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Peculiarities of sintering of foamy ceramic filters based on submicron aluminum oxide powders with additions of titanium oxide and manganese dioxide nanopowders are considered. The processes of removal of polymeric and binder paraffin material during sintering have been studied. The physical and mechanical properties of the obtained porous permeable filters with a foamy structure were analyzed in details. At a sintering temperature in an air atmosphere of 1350 °C, sufficiently high physical and mechanical properties were obtained, which made it possible to use the developed filters as catalyst carriers for vehicle exhaust gases. Bench comparative tests have shown that ceramic filters with a foamed structure are promising catalysts for afterburning car exhaust gases instead of ceramic honeycomb blocks of catalyst carriers. The developed technology allows reducing the sintering temperature of porous foam ceramic filters to 1350 °C and replacing expensive high-temperature ceramic heaters with cheaper nickel-chromium ones. [ABSTRACT FROM AUTHOR]

The ceramic foam filters are commonly applied in metal casting. However, this kind of filter has a number of drawbacks, such as weak impact resistance, uncontrollable technical parameters, and a long producing cycle. Our work developed a better manufacturing method for ceramic filters based on SLA-3D printing technology in which the structure of filters can be designed according to demands of porosity and hole density. Firstly, it is to propose a ceramic filter model with good mechanical properties under various porosities and hole densities using mechanical simulation and topology optimization. Secondly, SLA-3D printing technology was used to manufacture ceramic filter models with various characteristics. The results demonstrate that the porosity can be achieved with a wide range, and the higher porosity and hole density can approach 90% and 50 PPI, respectively. The preparation error of the internal pillars inside the filters model also can be revised to precisely control the porosity error of filters. Finally, the pore characteristics and compressive performance of the SLA printed ceramic filters were much better than that of the ceramic foam filters. [ABSTRACT FROM AUTHOR]

In the present study, the effect of silica nanoparticles on the formation of nano-mullite phase for use in the manufacture of silicon carbide based ceramic foam filters has been investigated. Polyurethane foam filters were impregnated with nanosilica particles by slip casting. In this method, the effect of different percentages of nanosilica particles in the slurry on compressive strength, density and porosity of ceramic foam filters was investigated. The effect of silica nanoparticles on viscosity of slurry was studied using rheometric test. So, sample S 15 was selected to proceed. For thermal treatment of ceramic foams, different sintering temperatures were investigated and the best temperature was reported at 1250 °C. Compressive strength results showed that with increasing nano-silica content, CCS increased. XRD results from the samples showed that the nano-mullite phase was formed at 1250 °C along with silicon carbide and alumina phases. Scanning electron microscope images (SEM) showed that the mullite phase was formed in nano-dimensions in ceramic foam bodies. The formation of mullite phase in the microstructure of the filters is one of the factors of strengthening and increased refractory characteristics. EDS analysis by the scanning electron microscopy of the filter which passed ductile iron melt showed that cast iron inclusions and impurities were mostly consisted from FeO, MnO, SiO 2 , Al 2 O 3 , MgO and CO, which were trapped inside the ceramic filter. [ABSTRACT FROM AUTHOR]

In order to understand the influence of the geometry of ceramic filter orifices on the movement of micro-scale inclusions, a transient 3D coupled numerical model has been established. The inclusion trajectory was described using the two-way coupled Euler-Lagrange approach. The gravity, buoyancy, drag, virtual mass, lift, pressure gradient, centrifugal forces, and moment of inertia were taken into account. The random walk module was invoked to include the chaotic effect of the turbulence. For estimating the collision and coalescence of the inclusion, the stochastic collision module was utilized. Besides, three detachment criteria have been introduced to represent the adherence behavior between the inclusion and the refractory wall. Necessary measurements were carried out for validating the model experimentally. Due to the swirling flow and the centrifugal effect, the inclusion removal ratio of the helical orifice is 31.02%, which is higher than the value of 16.35% associated with the straight orifice. Unlabelled Image • Helical orifice was proposed to improve inclusion removal. • A transient 3D coupled numerical mode was developed to describe inclusion motion. • Three detachment criteria were introduced to define inclusion adherence behavior. • Effect of helical orifice structure parameter on inclusion motion was clarified. [ABSTRACT FROM AUTHOR]

In this work, a CFD-based method for simulating the real-time pressure drop and dust cake distribution of the ceramic filter at the macro-scale is presented. In this CFD-based method, a unique mesh grids zone, i.e., a dust cake zone, is created to model the particle deposition process on the ceramic candle surface. In the dust cake zone, the mesh grids on the same ray are arranged into a queue to mimic the dust cake growth trajectory, and the pressure drop and porosity of the dust cake layer are modeled by 1-D empirical formulas. In order to determine the exact grid cell for particle deposition, a novel algorithm is developed, and near-wall corrections of the drag and lift force are applied. Then, a steady and a transient simulation were performed and compared to the experimental data. The comparison results of the pressure drop across the ceramic filter show that the deviation of the pressure drop between experiment and simulation is below 3.6% and 6% in the steady and transient simulation, respectively. Additionally, the dust cake thickness at different locations was tested and compared to the simulation results, and the difference is between 3.9% and 12.9%. Moreover, some less-particle-deposition-zones (LPDZs) are found in the middle and lower portion of the ceramic candles. The size and position of these LPDZs are well predicted by the transient simulation, and their forming reasons are carefully analyzed. Unlabelled Image • A macro-scale CFD-based method for modeling particle deposition process is developed. • Mesh grids on the same ray are arranged into a queue to mimic the dust cake growth trajectory. • Near-wall corrections of drag and lift force are applied. • Dust cake distribution is well predicted. • Different vorticity field direction could lead to a different deposition result. [ABSTRACT FROM AUTHOR]

