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Purpose: This study evaluates the suitability of construction and demolition waste (CDW) and a preselected plant palette for removing contaminants from light gray water (LGW) in nature-based solutions. Methods: One-liter containers were packed with one of the following types of CDW: concrete aggregates (CAs), crushed permeable pavement (CPP), crushed recycled bricks (CRBs), or crushed recycled tiles (CRTs) as well as a soil layer on top of each type of CDW. Containers were planted with vascular plants (Portulaca grandiflora, Chrysopogon zizanioides, Tradescantia pallida, or Nephrolepis obliterata). Plant-free controls were also prepared for each type of CDW. The containers were fed once a week for eight weeks with real LGW, and the effluents were collected to analyze turbidity, electrical conductivity, pH, ammonia nitrogen, phosphates, and chemical oxygen demand (COD). Results: CDW correctly supports the growth of the tested vascular plants and removes the analyzed pollutants in the following order of efficiency: CAs > CPP > CRBs > CRTs. The quality of effluents treated with CAs improved significantly with each tested plant, especially C. zizanioides; this combination removed 32% turbidity, 38% ammonia nitrogen, 33% phosphates, and 34% COD. Conclusions: CAs and C. zizanioides are promising elements for nature-based solutions such as rain gardens, bioswales, or green walls aimed to treat LGW. However, the leaching of electric conductivity from CDW, the proportion at which soil and CDW are added, and a more significant hydraulic retention time than the one used in this study must be considered to improve LGW treatment. [ABSTRACT FROM AUTHOR]

The complex air environment makes it urgent to build good and safe indoor environments, and the study and application of new materials have become the focus of current research. In this study, we tested and analyzed the structural parameters and filtration performances of the four most commonly used new filter materials in the current market. The results showed that all four new filter materials showed a trend of first increasing and then decreasing their filtration efficiency with an increase in filtration velocity. The filtration efficiency of the materials was as follows: PTFE > glass fiber > nanomaterial > electret. The filtration efficiency of all materials reached its maximum when the filtration velocity was 0.2 m/s. The filtration efficiency of the PTFE for PM10, PM2.5, and PM1.0 was higher than that of the other three materials, with values of 0.87% to 24.93%, 1.21% to 18.69%, and 0.56% to 16.03%, respectively. PTFE was more effective in capturing particles smaller than 1.0 μm. Within the testing velocity range, the resistance of the filter materials was as follows: glass fiber > PTFE > electret > nanomaterial, and the resistance of the four materials showed a good fitting effect. It is also necessary to match the resistance with the filtration efficiency during use, as well as to study the effectiveness of filter materials in blocking microorganisms and absorbing toxic gases. Overall, PTFE showed the best comprehensive performance, as well as providing data support for the selection of related materials or the synthesis and research of filter materials in the future. [ABSTRACT FROM AUTHOR]

The use of droplet digital polymerase chain reaction (ddPCR) has greatly improved the quantification of harmful protists, outperforming traditional methods like quantitative PCR. Notably, ddPCR provides enhanced consistency and reproducibility at it resists PCR inhibitors commonly found in environmental DNA samples. This study aimed to determine the most effective filter material for ddPCR protocols by assessing the reproducibility of species-specific gene copy numbers and filtration time across six filter types: cellulose acetate (CA), mixed cellulose ester (MCE), nylon (NY), polycarbonate (PC), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). The study used two species of Chattonella marina complexes as a case study. Filtration rates were slower for NY, PC, and PVDF filters. Moreover, MCE, NY, PES, and PVDF yielded lower DNA amounts than other filters. Importantly, the CA filter exhibited the lowest variance (38-39%) and the highest determination coefficients (R2 = 0.92-0.96), indicating superior performance. These findings suggest that the CA filter is the most suitable for ddPCR quantification of marine protists, offering quick filtration and reliable reproducibility. [ABSTRACT FROM AUTHOR]

In this framework, the ternary Cd50Pb30S20 bulk alloy and the derived-thin films at different thicknesses (d = 120, 180, 240, and 300 nm) were studied. DSC measurements were carried out at different heating rates from 5 to 20 K/min to extract thermal parameters in the temperature range of (300–700 K). (XRD) and (SEM) techniques showed polycrystalline CdS and PbS phases in the studied films. From optical measurement pathways (T, R), it was found that the films have the ability to block UV light and transmit up to 48% of light in the sub-pass range, which is at the beginning of the visible range and allows about 97% of the infrared through its surface. It was confirmed that orbital transition energies, also referred to as transport bandgaps or onset gaps, were associated with the fundamental absorption edge and the sub-absorption edge of the studied thin films. The optical constants (k and n) and the dispersion parameters (Eo and Ed) were determined. DC conductivity test in the temperature range (300–700 K) was discussed. Different models based on the typical hopping of charge carriers were used to determine the conduction mechanism. In the extended state region located in the high-temperature range, Arrhenius and Schnakenberg's models were used to extract the related parameters. While, Mott and Greaves's models were utilized to compute the electrical parameters in the hopping state region located in the low-temperature range. The Greaves VRH model provided the best insight into the conductivity pathways of the studied films in the low-temperature range. [ABSTRACT FROM AUTHOR]

