Fabrication Of Filters Research Articles

Chitosan interpenetrating polymer network hydrogels for oil–water and emulsion separation

AbstractHydrogels have obtained extensive attention in oil–water separation due to their high hydrophilicity and weak viscosity. However, most hydrogels have limited applications due to their subpar mechanical qualities. The interpenetrating network gives the hydrogel material high mechanical properties due to the presence of physical and chemical crosslinking. Hence, polyvinyl alcohol/chitosan/polyacrylamide interpenetrating polymer network hydrogel (HAPC‐Gel) was created in this study. HAPC‐Gel coating filter cloth showed underwater super‐oleophobic (the oil contact angles about 159°) and could stably separate oil–water mixtures in different oil phases and complex environments (acids, bases, salts), and the removal rate is still above 99% after 20 cycles of separation. Furthermore, the water could be divided from the oil‐in‐water emulsion. These results indicate that HAPC‐Gel composites have promising applications in oil–water separation.

Fabrication of mixed matrix nanofibers with electrospraying and electrospinning techniques and their application to gas toluene removal

This study describes the fabrication and characterization of mixed matrix nanofiber air filters having adsorptive and photocatalytic properties. Two fabrication techniques were applied as (i) single electrospinning (SE) and (ii) successive electrospinning and electrospraying (SEE) for doping of photocatalyst (TiO2) in nanofiber structure. Polyacrylonitrile (PAN) was used as main polymer, the nanoclay (NC) was used with ratios of 0.5%, 1.0% and 2.0% (w/w) as nanoadsorbent and TiO2 was used as photocatalytic oxidation agent. TiO2 was integrated to the nanofiber structure with two doping methods (blended in solution and sprayed) providing as same TiO2 mass (0.2 g TiO2/g PAN) in unit area of final nanofiber structure. The water vapor transmission rate (WVTR) values showed a decreasing trend with the addition of NC and varies between 80 and 150 g/m2h. The presence of NC played a critical role in increasing of toluene adsorption capacity of nanofiber from 15% to 40% with increasing of NC amount. The maximum toluene degradation rates of mixed matrix nanofiber were found as 0.09 ppm/min for the NC2.0-TiO2-S coded nanofiber and 0.05 ppm/min for the NC2.0-TiO2 coded nanofiber. The integration of TiO2 to nanofibers with SEE was found as more effective for toluene oxidation than SE. With the electrosprayed TiO2, the contact area of nanofiber is further increased and the UVA light more easily activates TiO2 onto nanofiber. Among all nanofibers, NC2.0-TiO2-S coded nanofiber (doped TiO2 with SEE) is promising for air filter considering its filtration properties in general, as it has high toluene adsorption and oxidation efficiency, good air permeability, 93% particulate matter filtration efficiency and low pressure drop.

A state-of-the-art review on advanced ceramic materials: fabrication, characteristics, applications, and wettability

PurposeThe purpose of this study is to prepare a state-of-the-art review on advanced ceramic materials including their fabrication techniques, characteristics, applications and wettability.Design/methodology/approachThis review paper presents the various types of advanced ceramic materials according to their compounding elements, fabrication techniques of advanced ceramic powders as well as their consolidation, their characteristics, applications and wetting properties. Hydrophobic/hydrophilic properties of advanced ceramic materials are described in the paper with their state-of-the-art application areas. Optical properties of fine ceramics with their intrinsic characteristics are also presented within. Special focus is given to the brief description of application-based manipulation of wetting properties of advanced ceramics in the paper.FindingsThe study of wetting/hydrophobicity/hydrophilicity of ceramic materials is important by which it can be further modified to achieve the required applications. It also makes some sense that the material should be tested for its wetting properties when it is going to be used in some important applications like biomedical and dental. Also, these advanced ceramics are now often used in the fabrication of filters and membranes to purify liquid/water so the study of wetting characteristics of these materials becomes essential. The optical properties of advanced ceramics are equally making them suitable for many state-of-the-art applications. Dental, medical, imaging and electronics are the few sectors that use advanced ceramics for their optical properties.Originality/valueThis review paper includes various advanced ceramic materials according to their compounding elements, different fabrication techniques of powders and their consolidation, their characteristics, various application area and hydrophobic/hydrophilic properties.

