Pulse cleaning flow models and numerical computation of candle ceramic filters

Analytical and numerical computed models are developed for reverse pulse cleaning system of candle ceramic filters. A standard turbulent model is demonstrated suitably to the designing computation of reverse pulse cleaning system from the experimental and one dimensional computational result. The computed results can be used to guide the designing of reverse pulse cleaning system, which is optimum Venturi geometry. From the computed results, the general conclusions and the designing methods are obtained.

Identification of an Appropriate Formulation for Domestic Water Ceramic Filters from Soukamna Clay(Cameroon)

This paper deals with the formulation of ceramic filters having the porosity adapted to domestic potable water treatment.The filters were made from clays and rice husk obtained from the Far North region of Cameroon(Logone Valley).Nine formulations were investigated to choose those that might have the porosity standing between 35 and 50%(the ideal porosity adapted for water treatment).The nine formulations investigated were as follows:clay:rice husk mixture weight ratio 0.7:0.3;0.8:0.2 and 0.9:0.1 with the particle size of 100:100 microns.The sintering temperatures of 900℃,950℃ and 1000℃ were applied for each of the mixtures.The results showed that only filters with weight ratio 0.7:0.3 sintered at 900℃,950℃ and 1000℃ had porosity between 35 and 50% with values of 39.41±0.96;40.15±1.59;40.14±1.31 respectively.Mechanical strength,permeability and iron leaching behavior were investigated for these three formulations.The formulation 0.7:0.3 with sintering temperature of 1000℃ had the higher permeability and was the more stable for iron leaching so it is the more adapted for water treatment in terms of flow rate and iron leaching behavior,pore size distribution showed that these filters were macroporous and designed for microfiltration with average pore diameter of 0.46μm.

Elaboration of Ceramic Pot Filter from Kaolinite (Cameroon Clay) for the Elimination of Suspended Particles from Domestic Drinking Water

The objective of this work was to elaborate ceramic water filters from Kaolinite (Cameroon) clay for the elimination of suspended particles from domestic drinking water. In Sub-Sahara Africa and in Cameroon in particular health issues have been linked to the consummation of domestic tap water of high turbidity values both in the rural and urban areas. In order to remedy these problems, ceramic water pot filters have been elaborated in a pilot scale unit with aim of putting in place a unit production. The chemical composition, the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses of the raw materials (clay and rice husks) was determined. The crystal phases and scanning electron microscope of Wack clay was also determined. The ceramic pot filter membranes were fabricated from the formulations 70/20/10 of clay/porogen/chamotte respectively with the particle size of the raw material less than or equal to 500 μm. The formulated ceramic pot filters were then sintered at 900˚C in a furnace. These ceramic pot filters were characterized by determining their porosity, withdrawal percentages, water permeability, mechanical and chemical resistance. The study of the efficiency consisted in evaluating the retention rate and permeate flux with respect to time (days) with synthetic water suspensions of turbidity 100 NTU and particle size of 2 μm. The ceramic pot filters were made aiming at studying the efficiency after physical defouling of filters. Physical defouling consisted in brushing the inner surface of the ceramic pot filters with water and drying them at ambient temperature after being used for 11 days and reusing them under the same initial conditions. The produced ceramic pot filter had a volume of 4 L, an average porosity of 36.15%, shrinkage in mass or withdrawal percentage of 18.23%, a water permeability of 59.6 × 103 L∙h−2∙m−2, mechanical resistance of 6.8 MPa and corrosion resistance of 1.6% in acidic medium and 0.8% in alkaline medium. The evaluation of the retention efficiency reveals that the retention rate of 99.9% was obtained from the 9th day of filtration reducing the turbidity value from 100 NTU to less than 0.1 NTU. From the filtration test carried out during the 11 consecutive days, the flow rate varied between 1.46 L∙h−1 to 2.63 L∙h−1. Similar results of retention and flow rate were obtained after physical defouling of the ceramic pot filter membranes and re-using for 11 consecutive days, showing the efficiency of the ceramic pot filter membranes in eliminating suspended particles from drinking water. Cost evaluation for the production unit reveals a total cost of production for 50 ceramic pot filters of 1593.6 USD consisting of fixed assets and variable assets. An estimated selling price of 3.3 USD was obtained which is affordable for both the urban and rural population in Cameroon and in sub-Saharan Africa.