Leaching characteristics of filter materials of the improved subsurface drainage are very important for nitrogen and phosphorus loss. In this paper, the leaching characteristic of soil, sand, straw, and zeolite under different layouts were studied by HYDRUS-2D simulation based on calibration and validation according to laboratory data. Two scenarios were considered, including different soil and filter layouts, and mixed filter materials of straw and sand or zeolite. The results indicate that zeolite showed good adsorption characteristics of both ammonia nitrogen and phosphorus, while the straw's adsorption characteristics were very different between ammonia nitrogen and phosphorus. Nitrogen and phosphorus concentrations of the outflow were mostly determined by the materials around the outlet. Compared with the cases of no lower soil, when the lower soil depth was 5 cm, the ammonia nitrogen concentrations under sand and straw decreased 54.5% and 96.3%, and the corresponding decreased phosphorus concentrations were 84.1% and 96.2%. In views of mixed filter with straw and the different layouts, that the ratio of straw and sand was 1:1, or the ratio of straw and zeolite was 2:1; at the same time, sand and zeolite should be set around the outlet, and may be better for ammonia nitrogen and total phosphorus concentrations reduction. [ABSTRACT FROM AUTHOR]

Drinking water is an essential daily intake to hydrate the body. It is conceivable that water, when endowed with antioxidant properties, will be the most natural radical terminator surpassing conventional pill-based or food-derived antioxidants. However, current end-of-pipe purification of municipal water generally depletes minerals pivotal for antioxidant potency. To surmount this dilemma, we assemble a multistage and multifunctional water treatment system using various filter materials that dislodge contaminants, mineralize water and impart reductive attributes. The mineralized reduced water (MRW) generated by this system possesses an ideal antioxidant water quality with weak alkalinity, negative oxidation-reduction potential and rich minerals including calcium, magnesium, zinc and silicon. This water decreases oxidative products in vivo via counteracting reactive oxygen species and activating the endogenous antioxidant system governed by nuclear factor erythroid 2-related factor 2. Moreover, long-term intake of MRW effectively retards xenografted tumor growth without any discernible hematologic and organic toxicity. These findings portend enormous promise for MRW in the prevention and treatment of oxidative stress-related maladies and even antiaging.

Efficient air filter element is a key component to prevent erosion, corrosion and solids precipitation in the flow path of gas turbine. However, the performance of the air filter element is significantly reduced in high humidity environment, which seriously affects the safe operation of gas turbine. Herein, the filtration performance of four types of filter element made of F9 filter materials was tested. By comparing the tensile strength of the filter materials under different conditions, the change of pressure drop and efficiency of the filter element was measured in the conditions with different droplet mass concentration. The results show that the moisture resistance of the filter material mainly depends on the fiber composition. The synthetic fiber can effectively reduce the water absorption rate of the filter materials, and the filter element made of materials with low water absorption rate has a stronger capability to maintain its original performance with the influence of water spray. The research results could provide technical reference for the operation and maintenance of gas turbine inlet filtration system and the development of efficient moisture-resistant filter elements.

Filtration of molten metals using open cell ceramic filters has proven the premises regarding the improvements of the final product quality. The Collaborative Research Center 920 has made a substantive record in developing carbon‐bonded alumina (C−Al2O3) filters. Considering the mechanical loads carried by these filters, material strength determination is a necessary step to improve their performance. The Brazilian disc test (BDT) is a method to determine mechanical properties of brittle materials with indirect tensile stresses. The simplicity of the specimen production, test application, as well as results evaluation makes this test attractive. Herein, experimental investigations of different variations of the BDT setup on C−Al2O3 specimens are conducted. Test variations mainly concern the geometry of the load application to ensure a defined failure of the specimens. Digital image correlation (DIC) technique is used to extract the necessary data for the evaluation of the results. Moreover, within an inverse parameter identification method finite element analysis is used to determine strength and elastic material parameters. Additionally, a high‐speed camera is used for the detection of crack formation. It can be concluded that a special variation of the BDT is a suitable method to evaluate the mechanical properties of C−Al2O3. [ABSTRACT FROM AUTHOR]

As a core part of personal protective equipment (PPE), filter materials play a key role in individual protection, especially in the fight against the COVID‐19. Here, a high‐performance multiscale cellulose fibers‐based filter material is introduced for protective clothing, which overcomes the limitation of mutual exclusion of filtration and permeability in cellulose‐based filter materials. With the hierarchical biomimetic structure design and the active surface of multiscale cellulose fibers, high PM2.5 removal efficiency of ≈92% is achieved with the high moisture transmission rate of 8 kg m−2 d−1. Through a simple and effective dip‐coating and roll‐to‐roll process, the hierarchical filter materials can be made on a large scale and further fabricated into high‐quality protective clothing by industrial production equipment. [ABSTRACT FROM AUTHOR]

