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1
khan, Nida tabassum. "Nanofiltration-Concept and Prospects". Pharmaceutics and Pharmacology Research 4, n. 4 (3 dicembre 2021): 01–04. http://dx.doi.org/10.31579/2693-7247/047.
Testo completoAbstract (sommario):
Nanofiltration is a pressure-driven film measure for fluid stage detachments. It is employed in numerous applications due to lower energy utilization and higher motion rates. The properties of nanofiltration membranes lie between those of non-permeable reverse osmosis layers and permeable ultrafiltration layers where partition is typically thought to be because of size rejection and, sometimes, charge impacts. The improvement of nanofiltration development as a practical association over continuous years has provoked a pivotal extension in its application in different endeavours, for instance, treatment of blurring effluents from the material industries, division of medications from development stocks, demineralization in the dairy business, and metal recovery from wastewater and disease clearing
2
Ramli, Mohd Redzuan, Nik Meriam Nik Sulaiman, Mustafa Ali Mohd e Mohamad Fairus Rabuni. "Performance of chlorination process during nanofiltration of sulfonamide antibiotic". Water Science and Technology 72, n. 9 (20 luglio 2015): 1611–20. http://dx.doi.org/10.2166/wst.2015.367.
Testo completoAbstract (sommario):
The effectiveness of combined nanofiltration and disinfection processes was studied by comparing the pre-disinfection and post-disinfection when in combination with nanofiltration. Four types of sulfonamide (sulfanilamide, sulfadiazine, sulfamethoxazole, and sulfadimethoxine) were chosen as substrates, with sodium hypochlorite as a disinfectant. A laboratory-scale nanofiltration system was used to conduct the following sets of experiment: (1) a pre-chlorination system, where the free active chlorine (FAC) was added to the membrane influent; and (2), a post-chlorination system, where the FAC was added to the membrane effluent. Overall, the pre-disinfection nanofiltration system showed higher sulfonamide removal efficiency compared to the post-chlorination nanofiltration system (>99.5% versus >89.5%). In the case of limited FAC ([FAC]0: [sulfonamide]0 ≤ 1), the removal efficiency for the post-chlorination nanofiltration system was higher, due to the prior nanofiltration process that could remove 12.5% to 80% of sulfonamide. The flux of the treated feed system was considerably higher than in the untreated feed system; however, the membrane was observed to be slightly damaged due to residual chlorine attack.
3
Liu, Xi, e Wei Wang. "The Application of Nanofiltration Technology in Recovery of Ionic Liquids from Spinning Wastewater". Applied Mechanics and Materials 178-181 (maggio 2012): 499–502. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.499.
Testo completoAbstract (sommario):
In this paper, the effects of the concentration, temperature, and run-time of ionic liquids solution, on the rejection capacity of home-made hollow fiber composite nanofiltration membrane were studied. Then the nanofiltration membrane was used to the recover ionic liquids by concentrating spinning wastewater. The results shows that: The rejection rate of the composite nanofiltration membranes and its water fluxes lightly down with the concentration of ionic liquids increase; with running-time and temperature of ionic liquid solution increase, the rejection rate of the composite nanofiltration membranes decreases, but its water flux increases; the nanofiltration membrane can be use for recovering ionic liquid from the spinning wastewater and get very good recovery effects.
4
Liikanen, R., H. Kiuru, T. Tuhkanen e M. Nyström. "Nanofiltration membrane fouling by conventionally treated surface water". Water Supply 3, n. 5-6 (1 dicembre 2003): 183–90. http://dx.doi.org/10.2166/ws.2003.0165.
Testo completoAbstract (sommario):
Nanofiltration is a very effective technique for improving the removal of trace organics after a conventional chemical water treatment train. However, the fouling of the membranes decreases the applicability of the process, and thus, an understanding and control of membrane fouling are crucial for a more widespread use of nanofiltration in water treatment. The fouling of different nanofiltration membranes by pre-treated surface waters was investigated in a laboratory-scale filtration unit in this study. The results indicate that the traditional chemical treatment does not remove membrane foulants from the surface water. No correlation was found between the feed water constituents and nanofiltration performance, but most feed water components are expected to interact in membrane fouling. Actually, the performance of the nanofiltration process was more related to membrane than to feed water characteristics.
5
Weng, Rengui, Guohong Chen, Xin He, Jie Qin, Shuo Dong, Junjiang Bai, Shaojie Li e Shikang Zhao. "The Performance of Cellulose Composite Membranes and Their Application in Drinking Water Treatment". Polymers 16, n. 2 (20 gennaio 2024): 285. http://dx.doi.org/10.3390/polym16020285.
Testo completoAbstract (sommario):
Water scarcity and water pollution have become increasingly severe, and therefore, the purification of water resources has recently garnered increasing attention. Given its position as a major water resource, the efficient purification of drinking water is of crucial importance. In this study, we adopted a phase transition method to prepare ZrO2/BCM (bamboo cellulose membranes), after which we developed IP-ZrO2/BC-NFM (bamboo cellulose nanofiltration membranes) through interfacial polymerization using piperazine (PIP) and tricarbonyl chloride (TMC). Subsequently, we integrated these two membranes to create a combined “ultrafiltration + nanofiltration” membrane process for the treatment of drinking water. The membrane combination process was conducted at 25 °C, with ultrafiltration at 0.1 MPa and nanofiltration at 0.5 MPa. This membrane combination, featuring “ultrafiltration + nanofiltration,” had a significant impact on reducing turbidity, consistently maintaining the post-filtration turbidity of drinking water at or below 0.1 NTU. Furthermore, the removal rates for CODMN and ammonia nitrogen reached 75% and 88.6%, respectively, aligning with the standards for high-quality drinking water. In a continuous 3 h experiment, the nanofiltration unit exhibited consistent retention rates for Na2SO4 and bovine serum protein (BSA), with variations of less than 5%, indicating exceptional separation performance. After 9 h of operation, the water flux of the nanofiltration unit began to stabilize, with a decrease rate of approximately 25%, demonstrating that the “ultrafiltration + nanofiltration” membrane combination can maintain consistent performance during extended use. In conclusion, the “ultrafiltration + nanofiltration” membrane combination exhibited remarkable performance in the treatment of drinking water, offering a viable solution to address issues related to water scarcity and water pollution.
6
Khramtsov, A. G., e V. N. Sergeev. "Technological breakthrough of the agrarian-and-food innovations in dairy case for example of universal agricultural raw materials. Nanofiltration". Agrarian-And-Food Innovations 12 (25 dicembre 2020): 7–19. http://dx.doi.org/10.31208/2618-7353-2020-12-7-19.
