Uniaxial Dry Compaction Research Articles

Utilizing bioinspired AgNPs as an antibacterial agent to enhance ceramic membrane performance

In this study, a ceramic membrane using kaolin (40% w/w) as a primary precursor was fabricated by the uniaxial dry compaction technique at a sintering temperature of 900 °C (as negligible weight loss >850 °C) and functionalized by bioinspired Ag nanoparticles (AgNPs) synthesized using Sechium edule extract for the treatment of sewage water. The Ag+ adsorption of 99% on the bare membrane was achieved at pH 7. The X-ray diffraction pattern not only confirmed significant phase transformations during the sintering operation but also the presence of highly crystalline AgNPs in the modified membrane. UV-Vis spectroscopic analysis was used to study AgNPs formation based on surface plasmon effect, if any, on the modified membrane surface. AgNPs modified membrane showed a 60.5% decrease in surface area compared to bare membrane due to AgNPs impregnation. AgNPs (average size 29.54 nm) exhibited a uniform morphological distribution on the modified membrane, which decreased its average pore size and porosity from 3.09 to 2.64 µm and 47.91–44.97%, respectively. The pure water flux of bare and AgNPs modified membranes were 8.1 ± 0.09 × 10−4 and 6.33 ± 0.12 × 10−4 m3.m−2.s−1, respectively. The antimicrobial activity of bare membrane against E. coli, S. aureus, and bacterial strains in sewage water was found to be 37.03 ± 2.73, 52.64 ± 3.49, and 53.03 ± 6.80%, respectively. AgNPs functionalized ceramic membrane could completely (∼100%) inhibit the growth of E. coli, S. aureus, and bacterial strains in sewage water during filtration.

Batch and continuous of oil removal using organoclay and low-cost ceramic membrane

The objective of this work was to compare two oily effluent treatment systems, batch process and membrane separation process (PSM). In the batch process an organophilic clay was used and in the PSM a low cost ceramic membrane was used. A bofe clay was used as raw material for the preparation of organophilic clay prepared with surfactant, via direct method and characterized by X-ray diffraction. The sorption properties of this organoclay were evaluated to remove oil. The low-cost, disc-shaped ceramic membrane was obtained from natural bofe clay from Boa-Vista, Paraíba, Brazil. The uniaxial dry compaction method and sintering at 650 °C was used. The membrane was characterized by XRD and water permeability and its performance was evaluated by oil/water emulsion separation tests from a synthetic effluent, using a stainless steel module under the conditions of initial concentration of the emulsion 125 mg.L-1, temperature of 25 °C and pressure of 2.0 bar. It is concluded that the two processes (PSM and batch system using bofe organophilic clay as adsorbent) can be used and are promising for the treatment of oily water.

Study of the influence of the aluminum source (acetate or sulfate) on the synthesis of the ceramic membrane and applications of emulsion oil water: use and reuse

The objective of this work was to prepare ceramic membranes and to evaluate the effect of the raw material on the ceramic membrane and on the efficiency of the emulsion separation oil/water. The ceramic membranes were manufactured using the uniaxial dry compaction method, from the thermal decomposition of aluminum sulfate or aluminum acetate, to evaluate the effect of the raw material (aluminum acetate or aluminum sulfate) on the efficiency in the emulsion oil/water separation. Ceramic membranes were characterized by measurements of X-ray diffraction patterns, scanning electron microscopy, mechanical strength, bubble point and water flow. In this study, membranes were produced with different characteristics. The values found for the permeate for the A1 membrane were 9.20 mg / L due to characteristics such as porosity and mechanical strength (44.63 % and 1.3 MPa), while the values A2 membrane was 6.52 mg / L, 18.86 % and 6.7 MPa. In conclusion, the membranes prepared are effective in removing the oil from the oily waste water. According to the results, the treatment of oil-water emulsions by microfiltration facilitates a significant reduction in the concentration of permeate oil.

