Tami Industries Research Articles

The influence of pH and BSA on the retention of selected heavy metals in the nanofiltration process using ceramic membrane

Abstract One of the alternative wastewater treatment methods aimed at the elimination of heavy metals is membrane separation supported by the use of metal-complexing polymers. Many sectors of industry generate wastewater containing both heavy metals and protein substances which show complex-forming properties. In this study, a 450 Da molecular weight cut-off nanofiltration ceramic membrane (TAMI Industries, France) was tested to evaluate the retention of Zn, Cd, Pb, Cu and Fe complexed with bovine serum albumin (BSA). Retention levels were tested in water solutions solely for the metals and for the metals with the addition of BSA, depending on the pH of the solutions (from 2.0 to 9.0). It was noted that the retention tended to increase as the pH increased. For solutions composed with only metals, retentions exceeding 80% were noted for pH > 6.9. The addition of a complexing agent resulted in high retentions of Cu, Cd and Zn already at pH = 2.0. Maximum retentions for Zn, Cd, Pb, Cu and Fe were noted for solutions containing the mixture of metals and BSA at pH = 6.0 (97, 96, 90, 95 and 71%, respectively) and at pH = 9.0 (93, 99, 93, 99 and 85%, respectively). The studies confirmed the high metal-complexing capacity of BSA and indicated that heavy metals might be effectively removed from wastewater containing protein in the process of membrane separation using a ceramic membrane.

Cheese whey treated by membrane separation as a valuable ingredient for barley sourdough preparation

Abstract Utilisation of cheese whey for production of healthier food has been the main task of this study. Cheese whey, which is often considered as a waste material, was treated by a series of processes including fermentation, membrane filtrations, mixing with barley flour, drying, and/or extrusion to produce barley sourdough. In the first series of experiments, the effect of membrane ultrafiltration (UF) and nanofiltration (NF) on separation of whey components has been studied. Non-fermented sweet cheese whey was treated by pilot-plant membrane ultrafiltration (50 kDa tubular ceramic membrane, TAMI Industries, France), followed by three step diafiltration to minimise losses of lactose, glucose, galactose, and organic acids (namely lactic acid) in retentate. The UF permeates were used for the subsequent nanofiltration and diafiltrations (spiral wound membrane NF 270-2540, Filmtec, Dow Chemicals, USA). The results showed high recovery of proteins (81%) during UF and reduction of lactose and propionate losses by using diafiltration. Rejections of components on the NF membrane were: 93% lactose, 77% galactose, and 76% lactic acid. However, the diafiltration on the NF membrane reduced the relative recovery both for carbohydrates and organic acids. In the second series of experiments, cheese whey was concentrated by reverse osmosis (RO) and the obtained retentate was fermented with Lactobacillus plantarum , Lactobacillus sanfranciscensis and Propionibacterium freudenreichii subsp . freudenreichii. Part of the fermented whey was mixed with barley flour and dried by cold air fluid drying to produce sourdough pellets. The other part of fermented whey was filtered by nanofiltration and both permeate and retentate were sprayed on the surface of sourdough pellets in several layers and dried again. The extrusion of a mixture containing barley flour and fermented whey was tested for pellet production as well. The main aims were to obtain sourdough rich in natural preservatives, and maintain the present microorganisms active. That is why all the technological processes, including drying, were carried out under low temperatures. The content of organic acids (lactic, acetic and propionic) was analysed in final sourdough samples.

Ceramic membrane behaviour in anionic dye removal by ultrafiltration

®(Tami Industries) of various cut-off values (15 and 150 kDa). The ultrafi ltration (UF) experiments were performed at a transmembrane pressure of 0.2 MPa with the use of cross-fl ow system J.A.M INOX PRODUKT. Comparable studies including the effect of hydraulic conditions existing in the system on membrane performance were reported. Transport and separation properties of the membranes towards dye solutions were investigated at varied linear velocity in the modules (1.5; 2.9; 4.4; 5.9, and 6.9 m/s). Seven anionic organic dyes (Methyl Orange, Indigo Carmine, Amido Black, Titan Yellow, Direct Blue, Direct Green, and Direct Black) of molecular weight ranging from 327 to 1084 Da were used in the tests. The UF tests were carried out with dye solutions and dye solutions containing mineral salt (NaCl). The results showed that increasing the linear velocity generally improved the membrane permeability, whereas dye selectivity was strongly affected by the molecular weight of the dye tested and the membrane cut-off. Nevertheless, the ceramic membranes yielded an 85–99% retention of the high-molecular-weight dyes (above 600 Da) irrespective of the hydraulic conditions in the module, membrane cut-off and dye solution composition.