Testo completoAbstract (sommario):
Aim. Consideration nanofiltration as a process of membrane technology – directed and controlled filtration of whey through special semipermeable partitions (membrane filters) with a pore size of 1-5 nm, carried out at a pressure of 0.7-4.0 MPa with the release of particles with a molecular weight of 0.5-1.0 kDa. Discussion. Nanofiltration allows you to separate the whey as a system by the size of the components – microparticles and macromolecules. In this case, from pre – separated, processed by microfiltration and ultrafiltration of whey to nanoconcentrate (retentate) pass almost all the compounds of whey, and in nanofiltrate (permeate) - only monovalent ions of mineral salts and partially some organic acids. Nanofiltration, in the logistics of molecular sieve separation of whey, takes over from ultrafiltration and is a harbinger of reverse osmosis. The theoretical foundations of the nanofiltration process are developed at a fairly good level. The basic element of the process is the membranes. Based on the conducted research, we can recommend the nanofiltration process for industrial processing of salted whey into milk sugar (lactose) and for concentrating whey and its ultrafiltrates before electrodialysis or ion exchange desalination. Nanofiltration is already widely used in the production of high-quality lactose (milk sugar). Considerable interest nanofiltration cottage cheese (acid) whey with the purpose of concentration, demineralization and sensory nanoconcrete for the enrichment of ice cream. Conclusion. Nanofiltration can be quite reasonably used for processing, within the framework of the Technological Breakthrough, universal agricultural raw materials – for example, whey and its ultrafiltrates – for the purpose of concentration, directed demineralization, lowering the level of organic acids and controlling sensorics. The resulting nanoconcentrate (retentate) can be used to scale functional products.
7
Inouye, Masaharu, e Thierry Burnouf. "The Role of Nanofiltration in the Pathogen Safety of Biologicals: An Update". Current Nanoscience 16, n. 3 (2 aprile 2020): 413–24. http://dx.doi.org/10.2174/1573413715666190328223130.
Testo completoAbstract (sommario):
Nanofiltration technology to remove possible pathogenic viruses during biopharmaceutical manufacturing was introduced in the biopharmaceutical industry in 1989. The very first industrial implementation took place in the early 1990s, through commercial manufacturing processes of plasma- derived medical products. Then it was applied to recombinant protein medical products, including monoclonal antibodies. In the first review published in 2005 in this journal, the technology was already considered promising and was much welcomed by the industry, but it was still a relatively emerging technology at that time, and many questions were raised about its robustness as a reliable virus-removal tool. We conducted a review to update the published information (SCI journals and suppliers’ documentation) existing on the use of nanofiltration as an industrial process for removing viruses from various biologicals. After almost a decade from the previous review, nanofiltration has established itself as a routine production step in most biopharmaceutical manufacturing. It has become one of the essential manufacturing processes used to assure safety against viral contamination. The technology is applied to manufacturing processes of various biologicals (human plasma products and complex recombinant proteins, such as coagulation factors and monoclonal antibodies made from mammalian cells). Many biologicals that undergo nanofiltration are licensed by regulatory authorities, which illustrates that nanofiltration is recognized as a robust and safe virus-removal method. No adverse events related to the use of nanofiltration have been recorded. New trends in nanofiltration technology continue to appear. As was identified during its introduction to the market and predicted in the previous review, nanofiltration has achieved major technical breakthroughs for ensuring the safety of biologicals, particularly human plasma-derived products, against viruses.
8
Chang, F. F., e W. J. Liu. "Arsenate removal using a combination treatment of precipitation and nanofiltration". Water Science and Technology 65, n. 2 (1 gennaio 2012): 296–302. http://dx.doi.org/10.2166/wst.2012.833.
Testo completoAbstract (sommario):
A combination treatment of Ca-precipitation and nanofiltration membrane was studied to remove arsenate from water. The selected nanofiltration membrane was an amphoteric charged membrane, proved by the results of ATR-FTIR spectra and zeta potential. The arsenate and calcium removal efficiencies had the lowest values at the isoelectric point of the nanofiltration membrane, attributed to the loosest steric hindrance and the weakest electrostatic repulsion. Above the isoelectric point, arsenate precipitated with calcium ion to form the low solubility compound calcium arsenate, while steric hindrance was the main mechanism of arsenate removal. In contrast, below the isoelectric point, the nanofiltration membrane with positive charges rejected calcium ion by electrostatic repulsion. The high electrostatic shielding of calcium ion prevented arsenate from coming close to the NF membrane. Either high feed arsenate concentration or high calcium oxide dose improved the removal amount of arsenate during the nanofiltration membrane separation process. In addition, the arsenate removal efficiency approached the highest value at 200 μg/L of feed arsenate concentration. The optimal transmembrane pressure was in a range of 0.5–0.7 MPa to restrict the formation of fouling cake on the nanofiltration membrane surface.
9
Wang, Xin Miao, e Hai Yan Yang. "The Nanofiltration Technology of Metoprolol in the Water Environment". Advanced Materials Research 955-959 (giugno 2014): 1013–19. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.1013.
Testo completoAbstract (sommario):
Metoprolol (MET) is a common kind of Pharmaceuticals and personal care products (PPCPs), which belongs to a new type of organic micropollutants. And conventional water and wastewater treatment technology cannot remove the MET effectively, so it is necessary to adopt nanofiltration technology for advanced treatment. The influence factors on removal of Metoprolol (MET) in water by nanofiltration are mainly investigated in the study. According to the results, the removal rate of MET by nanofiltration all can reach more than 99% with the initial concentration increasing. Then the removal rate of MET by nanofiltration at different pressure values, pH, salt ionic strength conditions are also studied. The results have shown that the removal rate is increasing from 90.0% to about 99.0% while pressure goes up. When pH=5, the removal rate of MET by nanofiltration is slightly increasing. And the removal rate is decreasing from more than 98.0% to more than 92.0% with salt ionic strength increasing.
10
Liu, Qian Ying, Jun Rui Wu, Yi Ming Liu e Ri Na Wu. "The Desalination Effect Comparison of Two Kinds of Nanofiltration Membrane". Applied Mechanics and Materials 508 (gennaio 2014): 40–43. http://dx.doi.org/10.4028/www.scientific.net/amm.508.40.
Testo completoAbstract (sommario):
The desalination effect of two kinds of nanofiltration membrane, NF-1812-270 and NF-1812, were compared. Under the conditions of different pressure, made the comparison of the quotas between two different nanometer filtration membranes, including membrane flux, ash content, retention rate of chlorine, conductivity. The test results showed that the effect of desalination of NF-1812 nanofiltration membrane was better than the effect of desalination NF-1812-270 nanofiltration membrane.
11
Boudin, Mathieu, Marco Bonafini, Tess van den Brande e Ina Vanden Berghe. "Cross-Flow Nanofiltration of Contaminated Protein-Containing Material: State of the Art". Radiocarbon 59, n. 6 (dicembre 2017): 1793–807. http://dx.doi.org/10.1017/rdc.2017.137.
Testo completoAbstract (sommario):
ABSTRACTRadiocarbon (14C) dating of protein-containing material (collagen, hair/wool, silk, leather) contaminated with extraneous carbon (e.g. humic substances) might result in unreliable dates when pretreated with the conventional but inadequate protocols. In this study cross-flow nanofiltration was applied to pretreated, protein-containing material. This method is able to remove low-molecular and high-molecular weight contaminants as demonstrated in previous studies. The sample quality improvement by cross-flow nanofiltration is verified by measuring the C:N ratio before and after nanofiltration. If the C:N ratio of the permeate (sample after cross-flow nanofiltration) falls within the C:N boundaries for uncontaminated wool/hair, silk and bone collagen, it is assumed to be contamination free. In our study, we focused on wool, silk, and collagen samples of known historical age. All samples treated by cross-flow nanofiltration effectively outputs C:N ratios within the expected range and yield for more accurate 14C date in agreement with historical expectations whereas bulk samples with C:N ratio out of the expected ranges, give either younger or older dates. We thus highlight both that C:N ratio is a good indicator of contamination and that cross-flow nanofiltration is an efficient method to treat protein-containing materials prior to 14C dating.