Composite Membrane and Evaluation on Separation Oil/Water

Background: The generation of wastewater contaminated with organic compounds, release or spill into these water bodies can lead to serious environmental problems. The removal of chemical pollutants in water presents itself as one of the central issues regarding the issue of environmental remediation. In this sense, membranes, haves gained increasing importance in the environmental area. Objective: This present study aims to develop a composite membrane using UHMWPE/LDPE/CTAC-HGC to be used for oil/water separation of wastewater effluents. Methods: The polymeric membrane and composite membrane were prepared by uniaxial dry compaction and sintering. Both hard green clay (HGC) and hard green clay organophilized with cetyl trimethyl ammonium chloride (CTAC-HGC) were characterized by X-ray Diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). UHMWPE, polymeric membrane and composite membrane were characterized by XRD and SEM. Result: The water flux through the composite membrane was evaluated using pure water as a permeate. The potential of the composite membrane to separate oil-water emulsions was tested. Conclusions: The composite membrane showed excellent removal of the oil, exhibiting removal of more than 99.60 %, evidencing the process of composite membrane separation as an alternative technology for the treatment of oil.

CHEMICAL CLEANING OF MICROFILTRATION CERAMIC MEMBRANE FOULED BY NOM

Microfiltration membrane made from Sayong ball clay by using uniaxial dry compaction method was used to treat natural organic matter (NOM) source water. A sintering temperature of 900 °C to 1000 °C were applied. The effect of sintering temperature on membrane porosity, strength and water flux were identified. The porosity of the membrane decreased with increasing sintering temperature and the strength and flux increased with temperature. The membrane was subjected to NOM filtration experiments. The results showed an improvement to the quality of permeate water, where there is a reduction in COD, TSS, BOD5, turbidity, hardness and salinity; and an increased pH value. The effect of chemical cleaning on the fouled membrane also was studied. After cleaning with NaOH solution, a high flux recovery was achieved (up to 50% from the initial pure water flux). The degree of cleanliness of fouled membranes after chemical cleaning was further observed with SEM and EDX analysis.

Fly ash based ceramic microfiltration membranes for oil-water emulsion treatment: Parametric optimization using response surface methodology

This article addresses the fabrication of ceramic microfiltration membranes (M1-M3) with uni-axial dry compaction method and fly ash, quartz and calcium carbonate as inorganic precursors. Raw material and membrane characterizations were conducted using particle size (PSD), thermo gravimetric (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), mechanical stability, chemical stability, porosity, pore size and pure water permeability analyses. Dead-end flow microfiltration (MF) experiments were conducted to evaluate the membrane performances with 50–200mg/L synthetic oil-water emulsions. The MF experiments enabled to evaluate (M1-M3) membrane performance in terms of flux and rejection for variant combinations of feed concentrations and applied pressures. Among all membranes, M2 membrane demonstrated superior rejection (80.82–99.99%) and membrane flux (0.337–4.42×10−4m3/m2s). Response surface methodology (RSM) via central composite design (CCD) was employed to optimize and understand the interaction of possible influencing process variables on the treatment efficiency in terms of flux and rejection. The optimum parametric conditions are found to be at an applied pressure of 345kPa and feed concentration of 176.07mg/L at which M2 membrane exhibits a maximum oil rejection of 97% with permeate flux of 2.6×10−4m3/m2s.

Effect of Alkaline-Earth Oxide Additives on Flexural Strength of Clay-Based Membrane Supports

Low-cost ceramic membrane supports with pore sizes in the range of 0.52-0.62 μm were successfully prepared by uniaxial dry compaction method using inexpensive raw materials including kaolin, bentonite, talc, sodium borate, and alkaline-earth oxides in carbonate forms (e.g., MgCO₃, CaCO₃, and SrCO₃). The prepared green supports were sintered at 1000℃ for 8 hr in air. The effect of alkaline-earth oxide additives on the flexural strength of clay-based membrane supports was investigated. The porosity of the clay-based membrane supports was found to be in the range of 33-34%. The flexural strength of the clay-based membrane supports with 1% alkaline-earth carbonates was found to be in the range of 42.8-52.7 MPa. The addition of alkaline-earth carbonates to clay-based membrane supports resulted in large increases (47-80%) in the flexural strength of the membrane supports, compared to that of membrane supports without alkaline-earth carbonates. The typical flexural strength of the clay-based membrane support with 1% SrCO₃ was 52.7 MPa at 33.8% porosity.