Seawater Desalination Using Modified Ceramic Membranes

Nanofiltration has many applications such as pretreatment and partial demineralization in seawater desalination processes. This paper studies the performance of commercial ceramic membranes, modified by depositing either platinum or silver, to reject salts of seawater. The membrane used is multilayer structured with a titania layer (5 kD MWCO) manufactured by TAMI Industries (Nyons, France) and anionic impregnation was used to depose platinum or silver onto the membrane. The effect of salts rejection of membranes was investigated using seawater from the Mexican Pacific coast. The tests were carried out at pressure of 6 bar and the experimental results showed that modified membranes could achieve a salt rejection close to 30% in total dissolved solids (TDS) whereas the rejection in nonmodified membranes was less than 5%. Anion and cation rejection was also determined, with higher values obtained for cation removal.

Application of ceramic membranes for the separation of dye particles

Abstract This study reports the results of ultrafiltration experiments on model dye solutions containing anionic dyes and anionic surfactant. The ceramic membrane modules CeramINSIDE (TAMI Industries) of various cut-off values (1, 5, 8, 15, and 30 kDa) were used in the experiments. The suitability of ceramic membranes for the decolourization of dye solutions was evaluated. Seven anionic organic dyes of molecular weights ranging from 327 to 1084 Da were used in the tests. The anionic surface active agent (sodium dodecyl sulphate, SDS) was added to the dye solutions. The experiments were conducted at 0.03–0.1 MPa with the use of a laboratory and semi-pilot UF installation. The effect of the molecular weight of the dyes as well as the SDS presence in the separated solutions (in the range below the CMC) on the process efficiency was studied. It was found that membrane properties (permeability and dye separation factor) were almost identical for membrane modules of cut-off equal to 1, 5, and 8 kDa. For high-molecular-weight dyes above 600 Da retention amounted to 95–98% and was slightly influenced by the SDS presence in the dye solution. Ceramic membranes with a cut-off of 15 and 30 kDa exhibited insignificantly poorer properties.

Analysis and optimization of the influence of operating conditions in the ultrafiltration of macromolecules using a response surface methodological approach

In this work, the ultrafiltration of macromolecules was analysed using a response surface methodological approach. The behaviour of two different inorganic membranes was investigated. The membranes selected were a Carbosep M2 membrane (Orelis, France) with a molecular weight cut-off (MWCO) of 15 kDa and a Tami MSKT membrane (Tami Industries, France) with a MWCO of 5 kDa. The solute employed was polyethylene glycol of 35 kDa molecular weight. The influence of transmembrane pressure (0.1, 0.2, 0.3, 0.4 and 0.5 MPa), crossflow velocity (1, 2 and 3 m/s) and feed concentration (5, 10 and 15 g/L) on permeate flux and permeate flux decline was investigated. Analysis of variance was proved to be a useful tool to determine the effect of operating variables on both parameters. The method used demonstrated the presence of coupled effects between factors as well as squared effects that are relevant to the ultrafiltration process. The surface contours obtained from fitted models were used for the optimization of the operating conditions. The goal was to simultaneously maximize the average permeate flux and minimize the flux decline. The optimal operating conditions for the Carbosep M2 membrane were a transmembrane pressure of 0.38 MPa and a crossflow velocity of 3 m/s. The optimal operating conditions for the Tami MSKT membrane could not be determined by means of multiple response optimization due to the low accuracy of the regression model obtained for the cumulative permeate flux decline (SFD) response variable.

An approach to theoretical prediction of permeate flux decline in ultrafiltration

Permeate flux decline was predicted by means of Song and Elimelech's [1] model. Theoretical results were compared with those obtained in ultrafiltration experiments where TMP and crossflow velocity were varied. Polyethylene glycol (PEG) of 35000 Da was used in the feed solution in a concentration of 10 g/L. The experiments were performed with monotubular ultrafiltration ceramic (Al2O3-TiO2) membranes of 5 kDa (Tami Industries, France). The model predicted a reduction in the influence of transmembrane pressure (TMP) on permeate flux as TMP increased. This was consistent with the experimental results for the lowest crossflow velocity tested (1 m/s). For higher crossflow velocities the reduction in the influence of TMP on permeate flux as TMP increased was higher than that predicted by the model. Model predictions were better for low crossflow velocities, as expected with a model that considers cake formation as the main fouling mechanism. Rapid initial pore blocking may be the main cause of the discrepancie...

Ultrafiltration permeate flux decline prediction for gel layer forming solutes using monotubular ceramic membranes

Abstract Experimental results on permeate flux decline with time obtained from ultrafiltration tests were compared with those predicted by means of Song and Elimelech's model. Feed solutions consisted of aqueous solutions containing 15 g/L of polyethylene glycol 35 kg/mol. All model parameters were theoretically estimated, except the gel layer concentration that was estimated as described by Lee et al. Experimental tests were performed with monotubular ceramic Tami MSKT membranes from Tami Industries (France). TMP (0.2, 0.3, 0.4 and 0.5 MPa) and crossflow velocity (1, 2 and 3 m/s) were varied. Permeate flux slightly decreased with time for all the experimental conditions tested. The best predictions were obtained for long time scales for a crossflow velocity of 1 m/s. For those experimental conditions the probability of gel layer formation on the membrane surface is the highest. For short time scales, model predictions showed a rapid initial permeate flux decline that was not experimentally observed because it may occur instantly before the first permeate was collected.