12
Rezaei Hosseinabadi, S., K. Wyns, V. Meynen, R. Carleer, P. Adriaensens, A. Buekenhoudt e B. Van der Bruggen. "Organic solvent nanofiltration with Grignard functionalised ceramic nanofiltration membranes". Journal of Membrane Science 454 (marzo 2014): 496–504. http://dx.doi.org/10.1016/j.memsci.2013.12.032.
Testo completo
13
dos Santos Cavaleiro, Rosely Maria, Tiago da Silva Arouche, Phelipe Seiichi Martins Tanoue, Tais Souza Sá Pereira, Raul Nunes de Carvalho Junior, Fabio Luiz Paranhos Costa, Tarciso Silva de Andrade Filho, Rosivaldo dos Santos Borges e Antonio Maia de Jesus Chaves Neto. "Hormones Nanofiltration in Carbon Nanotubes and Boron Nitride Nanotubes Using Uniform External Electric Field Through Molecular Dynamics". Journal of Nanoscience and Nanotechnology 21, n. 11 (1 novembre 2021): 5499–509. http://dx.doi.org/10.1166/jnn.2021.19467.
Testo completoAbstract (sommario):
Hormones are a dangerous group of molecules that can cause harm to humans. This study based on classical molecular dynamics proposes the nanofiltration of wastewater contaminated by hormones from a computer simulation study, in which the water and the hormone were filtered in two single-walled nanotube compositions. The calculations were carried out by changing the intensities of the electric field that acted as a force exerting pressure on the filtration along the nanotube, in the simulation time of 100 ps. The hormones studied were estrone, estradiol, estriol, progesterone, ethinylestradiol, diethylbestrol, and levonorgestrel in carbon nanotubes (CNTs) and boron nitride (BNNTs). The most efficient nanofiltrations were for fields with low intensities in the order of 10-8 au and 10-7 au. The studied nanotubes can be used in membranes for nanofiltration in water treatment plants due to the evanescent field potential caused by the action of the electric field inside. Our data showed that the action of EF in conjunction with the van der Walls forces of the nanotubes is sufficient to generate the attractive potential. Evaluating the transport of water molecules in CNTs and BNNTs, under the influence of the electric field, a sequence of simulations with the same boundary conditions was carried out, seeking to know the percentage of water molecules filtered in the nanotubes.
14
Ozaki, H., K. Sharma, W. Saktaywin, D. Wang e Y. Yu. "Application of ultra low pressure reverse osmosis (ULPRO) membrane to water and wastewater". Water Science and Technology 42, n. 12 (1 dicembre 2000): 123–35. http://dx.doi.org/10.2166/wst.2000.0255.
Testo completoAbstract (sommario):
There is a worldwide grave concern about water pollution control. To mitigate the water scarcity, in arid zones and in the areas with no other sources but brackish water, reverse osmosis technology has played an important role. In an effort to reduce the cost of energy requirement for RO operation, nanofiltration has been developed. Until recently the nanofiltration has been used in water softening and removal of disinfection byproduct (DBO). Use of nanofiltration to desalinate brackish water has been ruled out due to low rejection of salts. The introduction of ultra-low pressure reverse osmosis membrane, categorically a nanofiltration, has widened the horizon of using the nanofiltration in desalinating brackish water as well as surfacewater and wastewater. This development ensures the increase in flux due to improvement in active surface layer formation with the application of very small pressure. The surface charge and hydrophilicity on the surface material of the membrane have shown better flux stability in the high fouling conditions. With the addition of higher flux and higher rejection based on the same chemistry, ULPRO has made another step forward. This introduction will certainly reduce the operation cost and, more importantly, improve the overall reliability of the RO system. Application of nanofiltration is broadened to surface water treatment, wastewaters for nutrient removal and heavy metal rejection from wastewater.
15
Porte, Pierre, Jean-Thierry Aubin, Samuel Arrabal, Christine Kimmel-Jehan, Sami Chtourou e Benoit Flan. "Solvent-Detergent Treatment and Ion-Exchange Chromatography Have No Impact on Prion Removal by 15 nm Nanofiltration in the Manufacture of Factane®." Blood 106, n. 11 (16 novembre 2005): 4177. http://dx.doi.org/10.1182/blood.v106.11.4177.4177.
Testo completoAbstract (sommario):
Abstract The transmission risk for new variant Creutzfeldt-Jakob Disease by medicinal plasma-derived products (MPP) is considered as very low, even theoretical, as to date no cases associated with these products have been reported. As a precautionary measure, European Regulatory authorities require that manufacturers of MPP perform an assessment of their manufacturing processes capacity to remove transmissible spongiform encephalopathy (TSE) agents. In the absence of scientific data, manufacturers are required to perform specific studies demonstrating their processes efficacy towards prion removal. We investigated the efficacy of 3 manufacturing steps in the Factane® process: step 1: precipitation combined with alumina gel adsorption and filtration through positively charged membranes; step 2: ion-exchange chromatography in the presence of Solvent-Detergent (SD) and step 3: combined 35 nm + 15 nm nanofiltration. Removal of TSE infectivity was assessed either by independent experiments, to determine the reduction factor associated with each individual step, or by a study combining several steps in order to investigate the impact of upstream process steps (SD treatment and Chromatography) on the efficacy of nanofiltration. Intermediate products collected from industrial batches were spiked with a microsomal fraction purified from a hamster brain homogenate (scrapie 263K strain). Detection and titration of the infectious agent were performed by Western Blot (WB) and/or Bioassay. When each step was studied individually, step 1 led to a reduction factor of 1.5 log10 (WB, clearance factor: 3 log10) and step 2 to a reduction factor of 1.7 log10 (WB). Step 3 led to reduction factors higher than or equal to 3.3 log10 by WB as well as by Bioassay. In a study combining steps 2 and 3, the total reduction factor was higher than or equal to 5.1 log10 (WB). The bioassay corresponding to this combined study is ongoing. Results from investigational studies of the Factane® manufacturing process highlight the contribution of the 3 identified steps towards prion removal which is in line with previously reported data. Nanofiltration shows a very significant contribution to the removal of TSE agents as evidenced by WB and bioassay experiments. This observation is in agreement with the estimated size of TSE agents (15-45 nm) as well as with their biophysical properties (agregability, insolubility and hydrophobicity). Data from the combined study (reduction factor ≥ 5.1 log10) are compatible with the cumulative effects of the chromatography and the nanofiltration steps. This observation shows that nanofiltration’s efficiency in removing prions is unchanged by the upstream treatments, namely SD treatment, and supports the hypothesis that the overal global reduction factor for the manufacture process is equal to the sum of the individual steps. These data confirm the interest of nanofiltration as an additional safety step in increasing the safety margin of plasma products towards the theoretical TSE transmission risk.
16
Verberk, J. Q. J. C., J. Post, W. G. J. van der Meer e J. C. van Dijk. "Direct capillary nanofiltration for ground water and surface water treatment". Water Supply 2, n. 5-6 (1 dicembre 2002): 277–83. http://dx.doi.org/10.2166/ws.2002.0180.