Elaboration of Ceramic Pot Filter from Kaolinite (Cameroon Clay) for the Elimination of Suspended Particles from Domestic Drinking Water

The objective of this work was to elaborate ceramic water filters from Kaolinite (Cameroon) clay for the elimination of suspended particles from domestic drinking water. In Sub-Sahara Africa and in Cameroon in particular health issues have been linked to the consummation of domestic tap water of high turbidity values both in the rural and urban areas. In order to remedy these problems, ceramic water pot filters have been elaborated in a pilot scale unit with aim of putting in place a unit production. The chemical composition, the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses of the raw materials (clay and rice husks) was determined. The crystal phases and scanning electron microscope of Wack clay was also determined. The ceramic pot filter membranes were fabricated from the formulations 70/20/10 of clay/porogen/chamotte respectively with the particle size of the raw material less than or equal to 500 μm. The formulated ceramic pot filters were then sintered at 900˚C in a furnace. These ceramic pot filters were characterized by determining their porosity, withdrawal percentages, water permeability, mechanical and chemical resistance. The study of the efficiency consisted in evaluating the retention rate and permeate flux with respect to time (days) with synthetic water suspensions of turbidity 100 NTU and particle size of 2 μm. The ceramic pot filters were made aiming at studying the efficiency after physical defouling of filters. Physical defouling consisted in brushing the inner surface of the ceramic pot filters with water and drying them at ambient temperature after being used for 11 days and reusing them under the same initial conditions. The produced ceramic pot filter had a volume of 4 L, an average porosity of 36.15%, shrinkage in mass or withdrawal percentage of 18.23%, a water permeability of 59.6 × 103 L∙h−2∙m−2, mechanical resistance of 6.8 MPa and corrosion resistance of 1.6% in acidic medium and 0.8% in alkaline medium. The evaluation of the retention efficiency reveals that the retention rate of 99.9% was obtained from the 9th day of filtration reducing the turbidity value from 100 NTU to less than 0.1 NTU. From the filtration test carried out during the 11 consecutive days, the flow rate varied between 1.46 L∙h−1 to 2.63 L∙h−1. Similar results of retention and flow rate were obtained after physical defouling of the ceramic pot filter membranes and re-using for 11 consecutive days, showing the efficiency of the ceramic pot filter membranes in eliminating suspended particles from drinking water. Cost evaluation for the production unit reveals a total cost of production for 50 ceramic pot filters of 1593.6 USD consisting of fixed assets and variable assets. An estimated selling price of 3.3 USD was obtained which is affordable for both the urban and rural population in Cameroon and in sub-Saharan Africa.

Suitability of Some Selected Clay Deposit from Edo, Ogun, Ondo and Ekiti State of Nigeria for Ceramic Water Filters Production

This study is designed to investigate the suitability of selected Nigeria clay deposit for clay based ceramic water filters (CWFs). Clay samples were taken from five randomly selected locations in Nigeria Namely: Okpella (Edo1) and Ojirami (Edo2) in Edo;Ikere in Ekiti state;FUTA in Ondo state and Onibode in Ogun to determine their suitability for clay based ceramic water filters (CWFs). Experimental analysis for linear shrinkage, water absorption, bulk density, compressive strength X-ray diffraction (XRD) and X-ray Fluorescence (XRF) was carried out on each of the clay samples. Test results reveal that all the clays contain high contents of alumina (Al2O3) and silica (SiO2) with minor contents of P2O5, Fe2O3, MgO, K2O, MnO and TiO2. The average crystal sizes of the clay were between 15 and 27 nm. Lattice structure indicates that the sample is Monoclinic and Anorthic. Ceramic water filters (CWFs) were made from a mixture of clay and sawdust at different volume ratios, and processed into test samples. Water absorption, linear shrinkage and compressive strength of the clay based ceramic filters (CWFs), reveal that as the volume ratio of sawdust increases these properties decrease. Flow rate analysis indicates that Edo and Ekiti ceramic water filters (CWFs) have higher flow rates. The research indicates that Edo and Ekiti Clay with specification of some industrial clays shows that the samples can be recommended for use in clay based ceramic water filters production.

Current Status and Application of Ceramic Foam Filter for Aluminum Melt

The importance of purification for aluminum and aluminum alloy casting was outlined. By comparing ceramic foam filters （CFF） in China and overseas, the existing problems and challenges of China＇ s CFF for aluminum were given. Measures to improve the performance of CFF were put forward based on material, preparation process, utility evaluation, etc.

Preparation and Characterization of Nanotitanium Dioxide Coating Film Doped with Fe^(3+) Ions on Porous Ceramic

The nanotitanium dioxide （TiO2） photocatalytic and porous ceramic filtering technique is one of the advanced methods to effectively treat organic wastewater. The TiO2 sol doped with Fe^3＋ ions was prepared by sol-gel processing. The influences of the process conditions of coating nanophotocatalytic material- Fe^3＋-TiO2 film on the surface of porous ceramic filter by dipping-lift method on the performance of porous ceramic filter were studied. The porous ceramic filters have two functions at the same time, filtration and photocatalytic degradation. The results of this study showed that the pH and viscosity of the sol, amount of Fe^3＋ ions doped as well as the coating times greatly affect the quality of coating film, the performance parameters and the photocatalytic activity of the porous ceramic filter. When the pH of the sol is 3-4, the viscosity is about 6 mPa.S, the amount of doped Fe^3＋ ions is about 2.0 g/L, the porous ceramic filter has been shown to have the best filtering performance and photocatalytic activity. In this condition, the porosity of porous ceramic is about 42.5%, the pore diameter is 8-10μm. The degradation of methyl-orange is 74.76% under lighting for 120 rain.