Extended wet sieving method for determination of complete particle size distribution of general soils

The traditional standard wet sieving method uses steel sieves with aperture ≥0.063 mm and can only determine the particle size distribution (PSD) of gravel and sand in general soil. This paper extends the traditional method and presents an extended wet sieving method. The extended method uses both the steel sieves and the nylon filter cloth sieves. The apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm, 0.038 mm, 0.014 mm, 0.012 mm, 0.0063 mm, 0.004 mm, 0.003 mm, 0.002 mm, and 0.001 mm, respectively. The extended method uses five steps to separate the general soil into many material sub-groups of gravel, sand, silt and clay with known particle size ranges. The complete PSD of the general soil is then calculated from the dry masses of the individual material sub-groups. The extended method is demonstrated with a general soil of completely decomposed granite (CDG) in Hong Kong, China. The silt and clay materials with different particle size ranges are further examined, checked and verified using stereomicroscopic observation, physical and chemical property tests. The results further confirm the correctness of the extended wet sieving method.

Implementation of a second‐order frequency selective surface filter at mmWave using paper and silver ink

AbstractIn this work, fabrication of frequency selective surface filters by coating paper with silver ink and subsequent laser etching the frequency filter pattern has been investigated. Three filter structures consisting of a combination of square and ring patches operating at 102, 113, and 126 GHz and with corresponding signal attenuation of −15.2, −15.4, and −14.5 dB were fabricated and simulated; −5 dB bandwidths were following, 93.3–112.2 GHz, 101.9–121.1 GHz, and 112.7–132.3, respectively. Also, the proposed screen printing with assistive laser etching could be used to reduce the number of used screens. Furthermore, paper based fabrication using a biodegradable ink could be an alternative fabrication process in future electronic manufacturing.

Prediction of air filtration efficiency and airflow resistance of air filter media using convolutional neural networks and synthetic data derived from simulated media

In the absence of experimental air filtration test data, it is difficult to predict the air filtration efficiency and airflow resistance of filter media. In this novel work, an effort is undertaken to predict the air filtration efficiency and airflow resistance of filter media based solely on scanning electron microscopy (SEM) images of the filter fabric. The analytical single fiber efficiency (SFE) model is incorporated into a machine-learning model designed to analyze digital imagery. A convolutional neural network (CNN) is developed and optimized using synthetic training data produced from digital replication of air filter media. Simulated air filter media were created to replicate the physical characteristics of actual nonwoven nanofibrous air filter media. Digital grayscale images of the simulated media provided the input data for the CNN. Analytical calculations of efficiency and resistance based on the SFE model provided target data for the CNN. The regression model included seven convolution layers and two hidden fully connected layers along with width reduction and depth expansion methods. Twelve model parameters were optimized using training and validation data of 2100 iterations of simulated media. The model was then employed to predict the air filtration behavior of actual air filter media based on an SEM image of the media. The resulting predictions of air filtration efficiency and airflow resistance based solely on an SEM image suggests the potential viability of using synthetic data derived from simulated media to train machine learning models for real-world applications. To the knowledge of the authors, this is the first such application of a CNN to predict air filtration efficiency and airflow resistance using an SEM image, synthetic data created from simulated media, and the SFE analytical model.