Testo completoAbstract (sommario):
Capillary nanofiltration is a new concept in membrane filtration. This technique combines the advantages of the good water quality obtained from nanofiltration membranes with the easy hydraulic cleaning of capillary membranes. Direct capillary nanofiltration can be used to treat ground water or surface water without pre-treatment. At the Delft University of Technology several MSc-thesis projects have been carried out on this subject. This paper will describe some results of these studies. A model based on a mass balance to predict the flux of a capillary nanofiltration installation treating groundwater is proposed. In this model the only resistance taken into account is the concentration polarisation. Also a model to predict the flux when treating surface water has been developed. This model takes into account the resistance due to cake filtration.
17
Yang, Qing, Xin Qiu e Xiang Shen. "Concentration Polarization BP Model of Nanofiltration Separation". Advanced Materials Research 305 (luglio 2011): 247–50. http://dx.doi.org/10.4028/www.scientific.net/amr.305.247.
Testo completoAbstract (sommario):
In order to effectively control the influence of Concentration Polarization (CP) during the nanofiltration separating wastewater process, this study applied parameters characterization of membrane flux attenuation coefficient (mwt) and the Back-propagation (BP) neural network algorithm to simulate the development rules of CP and membrane pollution, set up CP BP Model of Nanofiltration Separation, based on the tested data of NF90. The correlation coefficient between simulation and test of the simulation BP model was over 0.99, with the absoluteness error below 1.5%. According to the model’s prediction, the separation effect of nanofiltration technology become attenuate with running time increasing in nanofiltration separating wastewater process. mwtstart raised obviously within first 0.5h in operation and stay stable after 1h. It was advised to appropriately maintain u>0.2m/s for NF90 membrane effectively controlling mwt<0.1.
18
Mu, Tao, Qiang Wang, Liang Cao, Xiaohang Zhu e Zhiru Zhao. "Preparation and characterization of a novel emphatically charged strengthened chitosan composite nanofiltration membrane". MATEC Web of Conferences 358 (2022): 01025. http://dx.doi.org/10.1051/matecconf/202235801025.
Testo completoAbstract (sommario):
In this paper, chitosan was grafted with acrylic acid and positively charged elements, and a series of reinforced nanofiltration membranes were prepared by coating modified chitosan polymer with polysulfone ultrafiltration membrane as support. The structure of chitosan derivatives and polymers was characterized by infrared spectrum, and the membrane structure was characterized by scanning electron microscope and atomic force microscope. The performance of composite nanofiltration membrane was closely related to the structure of polymer and the electrical properties of positively charged elements. The rejection rate of 50% molar ratio composite nanofiltration membrane to CaCl2 reached 97.4%. The corresponding flux is 430.7 Lm-2h-1. The retention order was: CaCl2 > NaCl > Na2SO4. The tensile strength increased by 27.3%. Acid resistance (5%HCl)) was improved by 50.5%. Alkali resistance (5%NaOH) increased by 42.2%. The results showed that the positive charge enhanced chitosan composite nanofiltration membrane had excellent performance. The charge effect had no effect on NaCl and Na2SO4, but had significant effect on CaCl2. The membrane is a typical positive charged nanofiltration membrane suitable for separating high-valent cations from weak acids or weak bases.
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Povarova, N. "Influence of functional feeding of young chickens-browser of meat cross on meat quality and safety". Ukrainian Black Sea region agrarian science 112, n. 4 (2021): 78–88. http://dx.doi.org/10.31521/2313-092x/2021-4(112)-8.
Testo completoAbstract (sommario):
This article focuses on the study of the membrane concentration process using buttermilk ultrafiltration nanofiltration membranes. Two types of Vladipor OPMN nanofiltration membranes are being investigated in order to identify the main filtration dependencies. For each type, a pressure in the range of 0.5 to 2.0 MPa and a temperature of 20 to 40 ° C are applied. The results indicate that both types of membranes effectively retain lactose at a pressure of 2.0 MPa, a temperature of 40 ° C and a concentration factor. about 2. Varying the flow velocity above the membrane from 0.5 m / s to 1.5 m / s allows obtaining an increase in specific productivity by 15% from the initial one. The influence of the effects of concentration polarization on the specific productivity of nanofiltration membranes is established. The limitation of the concentration factor due to the increase in the osmotic pressure of the solution is determined. The conclusion is made about the possibility of large-scale introduction of nanofiltration of secondary material resources of milk processing in the study of membrane regeneration processes. Key words: buttermilk, ultrafiltration, nanofiltration, lactose, membrane concentration.
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Bondar, S., A. Trubnikova, O. Chabanova, T. Sharachmatova e T. Nedobiichuk. "Application of nanofiltration for regulation of properties of secondary products of processing of animal raw materials". Ukrainian Black Sea region agrarian science 112, n. 4 (2021): 66–77. http://dx.doi.org/10.31521/2313-092x/2021-4(112)-7.
Testo completoAbstract (sommario):
This article focuses on the study of the membrane concentration process using buttermilk ultrafiltration nanofiltration membranes. Two types of Vladipor OPMN nanofiltration membranes are being investigated in order to identify the main filtration dependencies. For each type, a pressure in the range of 0.5 to 2.0 MPa and a temperature of 20 to 40 ° C are applied. The results indicate that both types of membranes effectively retain lactose at a pressure of 2.0 MPa, a temperature of 40 ° C and a concentration factor. about 2. Varying the flow velocity above the membrane from 0.5 m / s to 1.5 m / s allows obtaining an increase in specific productivity by 15% from the initial one. The influence of the effects of concentration polarization on the specific productivity of nanofiltration membranes is established. The limitation of the concentration factor due to the increase in the osmotic pressure of the solution is determined. The conclusion is made about the possibility of large-scale introduction of nanofiltration of secondary material resources of milk processing in the study of membrane regeneration processes. Key words: buttermilk, ultrafiltration, nanofiltration, lactose, membrane concentration.
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Wijaya, Hans, Kengo Sasaki, Prihardi Kahar, Emmanuel Quayson, Nova Rachmadona, Jerome Amoah, Shinji Hama, Chiaki Ogino e Akihiko Kondo. "Concentration of Lipase from Aspergillus oryzae Expressing Fusarium heterosporum by Nanofiltration to Enhance Transesterification". Processes 8, n. 4 (11 aprile 2020): 450. http://dx.doi.org/10.3390/pr8040450.
Testo completoAbstract (sommario):
Nanofiltration membrane separation is an energy-saving technology that was used in this study to concentrate extracellular lipase and increase its total activity for biodiesel production. Lipase was produced by recombinant Aspergillus oryzae expressing Fusarium heterosporum lipase (FHL). A sulfonated polyethersulfone nanofiltration membrane, NTR-7410, with a molecular weight cut-off of 3 kDa was used for the separation, because recombinant lipase has a molecular weight of approximately 20 kDa, which differs from commercial lipase at around 30 kDa for CalleraTM Trans L (CalT). After concentration via nanofiltration, recombinant lipase achieved a 96.8% yield of fatty acid methyl ester (FAME) from unrefined palm oil, compared to 50.2% for CalT in 24 h. Meanwhile, the initial lipase activity (32.6 U/mL) of recombinant lipase was similar to that of CalT. The composition of FAME produced from recombinant concentrated lipase, i.e., C14:1, C16:0, C18:0, C18:1 cis, and C18:2 cis were 0.79%, 34.46%, 5.41%, 45.90%, and 12.46%, respectively, after transesterification. This FAME composition, even after being subjected to nanofiltration, was not significantly different from that produced from CalT. This study reveals the applicability of a simple and scalable nanofiltration membrane technology that can enhance enzymatic biodiesel production.