The present study aims to develop a filtration system consisting of ceramic wastes as a treatment process of bathroom greywater to reduce chemical oxygen demand (COD), Total suspended solids (TSS), Total nitrogen (TN), and turbidity. Optimization of the reduction efficiency was investigated using response surface methodology (RSM) as a function of the ceramic practical sizes (0.25–1.18 mm) and hydraulic retention time HRT (1–3 h). The functional groups on the surface of the ceramic filter media were determined using Fourier transform irradiation (FTIR), while the scanning electron microscope (SEM) was used to determine the microstructure and the surface morphology of the ceramic particles. Results revealed that the optimal reduction of COD, TSS, TN, and turbidity was influenced by active sites of the filter media (C C, C O, C O H, and OH − ) and was achieved under the operating conditions of 0.25 mm of ceramic particles after 3 h of HRT, the observed and predicted reduction for COD, TSS, TN, and Turbidity were 38.8 vs. 39.8%; 58.47 vs. 59.59%; 66.66 vs. 67.32%; 88.31 vs. 89.02%, respectively. It can be concluded that the effectiveness of the ceramic filter media is a potential source for the filtration of bathroom greywater. [ABSTRACT FROM AUTHOR]

Radioactive Cs released from damaged fuel materials in the event of nuclear accidents must be controlled to prevent the spreading of hazardous Cs into the environment. This study describes a simple and novel process to safely manage Cs gas by capturing it within ceramic filters and converting it into monolithic waste forms. The results of Cs trapping tests showed that CsAlSiO 4 was a reaction product of gas-solid reactions between Cs gas and our ceramic filters. Monolithic waste forms were readily prepared from the Cs-trapping filters by the addition of a glass frit followed by thermal treatment at 1000 °C for 3 h. Major findings revealed that the Cs-trapping filters could be added up to 50 wt% to form durable monoliths. In 30–50 wt% of waste fraction, CsAlSiO 4 was completely converted to pollucite (CsAlSi 2 O 6 ), which is a potential phase for radioactive Cs due to its excellent thermal and chemical stability. A static leaching test for 28 d confirmed the excellent chemical resistance of the pollucite structure, with a Cs leaching rate as low as 7.21 × 10 −5 g m −2 /d. This simple scheme of waste processing promises a new route for radioactive Cs immobilization by synthesizing pollucite-based monoliths. [ABSTRACT FROM AUTHOR]

It was found that spectra obtained for bacteria on SERS substrates fabricated by filtering citrate-generated Ag nanoparticles (NPs) onto rigid, ceramic filters exhibited peaks due to citrate as well as the bacteria. In many cases the citrate spectrum overwhelmed that of the bacteria. Given the simplicity of the method to prepare these substrates, means of eliminating this citrate interference were explored. It was found that allowing a mixture of bacteria suspension and citrate-generated Ag NPs to incubate prior to filtering onto the ceramic filter eliminated this interference. [ABSTRACT FROM AUTHOR]

• Novel loaded filter model based on discrete pore distribution. • Validations with systematic engine PN data from CPC and EEPS. • Great accuracy (within 1%) across diesel and natural engine certification cycles. Ceramic particulate filters have become indispensable components of internal combustion engine aftertreatment systems to meet the stringent PM and PN emission regulations. Accurate modeling and simulating of the filtration performance of ceramic filters under transient cycles have been proved to be quite challenging. In the present study, a new filtration model based on discrete pore size distribution was developed to predict both the clean and loaded states filtration performance. New correlations and equations have been derived to describe the filtration efficiency when polydisperse cells are loaded with soot in the transient cycles. Systematic experiments of both natural gas and diesel engines have been conducted with CPC and EEPS measurements. It is demonstrated that the simulated results with the new filtration model agree quite well with the filtration data at different loading conditions and engine operating cycles. This new dynamic filtration model incorporating flow, filtration, and catalytic reaction can provide high-fidelity guidance in practical filter design and development. [ABSTRACT FROM AUTHOR]

SERS substrates were fabricated by filtering either Ag or Au colloidal particles onto rigid, ceramic filters – onto which suspensions of bacteria were then filtered. SERS spectra of the bacteria were obtained using a Raman spectrometer that has an ‘orbital raster scan’ capability. It was shown that bacteria samples prepared in this manner were uniformly distributed onto the surface of the SERS substrate. The effect of common buffer systems on the SERS spectra was investigated and the utility of using the SERS technique for speciation of bacteria was explored. [ABSTRACT FROM AUTHOR]

A laboratory study was carried out to determine the best domestic water filter with respect to cost, volume of treated water, and effectiveness in improving the quality of potable water. Six types of filters were tested including sand, five micron cartridge, ceramic, carbon block, ultra violet (UV) sterilization unit, and reverse osmosis combined filters. Water samples were collected upstream and downstream of each type of filter. These samples were analyzed for pH, EC, TDS, TSS, turbidity, TOC, chlorine concentration, and various bacteria. Also, the volume of treated water produced by each type of filter was measured. The laboratory results indicated that inlet water had low salinity (TDS value 275–438 mg/l), low TSS (0–7 mg/l), chlorine (0.13–0.78 mg/l) contents, and high content of bacteria (1–1212 MPN/100 ml). The results revealed that the membrane of the RO combined filter set was exposed to severe damage by the residual chlorine in the water, rendering the membrane unable to reduce water salinity effectively and causing high total bacteria counts in the filtered water. Additionally, a biological slime layer formed at the surfaces of cartridge filters, and produced high values of TSS and bacteria in the filtrate samples. The results showed that the best type of filter was the five micron filter on the basis of cost, volume of filtered water, and improvement in water quality. [ABSTRACT FROM PUBLISHER]

