Low-cost Ceramic Microfiltration Membrane Research Articles

Fabrication of low-cost kaolinite/perlite membrane for microfiltration of dairy and textile wastewaters

This work is addressing the preparation of low-cost ceramic microfiltration membrane from cheap geomaterials namely kaolinite and perlite for the clarification of dairy and textile wastewaters. The effect of sintering temperature (950–1100 °C) and perlite content (25–75 wt%) on phase transformation, porosity, mechanical strength and permeability were investigated. The resulting membrane shows a good cohesion and a high flexural strength thanks to the heterogeneity of the microstructure of used geomaterials. The optimized kaolinite/perlite membrane containing 50 wt% of perlite sintered at 1050 °C exhibits a permeability of 1779 L h−1 m−2 bar−1 and an average pore diameter of 1.25 µm. More importantly, the clarification of dairy and textile wastewaters using kaolinite/perlite membrane could remove more than 97% of turbidity of both wastewaters, and reject 45% and 80% of total organic carbon respectively for dairy and textile wastewaters. In addition, the flux is mostly recovered after membrane cleaning and it reaches 90.17% and 75.23% for dairy and textile wastewater respectively. Besides, the cost of the prepared membranes was estimated to be 7.7 $ m−2 suggesting possible industrial scaling-up.

Separation of TiO2 particles from suspension using indigenous low-cost ceramic microfiltration membrane

The increased use of TiO2 nanoparticles in manufacturing and commercial products has led to environmental contamination and health issues. This study aimed to apply tubular ceramic membrane fabricated using low-cost clays (kaolin, quartz) along with hydroxypropyl methylcellulose binder for the separation of TiO2 nanoparticles from water. The prepared tubular ceramic membrane exhibited excellent water permeability (1.4945 × 10−7 m3/m2s kPa) with an average pore size of 0.178 μm and porosity of 40 %. Cross flow microfiltration experiments using TiO2 nanoparticles suspension were performed by varying the applied pressure (138–414 kPa), cross flow velocity (2.41 × 10−3 - 5.63 × 10−3 m/s), pH (4–11) and feed concentration (0.05–1 wt%). The permeate flux increased linearly with an increase in the pressure as well as cross flow velocity with a maximum permeate flux of 4.24 × 10−5 m3/m2s at 414 kPa, whereas a reduction in permeate flux was observed with increasing feed concentration of TiO2. The membrane displayed 100 % separation efficiency at all the investigated pressures. Furthermore, the membrane fouling mechanism during the microfiltration process was analyzed using resistance-in-series model. Results demonstrated that filtration resistance (Rf) and total resistance (Rt) decreased with increasing cross flow velocity from 2.41 × 10−3 m/s to 5.63 × 10−3 m/s, whereas filtration resistance remained constant at high pressures. The estimated membrane cost is 253 USD/m2 based on raw materials, energy consumption, manpower and equipment cost. These promising results elucidated the suitability of tubular ceramic membrane towards the removal of TiO2 from wastewater.

Hybrid ceramic membrane microfiltration and electrolysis process for Cu-removal from aqueous solutions

This study aims to fabricate a low-cost ceramic microfiltration membrane by mixing kaolin 4.2 wt%, silica 5.8 wt%, starch 20 wt%, graphite 30 wt%, and sodium silicate 40 wt%. The produced paste was molded into a cylinder (1.0 cm high, 5 cm diameter) and dried in an oven at 90°C for 1 h, and then sintered in a furnace at 650 °C for 2 h. The characterization of the produced ceramic membrane was performed by X-ray diffraction analysis, Fourier transformed infra-red spectroscopy, and scanning electron microscopy. Furthermore, the contact angle of the membrane surface was measured, thus demonstrating that the surface is hydrophilic. The fabricated ceramic membrane was investigated for its chemical resistance in strongly acidic and alkaline media. The mass loss of membrane in HCl solution at pH = 2 for 200 h was not more than 0.18%, while it was 2% in alkaline NaOH solution (pH = 12). The fabricated ceramic membrane was combined with an electrolysis process for applying as a new hybrid process for copper ions removal from an aqueous solution. The effects of three operating parameters of electric voltage, initial pH, and initial copper concentration on the performance of copper removal percentage were investigated. To investigate the independent effect of the hybrid electrolysis process versus microfiltration, two experiments with and without an electric field were conducted in 100 min. The copper concentration was decreased from 350 to 160 ppm only by applying the microfiltration method, whereas hybrid electrolysis and microfiltration decreased the copper concentration from 350 to 10 ppm. The regeneration of the composite membrane was evaluated in four consecutive cycles. The percentage of copper ions removal after 4 cycles without washing is about 97%. The proposed process is effective and fast for copper ions removal from the solution, with an excellent yield of 97.4%.