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Mohammad, Abdul Wahab. "Editorial: Nanofiltration membranes". Desalination 315 (aprile 2013): 1. http://dx.doi.org/10.1016/j.desal.2013.02.012.
Testo completo
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Sherhan, Bashir Y., Areej D. Abbas, Hussein A. Alabdly, Thamer J. Mohammed, Qusay F. Alsalhy, Thamera Kidher, Lamees H. Fahad, Hamsa Ahmed e Remonda H. Melkon. "Preparation of PPSU Hollow Fiber Nanofiltration Membranes for Nanofiltration Application". Iraqi Journal of Chemical and Petroleum Engineering 18, n. 2 (30 giugno 2017): 13–25. http://dx.doi.org/10.31699/ijcpe.2017.2.2.
Testo completoAbstract (sommario):
PPSU hollow fiber nanofiltration membranes are prepared by applying two concentrations and various extrusion pressures according to the phase inversion method. Cross-sectional area and outer structures were characterized by using scanning electron microscope (SEM) and atomic force microscopy (AFM). In additional to the pore size distribution, either the mean roughness or the mean pore size of the PPSU hollow fiber surfaces was evaluated by AFM. It was found that the morphology of the PPSU fibers had both sponge-like and finger-like structures through different extrusion pressures and PPSU concentrations. The mean pore size and mean roughness for inner and outer surfaces were seen to be decreased with the increase of extrusion pressure at two different PPSU concentrations. Moreover, the lead ion rejection was significantly improved from 19 to 78 % with increasing the extrusion pressure from 2.5 to 3 bar at 25 wt.% PPSU concentration.
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Mitko, Krzysztof, Ewa Laskowska, Marian Turek, Piotr Dydo e Krzysztof Piotrowski. "Scaling Risk Assessment in Nanofiltration of Mine Waters". Membranes 10, n. 10 (15 ottobre 2020): 288. http://dx.doi.org/10.3390/membranes10100288.
Testo completoAbstract (sommario):
Nanofiltration can be applied for the treatment of mine waters. One of the main problems is the risk of crystallization of sparingly soluble salts on the membrane surface (scaling). In this work, a series of batch-mode nanofiltration experiments of the mine waters was performed in a dead-end Sterlitech® HP 4750X Stirred Cell. Based on the laboratory results, the concentration profiles of individual ions along the membrane length in a single-pass industrial-scale nanofiltration (NF) unit was calculated, assuming the tanks-in-series flow model inside the membrane module. These calculations also propose a method for estimating the maximum achievable recovery before the occurrence of the calcium sulfate dihydrate scaling in a single-pass NF 40″ length spiral wound module, simultaneously allowing metastable supersaturation of calcium sulfate dihydrate. The performance of three membrane types (NF270, NFX, NFDL) has been evaluated for the nanofiltration of mine water.
25
Huliienko, Serhii, Yaroslav Kornienko, Svitlana Muzyka e Kateryna Holubka. "Mathematical Simulation of Nanofiltration Process: State of Art Review". Chemistry & Chemical Technology 18, n. 2 (14 giugno 2024): 187–99. http://dx.doi.org/10.23939/chcht18.02.187.
Testo completoAbstract (sommario):
A review of publications devoted to the mathematical simulation of the nanofiltration process was carried out, the advantages, limitations, and areas of application of various modeling approaches were determined. It was found that the most effective approaches are based on the extended Nernst-Planck equation, Donnan equilibrium, as well as methods of computational fluid dynamics and molecular dynamics. The use of software for solving nanofiltration simulation problems was considered.
26
Macedo, Antónia, Joana Monteiro e Elizabeth Duarte. "A Contribution for the Valorisation of Sheep and Goat Cheese Whey through Nanofiltration". Membranes 8, n. 4 (20 novembre 2018): 114. http://dx.doi.org/10.3390/membranes8040114.
Testo completoAbstract (sommario):
The amount of cheese whey generated from the production of speciality sheep and goat cheese is significantly growing due to the acclaimed nutritional and medicinal benefits of the milk from these species. However, most of the cheese whey generated has no applications, thus giving rise to environmental problems. This work focuses on the study of the performance of the nanofiltration process for recovering the permeates of ultrafiltration from sheep and goat cheese whey. Nanofiltration experiments were carried out with membranes of nanofiltration (NF) in total recirculation and concentration modes, at 25 °C. Nanofiltration of the ultrafiltration permeates from sheep cheese whey was done at a pressure of 3.0 × 106 Pa and a circulation velocity of 1.42 m·s−1, until a volume concentration factor (VCF) of 2.5. Nanofiltration of the permeates from ultrafiltration of goat cheese whey was performed at a pressure of 2.0 × 106 Pa and a circulation velocity of 0.94 m·s−1, until a VCF of 2.0. From the results, it was concluded that osmotic pressure was the most important factor affecting the performance of the process. In both cases, the final permeates had a much lower organic load and its future use in the process of cheese making should be evaluated.
27
Cornelissen, E. R., W. G. Siegers, J. Ogier e E. F. Beerendonk. "Influence of calcium-NOM complexes on fouling of nanofiltration membranes in drinking water production". Water Supply 6, n. 4 (1 ottobre 2006): 171–78. http://dx.doi.org/10.2166/ws.2006.765.
Testo completoAbstract (sommario):
The application of nanofiltration is growing rapidly in drinking water and wastewater treatment. The main problem during the operation of nanofiltration membranes is membrane fouling, part of which is due to the presence of Natural Organic Matter (NOM) in sources for drinking water. In this work the effect of calcium was investigated on the nanofiltration fouling behavior in relation to NOM. From Li and Elimelech (2004) it is known that calcium enhanced membrane fouling significantly due to the formation of calcium-NOM complexes. Two techniques were used in our research to determine the part of calcium which is complexated by NOM and the free calcium ion in solution. Results showed that a minimum calcium concentration and a minimum NOM concentration were required for calcium-NOM complex formation. Furthermore, the influence of the calcium concentration on the flux decline during nanofiltration experiments was investigated for different types of feed water. The observed flux decline was proven to be only caused by NOM fouling rather than other membrane fouling types, such as biofouling, scaling or particulate fouling. Fouling of nanofiltration membranes was related to the calcium content in the feed water, and more specifically to the calcium-NOM complex concentration. Membrane cleaning with SDS was found to be very effective.
28
Chiao, Yu-Hsuan, Tanmoy Patra, Micah Belle Marie Yap Ang, Shu-Ting Chen, Jorge Almodovar, Xianghong Qian, S. Ranil Wickramasinghe et al. "Zwitterion Co-Polymer PEI-SBMA Nanofiltration Membrane Modified by Fast Second Interfacial Polymerization". Polymers 12, n. 2 (27 gennaio 2020): 269. http://dx.doi.org/10.3390/polym12020269.