Abstract: In the present study, a monolithic alumina coated microfiltration ceramic membrane was used for solid particulate removal and nutrient recovery from anaerobic digester complex effluent streams. The aim was to test the effect of the cake layer developed by the solids, on the surface of the membrane channels, to the filterability of these materials. The solid content ranged between 2.6g/L to 15.1g/L. During practical application, two processing techniques targeting the enhanced recovery of the materials of interest including ammonia, phosphate, calcium bicarbonate and volatile fatty acids, namely dewatering and diafiltration, were used. These had an immediate effect on the solid content (PDS 13μm to 3.97μm) enhancing the filterability of the effluents. Their processability was evaluated in terms of flux, cross flow velocity, membrane resistance and cake resistance. An important finding of this study is the nonalignment of the flux rates to the cake resistance, explained by the formation of a compressible, permeable cake layer that allowed the continuous operation of the system, under constant low pressure conditions (TMP 15psi). Permeate flux remained constant to 120L/m2 h when applying diafiltration, while when dewatering process is used the permeate flux remained constant at 115.4L/m2 h. [Copyright &y& Elsevier]

[Display omitted] • Removal of bacteria using ceramic disk filters coated with modified g-C 3 N 4. • The effects of coating amount, light intensity, and water chemistry conditions were explored through factorial analysis. • The mechanism for the bacterial inactivation and removal was investigated. • The developed ceramic disk filter exhibited excellent practicability. Access to safe drinking water is a challenge in remote and rural areas, where thus urgently need cost-effective household drinking water purification device. In this study, a ceramic disk filter coated with modified g-C 3 N 4 (MCN@CDF) was developed for drinking water disinfection and purification. Factorial analysis results showed that factors including the coating amount of MCN, light intensity, influent humic acid (HA) concentration, influent turbidity, and influent pH had significant positive effects on the E. coli removal efficiency of MCN@CDF. However, the influent turbidity had a significant negative effect on the permeability. The significant 2-factor interaction effects on the performance of MCN@CDF were also discussed. The developed MCN@CDF showed an exceptional performance in bacterial removal, and the log reduction value (LRV) could reach up to 7.14. This could be ascribed to the synergistic effect of physical retention and photocatalytic disinfection. The photocatalytic disinfection was induced by MCN under light irradiation, which produced H 2 O 2 and h+ to inactivate E. coli. These reactive species could attack E. coli cells, causing changes in the cell shape and damage to DNA. The developed MCN@CDF also exhibited excellent practicability during treating realistic ground water, which met the standard of drinking water after purification with MCN@CDF. This study provided a low-cost and safe alternative for household drinking water purification in rural areas. [ABSTRACT FROM AUTHOR]

Abstract: The next generation of ceramic hot gas filter system of Pall Corporation with advanced venturi ejector blowback system, longer filter candles and safety fuses integrated in the venturi ejector is presented. The cleaning performance of the advanced venturi ejector blowback system has been investigated using filter candles of 1.5m length with additionally installed safety fuses and with 2m long filter candles with and without safety fuses. Measurements of the pressure profiles in the filter elements have been performed for a group of 48 filter elements. The results of these measurements are reported and discussed. The results are compared to reference measurements using the previous standard venturi ejector blowback system with 1.5m long filter elements. [Copyright &y& Elsevier]

Abstract: Africa is one of the most water-scarce continents in the world but it is the lack of potable water which results in diarrhoea being the leading cause of death amongst children under the age of five in Africa (696 million children under 5years old in Africa contract diarrhoea resulting in 2000 deaths per day: WHO and UNICEF, 2009). Most potable water treatment methods use bulk water treatment not suitable or available to the majority of rural poor in Sub-Saharan Africa. One simple but effective way of making sure that water is of good quality is by purifying it by means of a household ceramic water filter. The making and supply of water filters suitable for the removal of suspended solids, pathogenic bacteria and other toxins from drinking water is therefore critical. A micro-porous ceramic water filter with micron-sized pores was developed using the traditional slip casting process. This locally produced filter has the advantage of making use of less raw materials, cost, labour, energy and expertise and being more effective and efficient than other low cost produced filters. The filter is fitted with a silicone tube inserted into a collapsible bag that acts as container and protection for the filter. Enhanced flow is obtained through this filter system. The product was tested using water inoculated with high concentrations of different bacterial cultures as well as with locally polluted stream water. The filter is highly effective (log10 >4 with 99.99% reduction efficiency) in providing protection from bacteria and suspended solids found in natural water. With correct cleaning and basic maintenance this filter technology can effectively provide drinking water to rural families affected by polluted surface water sources. This is an African solution for the more than 340 million people in Africa without access to clean drinking water (WHO and UNICEF, 2008). [Copyright &y& Elsevier]