New Low-Cost Ceramic Microfiltration Membranes for Bacteria Removal.

Safe water provision in low-income countries is constrained by limited financial resources, and the problem is worsened during natural disasters. Thus, there is a need to develop efficient low-cost technologies for point-of-use water treatment. This work reports on the development of new ceramic microfiltration membranes made from mixtures of inexpensive raw materials available locally (kaolin, bentonite and limestone) and their efficiency in rejecting bacteria such as Escherichia coli and Staphylococcus aureus. Thermogravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray diffraction, mercury intrusion porosimetry, flexural strength and water uptake were used to characterize the raw materials and membranes. The addition of limestone in the membrane fabrication increased the pore size, the porosity and, thus, the permeability of the membranes but at the expense of the rejection performance. Among the different compositions studied, the membrane made of 83% kaolin, 10% bentonite and 7% limestone showed the best performance compromise with water permeability of 566 L·h−1·m−2·bar−1 and 100% rejection of both Escherichia coli and Staphylococcus aureus. These new low-cost microfiltration membranes are expected to have potential applications in water treatment and household applications.

Low-cost ceramic microfiltration membranes made from Moroccan clay for domestic wastewater and Congo Red dye treatment

Low-cost ceramic microfiltration membranes made from Moroccan clay for domestic wastewater and Congo Red dye treatment

Elaboration and properties of low-cost ceramic microfiltration membrane from local Tunisian clay for wastewater treatment

Abstract This study focused on the development and preparation of a microfiltration membrane, based on a low-cost natural Tunisian clay powder, deposited on macro-porous ceramic support. The deposit was made through a dip-coating technique, followed by a drying process and sintering at 700 °C. Results revealed that the obtained membrane was characterized by a good adhesion between the membrane layer and the ceramic support, an average pore diameter of 0.34 mm, and a porosity of 39%. This membrane was applied in the treatment of wastewater generated by the wastewater treatment plant of Sfax, Tunisia. The performances in terms of permeate flux and efficiency were determined in order to reduce the pollutant content expressed in terms of turbidity, biochemical oxygen demand (BOD5), and suspended matter (MES). Results showed an MES retention value of about 15%, and turbidity and BOD5 retention rate of 99% and ~100%, respectively.

Low-cost ceramic microfiltration membrane made from natural phosphate for pretreatment of raw seawater for desalination

A novel ceramic microfiltration (MF) membrane was prepared from natural phosphate and its properties were thoroughly characterized. An investigation of the effect of sintering temperature on the features of phosphate membrane was carried out in the range from 900 to 1100 °C. The optimized membrane sintered at 1000 °C exhibits 697 L h−1 m-2 bar−1 of permeability, 25.6 % of porosity, 0.26 μm of average pore size and 19.7 MPa of flexural strength. When evaluated for filtration of raw seawater as a potential pretreatment for reverse osmosis desalination, the prepared membrane reduced total organic carbon (TOC) and turbidity by 73 and 98 %, respectively, as well as reducing silt density index (SDI) from 5.41 to 3.25. Furthermore, the fouling mechanism and the flux recovery were also studied. Finally, simple cleaning of the prepared membrane performed after the MF experiment led to recover 74 % of its original water flux.

New low-cost ceramic microfiltration membrane made from natural magnesite for industrial wastewater treatment

This paper mainly focuses on the preparation of new low-cost ceramic microfiltration membrane made from natural magnesite. Firstly, local Moroccan magnesite was deeply characterized in order to understand its chemical and mineralogical composition, and its thermal behavior. It was confirmed that used natural magnesite exhibits high purity degree in terms of magnesite mineral. Next, flat magnesite membrane was fabricated via uniaxial pressing and sintering methods. The effect of sintering in the range 900−1200 °C on morphology, porosity, pore size, permeability and mechanical strength was investigated. Based on experimental results, the optimized membrane (sintered at 1100 °C) has a porosity of 48.15 %, a pore size of 1.12 μm, a water permeability of 922 L h−1 m-2 bar-1 and a mechanical strength of 6.1 MPa. Finally, the optimized magnesite membrane was subjected to filtration of industrial textile wastewater in order to evaluation its performance as microfiltration membrane. Importantly, experimental results are clearly demonstrated that magnesite membrane effectively clarifies textile wastewater. It was showed that turbidity and chemical oxygen demand removals could achieve 99.9 and 69.7 %, respectively.