Testo completoAbstract (sommario):
Nanofiltration membranes have evolved as a promising solution to tackle the clean water scarcity and wastewater treatment processes with their low energy requirement and environment friendly operating conditions. Thin film composite nanofiltration membranes with high permeability, and excellent antifouling and antibacterial properties are important component for wastewater treatment and clean drinking water production units. In the scope of this study, thin film composite nanofiltration membranes were fabricated using polyacrylonitrile (PAN) support and fast second interfacial polymerization modification methods by grafting polyethylene amine and zwitterionic sulfobutane methacrylate moieties. Chemical and physical alteration in structure of the membranes were characterized using methods like ATR-FTIR spectroscopy, XPS analysis, FESEM and AFM imaging. The effects of second interfacial polymerization to incorporate polyamide layer and ‘ion pair’ characteristics, in terms of water contact angle and surface charge analysis was investigated in correlation with nanofiltration performance. Furthermore, the membrane characteristics in terms of antifouling properties were evaluated using model protein foulants like bovine serum albumin and lysozyme. Antibacterial properties of the modified membranes were investigated using E. coli as model biofoulant. Overall, the effect of second interfacial polymerization without affecting the selectivity layer of nanofiltration membrane for their potential large-scale application was investigated in detail.
29
Chugunov, Aleksandr S., e Vadim A. Vinnitskii. "Nanofiltration fractionation of radioactive solution components as a method for reducing the volume of wastes intended for permanent disposal". Nuclear Energy and Technology 5, n. 2 (17 maggio 2019): 123–28. http://dx.doi.org/10.3897/nucet.5.35801.
Testo completoAbstract (sommario):
Baromembrane purification methods as part of liquid radioactive media processing complexes are increasingly included in the practice of radioactive waste management. The paper presents the results of a comparative study of the performance of commercially available hyper- and nanofiltration elements when a simulated solution is continuously phosphatized. The study revealed the influence of changes in the feed solution salinity on the permeability, working pressure in the brine chamber of the hyper- and nanofiltration apparatus and the permeate salinity. It is shown that, in a closed loop of liquid radioactive waste, the introduction of polyphosphates to stabilize the truly dissolved forms of multivalent metals on the ULP reverse-osmotic membrane leads, as expected, to a systematic performance degradation, first of all, in the membrane permeability at a fixed pressure in the apparatus. The permeate of the system with a nanofiltration membrane, VNF (Vontron NanoFiltration), contains a sufficiently high salt concentration indicating that sodium salts formed during complexation are removed from the circuit, thereby reducing the solution osmotic pressure which critically affects the yield of the purified solution. Thus, nanofiltration in combination with chelating agents can be an effective tool for fractionating components of radioactive solutions, ensuring the achievement of standard indicators for wastewater and biologically hazardous substances that are subject to permanent disposal.
30
Marin Galvin, R., e J. M. Rodriguez Mellado. "Quality Improvement of a Small Water Supply. A Practical Application of a Full System of Nanofiltration". Engineering, Technology & Applied Science Research 3, n. 2 (7 aprile 2013): 381–86. http://dx.doi.org/10.48084/etasr.294.
Testo completoAbstract (sommario):
The THM level in the Spanish drinking water is limited to less than 0.100 mg/L, due to its potential toxicological effect on humans. This paper investigates the comparison of the results obtained in a small supply of water that historically presented THM contents out of the Spanish normative, versus the results there obtained when the treatment was modified with the inclusion of a nanofiltration system. So, the conventional treatment first applied was that of pre-oxidation with chlorine and/or KMnO4, followed by coagulation with aluminum salts directly on closed sand filter, and disinfection final by chlorination: with this system, THM levels lower than 0.100 mg/L were not always secured. Thus, to improve the water quality, a full system of nanofiltration was implemented, after the above treatment, consisting in: pre-filtration through cartridges, filtration over activated carbon, post-filtration for retaining impurities, and finally, nanofiltration and chlorination of water after nanofiltration. In this order, the new treatment scheme has usually produced water with maximum THM levels of 0.058 mg/L, and average values of 0.013 mg/L, 0.30 mg/L for organic matter concentrations, and water always microbiologically pure. Also, the contents of Fe, Mn and Al in the treated water were significantly reduced with respect to the previous situation without nanofiltration.
31
Mänttäri, M., e M. Nyström. "Ultrafiltration and nanofiltration in the pulp and paper industry using cross-rotational (CR) filters". Water Science and Technology 50, n. 3 (1 agosto 2004): 229–38. http://dx.doi.org/10.2166/wst.2004.0200.
Testo completoAbstract (sommario):
Ultra- and nanofiltration with high shear CR-filters have been utilized for cleaning of clear filtrates and effluents from the pulp and paper industry. The aim was to find out how different nanofiltration membranes operate at high shear conditions. The filtration efficiency of the membranes was evaluated by measuring flux, retention and fouling at various recovery and pH conditions. High fluxes (∼100 L/(m2h)) for nanofiltration membranes were measured when circulation waters from the paper machine were filtered at neutral conditions. In the filtration of discharge of external activated sludge treatment plants we measured fluxes around 150 L/(m2h) even at a concentration factor of 12. The best NF membranes removed over 80% of the organic carbon and of the conductivity and almost completely eliminated the color. With acidic waters fluxes and retentions were significantly lower. The NF270 membrane from Dow and the Desal-5 membranes from Osmonics had the highest flux and retention properties. However, the Desal-5 membrane lost its retention properties slowly, which restricts its use in the high shear CR-filter. CR-nanofiltration can be used in the pulp and paper industry without feed pre-treatment by ultrafiltration. This increases the attractiveness of high shear CR-nanofiltration.
32
Chen, Hong Mei, Hong Xia Guo, Yue Ma, Zhen Ping Qin e Guo Li Xie. "Rejection of Heavy Metal Ions with Polyelectrolyte Composite Nanofiltration Membrane". Applied Mechanics and Materials 529 (giugno 2014): 87–91. http://dx.doi.org/10.4028/www.scientific.net/amm.529.87.
Testo completoAbstract (sommario):
Nanofiltration membrane was prepared by static layer-by-layer (LBL) self-assembly of poly (ethyleneimine) (PEI) and poly (sodium 4-styrenesulfonate) (PSS) on the modified poly-arcylonitrile ultra-filtration membrane. Study on self-assembly of polyelectrolyte membranes with changing surface charges and wettability, rejection properties of nanofiltration membrane in different conditions and pH with respect to heavy metal ions, namely Ni2+and Cd2+were investigated. The results show that the PEI/PSS membrane composed of 4 bilayers at operating pressure 0.4MPa, rejection of PAN-PEI/PSS nanofiltration membrane towards these 2 kind of heavy metal ions reached no less than 90%.
33
Vakili-Nezhaad, G. R., e Z. Akbari. "A Case Study of Nanofiltration Using an Irreversible Thermodynamics-Based Model". ISRN Thermodynamics 2012 (2 febbraio 2012): 1–4. http://dx.doi.org/10.5402/2012/878279.
Testo completoAbstract (sommario):
The extended Spiegler-Kedem model that can be solved by using genetic algorithm (GA) has been used for study of the rejection of charged and uncharged solutes in a nanofiltration process. In this work, the accuracy and applicability of this model were tested with the data obtained from the nanofiltration of a real solution. The permeated solution was obtained from the whey ultrafiltration system (ultrafiltered whey). The studied process separates lactose and mineral salts from ultrafiltered whey. Moreover, the ultrafiltered whey nanofiltration system has been simulated with higher precision compared to the other sources of existing data.