Role of electrolyte type on TiO 2–ZrO 2 nanofiltration membranes performances

Separation efficiency of ceramic NF membranes manufactured by Tami Industries (Nyons, France) is investigated for the separation of aqueous solutions containing strong inorganic electrolytes. The membrane used is multi-layer structured with a mixed titania and zirconia selective layer (1000 Da MWCO) supported on α-Al2O3, TiO2 and ZrO2. Experimentation was performed testing the membrane with binary aqueous solutions containing NaCl, Na2SO4 or CaCl2 in a wide range of compositions, at two pH values kept in the feed side, at various recirculation rates. pH and electrolyte concentration effects were studied both on salt rejection and on total flux. Total transmembrane flux was measured as a function of time until steady conditions were approached. No sensible time effect was observed in the salt rejection. The effect of the electrolyte type and the role of concentration polarisation on membrane permeability were investigated. Although the role of concentration polarisation phenomena in the feed side is not negligible for all the cases investigated, the role of the electrolyte type is dominant in determining a flux decline as a function of time. The membrane requires a long-time stabilisation to the electrolyte solution (40–60 h), which leads to a decrease of the membrane permeability with respect to the values measured with pure water and washed membrane. The reduction of membrane permeability is essentially related to specific interactions between dissolved ions and the amphoteric membrane material. It mainly depends on pH conditions: at alkaline pH, salts with common cation (NaCl and Na2SO4) approach similar asymptotic values, whereas CaCl2 solutions give lower permeabilities; on the contrary, at acidic pH all the salts investigated approach the same asymptotic values.

Permeate flux decline prediction in the ultrafiltration of macromolecules with empirical estimation of the gel layer concentration

Abstract Permeate flux decline with time was estimated by means of a model [1] that considers gel layer formation as the main fouling mechanism. Several experiments were performed with two different membranes. Both of them were monotubular ceramic membranes. One of them was made of ZrO 2 –TiO 2 with a molecular weight cut off (MWCO) of 15 kDa (Orelis, France) and the other was made of Al 2 O 3 –TiO 2 with a MWCO of 5 kDa (Tami Industries, France). The feed was an aqueous solution of polyethylene glycol with a molecular weight of 35 kDa. All the experiments were carried out at the crossflow velocity of 1 m/s, when the cake layer is more likely to form. Transmembrane pressure (TMP) was varied between 0.1 and 0.5 MPa and the feed concentration was in the range of 5–15 g/L. The experimental results and those predicted by the model were compared for the experimental conditions tested. Model predictions were better for the Orelis membrane than in the case of the Tami Industries membrane under the same experimental conditions.

Recovery of iron (III) from aqueous streams by ultrafiltration

Biological wastewater treatment plants (BWWTP) are widely used to treat effluents from chemical process industry. However, there exist refractory substances, such as phenolic compounds, which require previous treatments. Advanced oxidation processes (AOP) are thoroughly being studied as pre-treatment to deal with such phenolic compounds before a BWWTP. Metal salts are widely used as homogeneous catalysts in AOP because they present higher activity than those heterogeneous. Unfortunately, to prevent subsequent environmental damage, they have to be recovered (and/or recycled) from the reactor effluent, which increases the treatment cost. Iron is often added as effective catalyst in the abovementioned AOP. In this study, a 5 kDa molecular weight cut-off (MWCO) ultrafiltration ceramic membrane (TAMI Industries, France) is tested to directly retain iron species from water. The influence of transmembrane pressure, solution pH, iron concentration and iron valence (Fe 2+ and Fe 3+ ) over iron retention at room temperature is investigated. The results indicate that there is a strong connection between iron speciation and recovery efficiency. When soluble charged iron hydroxide species are present in solution, high retention is attained, up to 99.9%. Thus, the retention mechanism involved could be the interaction between these metal hydroxides in solution and the membrane surface, forming a dynamic membrane.

Influence of feed concentration on the accuracy of permeate flux decline prediction in ultrafiltration

Abstract A theoretical model was used for permeate flux decline prediction. Ultrafiltration experiments were performed varying TMP and feed concentration. The feed solution consisted of an aqueous solution of polyethylene glycol with a molecular weight of 35,000 Da. Monotubular Al 2 O 3 –TiO 2 ceramic membranes with a molecular weight cut off (MWCO) of 5 kDa (Tami Industries, France) were used in the experiments. Experimental data and model predictions were compared. The influence of feed concentration in the accuracy of permeate flux decline prediction was studied. The model predicted very accurately the reduction in the influence of transmembrane pressure (TMP) on permeate flux as the feed concentration increased. The best predictions were obtained for the highest feed concentration tested. For this feed concentration the influence of TMP on experimental and predicted permeate flux was very low.