In this study, an attempt has been made to compare the quality of different filter materials used for dam filters available in different districts of Kashmir Valley of Jammu and Kashmir, India. In order to access the cementation potential/quality of the filter materials the filter materials must undergo strict and accurate composition analysis to improve the filter performance. The amounts of chemical constituents like SiO, Al O, Fe O, CaO, alkalies, and loss on ignition (LOI) were determined in 2 2 3 2 3 accordance with standard procedures and specifications. The performance of filter materials for embankment dams dependent the characteristics like high silica content, low loss on ignition and ferric oxide of the filter material; therefore, the performance depends on the source of the material. The samples from Ganderbal were found to be the most feasible materials for dam filter application because of their high silica content, low loss on ignition and ferric oxide. Due to poor silica content, significant loss on ignition, and ferric oxide, the Budgam sample should be avoided. Thus, it is envisaged that this study will improve the understanding for the selection of more durable and reliable filter materials used in embankment dams in Kashmir valley of Jammu and Kashmir. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are engineered systems for treating wastewater by sequestering nutrients and contaminants. Our aim was to assess the main phosphorus (P) binding states in operating CWs to assess P saturation and indications on P recycling potential of filter materials, which might be necessary under future peak P scenarios. The investigated vertical flow CWs (operation time up to 16 years) are based on either fluviatile (Fluv) sand or zeolite‐ (Ze‐LS) and clinopyroxene (Cl‐LS)‐dominated lava sand. Organic and inorganic P accumulated in all CWs independent of filter materials and showed a considerable increase with operation time. Concentrations of P decreased sharply with depth in the Fluv‐CWs compared to only a slight decrease in the lava sand CWs, with P concentrations of deeper horizons approximating the relatively P enriched original lava sand substrates. Orthophosphate was the dominant pool in all CWs, while the sum of organic fractions ranged between 11% and 33%. Sequential extraction indicated that P was mainly associated with Fe and Al (hydr)oxides for Fluv‐CWs and Ze‐LS‐CWs, while Ca and Mg bound mineral phosphates dominated in Cl‐LS‐CWs. Oxalate extractions pointed to a clear dominance of P fractions associated with poorly crystalline Fe‐ and Al‐(oxy)hydroxides. Solution 31P NMR analyses revealed that inositol hexakisphosphates were a major pool of organic P in surface layers of CWs, which increased with operation time. With a maximum of 0.5% P content, filter sands do not appear to be a suitable fertilizer for direct application to agricultural fields. The dominance of inorganic, poorly crystalline P species point to potentially high desorption capacity which might be investigated further, to assess recycling potential of P or usage of filter materials as soil amendments with relatively high plant available P. The latter might become feasible and economically attractive under future P scarcity. Simultaneously, P saturation indexes (DPS) did not indicate an imminent P saturation of filters, since P accumulation was not restricted by binding to Al and Fe minerals. [ABSTRACT FROM AUTHOR]

This research aims to assess different filter materials in horizontal subsurface flow constructed wetland (CW) planted with combined Phragmites australis Cav. and Cyperus alternifolius L. for treatment of real swine wastewater at a large pig farm in Vietnam. Four CW models including CW1 (gravel), CW2 (gravel, limestone), CW3 (gravel, limestone, and sand), and CW4 (gravel, limestone, and rice husk) were designed and conducted during 90 days of the experiments. The results showed that the removal efficiencies of chemical oxygen demand (COD), total suspended solids (TSS), nitrogen, and phosphorus from swine waster by the CW3 and CW4 models were higher than those by CW1 and CW2. The highest removal efficiency of COD, NH4+-N, TN, and TP by CW3 was 82 ± 2%, 82 ± 4%, 77 ± 1%, and 82 ± 3%, respectively. The result of this study indicates the capacity of combined gravel, limestone, and sand as suitable substrate filter for swine wastewater treatment. [ABSTRACT FROM AUTHOR]

The aim of the work is to study the features of the formation of a knitwear three-dimensional structure, including those made using multifilament yarns. Experimental samples of products are made. The peculiarities of the structure of high-volume knitted garments of plush interlacing made of multifilament polyester yarns of JSC "Svetlogorsk Khimvolokno" are investigated. The expediency of using multi-filament yarns produced by JSC "SvetlogorskKhimvolokno" for manufacturing high-volume knitted garments is established.