The Comparison of the Characteristics of Displacement Isolines in the Cylindrical Green Compact under Ultrasonic Vibration

This research is a comparison of the characteristics of the displacement isolines due to powder-die-wall friction that arise during the compaction of ceramic powders in conventional die. It has been done using the CosmosWorks software package of the SolidWorks simulation software. The results of comparative simulation with FEM showed that the comparison of the displacement isolines and distribution of deformation of the ceramic powders. In the case of conventional uniaxial dry compaction for long length cylindrical green compact, considerable bending of the layers in the form of a cone can be observed. It is symmetry along centerline of cylindrical green compact. The distributions of the deformation of the green compacts (diameter 14 mm, height 20 mm) as a result of conventional compaction under ultrasonic vibration with power 1 and 2 kW are reduced to 4% and 6.5% when compared with conventional compaction without ultrasonic vibration respectively. Thus, density distribution can be minimized by increasing the power of ultrasonic vibration.

Microfiltration of Synthetic Bacteria Solution Using Low Cost Ceramic Membranes

This work addresses the development and identification of optimal low cost membrane morphologies for bacteria separation applications. Using uniaxial dry compaction method, ceramic membranes (CM1–CM3) were prepared using kaolin, quartz, calcium carbonate, sodium carbonate, boric acid, sodium metasilicate, and poly-vinyl alcohol (PVA) precursors. The fabricated membranes possessed diverse pore morphologies (0.7-4.5 μm average pore size and 39.4–19.3% porosity). Amongst all membranes, the CM3 membrane with wide pore morphology (average pore size of 4.5 μm and porosity of 19.3%) provided the best performance during the direct-flow MF of synthetic Escherichia coli (DH5α strain) solutions. The CM3 membrane provided a trans-membrane flux varying from 1.21 × 10− 2 –3.51 × 10−3 m3/m2.s after 10 minutes of direct-flow MF for a variation in feed concentrations of 0.004 –14.9 × 106 CFU/mL. Corresponding bacterial removal efficiency and log10 reduction value (LRV) values varied from 99-99.9999% and 2-6 respectively. Further, various fouling models have been evaluated for their use in measuring flux decline data. The results indicated that both membrane pore morphologies and concentration of E. coli strains significantly influenced the measured transmembrane flux, fouling index, and separation efficiency.

Development of ceramic membranes from low-cost clays for the separation of oil–water emulsion

This work addresses the fabrication of ceramic microfiltration membranes by uniaxial dry compaction method. Four membranes, namely SP1, SP2, SP3, and SP4 were prepared with various compositions of fly ash and titanium dioxide (TiO2) followed by sintering at 1,100°C. The raw materials and the prepared membranes were characterized by particle size distribution, X-ray diffraction and field emission scanning electron microscope, porosity, pore size, and chemical and mechanical stabilities. As the TiO2 content increases in the precursor formulations, the porosity and mechanical stability of the membranes also increase while the average pore size reduces from 2.97 to 1.32 μm. The chemical stability of all the membranes demonstrates to be better in both acidic and basic medium. The performance of the membrane (SP4) is examined for the separation of oil–water emulsion and the membrane exhibits a maximum oil rejection of 99.2%.

Cross flow microfiltration of oil–water emulsions using kaolin based low cost ceramic membranes

Emphasizing upon the need to develop and target applications of low cost ceramic membranes, this work addresses the cross flow microfiltration (MF) of oil–water emulsions. Membranes prepared using uniaxial dry compaction method and possessing higher average pore sizes (3.06–2.16μm) and porosities (30.1–37.4%) have been used for cross flow MF studies. Cross flow runs were conducted using a feed oil concentration of 400mg/L of for various combinations of trans membrane pressure differentials (138–207kPa) and cross flow velocities (Reynolds number=3417 to 6835). The fitness of various fouling models indicates that combination fouling models could only represent the observed flux decline data which refers to existence of one of the pore blocking phenomena (complete/intermediate/standard pore blocking) during the first 10min of experimental run followed with cake filtration for the data obtained for later time periods. Experimental investigations inferred that the membrane performance is optimal for maximum combinations of trans membrane pressure (ΔP=207kPa), fabrication pressure (73MPa) and minimal cross flow velocity (Re=3417) at which conditions, an optimal combination of fouling index, steady state flux and rejection were obtained as 11.58%, 22.14×10−6m3m−2s and 98.52%, respectively.

