Filtration Purification Research Articles

Super-hydrophobic Cellulose Nanofiber Air Filter with Highly Efficient Filtration and Humidity Resistance.

High-air humidity, especially condensation into droplets under the influence of temperature, can pose a serious threat to air purification filters. This report introduces the use of methyltrimethoxysilane (MTMS) for the silanization hydrophobic modification of cellulose nanofibers (CNFs) and obtains an air filter with super-hydrophobicity (CA = 152.4°) and high-efficiency filtration of particulate matter (PM) through the freeze-drying technology. The antihumidity performance of CNFs filters that undergo hydrophobic modification in high-humidity air is improved. Especially in the case of high-humidity air forming condensed water droplets, the increase in the rate of filtration resistance of the hydrophobically modified CNFs filter is much lower than that of the unmodified filter. In addition, the water-vapor-transmission rate of the hydrophobically modified filter is improved. More importantly, adding MTMS can regulate the porous structure of CNFs filters and improve the filtration performance. The specific surface area and the porosity of the filter are 26.54 m2/g and 99.21%, respectively, and the filtering effects of PM1.0 and PM2.5 reach 99.31 and 99.75%, respectively, while a low-filtration resistance (42 Pa) and a quality factor of up to 0.122 Pa-1 are achieved. This work has improved the application potential of high-performance air-purification devices to remove particulate pollution and may provide useful insights to design next-generation air filters suitable for application in high-air humidity.

Study of the PTFE multi-tube high efficiency air filter for indoor air purification

Particulate matter air pollution has become a severe environmental issue because it poses a great threat to human health. In this work, a new type of Polytetrafluoroethylene (PTFE) multi-tube high efficiency particulate air filter was successfully prepared by applying PTFE sheet membranes that wrapped the nonwoven tube for the improvement of the indoor air quality. The properties and filtration performance of three types of PTFE sheet membranes were explored. The PTFE tubular membrane filters with different diameters, lengths and membrane layers were prepared and tested for the ability to remove particulate matter. The results revealed that the PTFE sheet membranes had excellent hydrophobicity and possessed the microstructure of nodes interconnected by fibrils. The thicker and smaller pore size membranes had higher efficiency, and the efficiency curves for the PTFE sheet membranes demonstrated the typical shape of a “V” from 10 to 300 nm at face velocities from 0.3–15 cm/s. The best type of tubular membranes in terms of diameter and length was dependent on the packing density and the height of the filter cavity. According to the test results, the filter contained two layers of membranes had the lowest pressure loss while achieving an ultra-high particle removal efficiency of over 99.98 % for particles (0.3 μm) and nearly 100 % for particles (2.5 μm). The fouling tendency in the staggered arrangement of tubes was less than that in the aligned arrangement. Therefore, the PTFE multi-tube air filter based on the sheet membrane might have a positive potential application for PM removal from air pollution.

Comparison of biopreservatives obtained from a starter culture of Pediococcus acidilactici by different techniques

Due to the increase by consumers of healthy products, the exploration of natural antimicrobial compounds has been promoted through the use of by-products of lactic acid bacteria. Therefore, the aim of this research was to obtain an antimicrobial powder (cell free) by freeze-drying (FD) and spray-drying (SD) from the microbial stabilisation (filtration or partial purification) of a Pediococcus acidilactici fermentation broths. The antimicrobial activity of these powders was quantified, in vitro, against Listeria innocua CECT 4032 as a target microorganism. The physicochemical properties tested on these powders were water content, hygroscopicity, water activity, porosity, colour and solubility. As results, microbiological stabilisation is potentially better to perform a partial purification since the antimicrobial capacity against L. innocua CECT 4032 is higher than with filtration. On the other hand, SD is the best technique to obtain the powder, since it obtains a better productivity with a lower cost and also a more stable powder during storage.

Hybrid Polyoxometalate Salt Adhesion by Butyltin Functionalization.

Polyoxometalate (POM)-based ionic liquids, with nearly infinite compositional variations to fine-tune antimicrobial and physical properties, function as water purification filters, anticorrosion/antibacterial coatings for natural stones, self-repairing acid-resistant coatings, catalysts, and electroactive, stable solvents. By combining hydrophobic quaternary ammonium cations (QACs; tetraheptylammonium and trihexyltetradecylammonium) with butyltin-substituted polyoxotungstates [(BuSn)3(α-SiW9O37)] via repeated solvent extraction-ion exchange, we obtained phase-pure hybrid POM salts (referred to as such because they melt above room temperature). If the solvent extraction process is performed only once, then solids with high salt contamination and considerably lower melting temperatures are obtained. Solution-phase behavior, based on POM-QAC interactions, was similar for all formulations in polar and nonpolar organic solvents, as observed by X-ray scattering and multinuclear magnetic resonance spectroscopy. However, solid thin films of the butyltin-functionalized hybrid POM salts were significantly more stable and adhesive than their inorganic analogues. We attribute this to the favorable hydrophobic interactions between the butyltin groups and the QACs. All synthesized hybrid POM salts display a potent antimicrobial activity toward Escherichia coli. These studies provide fundamental form-function understanding of hybrid POM salts, based on interactions between ions in these complex hybrid phases.