Experiments on washing of filter materials to remove uranium and REE (Ce) oxides using a Grad ultrasonic bath (model 180-35) with the generator power of 300 W and frequency of 35 kHz were performed. The following filter materials were tested: MTF metal fabric filter, high-performance fiberglass cellular folded filter (FYaS-E 13 N 0 05.1 P), two types of metal fabric filters with other gauze size, T-13 glass fabric [GOST (State Standard) 19170-2001 (19170-93)] and fine air cleaning filter (FTOV N13 270 × 640 × 500–11) made of glass paper based on microthin fiberglass. The influence exerted on the washing efficiency by the treatment time, ultrasonic generator power, working solution acidity, and process temperature was examined. Ultrasonic treatment intensifies washing of filter materials to remove surrogate powders based on UO2 and CeO2. More efficient washing of fiberglass filter materials requires increased power of the ultrasonic generator. [ABSTRACT FROM AUTHOR]

The fate of filter materials and microbial communities during the vermifiltration process were studied for 5 months while treating the concentrated greywater. Four filters were filled with 10 cm gravel of which a layer of medium size gravel (5 cm thickness, aggregate size 20–40 mm) at the bottom and a layer of coarse gravel (5 cm thickness, aggregate size 10–20 mm) at the top, then filled with 20 cm sand (d 60 = 0.2 mm, d 10 = 0.118 mm). Finally, Vermifilter 1 (VF1), control unit and Vermifilter 2 (VF2), were filled with 40 cm fine sawdust (0.05–5 mm) but Vermifilter 3 (VF3), was filled with 40 cm cow dung (0.05–5 mm). Three filters were inoculated with 200 individuals of Eudrilus eugeniae except for the control unit which was filled with sawdust. Five sampling ports were installed on the wall of the filters at 10 cm intervals with reference to the surface of the top layer. Three of the filters were supplied with concentrated greywater and VF1 was supplied with drinking water at the hydraulic loading rate of 16 L m−2.d−1 on batch basis, i.e., four times a day at 8:00 a.m., 11:00 a.m., 2:00 p.m. and 5:00 p.m. Weekly, samples from influent and effluent, and monthly, samples of filter materials collected via sampling ports, were collected and analyzed.The removal efficiencies of biological oxygen demand (BOD 5), total chemical oxygen demand (tCOD), and dissolved chemical oxygen demand (dCOD) of VF2 and VF3 were 5–7% higher than the control unit, but little differences were observed in terms of total suspended solids (TSS). However, the removal efficiencies of nutrients for the control unit was slightly better than VF2 and VF3. The pH and Moisture content (MC) of filter materials increased along the depth, but percentage of volatile solids to total solids (VS/TS) decreased through time due to the high number of microbial communities and earthworms dominating the top layer compared to the bottom. The performance of VF2-sawdust was slightly better than VF3-cow dung to treat concentrated greywater. • Fate of filter materials and microbial communities during vermifiltration process were studied. • Ratio of volatile solids to total solids decreased during vermifiltration process in filter materials. • The bacteria, actinomycetes and fungi intensified where earthworms dominated. • VF2-Sawdust performed slightly better than the VF3-Cow dung. [ABSTRACT FROM AUTHOR]

Drinking water containing environmental endocrine disruptor compounds (EDCs) endangers human health, and researching the purification process of drinking water for the effective removal of EDCs is vitally important. Filtering plays a crucial role in the bio-adsorption of EDCs, but the adsorption mechanism that occurs between the EDCs and filters remains unclear. In this study, a quartz crystal microbalance (QCM) was employed to elucidate the adsorption mechanism because QCM is a label-free method that possesses high selectivity, high stability, and high sensitivity. The results indicated that a pseudo-first-order kinetic model best fits the adsorption process of four different EDCs, which included bisphenol A (BPA), estrone (E1), estradiol (E2), and sulfamethoxazole (SMZ), on silica (quartz sand), a typical filter material surface. The order of the amount of individual EDCs absorbed on the silica surface was qE2 > qE1 > qSMZ > qBPA and related to their molecular structure, polarity, and chargeability. As the initial EDC concentration increased, the adsorbed amount of the four EDCs on the silica surface increased; however, the initial concentration had little effect on removal efficiency. The calculated Freundlich exponent (1/n) demonstrated SMZ and BPA showed a greater tendency for adsorption than E1 and E2. The mass response time on the surface of the silica gradually increased as the pH increased (from 5.5 to 8.5), indicating the adsorption rate was inhibited by the increase in pH. The addition of electrolytes shortened the mass response time of EDCs on the QCM chip. The pH and ionic strength produced no significant effects on adsorption because hydrophobicity was the primary contributor to adsorption. This study facilitated a better understanding of the interaction between EDCs and filters in water treatment. [ABSTRACT FROM AUTHOR]

Affordable clay-based ceramic filters with multifunctional properties were prepared using low-cost and active ingredients. The characterization results clearly revealed well crystallinity, structural elucidation, extensive porosity, higher surface area, higher stability, and durability which apparently enhance the treatment efficiency. The filtration rates of ceramic filter were evaluated under gravity and the results obtained were compared with a typical gravity slow sand filter (GSSF). All ceramic filters showed significant filtration rates of about 50–180 m/h, which is comparatively higher than the typical GSSF. Further, purification efficiency of clay-based ceramic filters was evaluated by considering important drinking water parameters and contaminants. A significant removal potential was achieved by the clay-based ceramic filter with 25% and 30% activated carbon along with active agents. Desired drinking water quality parameters were achieved by potential removal of nitrite (98.5%), nitrate (80.5%), total dissolved solids (62%), total hardness (55%), total organic pollutants (89%), and pathogenic microorganisms (100%) using ceramic filters within a short duration. The remarkable purification and disinfection efficiencies were attributed to the extensive porosity (0.202 cm3 g−1), surface area (124.61 m2 g−1), stability, and presence of active nanoparticles such as Cu, TiO2, and Ag within the porous matrix of the ceramic filter. [ABSTRACT FROM AUTHOR]