Oily Wastewater Treatment by Porous Ceramics Mediums with Surface Lipophilic Modification

Aiming at the treatment of difficult-to-handle oily wastewater, the ceramics filter mediums made from the iron and steel plant sludge were adopted to surface lipophilic modification so as to remove oil efficiently. The hydrolysis technique by FTIR and conductivity test indicated that under acid conditions hydrogen silicon oil did not hydrolyze but release hydrogen by chemical reaction under alkaline conditions. The results of the experiments including contact angle measurement, FTIR analysis, and SEM analysis illustrate that a layer of lipophile coating indeed exists evenly on the surface of filter mediums after modification. Furthermore, the hydrogen-containing silicone oil was combined through dehydration of Si-H bond with the-OH on the surface of ceramic filter medium.

Design of a Microwave Filter Based on a Novel Negative Coupling Structure with Conical Through-Hole

This article introduces the design theory of ceramic waveguide filter and proposes a new type of negative coupling structure with a conical throughhole,which has fine-adjustment of negative coupling without significantly increasing the insertion loss of the filter.Based on this,the article proposes an eightcavity ceramic waveguide filter design for 5G base stations.It also presents a detailed discussion on the influence of the cross-coupling slot lengths L2 and L4 on the transmission zeros positions during the filter optimization process and the relevant change rules.For the proposed optimized filter,the observed performance indicators include the center frequency of 3.5 GHz,working bandwidth of 200 MHz,an insertion loss of≤2.0 dB,return loss of≥19 dB,and out-of-band nearend suppression and out-of-band far-end suppression of≥39 dB and≥63 dB,respectively.The test performance results obtained for the sample,with structural parameters as per the simulation model,were in good agreement with the simulation results.

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges and opportunities

Drinking water source contamination poses a great threat to human health in developing countries.Point-of-use(POU)water treatment techniques,which improve drinking water quality at the household level,offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterbome diseases.Ceramic water filters(CWFs),fabricated from locally sourced materials and manufactured by local labor,are one of the most socially acceptable POU water treatment technologies because of their effectiveness,low-cost and ease of use.This review concisely summarizes the critical factors that influence the performance of CWFs,including(1)CWF manufacturing process(raw material selection,firing process,silver impregnation),and(2)source water quality.Then,an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs,including(1)simultaneous increase of filter flow rate and bacterial removal efficiency,and(2)removal of various concerning pollutants,such as viruses and metal(loid)s.To promote the application of CWFs,future research directions can focus on:(1)investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters;and(2)exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

Electromagnetically Modified Filtration of Liquid Aluminium With a Ceramic Foam Filter

Conventional Ceramic Foam Filter(CFF)technology has some difficulties in removing fine particulates(e.g.<20 μm)from liquid aluminium.In the present work the filtration behaviour of 30,50 and 80 ppi CFF filters have been studied in the presence of magnetic fields in the range of 0.06-0.2T,produced by induction coils operated at 50 Hz. A feed recipe containing 90 wt.%of the aluminium alloy A356 doped with 10 wt.%A356 composite,containing 15 wt% SiC particles with a particle size ranging from 13 to 23 μm,was used.When the results obtained for the experiments conducted under the influence of a magnetic field where compared with similar reference gravity filtration experiments profound changes were observed in the distribution of particulates within,over and below the filter.Significant improvements in the wetting behaviour of the liquid metal to the CFF surface were also observed.It is believed that a successful change in filtration mechanisms is obtained as a result of the presence of the Lorentz forces and the metal recirculation produced by the magnetic field.The magnitude of the Lorentz forces,i.e.the magnetic pressure,are in the present work discussed in relation to the filtration results,and quantified based on experimental data and validated 2D axial symmetric Finite Element Modelling(FEM).

Technical feasibility study of an onshore ballast water treatment system

To fulfill the requirements of Guidelines forapproval of ballast water management system(G8),a setof onshore ballast water treatment equipment utilizingmicro-pore ceramic filtration(MPCF)and UV radiation(MPCF&UV)system was designed and set up with amaximum flow rate of 80 m^(3)·h^(-1).Technical feasibilities ofMPCF&UV system were evaluated in three areas:removalefficiencies of indicator organism and oceanic bacteria,perdurability of a ceramic filter,and application on nativeseawater.The results showed that no indicator organism(Dunaliella)or oceanic bacteria was detected aftertreatment of 20 L MPCF and UV radiation at 1.3×10^(4)μW·s·cm^(-2).A 20 L ceramic filter can run continuouslyfor 5.3 h at the flow rate of 15 m3·h-1 before itspressure drop up to 0.195 MPa.The removal percentage oftotal plankton amounts were 91.9%at a flow rate of70 m^(3)·h^(-1)by 80 L MPCF and UV radiation at 1.3×10^(4)μW·s·cm^(-2).