Abstract: In this research project, the microbiological quality of the water processed by a low cost, newly developed micro-porous ceramic filter is evaluated. As 66% of the human body is made up of water, it is important to ensure the availability of clean, potable water that is free from pathogens. Even clean-looking water can still contain bacteria and other toxic impurities. Annually, millions of people contract severe illnesses from drinking water. One simple but effective way of making sure that water is of good quality is by making use of a household water filter. It is, however, of critical importance that such a low cost water filter is capable of removing suspended solids, pathogenic bacteria and other toxins from the drinking water. A low cost, micro-porous ceramic water filter with micron-sized pores was developed using the slip casting process. Naturally occurring water from two streams and a lake containing different species of bacteria was used in testing the ceramic filter’s effectiveness in eliminating bacteria. The filter proved to be effective in providing protection from bacteria and suspended solids found in natural water. This filtration process is suggested as a possible solution for the problem faced by more than 250 million people in Africa without provision of clean drinking water. [Copyright &y& Elsevier]

Abstract: The glassy composition (quartz, clinoptilolite and frit glass mixture) provides a filter having glassy pore wall microstructure and thus enables easily cleaning through the filter recovery by back flushing. The filter was obtained as multilayer compaction by one step slip cast-processing where a cylindrical filter, consisting of filtration layer on granular assemblies with specific interlayer was shaped by a fine particle migration phenomenon. The multilayer compaction has low resistance to liquid flow and thus the filter great potential to use for wastewater filtration. It is known that high capacity filtration also requires correct pore size/interval with respect to filtered particles. In this study, a wastewater overflow from marble factory (0.035wt.% of solid with a size distribution of 0.58–1.46μm) was filtered by different pore sizes of the glassy filters (pore size intervals: 0.4–10μm, 0.2–4μm, 0.1–1.5μm and 0.04–2μm) and significantly different filtering capacities was obtained; the irreversible fouling capacities were determined between 2.9 and 8.5m3 of filtrate per m2 of the filter area through the filtration produced 5min intervals. The filtration pressure was 5bar and backflushing was achieved at 1bar. The high filterability (8.1m3/m2 in 5min) with high filtrate clarity (∼0.5nephelometric turbidity units) could be obtained using finer pore sized filters. The large size filter was seriously clogged during the filtration. [Copyright &y& Elsevier]

Abstract: Safe drinking water is still not accessible to more than 15% of the world’s population. Decentralised water treatment with ceramic filter candles at the point-of-use (POU) level provides a low-cost and single-stage filtration process with which pathogenic microorganisms can be removed. However, the retention performance of such depth filters scatters for microbiological contaminants in literature. The purpose of this study was to gain a better understanding on the removal mechanisms in ceramic depth filters based on the natural material diatomaceous earth (DE). Therefore, we manufactured so-called ceramic filter candles by ram-extrusion process and subjected these filters to a detailed physical characterisation regarding porosity, pore size distribution, specific surface area, flowrate, surface charge and microstructure. Next, we investigated experimentally the removal of colloidal latex (polystyrene) particles having diameters from 100 to 500nm under various ionic strengths. Such particles were found to be removed due to adsorption of the colloids. Extended DLVO-theory was used to investigate the forces that account for the adsorption suggesting that hydrophobic interactions drag latex particles onto specific adsorption sites of the filter. It is hypothesised that these specific adsorption sites originate from the unique nanostructured surface of the diatomaceous earth. Furthermore, we believe that such latex particles may be suitable to model the removal of microorganisms if the surrogate and the target pathogen have similar characteristics. [Copyright &y& Elsevier]

Abstract: A low-cost membrane bioreactor (MBR) would be an option for wastewater treatment in developing countries. A ceramic filter made of locally available materials was developed for arsenic removal from groundwater. The applicability of this filter to MBR for wastewater treatment was examined in this study. A hollow, cylindrical-shaped filter was made with the combination of 80% clay soil and 20% rice bran and fired at 900°C. The filter was submerged in acrylic cylindrical column reactors. Synthetic wastewater was fed into the reactors continuously, and the effluent from the filter was obtained by gravitational pressure with different mixed liquor (ML) heights and BOD loads. Efficient activated sludge separation and high organic removal performance were obtained. Lower flux and removal efficiencies were observed in the non-aeration mode. The flux performance was obtained 0.1–0.2m3/(m2.day) for up to one year of operation without clogging of the filter. Batch experiments were also performed to determine the relationship of the flux with the pressure and MLSS. A linear relationship between the flux and ML height was found, whereas the MLSS concentrations did not show a clear effect on the flux. This ceramic filter would be applicable to MBR facilities in developing countries. [Copyright &y& Elsevier]

Abstract: Cross-flow filtration is has found considerable application in solid/liquid separation but is little-used in filtration of gases. In this filtration mode, a component of the particle-laden flow passes through the filter, depositing particles on the surface, while another component remains parallel to the surface, causing shear on the deposited cake. Solid/gas separation is usually carried out in the “dead-end” filtration mode, where the aerosol arrives at the filter on trajectories that are approximately perpendicular to it. Earlier studies [V. Sibanda, R.W. Greenwood, J.P.K. Seville, Powder Technology 118 (2001) 193–202] demonstrated that cross-flow filtration can be applied to gas filtration and that under certain operating conditions, particle aggregation can occur on the surface and the aggregates can subsequently be removed by the through-flow and collected in a downstream device. Particle size distribution measurements of the filter cakes formed at different cross-flow conditions also suggest that significant segregation of particles occurs in this filtration mode. Finer particles were observed to report to the filter cake at low cross-flow ratios and larger ones at higher cross-flow ratios. In this paper, measurements of the particle size distribution of filter cakes formed under a variety of cross-flow conditions were carried out and a mathematical model to describe the segregation was developed. The model is found to predict the segregation behaviour observed from the experimental measurements reasonably accurately. Segregation enhances the overall particle capture efficiency of the downstream device leading to a purer gas product and makes cross-flow gas filtration an attractive option. [ABSTRACT FROM AUTHOR]