Peptidomic analysis of low molecular weight antioxidative peptides prepared by lotus (Nelumbo nucifera Gaertn.) seed protein hydrolysates

Lotus (Nelumbo nucifera Gaertn.) seeds are rich in proteins and are considered to be a beneficial source of plant proteins. In this study, lotus seed protein hydrolysate (LSPH) was prepared using Flavourzyme and antioxidant activities were evaluated. The LSPH possessed the highest DPPH-scavenging (EC50 2.9 mg/mL), H2O2-scavenging (EC50 16.1 mg/mL), and reducing power activity (8.0 mg/mL) at 180 min of hydrolysis. After gel filtration and reverse phase HPLC purification, the low molecular weight fraction was then analyzed by Nano-LC-MS/MS. Sixteen peptides with corresponding mass from 1 to 2 kDa were identified. Peptides with hydrophobic features and acidic amino acids, Asp and Glu, are considered to contribute to overall antioxidant activities. These results show Flavourzyme hydrolysis of lotus seed protein successfully generates low molecular fragments that make them a potential nutraceutical or health promoting supplement.

КАЗАХСТАНСКИЕ ЦЕОЛИТЫ КАК ПЕРСПЕКТИВНЫЙ МАТЕРИАЛ В ПРОЦЕССАХ ВОДОПОДГОТОВКИ МОЛОЧНОЙ ОТРАСЛИ

In the modern world, there are practically no sources of clean water suitable for human consumption. As a result, at any enterprise in the food industry a number of sequential operations are carried out related to the purification of water necessary for the production of products. In all processes of processing dairy raw materials, water supply to enterprises is carried out from a public water supply network and / or from an artesian well. The article discusses the feasibility of using natural zeolites to ensure water safety. Research data of Kazakhstan zeolites of various deposits and their application in practice were studied.. As shown by the results of experimental studies, zeolites of the Taizhuzgen deposit significantly improve water quality. As a result of activation, the sorption ability of zeolite rises to 85-90%. Production tests of zeolites indicate the significant potential of this mineral raw material. Natural zeolites are cheap, resistant to mechanical wear and can be reused after regeneration. Studies have shown that Taizuzgen zeolite is a good sorption material and can be recommended in further studies with the aim of developing filters for water purification used in water treatment processes in the dairy industry.

One-Step Versatile Fabrication of Superhydrophilic Filters for the Efficient Purification of Oily Water.

As industrial oily wastewater can seriously damage ecosystems, the use of filtration technology with functional filters has emerged as an effective approach for purifying oily wastewater and protecting the environment. Although several methods for preparing functional filters with specific wettability have been reported, most methods are complicated, expensive, and time-consuming. Furthermore, these methods are only applicable to specific substrates, which hinder their practical applications. Here, a simple and versatile method for the fabrication of a superhydrophilic filter on any substrate using a one-step dipping process is reported. The method is easily scaled-up to fabricate large-area superhydrophilic filters; moreover, mass production is possible using a roll-to-roll process. The resulting filter is durable, stable, and, due to its stable hydrophilic layer, shows no deterioration in wetting behavior; it also exhibits self-cleaning properties. Based on its selective wetting characteristics, oil/water mixtures and oil-in-water emulsions stabilized by surfactants can be purified in a highly efficient manner. Importantly, owing to its self-cleaning properties, the filter can be reused after simply immersing and washing in water. This easy, cost-effective, fast, and versatile method for fabricating superhydrophilic filters can be practically applied in industries that need to purify oily water.