Tailings Filtration: Water Jet Spray Cleaning of a Blinded Iron Ore Filter Cloth

The global growth in demand for raw materials is leading to a continuous increase in the mining of ores and thus to an expanding volume of tailings to be stored. To ensure safer storage and an optimized recovery of process water, the tailings slurry is often thickened followed by filtration in filter presses and dry stacking. However, an increasing blinding effect during the time of operation requires cleaning or replacement of the filter media. Cloth washing using spray nozzles is a possible solution, but there is insufficient quantitative data published on the performance. For this reason, this article examines the cleaning of an iron ore cloth from tailings filtration by continuous water spraying. Water flux, spray time and direction (front- and back-wash) variation were investigated by evaluating cleaning performance using flow resistance measurement and comparison to the unused and industrially used state where blinding has occurred. Sufficient cleaning and achieving the flow rate of the unused cloth is possible. However, excessive spray cleaning should be avoided, as damage to the fibers may occur. Spray cleaning can be stated to be economically reasonable since a water demand of 2.5 m3 m−2 and an energy consumption of 6.5 kWh m−2 is necessary for a sufficient regeneration. Furthermore, the spray cleaning is assumed to cost USD 6 m−2, which is approximately similar to replacing the fabric but reduces plastic waste.

Advanced Synthesis and Precise Design of Inline Fully Canonical Filters With High Selectivity

This article presents an advanced synthesis and novel designs of inline fully canonical filters with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> cascaded extracted pole (EP) sections, providing higher band-edge selectivity and suppressing interference from adjacent bands. The conventional fully canonical prototype is reconfigured to significantly facilitate filter design and fabrication. Moreover, to synthesize realizable circuits, a general node scaling method based on admittance matrix is implemented. All associated elements, especially the junction susceptances, can be scaled directly without the aid of inverters, avoiding intricate equivalent circuit transforms. Furthermore, the importance of precise control over the junction susceptances in filter design is discussed for the first time. Accurate junction susceptance enables the exact mapping from synthesized circuits to physical structures, preventing brute-force optimization. In particular, a new and compact EP structure in coaxial technique is proposed with flexibly tuned loading phase and accurately regulated junction susceptance. The good measurement results of a coaxial EP filter with four reflection zeros (RZs) and four transmission zeros (TZs) validate the effectiveness of the proposed theories. Also, this is the first reported coaxial fully canonical filter with only build-in capacitive couplings to avoid passive intermodulation (PIM).

Jet Cleaning of Filter Cloths Used in Solid‐Liquid Separation: A High‐Speed Video Evaluation

AbstractCleaning avoids cross‐contamination and sustains production safety and efficiency. While there have been discoveries for technical surfaces, data on activities for filter cloth are still in the early stages. In the food industry, there is a lack of knowledge and innovative ideas on how to clean cloths efficiently. This study combined high‐speed recordings with cleaning experiments. Cleaning of eleven filters was captured, enabling time‐resolved analysis of the cleaning degree, the cleaning homogeneity, and insights into the mechanisms. The findings divide cloth cleaning into three phases, each significantly influenced by the properties of the cloth. Exemplarily, close‐mesh cloths have smoother surfaces that facilitate cleaning. Coarse structures with flow channels on the cloth surface can complicate cleaning.

Effect of Laser Parameters on Laser-Induced Graphene Filter Fabrication and Its Performance for Desalination and Water Purification.

Laser-induced graphene (LIG) is a low-cost, chemical-free single-step fabrication process and has shown its potential in water treatment, electronics, and sensing. LIG fabrication optimization is mostly explored for dense polyimide (PI) polymers. However, LIG-based filters and membranes for water treatment need to be porous, and additional steps are required to get porous surfaces from PI-based surfaces. Polyethersulfone (PES) porous membranes are cost-effective and are common in water purification as compared to PI; further, the optimization of LIG fabrication on PES-based porous membranes is not explored. So, this study demonstrated the fabrication, optimization, and characterization of LIG with different laser parameters such as power, speed, image density (ID), focusing, laser platforms, and membrane support layer effect on porous PES commercial (UP010) and lab-casted 15% PES (PES15) membranes. The performance of optimized LIG filters was tested for interfacial evaporation (IE)-based desalination in single and stacked layer configuration and water purification applications such as dye removal and disinfection. IE was done in Joule heating (JH) and solar heating (SH) modes, and the UP010-ID7 LIG filter showed the highest JH evaporation rates of ∼1.1, 1.8, and 2.82 kg m-2 h-1 in single, double, and triple stacked configurations, respectively. Using a JH IE setup, the best-performing UP010-ID7 LIG filters have also shown ∼100% removal of methylene blue dye from the contaminated water. Furthermore, all LIG filters showed a complete 6-log bacterial inhibition at the 5 V filtration experiments; at 2.5 V, the optimized LIG filters showed a higher removal than the non-optimized filters. Additionally, the LIGs obtained with the aluminum platform were the best quality. This work demonstrates that laser power, ID, platform, and membrane support are critical parameters for the best-performing PES-LIG filters, and they can be effectively utilized to fabricate PES-based LIG porous surfaces for various energy, environmental, and catalysis applications.