Abstract: Research in the fields of filtration and dewatering connected with the use of ultrasound (US) has been carried out mainly with small laboratory-scale batch or continuously operating devices. So far the only large scale industrial cake filtration applications have been developed and manufactured by Larox Oyj for mining industry. These applications apply ultrasound for cleaning of ceramic capillary action elements having at maximum total filtration area of approximately 150m2. Several hundreds of filter units have been delivered worldwide during the past two decades. [Copyright &y& Elsevier]

Groundwater constitutes a major source of fresh water globally. However, it faces serious quality challenges from both conventional pollutants and contaminants of emerging concern (CECs) such as pharmaceutically active compounds (PhACs), personal care products (PCPs) and pesticides. There exists a significant knowledge gap regarding the occurrence of CECs in groundwater, especially in Africa. This study presents unique data on the concentration of fourteen PhACs, five PCPs and nine pesticides in groundwater wells in Nzoia River basin, Kenya. Generally, PCPs were the most dominant class with concentrations up to 10 μg/L (methylparaben). Anti(retro)virals, being important in the treatment of HIV/AIDS, were more prevalent among the PhACs as compared to the developed world, with concentrations up to 700 ng/L (nevirapine). In contrast, pesticides were measured at lower concentrations, the maximum being 42 ng/L (metolachlor). A basic risk assessment shows that – among the detected CECs – carbamazepine may pose medium human health risk and requires further investigation among infants and children. Point-of-use (POU) technologies are being increasingly promoted especially in the developing nations to provide drinking water solutions at the household level, but very little data is available on their performance towards CECs removal. Therefore, besides measuring CECs in groundwater, we investigated ceramic filters and solar disinfection (SODIS) as possible POU treatment options. Both techniques show potential to treat CECs in groundwater, with removal efficiencies higher than 90% obtained for 41 and 22 compounds in ceramic filters and SODIS, respectively. Moreover, for the more recalcitrant compounds (e.g. sulfadoxin), the performance is improved by up to three orders of magnitude when using TiO 2 as a photocatalyst in SODIS. [Display omitted] • Drinking water shallow wells polluted with contaminants of emerging concern (CECs). • 28 CECs measured in Kenyan groundwater, with paraben concentrations up 10 μg/L. • Paracetamol, antibiotics and anti(retro)virals much more abundant than pesticides. • Indications for human risk (HQ > 0.1) because of exposure to pharmaceutical residues. • Promising CECs removal by easy to use and low cost point-of-use (POU) techniques. [ABSTRACT FROM AUTHOR]

Abstract: The present research investigates the removal of particulate matter smaller than 2.5 μm (PM2.5) from high-temperature exhaust gas using a twin ceramic candle filter. Computational fluid dynamics (CFD) is used to simulate gas flow behavior since the technique could provide crucial support to experimental investigation, especially for harmful conditions, as well as yield cost savings and fast results. In this research, the dynamic behavior of gas flow in a prototype twin-candles ceramic filter was studied. One interesting phenomenon not seen in single candle filtration systems is the unforeseen cleaning effect on an adjacent candle filter due to the pulsed cleaning of another. It is useful to investigate the face velocity distribution on the candle as it illustrates how the filter cake is formed on the filter surface and hence leads to improvement in the dust cleaning. The obtained simulation results were validated with available experimental data. [Copyright &y& Elsevier]

Abstract: Numerical simulation of ceramic filter unit was carried out in order to predict the gas flow in the filter vessel during the pulse cleaning process using FLUENT code. The particle movement and particles distribution were analyzed using both the Lagrangian and Eulerian approaches. Ceramic filter unit modeled in the study is composed of six elements of commercial filter in the normal hexagon. In the comparison of the single filter cleaning and two filters cleaning coincidently, the last mode leads to more uniform gas flow in the filter vessel during the pulse cleaning process. So far the numerical results show a good approach to predict the particle distribution in the vessel and the particle deposition on the filter element. And this study will provide the base for the intensive study on the analysis of the gas–particle flow in the filter vessel. [Copyright &y& Elsevier]

Abstract: Ceramic membrane filters consisting of a filtration layer of varying thickness coated on a tubular porous support made of quartz-based materials and with a pore size of about 10μm were fabricated. The filtration performance for spring water clarity was examined. The coatings were prepared by a filtration process with a dilute particle suspension of quartz-natural zeolite–lead borosilicate glass mixture. The filter matrix was of quartz type and the additives (frit glass and zeolite) made the filters with glassy pore walls as the sintering temperature applied was above their fusion temperature. The pores of the filtration layer have a relatively coarse size distribution and thus lead to clogging phenomena within the glassy pores during filtration operation. The pore clogging is a benefit for producing clear filtrate and the glassy pore walls favour the filter cleaning and recovery. It was observed that a sufficiently thick coating (>62μm) was required for good enough filtrate clarity (0.2 NTU turbidity) and cleaning of the filter was possible by filtrate backflushing and air blowing. [Copyright &y& Elsevier]