Metal-organic frameworks functionalized smart textiles for adsorptive removal of hazardous aromatic pollutants from ambient air

Organic pollutants, with their increasing concentrations in the ambient air, are posing a severe threat to human health. Metal-organic frameworks (MOFs), due to their active functionalities and porous nature, have emerged as potential materials for the capture of organic pollutants and cleaning of the environment/air. In this work, the functionalization of cotton fabric is reported by the in-situ growth of zeolitic imidazolate framework (ZIF-8 and ZIF-67) MOFs on carboxymethylated cotton (CM Cotton) by employing a rapid and eco-friendly approach. The physicochemical characterization of the MOF functionalized fabrics (ZIF-8@CM Cotton and ZIF-67@CM Cotton) revealed uniform and wash durable attachment of porous ZIF nanocrystals on the surface of the fabric. These ZIF functionalized fabrics possessed high surface area and have been observed to adsorb significantly high concentrations of organic pollutants such as aniline, benzene, and styrene from ambient air. Interestingly these fabrics could be regenerated and reused repeatedly without any deterioration in their adsorption capacity. The negative and low binding energies calculated by DFT confirmed the physisorption of the aromatic pollutants on the surface of MOF functionalized fabrics. Such fabrics have a huge potential as protective textiles, anti-odor clothing, air purification filters, and related products.

DEVELOPMENT OF CONTINUOUS ANTI-SOLVENT RECRYSTALLIZATION METHOD TO PRODUCE CEFTRIAXONE SODIUM NANO CRYSTALS INJECTION USING CERAMIC FILTRATION

The aim: In this work we developed a method of continuous recrystallization to meet industrial requirements. Materials and methods: Continuous recrystallization method was investigated using porous ceramic filter for water purification with pour size less than 1 μm, that ensures high mixing rate of ethanol and water. Results and conclusions: The results of experiments using crystallization through ceramic filter, gives superior products in particle size, and produced needle shaped ceftriaxone crystals form, that showed significant improvement in dissolution time and obtained ceftriaxone sodium powder to be reconstituted in injectable formula that give clear solution without insoluble microparticles.

3D-printed monolithic biofilters based on a polylactic acid (PLA) – hydroxyapatite (HAp) composite for heavy metal removal from an aqueous medium

High flux, monolithic water purification filters based on polylactic acid (PLA) functionalised with fish scale extracted hydroxyapatite (HAp) were prepared by solvent-assisted blending and thermally induced phase separation (TIPS), followed by twin-screw extrusion into filaments and processed via three-dimensional (3D) printing. The printed filters with consistent pore geometry and channel interconnectivity as well as homogenous distribution of HAp in the PLA matrix showed adsorption capabilities towards heavy metals i.e. cadmium (Cd) and lead (Pb) with maximum adsorption capacity of 112.1 mg gHAp−1 and 360.5 mg gHAp−1 for the metal salt of Pb and Cd, respectively. The adsorption was found to be driven by a combination of ion exchange, dissolution and precipitation on HAp and surface complexation.

Research on application of zeolite in air purification of ship cabins

It’s necessary to equip the ship cabins with suitable air purification device which can ensure the ship’s air quality without affecting the physical and mental health of the crew living in the limited space of a ship during ocean voyage. In this paper, zeolite’s characteristics and application in air purification are introduced, and three different types of air purification filters are designed with zeolite particles as main materials, then three development programs of air purification engineering machine for ship cabins are proposed based on modular design concept. The air-purifying machine models proposed in this paper have been trial-produced and tested, which provides new choices for ship cabins’ air-purifying devices.

The Composition and Properties of the Tailings of Quartzite Enrichment of “Gora Karaul’naya” Deposit

The JSC “DINUR” use enriched quartzite from the “Gora Karaul’naya” deposit in the production of dinas refractories. The tailings of quartzite enrichment are stored in the dump, not used, and thereby pollute the environment. Chemical, mineral and grain composition, physical, mechanical and technological properties of samples of quartzite tailings of the current output and selected from the dump are determined in this study. The tailings of current output contain less oxides of aluminum, iron and calcium and alkalis compared to the dump tailings. Their mineral composition is mainly represented by quartz as well as impurities of muscovite, hematite, magnetite, chlorite, shungite, zircon, rutile, pyrite with a total content of up to 3 %. The dump quartzite tailings contain particles less than 5 mm in size with a predominance of dust–like fractions (less than 0.16 mm). As to the grain composition, content of dust and clay particles, clay lumps and impurities tailings of the current output meets the requirements of Russian Standard no. 31424 (for the sand from sifting of crushing solid stone), belong to the class II, group of large sands; dump tailings belong to class I and the group of medium sands. Up to 30 % of the particles are plate– and needle–shaped. The features of changes in chemical composition, bulk density, content of dust–like, clay and organic impurities depending on the size of tailings fractions are considered. The possibility of using of tailings of quartzite enrichment as sand for construction works and fine fractions of tailings as molding material in foundry and granular loading in pressure and non−pressure filters for water purification is shown.
 Keywords: quartz, tailings, composition, properties, use