Abstract Owing to the ease and effectiveness of removing suspended substances (SSs), filtration has become a universal pretreatment step during water sample preparation. However, it can lead to the underestimation of contaminants if the targets easily associate with the SSs or filters. For the first time, this study comprehensively assessed issues related to filtration for the accurate quantification of 35 typical pharmaceuticals, including 28 antibiotics and seven non-steroidal anti-inflammatory drugs (NSAIDs), in water samples by comparing the effects of different filter materials, preservatives, and water matrices on the recoveries. The results showed that some sulfonamides and NSAIDs had an affinity for nylon filters, whereas trimethoprim and macrolides were easily retained on mixed cellulose ester filters. The use of glass fiber filter (0.7 μm) resulted in improved recovery of all the targets. Acidification promoted the adsorption of fluoroquinolones, tylosin, and roxithromycin on SSs, whereas 5% methanol resulted in desorption of macrolides from the SSs and other pharmaceuticals (sulfadiazine, trimethoprim, etc.) from the solid-phase extraction cartridges. Without additional detection of targets adsorbed on the SSs and filters, the addition of appropriate surrogates prior to filtration can help correct the loss. Graphical abstract Unlabelled Image Highlights • Issues relating to filtration for accurate detection of 35 drugs are first studied. • NSAIDs and macrolides readily interact with nylon and cellulose filters, respectively. • Fluoroquinolones, tylosin, and roxithromycin are affected by acidification. • Surrogates are recommended to be used before filtration in surface water analysis. [ABSTRACT FROM AUTHOR]

Curium targets are irradiated in high-flux reactors to produce californium-252 (Cf-252). Thermalized neutron spectrum is favorable for Cf-252 production, so traditional methods deploy moderators around the curium targets to optimize the neutron spectrum. However, using moderators alone cannot achieve fine spectrum optimization, and does not necessarily result in better Cf-252 production. We conducted refined neutron spectrum analysis and optimization research to improve production efficiency further. First, based on analysis of the transmutation chain during Cf-252 production, intermediate nuclides with a significant impact on production efficiency, known as "key nuclides," are identified. Then, the "fission-absorption ratio" and "direct loss rate" of these intermediate nuclides are quantitatively analyzed to determine the energy regions that have a greater negative impact on the production process. Finally, filter materials are selected to reduce the neutron flux in these energy regions, optimizing the neutron spectrum around the curium targets and increasing yield and conversion rate during Cf-252 production. The neutron spectrum optimization method for Cf-252 production based on key nuclides analysis helps improve the efficiency and economy of Cf-252 production. • Innovation: three new filter nuclides are proposed for Cf-252 production. • Universality: The analytical method helps the production process of other isotopes. • Feasibility: the conclusion has been verified in the HFIR reactor model. • Significance: the study improves the production efficiency of Cf-252. [ABSTRACT FROM AUTHOR]

Phosphorus (P) losses from tile-drained agricultural fields may degrade surface water quality by accelerating eutrophication. Among the different edge-of-field technologies, compact filter systems using different filter materials have been identified as potentially effective solutions for removing P from drainage water before discharge downstream. This study investigated the long-term (>696 days) P removal efficiency of 5 different filter materials in a column setup, using artificial drainage water (pH 6). Filter materials included two iron-based granulates (calcinated diatomaceous earth (CDE), ferric hydroxide granules (CFH)), and three calcium-based granulates (seashells, limestone, calcinated silicate/calcium oxide (Filtralite-P)). Experiments were performed under variable flow rates (0.037 and 1.52 L h -1 ; hydraulic retention time of 26-43 min and 18-30 h) and inlet P concentrations (0.14 and 0.7 mg L -1 ). An overall analysis revealed that the Fe-based materials achieved higher P retention than Ca-based materials. In particular, CFH was capable of retaining 99 and 98 % of the high and low inlet P concentrations, respectively. Conversely, limestone retained only 25 % of the high P load. CDE performed moderately well, independently of the inlet P concentration. Filtralite-P and Seashells performed well at high inlet P concentration but relatively poorly at low P concentration. The sensitivity of filter material P removal efficiency to variations in P loading was generally lowest for CFH and highest for limestone., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This research investigated the feasibility of effective cost filter materials for groundwater purification in the small and medium scale households in Vietnamese rural areas. The trial models could treat 30 L of groundwater with aeration flow 5 L/min for 15 min. After 24 h of sedimentation, the water was filtered through layers of gravel (h = 11 cm), sea sand (h = 11 cm), activated carbon (h = 15 cm), manganese sand (h = 12 cm), sea sand (h = 11 cm) and gravel (h = 11 cm). After treatment process, the concentration of Fe and Mn ions of the output trial models was lower than the Vietnamese standard for drinking water. The model has a simple structure and easy assembly for washing the filter materials which continued to be used for the next filtration process. These models provide in rural areas, where it promising solutions for supplying drinking water to households is difficult to get clean ground water. [ABSTRACT FROM AUTHOR]