Abstract: The flow field is simulated for a ceramic filter vessel containing three candle filters which are arranged in the form of an equilateral triangle. Grids generated by GAMBIT are adopted for the simulations. The Reynolds stress model provided by FLUENT code is applied to evaluate gas flow and temperature field in the filter vessel. The temperature profiles in the ceramic candle filter cavity during the pulse cleaning process are analyzed under different operating conditions and for different lengths of candle filter. The evolution of radial velocity in the porous wall of the filters being cleaned and the normal working filters as well as around the filters is discussed. Sharp temperature change takes place in the top of the candle filter which is subject to thermal stress. The phenomenon of temperature increase during the pulse cleaning process has been carefully observed and interpreted based on the effect of gas compression. The simulated results show qualitative agreement with the experimental field observations with the filter vessel. [Copyright &y& Elsevier]

Abstract: Filtration of molten metals with ceramic foam filters is a proven method in order to remove the inclusions. This paper develops a new approach for the production of ceramic foam filters. In the conventional method of ceramic foam filter production, polyurethane sponges are used. In this work, ceramic foam filter was produced by using expanded polystyrene. Polystyrene is expanded in a specially designed mold by steam to form polystyrene patterns. Various ceramic slurries are then poured into the polystyrene cell and allowed to air dry. After the shaping operation, filters are subjected to sintering process under various conditions. By this new method, filter channel sizes can be controlled and traps with desired configurations can be formed. Some tests were applied to the produced filters. Thermal shock tests ensured that the filters could withstand temperatures of 1450°C. Water absorption test showed that bauxide based material absorbed water more than the others. [Copyright &y& Elsevier]

Abstract: The usual process to produce NiTi shape memory alloys (SMA) is by vacuum induction melting (VIM) using graphite crucibles which contaminate the bath with carbon. Carbon reacts with titanium precipitating TiC influencing the matrix composition which, in turn, affects the martensitic transformation temperatures. Furthermore, the presence of TiC makes the final product difficult for mechanically process using cold working steps. In this study, we present preliminary results of our attempt to remove the TiC from the melt using ceramic filters during pouring and analyzed the efficiency of the filtering process and some results will be presented. [Copyright &y& Elsevier]

Dust cake compressibility of fine fly ashes (from a coal power plant of fluidized bed combustor) on a ceramic filter was carefully investigated under well-controlled conditions and by measuring the cake thickness under filtration conditions using a laser displacement measuring system. Overall cake porosity and pressure drop of dust cake of three different particles of geometric mean diameters: 1.2, 2.2, and 3.6 μm and the adjusted dynamic shape factors: 1.15, 1.28 and 1.64, respectively, were investigated, at face velocities of 0.02–0.08 m/s. Overall cake porosity was strongly dependent on face velocity and mass load but less dependent on particle sizes. It was understood that dust cake was compressed by reduction of previously formed cake layers with drag forces of lately formed dust layers. The expressions for overall cake porosity and pressure drop across the dust cake, based on the equation proposed by Endo et al. [Powder Technol. 98 (1998) 241] and considering the compression effect, were developed with good agreement with experimental results. [Copyright &y& Elsevier]

The dust-releasing behavior from a ceramic candle filter, which is a key technology of the hot gas cleaning system in advanced coal power generation processes such as pressurized fluidized bed combustion and integrated gasification combined cycle, is discussed based on the observation of the dust-releasing process using a high-speed video camera and the measurement of time change of pressure inside the filter. Time changes of dust-released area and geometrical characteristics and motion of released dust cake fragments were investigated by analyzing photo images from the video camera, compared with the time change and distribution of pressure inside the filter. In order to discuss the influence of porosity of the dust layer, a consolidated dust layer was prepared by clean air filtration at an elevated filtration velocity after the dust filtration. The dust-releasing process was found to be a multi-mode process, i.e. release occurred in a short time after the injection of cleaning air, followed by one or two intermittent releases afterwards. The amount of dust released by the first strike increased with tank pressure. The dust-releasing behavior was sensitive to the cake porosity: the mean size and perimeter of cake fragments increased with porosity and tank pressure for the consolidated dust layer. The initial radial velocity of cake fragment released just after the first strike increased with tank pressure and was almost independent of the filter location. [ABSTRACT FROM AUTHOR]

A multifunctional reactor allows substitution of two or more process units with a single reactor, where all the operations of interest are executed simultaneously. For example, when ceramic filter materials, used in flue gas cleaning, are doped with compounds of transition metals, high efficiencies in particulate separation and catalytic activity for the removal of NOx, CO and CHx are obtained. The present study addresses a kinetic analysis of NOx reduction occurring in the catalytic filter material, including experimental data reported in the literature. A numerical model, based on available knowledge of SCR kinetics, is developed, validated with catalytic filter data and with honeycomb profiles, and finally used for case studies regarding design variables (GHSV, inlet concentration). The results indicate that NOx conversion typically required is possible on time scales of gas flow through a catalytic filter medium in the temperature range 250–350 °C, with strong temperature effects due to the competition of the desired SCR reaction and NH3 oxidation with O2. Application of the model and parameter values derived from the catalytic filter analysis to a SCR honeycomb situation constitutes a sort of indirect validation. [Copyright &y& Elsevier]

Laboratory procedure for the preparation of a capillary ceramic filter from a high silica-containing glaze was described and its microstructure was investigated by scanning electron microscopy (SEM). Glaze powders with two different particle sizes were used for filter preparation. Attrition milling was used to prepare fine particles in aqueous medium. Thin filtering layers were shaped from the fine particles by uniaxial pressing and later sintered at a temperature of 800 °C for enough strength. The coarse glaze powders were inserted between these layers and further sintered at a temperature of 950 °C. The filtering layers showed that the uniform porosities, which were interconnected to each other, could be obtained. During this process, it was observed that grains were coated by glass. This type of microstructure is believed to have great potential for the use of this material as a capillary ceramic filter. [Copyright &y& Elsevier]