Microfiltration of oil–water emulsions using low cost ceramic membranes prepared with the uniaxial dry compaction method

Abstract This work addresses the comparative assessment of uniaxial dry compaction and paste methods for the preparation of low cost ceramic membranes. Kaolin based low cost membranes were fabricated using uniaxial dry compaction with the identified precursor formulation provided by Nandi et al. [5] . Fabricated membranes were characterized and used for the treatment of synthetic oily waste water solutions. It was observed that in comparison with the paste method, the membranes prepared with uniaxial dry compaction method possessed wider pore size distributions. Amongst several membranes, the membrane PM1 fabricated at a pressure of 25 Mpa provided highest flux of 24×10 −6 m 3 /m 2 s and an oil rejection of 95.2% but with a fouling index of 29.47% at a pressure of 206.70 kPa. On the other hand, PM3 membrane provided a lower fouling index of 15.54% at a pressure of 206.70 kPa with a membrane flux of 8×10 −6 m 3 /m 2 s and a rejection of 97.9%. For the obtained membrane morphology and chosen feed concentration, combination of pore blocking models provided best fit to represent flux decline data. High rejection values (80–90%) and good membrane flux (24×10 −6 m 3 /m 2 s) of the fabricated membranes was observed towards the treatment of oil water emulsions using low cost ceramic membranes.

Preparation and characterization of low cost ceramic membranes for mosambi juice clarification

This work addresses the preparation and characterization of microfiltration membranes using low cost inorganic precursors for juice clarification. Low cost ceramic membranes have been fabricated using the uniaxial dry compaction method at various fabrication pressures (29, 39 and 49MPa). The fabrication research has been dovetailed to identify the most critical parameters (such as fabrication pressure and particle size of the precursors) to achieve the desired membrane morphologies. The prepared membranes possessed average pore size (based on FESEM) varying from 1.85 to 0.89μm, hydraulic pore size varying from 1.69 to 0.72μm, porosity ranging from 35.4 to 39.4%, and flexural strength ranging from 7.81 to 11MPa. Amongst several membranes, the MF performance of M3 membrane (fabricated at 49MPa) for mosambi juice is highly satisfactory. The M3 membrane provided a membrane flux of 90 to 44×10−6m3/m2·s at 206.7kPa with a permeate juice quality of negligible AIS content for the enzyme treated centrifuged juice (ETCJ). Flux decline modelling analysis indicated that enzyme treatment followed by centrifugation minimizes irreversible fouling and is highly recommended before the MF.

Biomass assisted microfiltration of chromium(VI) using Baker's yeast by ceramic membrane prepared from low cost raw materials

This work deals with the preparation of ceramic microfiltration membrane from inexpensive raw materials such as kaolin, quartz, calcium carbonate by uniaxial dry compaction method. The prepared green membrane was initially dried at 100 °C for 24 h, 200 °C for 24 h and finally sintered at 900 °C for 6 h. The properties of the membrane such as porosity, flexural strength, chemical stability and hydraulic permeability were investigated. The fabricated membrane possessed an average pore diameter of 1.32 μm, porosity of 30% and flexural strength of 34 MPa. Furthermore, the chemical stability of the membrane was found to be excellent. Eventually, the separation performance of the membrane in terms of flux and removal of chromium(VI) ion using baker's yeast biomass as a function of applied pressure, pH, metal ion concentration and biomass dosage was also studied. The removal of Cr(VI) was found to be strongly dependent on the initial pH of the solution. At lower pH, the metal solution shows higher removal due to higher binding of the metal ion with biomass. It was also observed that the removal of Cr(VI) ion increases with increasing the biomass concentration and decreases with increasing the metal ion concentration. The removal of Cr(VI) was found to be independent of the applied pressure. The maximum removal of Cr(VI) was found to be 94% with the permeate flux of 2.07 × 10 -5 (m 3/m 2 s) for a metal solution concentration of 100 mg/L.