In order to develop nonwoven high-temperature resistance filter materials and to investigate the relationship between the needle-punched filter material and its processing technology, aramid fiber needle-punched nonwovens are composited with glass fiber weaving fabrics in the form of "sandwich" type by needle-punched technique, and the cross-section morphology, mechanical property, permeability, and the pore size distribution of the composite fabrics with different needle-punching densities are studied, and the pore size distribution and thermal stability of the composite fabrics treated by dif­ferent temperatures are investigated. The results show that with increasing the needle-punching density from 300 punches/cm2 to 500 punches/cm2, entanglement of composite mats became close then loose, strength reduced after increased first, permeability went up after got down first, pore size dis­tribution even then dispersed, and composite mats obtained optimal performance when the needle den­sity was 400 punches/cm2. With the increase of processing temperature from 100°C to 250 °C，and pore size distribution of composite mats with 400 punches/cm2 showed first even then dispersed pore size increased gradually, but the heat shrinkage rate is 0, indicating excellent high-temperature resist­ant performance. [ABSTRACT FROM AUTHOR]

Sorbents possessing high exchange capacity, chemical resistance, and mechanical strength were prepared by modification of acrylic fiber Nitron and suspension polyvinyl chloride with various amines. Some applications of the resulting anion exchangers in treatment of wastewater to remove heavy metal ions and microorganisms and of gaseous waste to remove acid gases were presented. [ABSTRACT FROM AUTHOR]

Abstract: The sorption of phosphorus (P) onto solid mediums (soil, sediment and P removing materials) is characterized by a rapid sorption phase followed by a slow phase. No studies have yet attempted to quantitatively distinguish between the two stages. In this study, efforts are made to develop a method that can separate the sorption process into fast and slow stages. According to the geometrical shape of P sorption curves, a maximum curvature value points (MCVP) algorithm is presented as the change point based on the most widely used P sorption models (Langmuir and Freundlich isotherm equation, first-order, second-order and Elovich kinetic equation). Results showed that the MCVP successfully separates the sorption process into a fast stage and then a relatively slow one. General analysis formulas of the MCVP for the most commonly used models are described in this paper. Two steps are recommended before the MCVP calculation: first, independent and dependent variables should be plotted in the same order of magnitude (1:1 is the best), free from the axis scale effect; second, the model that best describes the data points should be used to quantify the MCVP. With the MCVP, it is easy for researchers to obtain the change point by substituting the parameters of sorption models, particularly for materials that have been tested before. The significance of this study is that it allows for optimization of the reaction time in P removal technology and furthers our understanding of P distribution characteristics in soil or sediment. [Copyright &y& Elsevier]

In recent years, several best management practices have been developed for the removal of different types of pollutants from stormwater runoff that lead to effective stormwater management. Filter materials that remove a wide range of contaminants have great potential for extensive use in filtration systems. In this study, four filter materials (calcite, zeolite, sand, and iron filings) were investigated for their adsorption and efficiency in the removal of nutrients and heavy metals when they exist individually versus when they co-exist. Laboratory batch experiments were conducted separately under individual and mixed contaminants conditions at different initial concentrations. Adsorption capacities varied under the individual and mixed contaminant conditions due to different removal mechanisms. Most filter materials showed lower removal efficiency under mixed contaminant conditions. In general, iron filings were found effective in the removal of nutrients and heavy metals simultaneously to the maximum levels. Freundlich and Langmuir isotherms were used to model the batch adsorption results and the former better fitted the experimental results. Overall, the results indicate that the filter materials used in this study have the potential to be effective media for the treatment of nutrients and heavy metals commonly found in urban stormwater runoff. [ABSTRACT FROM PUBLISHER]