It is of great significance to develop a new gravity-driven filter to remove water pollutants, but it is still challenging. Here, a novel and simple strategy is demonstrated to manufacture fly ash (FA) ceramic foams showing a three-dimensional interconnected porous structure, with multiwalled carbon nanotubes (MWCNTs) implanted by combining carbamate grafting and polydimethylsiloxane coating. The polydimethylsiloxane formed a physical coating on the carbamate group, generating an effective thermal insulating layer on the outer side of the entire MWCNT. The FA foam, which shows a sufficient adsorption capacity for Pb(II) (51.67 ± 1.17 mg g−1) and Cd(II) (30.12 ± 0.37 mg g−1) at pH = 5, T = 25 °C, has a 96.33%, 95.12%, 89.50% removal efficiency for Cd(II), Pb(II), and particulate pollutants, and exhibits excellent recycling performance. This paper provides new opportunities to fabricate gravity-driven filters with low energy consumption for wastewater treatment. [Display omitted] • MWCNTs are modified by carbamate grafting and polydimethylsiloxane coating. • Modified MWCNTs are implanted into fly ash foam to improve filtration performance. • Fly ash foams effectively remove Pb(II), Cd(II), and particulate pollutants. • Fly ash foams are driven by gravity and the energy consumption is almost zero. [ABSTRACT FROM AUTHOR]

• A novel intensified catalytic filter system has been developed for qualified synthesis gas. • Cu-Zn 2 TiO 4 incorporated with CaSiO 3 filters were successfully synthesized by ball-milling. • Copper-doped zinc titanate amount considerably improved desulfurization under reducing and oxidizing atmospheres. • Ni/Al 2 O 3 coated on CaSiO 3 showed efficient benzene and methane degradation performance. • The integrated system were performed in series displayed attractive hydrocarbon reforming and desulfurization. Integrated gasification processes have been presented as a potential solution to intensify performance by combining unit operations. Hence, this study was aimed to arrange desulfurization and hydrocarbon reforming stages in series for biomass gasification technology. Cu-Zn 2 TiO 4 incorporated with CaSiO 3 filters (CuZT/pCF) were successfully synthesized by ball-milling for desulfurization step. The characterizations of the samples indicated CuZT grains were effectively placed into the host lattice. 20%CuZT loading remarkably enhanced the sulfur capture under reducing (48.1%) and oxidizing (39.8%) atmospheres by increasing affinity and preventing diffusion limitation. Besides, the impregnated filter with Ni/Al 2 O 3 exhibited higher catalytic activity towards simultaneously CH 4 (73%) and C 6 H 6 (85%) reforming, however the performances were decreased in the presence of H 2 S. The hindered performance was accomplished by integrating the catalyst filter with the 20%CuZT/pCF adsorbent in two-stage removal process. The integrated process displayed superior reforming efficiencies for methane and benzene degradation in the H 2 S atmosphere, which were 10 times higher for methane and 1.15 times higher for benzene than that of the single stage system. Meanwhile, the desulfurization rate of 71% was achieved at the end of 5 h. Herein, the innovative concept was found to be promising consecutive removal process for desulfurization and substantially hydrocarbon cracking. [Display omitted] [ABSTRACT FROM AUTHOR]

The groundwater with high arsenic concentration is widespread, especially in many remote areas of developing countries. Arsenic existing in drinking water sources has a high risk to human health. In this study, an innovative effort to remove As(V) from water using ceramic filters functionalized with CeO 2 nanocomposites (CF-CeO 2) was investigated. Considering removal efficiency and flow rate, the suitable coating amount of CeO 2 was determined for the production of CF-CeO 2. Based on the factorial analysis, influent arsenic concentration and pH were found to be significant factors in As(V) removal. Furthermore, CF-CeO 2 exhibited a good removal capability over a wide pH range and was insensitive to the change of background electrolyte concentration. In the treatment of natural water, the existence of medium and low turbidity levels facilitated As(V) removing, while the high turbidity level exhibited the opposite effect. Based on macroscopic experiments and microscopic characterizations, it was revealed that the As(V) removal mechanism by the CF-CeO 2 mainly included ion-exchange and electrostatic attraction. The findings in this study provided convincing evidence for the use of CF-CeO 2 as a high-efficiency, low-cost, and safe approach for water purification in the remote areas of developing countries. Unlabelled Image • Ceramic filter modified by nano-CeO 2 was produced for water purification. • Influent arsenic concentration and pH were significant influencing factors. • As(V) and turbidity in water were removed by CF-CeO 2 simultaneously. • The macro- and microscopic mechanisms of As(V) removal using CF-CeO 2 were revealed. • Using CF-CeO 2 is a cost-effective approach for arsenic removal in remote areas. [ABSTRACT FROM AUTHOR]