An improved procedure for calculating the pore size distribution of filter cloths in capillary flow porometry

Pore size distribution is one of the most important structural characteristics of filter cloths and can, in theory, be used to predict filtration performance. Capillary flow porometry is a common method to determine the pore diameter(s) and the pore size distribution of a porous material. Equipment applying this method has many advantages, but data processing and further calculations still require refining to be fit for purpose in calculations of flow capacity. The present study aims to develop a new procedure for processing volumetric flow rate data and corresponding pressure, which are measured by capillary flow porometry. The processed data are further used to calculate the pore size distribution of textile materials. Six industrial samples of polypropylene filter cloth were examined using scanning electron microscopy and capillary flow porometry. The raw data measured by the capillary flow porometer were processed using the developed method that considers changes in flow regimes as pressure increases. In addition, the nonideality of pores, originating from tortuosity, an irregular cross-sectional shape of the pore, and the number of pores, were considered in calculations by combining all these characteristics in one single parameter. This work shows that pores in a textile material are not ideal cylinders. The standard pore size distribution calculations should consider an imperfect pore structure and, therefore, be corrected.

A facile approach for the synthesis of ceramic filters for methyl orange, chromium and lead removal from water

The provision of safe drinking water is still a challenge in rural communities of low-income countries, partly due to the high cost of modern filtration systems. As a result, people often collect and use water without treatment, thereby compromising their health. Readily available material and waste products may provide a solution for drinking water challenges. Therefore, this study investigated the application of optimized ceramic filters for the removal of methyl orange, lead and chromium from water. The filter properties were fine-tuned by optimizing the compression pressure and content of macadamia nutshell (used as porogen) to obtain satisfactory flow rates and high pollutant removal. The raw material and resultant filters were characterized for chemical composition as well as filtration properties using various techniques. The best-performing filter had a flux of 289 L/m2h and removed methyl orange (40%), turbidity (95–98%), chromium (III) (40%) and lead (II) (71%). Improvement in filtration performance was attributed to an increase in filter porosity and hydrophilicity due to the presence of oxygen-rich functional groups. The proposed filter fabrication method is environmentally friendly, facile, cost-effective, less time-consuming and does not require expertise to reproduce. The performance of the filters is comparable to other filters reported in the literature and they are easy to maintain and are reusable.

Processes for the Clarification of the Crude Oil of Baobab Seeds Extracted by Pressing on Activated Carbon Elaborated from the Capsules of the Fruit (&amp;lt;i&amp;gt;Adansonia digitata&amp;lt;/i&amp;gt; L.)