Cotton Fiber and Carbon Materials Filters for Efficient Wastewater Purification

Carbon materials and cotton fibers (CFs) are eco-friendly and cost-effective solutions for water purification. However, enhancing the filtration efficiency of these materials remains challenging. In this study, the capacity of heat-treated sorbents (CFs and low-temperature graphite intercalation compounds (LT-GICs)) to improve the efficiency of wastewater purification from heavy metals and petroleum compounds, was investigated. The properties of the thermally modified CFs were studied in order to obtain a material which is highly efficient in purifying wastewater from heavy metal ions (HMIs). The duration of sorption equilibrium and the optimal ratio of heat-treated cotton fibers (HTCFs) and wastewater were determined. The adsorption capacities of CFs for iodine and methylene blue were determined before and after the heat treatment. Experimental results indicated that thermal treatment of CFs resulted in increased numbers of micropores and mesopores, indicating a high sorption capacity for petroleum products (PPs) in wastewater (A = 11.5 g/g) with an efficiency score of 90%. Furthermore, LT-GIC/CF composite filters were optimized for efficient purification. The results indicated that a filter with a composition of 1 g LT-GIC + 3 g CF had the highest sorption capacity for HMIs (28.7 mg/g) and PPs (80.6%) due to its looser surface structure. The X-ray phase analysis of the sintered composite filters showed the presence of carbon in the amorphous phase, which had a similar structure to the activated carbon from black coal. In summary, the high sorption capacities and simple preparation processes of LT-GIC/CF composites make them potential candidates for wastewater purification

Development of a novel type activated carbon fiber filter for indoor air purification

A novel type of activated carbon fiber filter was developed for indoor air purification. The filter is equipped with electrodes for thermo-electrical regeneration at the point of saturation. The electrodes are arranged in such a way that the filter forms a pleated structure with an electrode in the tip of each pleat. This allows for a uniform temperature distribution on the filter surface during the regeneration process and the pleated structure reduces the overall pressure drop across the filter. The latter was validated by Computational Fluid Dynamics, using Darcy-Forchheimer parameters derived in previous work. The CFD model was further used to perform a virtual sensitivity study in search for the optimal ACF filter design by varying the pleat length, pleat height and filter thickness. Finally, adsorption and desorption properties were investigated with acetaldehyde and toluene as model compounds. Freundlich and Langmuir adsorption parameters, derived in previous work were successfully validated with a Multiphysics model.

Improving the sustainability of metal-producing industries in Russia

In recent years, the metal-producing industries face a range of economic and ecological problems. The authors use content-analysis and statistical methods for analyzing the recent data and make proposals for the development t of metallurgy. The metallurgical industry is in second place among all other industries in terms of atmospheric emissions. Ferrous and non-ferrous metallurgy enterprises are forced to use ore with a very low content of useful components in the extraction of metals. Thus, a huge volume of ore is supplied to beneficiation and smelting, and this, in turn, generates large quantities of waste gases from unused components. The current position of metallurgy companies in Russia does not contribute to the development of new industries for several reasons: lack of funds for the development of large plants; lack of forecast for short-term global demand for ferrous metallurgy products; a growing group of competition from foreign manufacturers for the products provided by the industry. To reduce the level of negative impact of metallurgy on the environment, it is necessary to develop and use new technologies that are safe for the environment. Unfortunately, not all enterprises use purification filters and facilities, although this is mandatory in the activities of every metallurgical enterprise.

Bioproduced Polymers Self-Assemble with Graphene Oxide into Nanocomposite Films with Enhanced Mechanical Performance.

Graphene oxide (GO) has recently been highlighted as a promising multipurpose two-dimensional material. However, free-standing graphene oxide films suffer from poor strength and flexibility, which limits scaling-up of production and lifetime structural robustness in applications. Inspired by the relationship between the organic and inorganic components of the hierarchical structure of nacre found in mollusk shells, we have fabricated self-assembled, layered graphene-based composite films. The organic phase of our composite is produced via environmentally friendly and economical methods based on bacterial production of γ-poly(glutamic acid) (PGA). Composite films made of GO, PGA, and divalent cations (Ca2+) were prepared through a slow solvent evaporation method at ambient temperature, resulting in a nacre-like layered structure. These biobased nanocomposite films showed impressive mechanical properties, which resulted from a synergistic combination of hydrogen bonding with the bacterially produced PGA and ionic bonding with calcium ions (Ca2+). The GO/PGA/Ca2+ composite films possessed a high strength of 150 ± 51.9 MPa and a high Young’s modulus of 21.4 ± 8.7 GPa, which represents an increase of 120% and over 70% with respect to pure GO films. We provide rational design strategies for the production of graphene-based films with improved mechanical performance, which can be applied in filtration purification of wastewater in the paper, food, beverage, pigment, and pharmaceuticals industries, as well as for manufacturing of functional membranes and surface coatings.