• New ceramic filter functionalized with chitosan/TiO 2 nanocomposites was produced. • The physiochemical characteristics of CT-CDFs were characterized. • The mechanism for removing E. coli from water through CT-CDFs was revealed. • The effects of operation factors and their interactions were explored. • CT-CDF was proved to be an economic-feasible solution for water purification. The intaking of water with undesired substances may cause many water-borne diseases. It is required to develop efficient and low-cost water purification technologies for developing countries. In this study, a new ceramic disk filter functionalized by chitosan/TiO 2 nanocomposites (CT-CDF) for bacterial removal from drinking water was investigated. The characterization results showed that the chitosan/TiO 2 nanocomposites were attached to the surface of CDFs. The optimal conditions for producing CT-CDFs were 0.2 g of chitosan, 0.05 g of TiO 2 , and 0.04 g of coating amount, respectively. The factorial analysis indicated that the illumination time and lamp power promoted the reduction of E. coli , but influent E. coli concentration showed a negative effect. There was an interaction between lamp power and influent E. coli concentration. The bacterial removal of CT-CDFs was due to the retention by irregular pores in CT-CDF, the cell membrane damage caused by the attached chitosan/TiO 2 nanocomposites, and the oxidative stress in cells from ROS generated by nano-TiO 2. Prolonging illumination time and increasing lamp power can promote the photocatalysis, resulting in the enhanced removal efficiency of CT-CDFs. The results of this study can provides not only an insight into the bacterial removal involving multiple mechanisms, but also an economic-feasible solution for resolving the water safety issues in developing countries. [ABSTRACT FROM AUTHOR]

• Water treatment technologies are insufficiently evaluated in household settings. • We evaluated four technologies for effectiveness and use to inform design decisions. • Each household treatment technology improved microbiological drinking water quality. • Use of household water treatment declined over time, and some products failed. • Household evaluations are critical within water treatment product design cycles. Household water treatment (HWT) can improve drinking water quality and reduce diarrheal disease. New HWT technologies are typically evaluated under ideal conditions; however, health gains depend on consistent, effective household use, which is less often evaluated. We conducted four evaluations of three prototype HWT technologies: two filters and one electrochlorinator. Evaluations consisted of a baseline survey, HWT distribution to households (ranging from 60 to 82), and four visits (ranging from 1 week-14 months after distribution). Each visit included a survey, observation of treated water presence (confirmed use), and microbiological analysis of treated and untreated samples for E. coli. Consistent use was defined as the proportion of total visits with confirmed use. Overall, confirmed use declined 2.54% per month on average, and 2–72% of households demonstrated 100% consistent use. Consistent use was positively associated with baseline HWT knowledge and practice and belief that drinking water was unsafe, and negatively associated with technological problems. Reported barriers to use were behavioral, such as forgetting or when outside the home, and technological failures. Technologies demonstrated 68–96% E. coli reductions, with 18–70% of treated samples having detectable E. coli. Results highlight the importance of household use evaluations within prototype HWT technology design cycles, the need for standard evaluation metrics, and difficulties in achieving both consistent use and microbiological effectiveness with HWT technologies. [ABSTRACT FROM AUTHOR]

• A novel method for modeling the particle deposition in ceramic filter is presented. • The real-time pressure drop and dust cake distribution are well predicted. • The reasons of non-uniform dust cake distribution are investigated. In this study, the dust deposition process in the ceramic filter of the updraft, tangential, and downdraft flow filtration mode was modeled by a novel CFD-based method, in which a unique mesh grid zone referred to as "dust cake zone" was created to simulate the actual dust cake layer, and grid cells located in the same line were linked together by a fast neighborhood search algorithm to model the actual dust cake growth path. Next, a simulation of the updraft flow filtration (UFF) mode was first carried on and compared to the related experiment in detail to determine the optimal simulation setting. Then, the simulations of the tangential flow filtration (TFF) and downdraft flow filtration (DFF) mode were performed based on the verified CFD settings of the UFF mode, which was able to reduce the pressure drop relative error to less than 6%. Furthermore, the simulation results of these three kinds of filtration modes were carefully analyzed and compared. It was found that the dust cake distribution varied dramatically among different filtration modes, which was due to different patterns of the vortex-flow forming near the candle surface. Some less-particle-deposition-zones can be found on the ceramic candles' lower portion, middle-lower portion and upper portion in the UFF, TFF and DFF mode, respectively. Moreover, the TFF mode had the lowest pressure drop growth rate, while the most uniform dust cake layer was formed in the DFF mode. [ABSTRACT FROM AUTHOR]

This paper presents the results of silicon oxide nanoparticles-incorporated drilling fluid filtration through a porous medium with different permeability. A water-based clay suspension was used as a basic model for creating investigated fluid samples. AlN (aluminium nitride) particles were used as a dispersed phase. The concentration of microparticles varied from 0.5 to 4.00 wt%, while the microparticles size varied from 1 to 10 μm. The concentration of SiO 2 nanoparticles was changed within the range of 0.25 and 4.00 wt%, while the nanoparticles size varied from 5 to 100 nm. It was shown that filtration of drilling fluids with nanoparticles inclusions depends on their concentration, size and material, the concentration and size of microparticles and the pore sizes of ceramic filters. The addition of the nanoparticles leads to a significant reduction in filtration of a microsuspension and affects the structure and thickness of a cake formed on the surface of a filter. The main novelty of this work lies in the fact that the effect of the addition of nanoparticles on filtration losses depends on the ratio between nano and microparticles. It was shown that the positive effect of nanoparticle additives on filtration losses is determined not only by the properties of nanoparticles (size and concentration), but also by the properties of microparticles contained in the drilling fluid, as well as the characteristics of the rock (pore size). • The experimental investigation of filtration of drilling fluids with nano- and microparticles was carried out. • The dependence of filtration from the concentration and size of both nano- and microparticles was studied. • The influence of the filter permeability on the filtration of drilling fluids with nano- and microparticles was investigated. • It is shown that nanoparticles have a positive effect on the filtration of microsuspensions. [ABSTRACT FROM AUTHOR]