Purification of cellulase fermentation broth via low cost ceramic microfiltration membranes with nanofibers-like attapulgite separation layers

Abstract This paper reports the study of low cost ceramic microfiltration membranes with a separation layer of attapulgite nanofibers (attapulgite microfiltration membrane), used to clarify the cellulase fermentation fluid in order to enhance the quality of cellulase products. Based on resistance-in series model, the influence of membrane microstructure and operating conditions on the decline in membrane flux was investigated. The appropriate method for cleaning membranes that had undergone fouling was also found. The results show that an attapulgite microfiltration membrane with mean pore size of 0.12 μm is suitable for treating a cellulase fermentation fluid. The appropriate operating conditions were found to be the following: T = 30 ± 3 °C, ΔP = 0.10 MPa, and v = 4 m/s. The dominant component of the total resistance ( R t ) was the reversible fouling resistance ( R rev ), whereas the irreversible fouling resistance ( R irr ) was less important. In conditions of low trans-membrane pressure and high velocity, the fouled attapulgite microfiltration membrane could be satisfactorily regenerated using water rinsing and chemical cleaning. The results obtained in this work indicated that attapulgite microfiltration membrane separation may represent a feasible pretreatment for cellulase fermentation broth. The resistance-in-series analysis may provide additional insight into the relative importance of different fouling mechanisms.

Influence of starch content on the properties of low-cost microfiltration ceramic membranes

The use of starch as pore former is frequent in the fabrication of porous ceramic membranes, since starches are cheap, innocuous and environmentally friendly. A study has been conducted to evaluate the influence of potato starch content (0–30wt%) and sintering temperature (1100 and 1400°C) on low-cost ceramic microfiltration membranes. The raw materials were a mixture of kaolin, alumina and starch, from which membrane specimens were shaped by uniaxial dry pressing.The results indicated that the percentage of potato starch did affect the properties of the membrane. Thus, an increase of starch content provoked a reduction of bulk density (an increase of porosity) a rise of water permeability and a substantial modification (coarsening) of the pore size distribution. This effect deals with the role as pore former of starch, which burns out when fired. More interestingly, it was experimentally observed that the effect of starch was particularly effective for starch percentages higher than 10wt% once a connected coarse pore network is developed. On the other hand, an increase in sintering temperature from 1100 to 1400°C also influenced membranes׳ characteristics but the effect was much less significant than that of starch content.A percolation analysis based on the Effective Medium Approximation (EMA) contact model allowed to conclude that the critical porosity calculated corresponds to a starch content of 10.2wt%, which agrees quite well with the estimation from experimental results. Finally, tortuosity was calculated with a simple model derived from the Hagen–Poiseuille equation. The obtained data showed that tortuosity factor decreased as the starch content or sintering temperature increased. These findings are consistent with SEM analysis and pore size determination.

Effect of sodium phosphate addition on mechanical properties of porous Sigue quartz sand

Porous ceramic separation membranes exhibit many excellent properties, such as a high structural durability, a good thermal stability, a long operational life, and an especially high chemical stability in the corrosive media. In order to prepare low-cost membranes, many researchers have used low-cost starting materials such as clay, dolomite, and kaolin. This work addresses the development of low-cost ceramic microfiltration membrane supports from inexpensive raw materials, such Sigue quartz sand (SQS) and sodium phosphate (SP), using a uniaxially dry compaction method. The prepared samples were sintered at different temperatures ranging between 900 and 1,400°C. The raw materials and the prepared samples were characterized using X-ray diffraction (XRD), optical microscopy, Hg-porosimetry, and tensile strength using a diametral compression test. Subsequently, the effect of sintering temperature and SP amounts on support proprieties, such as the shrinkage, the phase transformation, the porosity, and tensile strength, were also investigated. It was observed that with increasing sintering temperature, dimensions of sintered samples increased; this was due to the phase transformation. XRD confirmed that SQS was transformed into cristobalite phase when both the sintering temperature and the holding time were increased. The porosity and average pore size (APS) increased in all cases (2 and 3 wt% SP) in the range of temperatures between 1,100 and 1,400°C. For example, the porosity increased from 25.4 to 32.9%, and APS increases from 11 to 27μm in the case of 3 wt% SP. The flexural strength was found to be acceptable. The value varied from 16 to 20 MPa, which corresponds well with the relatively high porosity and APS.