Swine manure valorization in fabrication of nutrition and energy.

Renewable energy can boost the growing population's need and rapid budgetary development. To reduce fossil fuel consumption is the initial purpose of renewable and sustainable energy, producing valuable bio-based products. The fermenters, using for pretreatment of swine manure, and involvement of swine carcasses are reported to enhance organic loading rate followed by improved biogas yield on household digesters. The compositions such as animal residues, pathogenic microbes, pharmaceutical residues and nutrient compositions including undigested feed are still confused. Therefore, it is mandatory to optimize and stabilize anaerobic practice and digestate filtration purification for consequential fertilizer consumption. The effective bio-methane recovery from energy-rich compounds is challenging due to slow degradation procedures. The pretreatment procedure could enhance lipid depolymerization and improve anaerobic fermentation. This article deeply focuses on biodegradation of swine manure. The components of this manure were evaluated and established several approaches to improve biogas production. Furthermore, recycling of co-digestates was discussed in detail as fertilizer consumption including hygienic aspects of manure and pretreatment strategies of biomass residues. KEY POINTS: • Co-digestion of manure and carcasses enhance bio-methane production. • Removel of ammonia from biogas digester may improve bio-methane gas. • A strong antimicrobial influence has been reported on biogas production.

Measurement of the porosity of a pseudo-spherical nanostructured particle deposit formed by filtration

In many applications involving nanoparticles, the question of controlling the properties of the films formed (particularly in terms of porosity) remains incomplete. These applications cover an extensive array of fields ranging from the manufacture of nanofilms to the prediction of the pressure drop of nanoparticle films formed on the surface of air purification filters. A review of the literature shows that the porosity of nanometric particle deposits has mainly been studied by numerical simulation. The few experimental studies conducted have focused on micron-sized particles or nanoparticle aggregates under limited operating conditions. The objective of this study is to confirm the porosity results of nanometric particle deposits obtained by the previous simulations and to correlate the porosity with relevant dimensionless numbers. The changes in porosity according to the various operating conditions confirm those obtained during the numerical simulations. All the experimental porosity values could be correlated to the Stokes number alone.

Technology of preparation of natural waters for irrigation

Research and search for the most effective and cost-efficient ways of water treatments is relevant today. We propose the use of a natural sorbent as a filter load of a sorption filter for the preparation of natural water for irrigation of crops. The object of study is the water of the Volga River in the Volgograd region. In this work, we propose the use of a sorption filter for purification of natural water, where natural zeolite will be used as a filter load. Before the experiment, a chemical analysis was performed to determine the contaminants in the water and their concentrations. The fractions of zeolite were selected using fractional sieves. Based on the results of sedimentation, the optimal fraction of natural zeolite in terms of absorption properties and contact time with the studied water was selected. Based on the results, the statistical processing of the experimental data was performed and the dependences presented in the form as a power model were obtained. Thus, on the basis of the conducted studies, it can be concluded that it is advisable to use a sorption filter with a zeolite filter load for the preparation of natural waters to be used in irrigation.

Influence of Biomass Combustion Products on Element Content and Thermal Stability of Latvian Sheep Breed Wool Filter Fibres

Sheep wool is natural, easy obtainable, renewable and biodegradable material with a perspective application as a sorbent in filters for purification of industrial emissions from various environmental pollutants. The element content and thermal stability of Latvian dark-headed sheep wool filter fibres was analysed and described before and after exposure to biomass combustion products. Based on the obtained results, it is concluded that the sheep wool filter fibres can sorb various gaseous combustion products, such as carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxides (NOx), however, the sorption processes of these gases are irreversible. The obtained results of total reflection X-ray fluorescence and inductively coupled plasma mass spectrometry suggest that the concentration of heavy metals, such as lead, zinc and iron, significantly increases in the sheep wool filter fibres after exposure to biomass combustion products. In thermogravimetric curves, no significant changes were detected for the sheep wool filter fibres after exposure to combustion products, while in differently thermal analysis curves, the formation of exothermic peak at around 580 °C was observed and could be related to autoignition. Using X-ray diffractometry and scanning electron microscopy coupled with energy dispersive X-ray spectrometry, the solid particles of biomass combustion products were observed on the scaly surface of the sheep wool filter fibres, and these particles mainly consist of potassium chloride, carbon, sulphur and various metal oxides.