The baobab, Adansonia digitata L. plays an important role in the economy of local populations. The oil from the seeds of the baobab fruit is nowadays highly prized because of its numerous cosmetic and therapeutic applications and its composition of unsaturated fatty acids, sterols and tocopherols. However, unlike refined oils, locally extracted baobab oil has not undergone purification operations to ensure its quality. Only a filtration on special cloths is carried out after decantation. Indeed, the oil obtained after pressing is cloudy because of the presence of various impurities. It therefore requires treatment operations to make it more attractive and of higher quality. Therefore, in order to provide innovative solutions to local companies to improve the quality of vegetable oils, a study of clarification (treatment) of crude oil is necessary. An experimental device has been developed in the laboratory. It includes a glass column and a filter bed of dune sand and activated carbon. This study has shown the efficiency of the experimental device. Indeed, the activated carbon, thanks to its adsorbing power, has allowed a significant decrease in turbidity at the 5% threshold, from 14.61 NTU for the raw oil to 0.08 NTU for the oil filtered on 3% carbon and 0.033 NTU for the oil filtered on 5% carbon. That is to say an abatement higher than 95%. This decrease in turbidity could be correlated with the decrease in brown index from 187.39a for the initial crude oil to 128.53d for the oil treated with 3% activated carbon versus 187.59a for the oil filtered on cloths. The lowest brown index was observed with the filtration using 5% activated carbon (35.99b). Thus, for the yellowness index, only the filtration on 5% charcoal allowed to obtain a significant decrease in yellowness. The yellowing index of the oil with 5% was 44.67b against 79.04a for the oil filtered with 3% activated carbon, 86.33a for the crude oil and 86.46a for the oil filtered on cloths. Finally, the oil sample treated with 5% activated carbon had the clearest clarity than the other samples with a clarity (L) equal to 97.98c against 95.63d for the oil treated with 3% carbon and 94.99b for the oil filtered on filter cloths. According to the results obtained, the experimental device made it possible to obtain a clearer baobab oil with a low brown index, thus improving the sensory quality of the oil.

Electroformed Dual-Mode Waveguide Filter With No Tuning Screws

This letter presents an X-band dual-mode rectangular waveguide resonator filter with transmission zeros fabricated by electroforming. The reason of employing electroforming in filter fabrication is that the rectangular waveguide resonators can avoid having rounded corners which are inevitable for filters fabricated by a commonly used method, milling. Having no rounded corners enables fast and accurate design supported by electromagnetic simulations. Hence, the fabricated filter produces the frequency response that agrees well with the simulated response although the filter employs the dual-mode technique and there are no tuning screws at all for fine tuning the resonant frequency of each resonator and the coupling values.

Spent coffee grounds utilization for green ultraviolet filter and nanocomposite fabrication

Spent coffee grounds utilization for green ultraviolet filter and nanocomposite fabrication

Fabrication and Application of Halloysite Nanotube-Embedded Photocatalytic Nanofibers with Antibacterial Properties.

With decreasing indoor air quality, increased time spent at indoors, and especially with the COVID-19 pandemic, the development of new materials for bacteria and viruses has become even more important. Less material consumption due to the electrospinning process, the easy availability/affordability of the halloysite nanotube (HNT), and the antibacterial effect of both TiO2 and ZnO nanoparticles make the study even more interesting. HNTs have attracted research attention in recent years due to their low cost, high mechanical strength, natural and environmentally friendly structure, and non-toxicity to human health and ecosystem. In this study, HNT-embedded composite nanofiber filters were fabricated as filter materials using the electrospinning method. Photocatalysts (TiO2 and ZnO) were incorporated into the composite nanofibers by the electrospraying method. The results showed that the combination of both HNT/TiO2 and HNT/ZnO additives was successfully integrated into the filter structure. The effect of embedding the HNT and spraying photocatalysts enables the fabrication of composite filters with lower pressure drop, high filtration efficiency, improved mechanical properties, and high antibacterial properties against Escherichia coli, making the nanofibers suitable and promising for face masks and air filter materials.