34
Oh, J. I., T. Urase, H. Kitawaki, M. M. Rahman, M. H. Rhahman e K. Yamamoto. "Modeling of arsenic rejection considering affinity and steric hindrance effect in nanofiltration membranes". Water Science and Technology 42, n. 3-4 (1 agosto 2000): 173–80. http://dx.doi.org/10.2166/wst.2000.0376.
Testo completoAbstract (sommario):
Rejection characteristics of arsenic compounds such as arsenite, dimethyl arsinic acid, and arsenate were examined regarding the effect of pH change in nanofiltration. Rejection mechanism of arsenic compounds was explained by comparing experimental rejection with calculation of the Extended Nernst-Planck model coupled with steric hindrance model. Nanofiltration membranes of the same material show similar rejection characteristics of arsenic compounds in different species. Steric hindrance and electrostatic effect in the nanofiltration membranes was well described by the model because the rejection of chloride, sulfate and arsenate ions, which exist in ionized forms at a wide pH range showed quite good agreement between model calculation and experimental result. The rejection of dimethyl arsenic acid and arsenite required the consideration of mutual interaction between membrane material and solutes as well as steric hindrance and electrostatic effect. A system with ultra low-pressure nanofiltration membrane coupled with pre-oxidation device was suggested for the treatment of arsenic in groundwater in Bangladesh.
35
Darbi, Ashref, Thiruvenkatachari Viraraghavan, Yee-Chung Jin, Larry Braul e Darrell Corkal. "Sulfate Removal from Water". Water Quality Research Journal 38, n. 1 (1 febbraio 2003): 169–82. http://dx.doi.org/10.2166/wqrj.2003.011.
Testo completoAbstract (sommario):
Abstract Sulfate occurs naturally in groundwater. Concerns regarding the health effects from sulfate in drinking water have been raised because of reports that diarrhea may be associated with water that contains high levels of sulfate. In the livestock production industry, there is a concern that high levels of sulfate in water can adversely affect productivity. Different methods can be used to remove sulfate from water. Proven technologies are ion-exchange, nanofiltration, reverse osmosis, and electrodialysis. A few earlier studies have shown that the use of bentonite/kaolinite for sulfate removal has produced encouraging results. Experimental work was undertaken to examine in detail the feasibility of such processes. Laboratory studies using bentonite showed poor or no removal in the case of high sulfate water. Ion exchange and nanofiltration were found to be very effective in removing sulfate. Ion exchange is likely to be more reliable than nanofiltration because of the sensitivity of the nanofiltration process to total dissolved solids and biofouling.
36
Zhao, Wenjie, Zhongyu Du, Ning Kuang, Hao Wang, Benliang Yu, Junfei Wu e Fushan Chen. "Simulation of the nanofiltration of pulping black liquor by dynamic blade cross-flow with membrane". BioResources 15, n. 3 (29 maggio 2020): 5593–615. http://dx.doi.org/10.15376/biores.15.3.5593-5615.
Testo completoAbstract (sommario):
This paper investigated the filtration of black liquor with blade cross-flow by membrane. The lignin content in black liquid filtered by the nanofiltration membrane (NP010) is high under the transmembrane pressure of 0.5 bar, 1 bar, 1.5 bar, and 2 bar at 300 rpm and 800 rpm. In this regard, the tangential velocity on the nanofiltration membrane surface and the pressure variation on the blade in the process of filtration are simulated and analyzed with Fluent software. The tangential flow velocity on the nanofiltration membrane surface and the dynamic pressure on the blade, as well as the law of change under different rotation speed and transmembrane pressure are obtained. The comparison between experimental and simulated results have validated the numerical model of the filtration of black liquid by the blade dynamic cross-flow. According to the experimental and simulated results, the optimized filtration conditions are obtained when the blade dynamic cross-flow uses 1 kDa nanofiltration membrane to filter black liquor.
37
Kukucka, Miroslav, e Nikoleta Kukucka. "Groundwater nanofiltration process efficiency improvement with additional concentrate membrane treatment". Chemical Industry 70, n. 5 (2016): 501–9. http://dx.doi.org/10.2298/hemind150627056k.
Testo completoAbstract (sommario):
Nanofiltration (NF) of waste water originated from nanofiltration drinking water plant stationed in town of Kikinda (Northern Serbia) was investigated. Experiments on removal characteristics of nanofiltration membranes when exposed to influent rich in arsenic and natural organic matter under different flux and transmembrane pressure (TMP) conditions were conducted in order to obtain drinking water from waste water and reduce total amount of waste water. Applied NF membranes showed remarkable removal characteristic. Also, obtained result for concentrate yield, an indicator of reduced concentrate amount, of 8.89% under optimum flux value presents considerable amount of reclamated drinking water. Calculated empirical and theoretical concentration factors quotients were indicated to probable accumulation of some inlet water components at NF membrane surface. Based on the obtained results that nanofiltration membranes remove natural organic matter, arsenic, ammonia and sodium with high efficiencies of 98%, 96%, 80% and 93% respectively, conceptual design of drinking water plant for City of Kikinda was defined and presented.
38
Lai, Dat Quoc, An Thanh Ngo, Phung Thi Kim Le, Dung Hoang Nguyen e Long Quang Nguyen. "TECHNICAL ASSESSMENT OF GAMMA-AMINO BUTYRIC ACID (GABA) PRODUCTION FROM RICE BRAN". Vietnam Journal of Science and Technology 57, n. 3B (12 novembre 2019): 137. http://dx.doi.org/10.15625/2525-2518/57/3b/14499.
Testo completoAbstract (sommario):
This research focused on technical assessment of GABA production from rice bran through fermentation by Lactobacillus brevis. Influence of operating pressure on separation of GABA by nanofiltration membrane was investigated and 4 bar was suitable for the nanofiltration process. The purification of GABA by nanofiltration with constant feed volume was carried out and purity of GABA reached 4.8 folds, compared to feed, at 5 volumes of added water. At 40 of concentration factor in concentration of GABA solution by nanofiltration with full recycle of retentate, content of GABA reached 49.8 g/L. The production of GABA from defatted rice bran at pilot scale was carried out at 1,000 L/batch (equal to 200 kg of rice bran) of fermentation. Estimation of mass balance showed that, with 200 kg of defatted rice bran, 7.0 kg of GABA powder was obtained. Results indicated that, it is potential to produce GABA from rice bran through the fermentation by Lactobacillus brevis.
39
Valentukeviciene, Marina, Ramune Zurauskiene e Youssef Amine Boussouga. "Fluoride Removal from Groundwater by Technological Process Optimization". Ecological Chemistry and Engineering S 26, n. 1 (1 marzo 2019): 133–47. http://dx.doi.org/10.1515/eces-2019-0010.
Testo completoAbstract (sommario):
Abstract Fluoride removal from aqueous solutions was studied using nanofiltration and sorption techniques which have always been best key ways to deal with water contaminated by fluoride. In this presented work, we were firstly interested on fluoridated rejected water overcoming the drawback of RO membrane process of groundwater treatment plant in Baltic region (Kretinga, Lithuania). Opoka sorbent has shown effective results of fluoride sorption with efficiency higher than 77 %. In order to understand the sorption phenomenon and to validate the results obtained, we have applied experimental data on Freundlich and Langmuir isotherms which allow us to determine isotherms parameters (KF; 1/n and KL; qmax) and to confirm the experiment. Because of the unacceptable tariff of drinking water treated by RO, defluoridation with nanofiltration method is proposed in this study as a solution which can replace reverse osmosis technique. For that, tests of nanofiltration for fluoride removal were carried out at laboratory scale by using nanofiltration flat sheet membranes (NF270 and NF90).