Performance of Low Cost Ceramic Microfiltration Membranes for the Treatment of Oil-in-water Emulsions

Using the uniaxial compaction method, ceramic disk type microfiltration membranes were fabricated using mixtures of clays to yield membranes M1, M2, and M3. These were obtained with distinct compositions of raw materials at a sintering temperature of 900°C. Membrane characterization was conducted using thermogravimetric analysis (TGA), particle size distribution (PSD), X-ray diffraction (XRD), and scanning electron microscope analysis (SEM). Morphological characterization of these membranes includes the evaluation of average porosity, pore size, mechanical stability, chemical stability, and hydraulic permeance. With varying composition of the raw materials, it is observed that the average porosity and pore size of the membrane varied between 23–30% and 0.45 to 1.30 µm. For all membranes, the flexural strength varied within the range of 10-34 MPa. Chemical stability tests indicate that the membranes are stable in both acidic and basic media. The hydraulic permeance of M1, M2, and M3 membranes is about 3.97 × 10−6, 2.34 × 10−6, and 0.37 × 10−6 m3/m2 s kPa, respectively. Further, the performance of these membranes was studied for the microfiltration of synthetic oily wastewater emulsions. Amongst all membranes, membrane, M2 performance is satisfactory as it provides oil rejection of 96%, with high permeate flux of 0.65 × 10−4 m3/m2 s at a lower transmembrane pressure differential of 69 kPa for the oil concentration of 200 mg/L.

Effectiveness of Biosorption-Assisted Microfiltration Process for Treatment of Domestic Wastewater

ABSTRACT The efficiency of a biosorbent prepared from Eichhornia crassipes roots (ECR) was explored for the treatment of domestic sewage water in combination with low-cost ceramic microfiltration membrane. Batch sorption studies were conducted as a function of biosorbent dose, initial chemical oxygen demand (COD) loading, and temperature. Sorption equilibrium data of varying initial COD values (116–800 mg/L) indicated high potential of ECR for COD removal. Using 0.25 g/L of biosorbent dose, the equilibrium adsorption capacity was obtained as 2480 mg/g at 20°C for an initial COD loading of 800 mg/L. Microfiltration study was performed using ceramic membrane made from composition of α-alumina and clay. The effect of operating parameters on filtration characteristics was observed in terms of permeate flux. Permeate samples were characterized in terms of various parameters both for the direct filtration, as well as biosorbent-assisted filtration. The filtration behavior of wastewater at varying transmembrane pressure was explained using various membrane fouling models. The results suggested that microfiltration of domestic wastewater with incorporation of biosorbent (0.25 g/L) was highly effective for removal of organic load (>90%), turbidity (>99%), and total suspended solids (TSS) (93–95%) and the treated water quality was suitable for reuse in various purposes, such as gardening, floor and car washing, etc.

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.

Preparation and characterization of low-cost ceramic microfiltration membranes for the removal of chromate from aqueous solutions

Low-cost ceramic microfiltration membranes were prepared using clay of IIT Guwahati. Two membranes were prepared by paste casting followed by sintering at different temperatures, the first one from clay only (membrane A) and the second one from clay with small amounts of sodium carbonate, sodium metasilicate and boric acid (membrane B). Both the membranes were characterized by TGA, SEM, XRD, water permeability test and acid–base treatment. With the increase of sintering temperature, pore size as well as permeability and flexural strength were increasing while porosity and pore density were decreasing. The overall performance of membrane B was better than membrane A. The average pore size, porosity, pore density and flexural strength of membrane B sintered at 1000 °C were 4.58 μm, 0.42, 2.06 × 10 10 m − 2 and 11.55 MPa respectively. This membrane was used for the removal of chromate from aqueous solutions by micellar enhanced microfiltration (MEMF) using cetylpyridinium chloride (CPC). 100% rejection of chromate ions were obtained at a feed ratio (CPC/chromate) of 10. Based on raw material prices, the membrane cost was estimated to be $19/m 2. The prepared low-cost membrane showed good promise for the treatment of wastewater containing such heavy metals.