Fabrication, physico-mechanical properties and turbidity reduction of disk-shaped ceramic water filters made for peri-urban rivers

Fabrication, physico-mechanical properties and turbidity reduction of disk-shaped ceramic water filters made for peri-urban rivers

Metal–Organic Framework@Graphene Oxide Composite-Incorporated Polyacrylonitrile Nanofibrous Filters for Highly Efficient Particulate Matter Removal and Breath Monitoring

Here, a zinc-based metal–organic framework-decorated graphene oxide (MOF@GO) nanocomposite was synthesized and incorporated within a polyacrylonitrile (PAN) nanofibrous filter to enhance the particulate matter (PM) removal efficiency. For this purpose, the PAN nanofibrous filters containing different contents of the MOF@GO nanocomposite (PAN/MOF@GO) were fabricated, and their morphology was studied using field-emission scanning electron microscopy. The results revealed the formation of uniform and bead-free nanofibers with the MOF@GO wrapping tightly around them. The resultant nanofibrous filters were evaluated for PM removal and possible breath monitoring. The results revealed good mechanical properties with freestanding ability and hydrophobic behavior of the PAN/MOF@GO nanofibrous filters, indicating the possibility of long-term application in high humidity conditions. More importantly, the optimized PAN/MOF@GO nanofibrous filter exhibited a high PM filtration efficiency (95.13%), low pressure drop (15.29 Pa), and superior quality factor (0.198 Pa–1). Moreover, the electrical resistance of the PAN/MOF@GO nanofibrous filter changed with different breathing patterns, indicating the possibility of using the developed nanofibrous filter for human respiration monitoring. This work provides new insights into the fabrication of nanofibrous filters with boosted performance for PM removal by the synergistic effect of GO and MOF particles.

KAJIAN PROSES PENGOLAHAN TAHU: STUDI KASUS INDUSTRI TAHU DI KECAMATAN KABANGKA KABUPATEN MUNA

This study aims to determine the process of tofu processing: a case study of the tofu industry in Kabangka District, Muna Regency. This type of research is descriptive qualitative research. The examination conducts the tofu industry in Wakobaloagung Village, Kabangka District, Muna Regency. Data was collected using the following methods: (a) literature study, (b) interviews, (c) observation, and (d) documentation. The results showed that the tofu production process in the tofu industry business, even though the processing process was still simple technology, including (a) basket tools, (b) filter cloth, (c) grinding machine, (d) tub to accommodate tofu slurry, which has is founding, and (e) the weights of the concrete blocks. Tofu processing includes: (a) preparation, (b) soaking and washing, (c) milling, (d) cooking, (e) tourism, (f) printing, and (g) cutting.

Development of a low-cost dispenser-type water filtration system

Water has always been one of the most significant utilities for humans because of its wide array of applications. The economic impact of the scarcity of supply to clean water for consumption in emergent nations like the Philippines, where a large proportion of the people suffer from water-related diseases due to scarcity of supply to clean water consumption. There is the proliferation of water refilling stations in the Philippines and the proportion of Filipino households relying on commercial water has been escalating but not everybody can adapt to this lifestyle. Another problem identified is, not every place has the access to such system like the communities living on the islands and near the shorelines. The low-cost dispenser-type water filtration system (LCDTWFS) developed will provide readily safe drinking water in the household. The equipment is made up of clay and has a volume capacity of 10 L. The clay used for filter fabrication has no harmful elements and no effect on the filtered water when used as a ceramic filter. The quality of the tap water was significantly improved after passing it through the LCDTWFS. The equipment was tested for 6 consecutive weeks after which, the characteristic of the filtered water is still within the standards of the Philippine National Standards for Drinking Water (PNSDW). The bacteriological/microbiological, chemical, and physical characteristics of the filtered water are within the allowable limits of the PNSDW making it potable and safe for consumption. LCDTWFS is effective yet affordable since it has no electricity requirements, is sustainable, environment-friendly, easily manipulated, and easily produced by local craftsmen. This study can also contribute to the prosperity of rural potters since introducing this newly innovated product could be their source of additional income. • Low-cost dispenser-type water filtration system (LCDTWFS) is effective. • LCDTWFS is made of clay and with a volume capacity of 10 L. • The clay used for filter fabrication has no harmful elements. • The quality of the tap water was significantly improved using the LCDTWFS. • Filtered water is within the Philippine National Standard for Drinking Water.