Abstract: Heavy metals wash from tires, automobile exhausts, road asphalt, fuel combustion, parking dust, and recreational land into urban stormwater runoff and its subsequent discharge into surface and subsurface water sources can create public health and environmental hazards. An in-ground permeable reactive filter system is proposed to treat contaminated urban stormwater. However, the filter materials should be carefully selected. Several series of batch experiments were conducted with synthetic stormwater containing individual metal contaminants at different concentrations to determine the adsorption and removal behavior of four potential permeable inorganic filter materials (calcite, zeolite, sand, and iron filings) for six common toxic heavy metal contaminants (Cd, Cu, Pb, Ni, Cr, and Zn). The adsorbed metals, pH, oxidation–reduction potential and electrical conductivity of batch samples were determined. Isotherm modeling was performed to assess the mechanisms and quantify the adsorption of each filter material for the contaminants. The extent of adsorption and removal of metals was found to depend on the type and concentration of metal as well as the filter material. Langmuir or Freundlich isotherm proved best to describe the metal adsorption behavior. The maximum removal rates achieved for individual metals were: 95–100% Cd, Cu, Pb and Zn by calcite, zeolite and iron filings, 90% Ni by zeolite, and 100% Cr by iron filings. Sand produced low results with maximum levels of 8–58%. Based on the maximum adsorption capacity of each filter material, the typical filter size and volume of stormwater that can be treated were estimated. No single filter material was capable of removing all metals to the maximum extent; therefore, a combination of filter materials should be investigated for the simultaneous removal of multiple heavy metals. [Copyright &y& Elsevier]

Highlights: [•] A field test using municipal solid waste (MSW) gas containing hydrogen sulphide. [•] Filtering through mineral wool waste (MWW) and rod mill waste (RMW). [•] Removed more than 98% of the hydrogen sulphate over a periode of 80 days. [ABSTRACT FROM AUTHOR]

Urban stormwater runoff is contaminated by nutrients that wash off of roadways, parking lots and lawns during storms. In-ground permeable filter systems that consist of carefully selected filter material have the potential to remove these nutrients from the run-off. In this paper, four filter materials, calcite, zeolite, sand and iron filings, were investigated using laboratory batch tests to evaluate their efficiency in the removal of nitrate and phosphate from the simulated stormwater at different initial concentrations under the same 24-h exposure time period. The range of removal for nitrate was from 39 % to 65 % for calcite, from 42 % to 77 % for zeolite, from 40 % to 70 % for sand, and from 74 % to 100 % for iron filings. The removal of phosphate ranged from 35 % to 41 % for calcite, 59 % to 100 % for zeolite, 49 % to 100 % for sand, and 73 % to 100 % for iron filings. The removal of nitrate is mainly attributed to electrostatic adsorption, except when iron filings were used as a filter material where additional processes such as electrochemical reduction, ligand complexation and precipitation may have contributed to the higher nitrate removal. Phosphate removal is also attributed to electrostatic adsorption in all filter materials; however, at higher phosphate concentrations, the precipitation process may be the dominant process for all of the filter materials except calcite. The Langmuir and Freundlich isotherms fitted the observed nonlinear adsorption results, but the mechanism of removal of phosphate changed from adsorption to precipitation at concentrations higher than 1 mg/l in zeolite, sand, and iron filings; therefore, the adsorption models are valid below this concentration limit. A typical application of these batch adsorption test results is presented in the design of a field in-ground permeable filter system. [ABSTRACT FROM AUTHOR]

In order to accomplish the water quality standards required for a specific use, the continental surface water is treated through a sequence of operations and unit processes. The treatment technological flowsheets carry out, partially or totally, the removal of various pollutants, every treatment step being used for improving one or more qualitative parameter. The treatment scheme is specific to water source type and water use. One of the basic operations for water treatment is the filtration, which is influenced by a series of parameters. The present paper aims at identifying the influence of the granular filtering material on the removal of solids in suspensions that are found in water in concentrations between 5 - 50 mg/L. In order to accomplish the experimental program, the studies were carried out using three types of filtering materials with various shapes of granular particles, respectively: quartz sand, perlite and anthracite. Using this types of materials were constituted Granular filters with different thicknesses of the filtering layer were used at different water flow rates. The type of granular filtering material with the highest degree of retention of solids was identified and recommended for large scale application. [ABSTRACT FROM AUTHOR]

Where subsurface drainage practices are employed, fertilizer nutrients and pesticides applied on farm fields and municipal locations are commonly intercepted by the buried drainage pipes and then discharged into local streams and lakes, oftentimes producing adverse environmental impacts on these surface water bodies. Various filter materials have the potential to remove nutrient and pesticide contaminants from subsurface drainage waters before these waters are released offsite. For this study, laboratory batch tests were conducted to evaluate the contaminant removal effectiveness and efficiency of five potential filter materials. The five materials, isolated from previous screening tests, were steam activated carbon, high calcium oxide-high carbon fly ash, iron sulfide, sulfur-modified iron, and surfactant-modified zeolite. Filter material effectiveness was tested against initial contaminant solution concentrations that varied between 10 and 200 mg L-1 for nitrate-N, 0.1 and 1.0 mg L-1 for phosphate-P, and 0.1 and 0.5 mg L-1 for atrazine, while filter material efficiency was evaluated with respect to exposure time by varying test durations from 1 to 24 h. Sulfur-modified iron proved best for treating nitrate, based on reductions greater than 95% across the range of initial concentration levels and exposure times. Surfactant-modified zeolite and high calcium oxide-high carbon fly ash affected the greatest removal of phosphate, 50% or more in all cases. For atrazine, the most promising results were obtained with steam activated carbon and high calcium oxide-high carbon fly ash, which removed almost 100% of this particular pesticide regardless of initial concentration level and exposure time. Consequently, there are several filter materials, when used either alone or in combination, that show promise for removing mixed contaminants from subsurface drainage water; however, more laboratory testing followed by field experiments are needed to completely evaluate their feasibility for widespread use. [ABSTRACT FROM AUTHOR]

