Papers by Keyword: Microfiltration

Abstract: In biodiesel industries, the removal of glycerol from biodiesel is very important in the downstream process of the biodiesel production since the presence of glycerol in biodiesel causes diesel engine problems. Glycerol is commonly separated from biodiesel by extraction method using water, however, this method results in a vast amount of wastewater and requires a high energy consumption. In this work, a ceramic microfiltration membrane made of α-alumina was applied to remove glycerol from biodiesel. The microfiltration experiment was carried out using biodiesel containing various glycerol concentrations as the feed. For all investigated glycerol concentrations from 1000 ppm until 10,000 ppm in the feed, the membrane showed an excellent separation performance with rejection values of 91 to 99%. The profile of the permeate flux against the permeation time showed a flux decline because of the fouling phenomenon during the crossflow microfiltration experiment, and stable permeate fluxes were obtained after 2 h of permeation time. The result of this work showed that the separation process using the microfiltration membrane is a promising method to purify biodiesel instead of the conventional water washing method.

Abstract: In this work, we investigated the applicability of polyethersulfone/polydopamine/copper (II) (PES/PDA/Cu²⁺) membrane composite in microfiltration. Pristine PES membrane was prepared via non-induced phase separation (NIPS), and the surface was modified by coating with PDA and deposition of Cu (II) to enhance its physical and antibacterial properties. The membrane was characterized using energy-dispersive X-ray spectroscopy, scanning electron microscopy and water contact angle measurement. The hydrophilic character of the PES membrane significantly increased and the mechanical properties were greatly improved. Results showed that the porosity of the membrane was affected by the concentration of the polymer in the casting solution, and the membrane was suitable for filtration application due to its open-cell structure. Pure water flux was enhanced upon surface modification implying that hydrophilicity has more influence on the flux than the shrinking of the pore size. The antibacterial assay suggested that the membranes possess antibacterial property.

Abstract: Innovative technologies are needed to attend the increasingly strict requirements for produced water treatment, since most of the separation processes are limited to particles larger than 10 μm. Separation processes using ceramic membranes are attracting great interest from academic and industrial community. Nevertheless, few studies, especially numerical, regarding the inorganic membrane’s application for the polluted water separation have been reported. In the present work, therefore, a study of fluid-flow dynamics for a laminar regime in porous tubes (tubular porous ceramic membrane) has been performed. The mass, momentum and mass transport conservation equations were solved with the aid of a structured mesh using ANSYS CFX commercial package. The velocity of local permeation was determined using the resistance in series model. The specific resistance of the polarized layer was obtained by Carman-Kozeny equation. The numerical results were evaluated and compared with the results available in the literature, where by a good agreement with each other was found. The numerical results, obtained by the proposed shell and tubular membrane separation module, indicate that there is facilitation of mass transfer and hence a reduction in the thickness of the polarized boundary layer occurs.

Abstract: In this work, polyamide 6 membranes (PA6) and hybrids with 1, 3 and 5% of montmorillonite clay (MMT) were obtained, adding potassium chloride (KCl) and calcium chloride (CaCl₂). These different additives are intended to promote formation and increase of the pores in the microporous membranes. The membranes in the form of thin films were prepared by the phase inversion technique, leading to flat selective barriers. The MMT clay was characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The membranes were characterized by XRD, FTIR, scanning electron microscopy (SEM), contact angle, water vapor permeation, flow measurements and yield. The clay XRD results showed characteristic peaks of bentonite containing accessory materials, as well as a peak at 5.93°, indicating the d₀₀₁ basal interplanar distance of 14.95 Å of MMT. In the spectrum in the infrared region of the clay, it was observed the presence of hydroxyls inherent to the adsorbed water, as well as characteristic bands of Si-O-Si bonds and the octahedral layer of MMT. The viscosities of the solutions of PA6 and their hybrids with CaCl₂ were higher compared to solutions containing KCl due the CaCl₂ possess a bivalent ion with a high degree of hydration and a molecular mass higher than KCl. In addition, these salts promote formation of hydroxides that precipitate the particles of MMT, decreasing the viscosities with the increasing percentage of clay. By means of the X-ray diffraction, it was possible to perceive that the hybrid membranes with the inorganic salts suggest an exfoliated and/or partially exfoliated structure. From the results of the FTIR analysis the bands obtained in the PA6 membranes and its hybrids remained practically unchanged, as there was an increase in the clay content and the introduction of the inorganic salts. From the photomicrographs obtained by SEM, it was observed that the addition of clay in the hybrid membranes provided an increase in the number of pores with the gradual increase of the percentage of clay. While the addition of the inorganic salts (KCl and CaCl₂) provided an increase in the pore size of the top surfaces of all membranes, by means of the contact angle, it was verified that the hybrid membranes presented smaller angles when compared to the PA6, probably, due to the superficial peculiarity of the clay to react with water. PA6 membranes with KCl and CaCl₂ showed lower water vapor permeations as compared to hybrid membranes due to the increase in the size and quantity of pores presented on their top surfaces. The distilled water flow in the membranes initially showed a decrease and after 30 minutes a stability of the permeate flow due to a compression occurred in the membranes. The water-oil separation tests of the membranes with CaCl₂, regardless of the pressure used, indicated a significant reduction of permeate oil with promising yields above 87% , presenting potential for the treatment of wastewater contaminated by oil.