Fabrication and properties of low cost ceramic microfiltration membranes for separation of oil and bacteria from its solution

This work addresses the development of low cost ceramic microfiltration membrane from inexpensive raw materials such as kaolin, quartz, calcium carbonate using uniaxial dry compaction method. The prepared membranes were sintered at different temperatures ranging between 900 and 1000 °C. The raw materials and the prepared membranes were characterized with thermogravimetric analysis (TGA), particle size distribution (PSD), X-ray diffraction and scanning electron microscope analysis. Subsequently, the effect of sintering temperature on the membrane properties such as porosity, flexural strength, chemical stability and pure water permeability was investigated and optimized for the sintering temperature. It is observed that with increasing sintering temperature, the porosity of the membranes decreases and the flexural strength, chemical stability and pure water permeability of the membranes increases. The flexural strength and chemical stability of the membranes are found to be excellent. Based on these results, the membrane sintered at 900 °C (porosity of 30%, flexural strength of 34 MPa, average pore size of 1.30 μm) is inferred as an optimum membrane for microfiltration applications. Solvent permeation studies have also been carried out for the membrane sintered at 900 °C and the results infer that the membrane is hydrophobic in nature. Further, the membrane is subjected to oil–water emulsion and bacteria separation experiments. The observed rejection decreased with an increase in the applied pressure and increased with an increase in the concentration of oil and bacteria, respectively. The results show a maximum rejection of 85% and 99% for oil (feed oil concentration of 250 mg/L) and bacteria (feed bacteria concentration of 6 × 10 5 CFU/mL), respectively.

Influence of Sintering Temperature on the Properties of Porous Ceramic Support Prepared by Uniaxial Dry Compaction Method Using Low-Cost Raw Materials for Membrane Applications

In this article, we have reported the fabrication of stable macroporous ceramic support using low-cost inorganic raw materials by uniaxial dry compaction technique. The supports were prepared by mixing of inexpensive raw materials such as kaolin, quartz, calcium carbonate, sodium carbonate, boric acid, sodium metasilicate, and polyvinyl alcohol as a binder. The prepared green supports were sintered at different temperatures ranging between 900 and 1000°C. The raw materials and the sintered supports were characterized by thermogravimetric analysis, particle size distribution (PSD), X-ray diffraction, and scanning electron microscopy analysis. The influence of sintering temperature on the membrane structure, porosity, flexural strength, chemical stability, and the pure water permeability was also examined. It was observed that the average pore size and the flexural strength of the sintered supports increase with an increase in the sintering temperature. The porosity of the sintered supports was obtained in the ranges between 22 and 40%. The chemical stability of the sintered supports was found to be good. Based on the results obtained, the support sintered at 950°C (porosity of 30%, mechanical strength of 28 MPa, and average pore size of 3.45 µm) was considered as the optimum support for membrane applications. The ceramic support cost was estimated to be $67/m2 according to the raw material price. Henceforth, these low-cost membrane supports with better properties could be suggested for cheaper application in chemical and biochemical processes.

Microstructure of ZrO2 nanoceramics

AFM was used to study the microstructure of nanoceramics prepared from a plasmochemical nanostructured powder ZrO2-5 wt.% Y2O3 by uniaxial dry compaction under strong ultrasonic (US) impact. It is found that nanoceramics samples have a complicated structural hierarchy consisting of crystallites, subgrains, grains, and agglomerates. The average size of structural elements in the sintered ceramics depends on nanopowder compaction conditions (compaction pressure and ultrasonic power). The XPS data on the chemical composition of nanoceramics fractures indicate correlation between Zr, Y concentrations (at. %) with average grain size. A significant Zr depletion (Y enrichment) of nanoceramics grain surface in comparison with the starting powder is discovered. The US-impact during nanopowder compaction is assumed to intensify intragrain diffusion during ceramics sintering