This paper will give an overview about the filter development for diesel particulate emission control in automotive applications. The material development for passenger car diesel particulate filters led to new materials like silicon carbide while for heavy duty applications still Cordierite plays a major role. But in the future other materials might also be used for passenger cars. This paper will show the basic difference between both applications and describe the material design in terms of filter properties (base material, back pressure aspects, filtration efficiency, coating impact). Current application on vehicles with catalysed soot filters (CSF) with and without oxidation catalyst will be presented. Furthermore an outlook will be given on materials for catalysed soot filters for the future. [ABSTRACT FROM AUTHOR]

Abstract: We used a clone library method to investigate changes in the biofilm microflora associated with the conditioning of filter materials in a recirculating water system for the culture of goldfish Carassius auratus. The microbial density was higher in the outer layer of biofilm from filter materials (1.7×1010–3.0×1010 cells/g) than in the inner layer (1.5×109–2.4×109 cells/g) throughout the experimental period. The clone library method using bacterial 16S rRNA genes collected from the outer layer of filter material yielded sequences from four (day 8), nine (day 15), twelve (day 22) and nine (day 64) taxonomic categories of bacteria including Acidobacteria, Actinobacteria, Bacilli, Bacteroidetes, Flavobacteria, Fusobacteria, Nitrospira, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Sphingobacteria, Verrucomicrobia and unclassified bacteria. The inner layer yielded sequences from six (day 8), eight (day 15), five (day 22) and five (day 64) taxonomic categories of bacteria including Acidobacteria, Actinobacteria, Bacilli, Flavobacteria, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Sphingobacteria, Verrucomicrobia and unclassified bacteria. Bacteria in the outer layer of biofilm belonged predominantly to the genera Acinetobacter, Cetobacterium, Comamonas, Flectobacillus, Flavobacterium, Ideonella and Pseudomonas, whereas those in the inner layer were predominantly members of the genera Flavobacterium, Flexibacter, Ideonella, Janthinobacterium, Pedobacter and Pseudomonas. As the filter materials became conditioned, the population of nitrite-oxidizing bacteria related to Nitrospira was restricted to the outer layer of the biofilm. In addition, phylogenetic analysis indicated the presence of both an indigenous Nitrospira and a distinct type of Nitrospira that appeared after conditioning had begun. [Copyright &y& Elsevier]

The isotopic analysis of boron from material that carries only trace amounts of boron requires low boron blank levels. Large efforts are taken to keep blank levels low by purifying reagents. We performed exposure experiments and determined procedure blanks before and after the air-handling system was modified from silicate glass filters to polyethylene/polystyrole and active carbon filters. Our investigations demonstrate that the air-handling system may be the major source of boron blank in many laboratories, as the widely used silicate glass filters, which contain boron as a major component, in the form of borax and boric acid, release significant amounts of boron to the air. [ABSTRACT FROM AUTHOR]

Abstract: The microbial communities associated with filter materials in closed recirculated systems of carp and goldfish were examined by the clone library method of 16S rRNA gene. The bacterial cells were efficiently recovered by the combination of six washing treatment and swabbing. The bacterial density on pebbles of well-conditioned recirculating water systems was 1.1×107 cells g−1 in the carp-rearing tank and 1.9×108 cells g−1 in the goldfish-rearing aquarium. The 91 cloned rDNA sequences were occupied by members within Alphaproteobacteria (52 clones belonging to 19 taxa), Betaproteobacteria (14 clones belonging to 8 taxa), Nitrospira (8 clones belonging to 1 taxon), Actinobacteria (6 clones belonging to 4 taxa), Bacilli (3 clones belonging to 3 taxa), Gammaproteobacteria (3 clones belonging to 3 taxa), Planctomycetacia (3 clones belonging to 3 taxa) and Sphingobacteria (2 clones belonging to 1 taxon). However, only three taxa, which are closely related to Hyphomicrobium denitrificans, Rhodovulum euryhalinum and Nitrospira moscoviensis, were commonly detected in both carp- and goldfish-rearing systems. These results reveal that there are great differences in both bacterial density and composition between the two different systems, and that the clone library constructed from carp-rearing tank is characterized by as many as 29 taxa of bacteria, and that those from goldfish-rearing aquarium is characterized by Hyphomicrobium facilis with occurrence of 42%. These results mean that at least 36% of total clones could utilize the inorganic nitrogen, NH4+, NO2− or NO3−, suggesting that they concern the dynamics of nitrogen in fish-rearing facilities equipped with the recirculating system. [Copyright &y& Elsevier]