Abstract: Industrial wastewater treatment and reuse is one of the principal tasks of present. For this purpose several physical, chemical and combined methods have been used. This paper deals with the study of sorption behaviour of natural zeolite with respect to Zn (II) and Cu (II) followed by cross-flow membrane microfiltration. The experiments realised were aimed at verification of effectiveness of ion exchange of selected metals from wastewater using zeolite – with main component clinoptilolite. The experimental data obtained were fitted using Langmuir and Freundlich isotherms. The sorption capacity was studied for zinc and copper uptake, followed by a study of microfiltration of zeolite suspension using a cross-flow microfiltration device with tubular ceramic membrane. According to experimental results the basic parameters of microfiltration process were evaluated. In comparison with other processes, the hybrid membrane microfiltration offers more effective way of water treatment.

Abstract: Uniformly-sized cylindrical pores on polycarbonate thin membranes were prepared using the nuclear fission reaction (nf) and chemical etching methods. A triuranium octoxide (U₃O₈)-coated plate was attached to commercial polycarbonate sheets before being bombarded with thermal neutrons (flux of 8.9 × 10⁹ n cm^-2 s^-1) from the thermal column of Thai Research Reactor-1/Modification-1 (TRR-1/M1) for 15 min. The paths of nuclear fission products were collimated to perpendicularly impact the membrane surface by an interlaid 5-mm-thick particle screener. The latent tracked membrane was then chemically etched with 6 N NaOH at 60°C for 60 min. The monodisperse porous membrane obtained has average pore density 1.04 x 10⁶ pore/cm² with average pore diameter 1.68 μm as determined by scanning electron microscope (SEM). The mechanical and physical properties such as fluid (water and air) flow rates were analyzed. The prepared membrane was demonstrated to be able to retain different sizes and types of particles.

Abstract: Aqueous technological liquids are widely used in industrial processes. However, due to limited resources, there is an increasing pressure on their protection and reduction of water consumption by, for example, closing water circulation. It is facilitated by the development of membrane technology. The article describes a method for regenerating aqueous technological liquids used in metal surface treatment processes and cleaning a production plant. This process was conducted in batch system using a mobile microfiltration installation. The working unit was equipped with tubular ceramic membranes having a nominal pore diameter of 0.2 μm, working in a cross-flow regime. The main advantage of the apparatus is its low weight and high mobility. The installation and method of regeneration were verified during the processing of a model alkaline liquid used for cleaning a plant in the dairy industry. It was found that microfiltration can be used to remove technological impurities (coagulated proteins and fats) from the liquid. The physicochemical properties of the liquid, including alkalinity, remained stable after repeated filtration. This indicates that the purified liquid can circulate in the system and be used in accordance with its original purpose. The proposed solution enables the reduction of water consumption and chemicals used for the preparation of these liquids.

Abstract: A isoporous brominated poly (phenylene oxide) (BPPO) microfiltration membrane system, fabricated by figure breath method, was demonstrated for the effective removal of impurity from contaminated water. The water permeation flux of BPPO membrane is higher. Such ordered isoporous membranes can also be applied in other size-based separation systems, enabling new opportunities in bioseparation and biosensors.

Abstract: Lake water is used as the raw water. The water carries the following characteristics: high organic content in individual sessions, high-algae and odor in summer. At present, the conventional treatment process is unable to cope with. The application of microfiltration system in the pilot test is studied. Filter effluent and air flotation effluent are used as the microfiltration influent. Membrane flux are 80L/m²/h, 90L/m²/h, 100L/m²/h.Water quality is stable. The average turbidity is 0.1NTU. Total coliform and total bacteria in effluent are not detected. The recovery of water is greater than 96.1%.Potassium permanganate preoxidation + powder carbon dosing + conventional treatment + microfiltration membrane system can effectively solve organics, high algae and odor problems. It also can improve the coping capacity to respond mutation of the water quality.

Abstract: The influence of transmembrane pressure on the permeate flux, and the critical and limiting fluxes in microfiltration of two sorbents Bentonite a natural sorbent, montmorillonite based clay and Lewatit S1468 a synthetic sorbent, styrene-divinylbenzene based copolymer were studied. An asymmetric single-channel inorganic ceramic membrane based on α-Al₂O₃ was used. The experimental data were obtained by continuous microfiltration equipment. According to the results the limiting flux ranged from 37 to 70 l.m^-2.h^-1 for Bentonite suspensions. It was not possible to estimate the limiting flux for Lewatit S1468 suspension.