Enzymatic cleaning of inorganic ultrafiltration membranes used for whey protein fractionation

The aim of this work was to study the cleaning of inorganic membranes fouled by whey protein solutions using proteolytic enzymes. Tami® 150+4T membranes (Tami Industries, S.A., 26110 Nyons, France) of 400 kg/mol molecular weight cut-off (MWCO) and a ZrO2 filtering layer were selected to carry out the tests and Maxatase® XL (Genencor International, 2333 CN Leiden, The Netherlands) and P3-Ultrasil® 62 (Henkel Ibérica, S.A., 08025 Barcelona, Spain) were investigated as cleaning agents. Cleaning efficiency was observed to be a function of the operating conditions. The operating conditions studied were the pH of the cleaning solution, the enzymatic agent concentration and cleaning time. Very high cleaning efficiencies (close to 100%) were achieved in short operating times (20 min). The proteolytic enzymes were observed to adsorb onto the inorganic membrane used. However, enzyme-cleaned membranes gave better results than chemically-cleaned ones when used for whey protein fractionation: higher permeate flux was obtained, while selectivity remained practically the same. No peptides were detected in the retentate and permeate streams resulting from hydrolysis of proteins by the adsorbed enzyme. The possibility of reusing the enzyme solutions for consecutive cleaning steps was also studied. A 30% loss in activity was observed during each cleaning cycle, irrespective of the initial activity of the solution.

Flat ceramic membranes for the treatment of dairy products: comparison with tubular ceramic membranes

TAMI Industries has developed and commercialized since 1996 a new range of original ceramic membranes with a plane geometry. This type of membrane associates the interest of the weak hydraulic diameters to important values of thermal, mechanical and chemical resistance of ceramics. Shaped in a cassette form with open channels, these new membranes showed their efficiency in the environmental market. The purpose of this paper is to describe the standardization of milk proteins and the whey concentration studied to test these new products in the dairy industry. The result is expressed under the form of classic curves of the permeate flux in function of the VCF. These curves were established for velocities of 0.5 m.s -1 , 1 m.s -1 and 2.5 m.s -1 and showed performances in the order magnitude of other types of membranes. By comparing with tubular products of TAMI industries, and on the basis of an industrial example (10 m 3 .h -1 of milk to process), two differences appeared: - on one hand, energy consumption by m 3 of permeate product were respectively for the plane geometry and the tubular geometry of 6 kW.m -3 and 9.4 kW.m -3 ; - on the other hand the cost of the system was 12 to 14 kF.m -2 for the tubular geometry and 8 to 10 kF.m -2 for the plane geometry. These differences were the consequence of the reduction of the hydraulic diameter. If one takes into account the shear constraint on the wall and the circulation speed as important parameters for the crossflow filtration, one observes that the diminution of the hydraulic diameter allows: -at constant velocity, to increase the shear constraint and to reduce energy. - at constant shear constraint, to reduce both the circulation speed and energy. In this case, membrane performances were identical and the equipment pricing became cheaper by reduction of the engineering costs. These comparisons were established between tubes and cassettes with opened channels and showed the interest to reduce the hydraulic membrane diameter what can simply be done by using the plane geometry. The particular case of a spacer, as a mean to reduce the hydraulic diameter, was not considered because of the complexity of the flow. Choosing open channels ceramic membrane plates allowed a global reduction of investment and functioning costs while keeping the interest of ceramics.

Porosity measurements by a gas penetration method and other techniques applied to membrane characterization

In this paper several methods that can be used to determine membrane porosities are studied. Apparent densities, water pycnometry, Hg porosimetry and the gas penetration technique can be considered direct methods since no specific pore geometry needs to be assumed, whereas computerized analysis of scanning electron microscopy images and air–liquid displacement techniques are indirect methods since pores are usually assumed to have a specific shape. Both direct and indirect methods for polymeric and very regular inorganic membranes, Cyclopore and Anopore filters respectively, are compared. Other porous films with more complex structures such as asymmetric or composite membranes are also analysed, namely polymeric ultrafiltration membranes made by Gelman and Desalination, and inorganic filters made by Tami industries. As a consequence of a detailed comparison of the porosities obtained, we conclude that the gas penetration volumetry is preferable when we aim to obtain the actual void volume fraction. This method is highly reproducible and gives precise results which allow us to detect very small pores without any interaction with the structure due to the inertness of He and the low pressures applied.