stems were chosen as the raw material because it is easy to obtain, has a cellulose content of ± 63%, and has antibacterial compounds in it. The stages of this research were sample preparation, phytochemical screening of banana stems, isolation of α-cellulose and synthesis of cellulose acetate from α-cellulose which were further characterized by using FTIR, manufacture of dop solution, manufacture of nanofiber membranes by electrospinning, and product application. The resulting product was then tested by pressure drop test, contact angle test, antibacterial activity test, SEM test, and porosity test. The test results showed that the resulting product was a nanofiber with a fiber diameter of ± 220.74075 nm, had antibacterial activity which was indicated by the formation of inhibition zone with a diameter of ± 14.8 mm in Escherichia coli and ± 9.8 mm in Staphylococcus. aureus, the filter is hydrophilic with an average contact angle of 60°. From the observations, it can be concluded that banana stems have the potential as an antibacterial filter on masks.

Effective preparation of environmentally friendly polyglycolic acid (PGA) nanofibrous membrane with antibacterial property for high-efficiency and low-resistance air filtration

In recent years, the antibacterial air filters have been crucial for protecting human health. However, most commercial filters are made of non-biodegradable petroleum polymers, which poses a great challenge for environment protection of recycling after large-scale use. Hence, the air filtration membrane, biodegradable polyglycolic acid loaded with antibacterial ε-polylysine-dialdehyde microcrystalline celluloses (PGA@EPL-DAMCs), was prepared by electrospinning. The incorporation of EPL-DAMCs varied the morphology of the resultant PGA@EPL-DAMCs and endowed them with good antibacterial activity. In addition, it was found that the PGA/EPL-DAMC-24% exhibited the best filtration efficiency (99.83%) and bacterial rate (up to 99.97% and 99.99% for E.coli and S.aureus, respectively). Finally, the degradation performance of the PGA electrospun membrane was also investigated, indicating that PGA@EPL-DAMCs composite nanofiber membranes had broad prospects in biodegradable filtration material, can be applied to develop biodegradable and environmentally friendly medical protective materials with highly efficient air filtration and significant antimicrobial effects.

Microfluidic Spinning of Metal–Organic Framework-Loaded Nanofibers toward High-Efficient Particulate Matter Removal and Antibacterial Filters

Microfluidic Spinning of Metal–Organic Framework-Loaded Nanofibers toward High-Efficient Particulate Matter Removal and Antibacterial Filters

The Enhanced Durability of AgCu Nanoparticle Coatings for Antibacterial Nonwoven Air Conditioner Filters.

Antibacterial nonwoven fabrics, incorporated with Ag, have been applied as masks and air conditioner filters to prevent the spread of disease from airborne respiratory pathogens. In this work, we present a comparison study of Ag ions: Ag and AgCu nanoparticles (NPs) coated onto nonwoven fabrics intended for use as air conditioner antibacterial filters. We illustrate their color changes and durability running in air conditioners using antibacterial activity testing and X-ray Photoelectron Spectroscopic (XPS) analysis. We found that AgCu NPs showed the best antibacterial efficacy and durability. XPS analysis indicated that the Ag concentration, on both the AgCu and Ag- NP-coated fibers, changed little. On the contrary, the Ag concentration on Ag ion-coated fibers decreased by ~30%, and the coated NPs aggregated over time. The color change in AgCu NP-coated fabric, from yellow to white, is caused by oxide shell formation over the NPs, with nearly 46% oxidized silver. Our results, both from antibacterial evaluation and wind blowing tests, indicate that AgCu NP-coated fibers have higher durability, while Ag ion-coated fibers have little durability in such applications. The enhanced durability of the AgCu NP-coated antibacterial fabrics can be attributed to stronger NP-fiber interactions and greater ion release.

Water filter application with zeolit composite material in laying hens farm towards the egg quality

This study aimed to analyze the physical, chemical, and microbiological properties of applying an antibacterial water filter made from zeolite composites in laying hens. This study used a completely randomized design with a factorial pattern with 2 factors and 3 replications for egg quality. Factor A is the zeolite treatment, and factor B is the day of egg collection after being filtered. If the measures show a significant difference, it is continued with the least significant difference test, and the chemical quali-ty of the eggs and the microbiology of the eggs are tested using the t-test analysis (paired samples). The results showed that there was a significant interaction between the zeolite treatment and the day after the filter was installed after the eggs were collected. This increases the value of egg length, egg width, shell weight, shell thickness, and haugh units. Furthermore, the chemical quality of eggs treated with zeolite alone on day 3 had a significant effect (P&lt;0.05) on the dry matter and egg fat content . The microbiological quality of the eggs also showed that the zeolite treatment reduced the TPC value and effectively killed Escherichia coli and Salmonella sp. It was concluded that the application of zeolite filters to the drinking water of laying hens could improve physical quality, maintain chemical quality, and is effective as an antibacterial against bacterial populations, Escherichia coli and Salmonella sp bacteria in eggs.

Three-Dimensional Printing of Ag Nanoparticle Meshes for Antibacterial Activity

Silver nanoparticles (Ag NPs) are decorated or encapsulated for use in antibacterial applications; however, their synthesis involves complex chemical processes. In this study, we developed a facile process for printing an Ag NP 3D microstructure to be applied as an antibacterial filter. The Ag NPs were printed in a mesh form using an aerodynamically focused nanomaterial (AFN) printing system. Unlike the conventional printing method, in the proposed method, the printed Ag NP mesh was peeled from a polydimethylsiloxane substrate. To examine this printing and peeling mechanism, molecular dynamics simulations were performed. In addition, characteristics of the Ag NP mesh were analyzed. The results of the analysis confirmed that the printed mesh retained the properties of Ag NPs. Meshes with various sizes and porosities were printed and their performance as an antibacterial filter was evaluated. Finally, a straw-shaped prototype water filter with three mesh layers was fabricated. A plate cultivated from a suspension filtered using this prototype contained zero active bacteria. This result indicates that the proposed Ag NP 3D printing process, which allows the preservation of antibacterial properties and has wide application scope, is an extensively viable process for manufacturing antibacterial microstructures.