40
Itoh, M., S. Kunikane e Y. Magara. "Evaluation of nanofiltration for disinfection by-products control in drinking water treatment". Water Supply 1, n. 5-6 (1 giugno 2001): 233–43. http://dx.doi.org/10.2166/ws.2001.0119.
Testo completoAbstract (sommario):
DBP control by nanofiltration was studied. Nine DBPs including THMs were selected as target compounds. Reagent DBPs and DBPs formed as a result of chlorination of NOM contained in river water, were applied to nanofiltration to examine DBPs removal. Humic acid was used to investigate DBP precursor control. Nanofiltration was conducted for about one day for each experiment using two 2-inch membrane modules. NF showed high performance for DBP precursor removal but little effect on the removal of DBPs themselves, especially THMs. In the experiment of DBP precursors removal, rejections were 98 to 100 percent for most of the DBPFPs. For NOM in river water, rejections of THMFPs were 96 to 99 percent. This shows nanofiltration is effective even at low concentrations of NOM. Nanofiltration can remove almost all organic substances with the apparent molecular weight of greater than 2,000 daltons. Molecular weight distribution patterns of the permeate were different depending on NF. THMs showed decreasing rejection as filtration proceeded because of adsorption on the membrane surface. THM rejections at 24 hours after filtration started were about 10 and 30 percent in Module-A and B, respectively. Haloacetic acids showed relatively higher rejections. It is recommended, from the viewpoint of THM control, that NOM removal using NF is much preferable to the removals of THM, formed by chlorination, using NF.
41
Sawadogo, Boukary, Yacouba Konaté, Seyram Kossi Sossou, Nana Fassouma Ado Saidou, Abdoul Wahab Nouhou Moussa e Harouna Karambiri. "Removal of Sulphate Ions from Borehole Water Using Nanofiltration and Reverse Osmosis". Water 14, n. 21 (27 ottobre 2022): 3422. http://dx.doi.org/10.3390/w14213422.
Testo completoAbstract (sommario):
Consumption of contaminated water poses health hazards to humanity and hence increases the need for treatment. An excessive level of sulphate in borehole water was detected in the drinking water supply of Garpéné village in Burkina Faso. This study aimed to evaluate the performance of nanofiltration and reverse osmosis for the removal of sulphate ions from borehole water. A combined nanofiltration and reverse osmosis pilot was used for the treatment of the raw borehole water and some prepared synthetic solutions. Different experimental conditions were used to evaluate the effects of the pressure, the nature of the solution to be filtered, and the ions accompanying the sulphate. The filtration tests were conducted at transmembrane pressures of 1, 2.5 and 4 bar with a nanofiltration NF270 membrane and at transmembrane pressures of 4, 6 and 8 bar with a reverse osmosis TW30 membrane. The membrane used were a thin-film composite (TFC) membrane from Filmtec. The pilot was fed with real water from the Garpéné borehole and synthetic solutions of calcium sulphate and sodium sulphate at three different concentrations (250, 500 and 1400 mg/L). The results demonstrated that the nanofiltration and reverse osmosis membranes achieved retention rates of sulphate ions ranging from 97.0% to 98.7% and 98.4% to 99.0%, respectively. The results also showed that the operating conditions had a significant effect on the retention of sulphate by reverse osmosis and nanofiltration membranes. With regard to the effect of the counter ion, it was observed that during nanofiltration, the retention rate of sulphate ions in the water to be treated was lower in the presence of calcium ions than that of sodium ions, whereas in reverse osmosis little influence of the counter ion was observed.
42
Ma, Guangqing, Song Zhao, Ying Wang, Zhi Wang e Jixiao Wang. "Conjugated polyaniline derivative membranes enable ultrafast nanofiltration and organic-solvent nanofiltration". Journal of Membrane Science 645 (marzo 2022): 120241. http://dx.doi.org/10.1016/j.memsci.2021.120241.
Testo completo
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Zhang, Hai-Zhen, Zhen-Liang Xu e Qian Shen. "High-performance nanofiltration membrane intercalated by FeOOH nanorods for water nanofiltration". Desalination 498 (gennaio 2021): 114802. http://dx.doi.org/10.1016/j.desal.2020.114802.
Testo completo
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Ghazali, Nazlee Faisal, e Lim Ki Min. "Mass Transport Models in Organic Solvent Nanofiltration: A Review". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 76, n. 3 (29 ottobre 2020): 126–38. http://dx.doi.org/10.37934/arfmts.76.3.126138.
Testo completoAbstract (sommario):
Membrane technology has been gradually used as an alternative to the conventional separation and purification method in various industries. In recent years, solvent-stable nanofiltration or organic solvent nanofiltration has becoming practicable through the development of solvent-stable commercial polymeric membranes. Organic solvent nanofiltration has a great potential to replace the conventional energy-demanding process such as distillation due to its ability of separating organic solvents and solutes on a molecular level without phase change and operation at relatively mild temperature. Predicting the performance of such membrane separations is crucial in the process design. Important performance indicator such as the permeate flux and the rejections are strongly related to the fluid dynamics, mass transfer and solute-solvent-membrane interactions. The aim of this paper is to review and assess the transport models of solute and solvent transport relevant to organic solvent nanofiltration. The link between concentration polarization and the hydrodynamics in various configurations are discussed. The effects of process variables on membrane performance and solute-solvent membrane interactions are also reviewed.
45
Kuzminova, Anna, Mariia Dmitrenko, Andrey Zolotarev, Aleksandra Korniak, Daria Poloneeva, Artem Selyutin, Alexei Emeline et al. "Novel Mixed Matrix Membranes Based on Polymer of Intrinsic Microporosity PIM-1 Modified with Metal-Organic Frameworks for Removal of Heavy Metal Ions and Food Dyes by Nanofiltration". Membranes 12, n. 1 (23 dicembre 2021): 14. http://dx.doi.org/10.3390/membranes12010014.
Testo completoAbstract (sommario):
Nowadays, nanofiltration is widely used for water treatment due to its advantages, such as energy-saving, sustainability, high efficiency, and compact equipment. In the present work, novel nanofiltration membranes based on the polymer of intrinsic microporosity PIM-1 modified by metal-organic frameworks (MOFs)—MIL-140A and MIL-125—were developed to increase nanofiltration efficiency for the removal of heavy metal ions and dyes. The structural and physicochemical properties of the developed PIM-1 and PIM-1/MOFs membranes were studied by the spectroscopic technique (FTIR), microscopic methods (SEM and AFM), and contact angle measurement. Transport properties of the developed PIM-1 and PIM-1/MOFs membranes were evaluated in the nanofiltration of the model and real mixtures containing food dyes and heavy metal ions. It was found that the introduction of MOFs (MIL-140A and MIL-125) led to an increase in membrane permeability. It was demonstrated that the membranes could be used to remove and concentrate the food dyes and heavy metal ions from model and real mixtures.
46
Yu, San Chuan, Zhi Wen Chen, Mei Hong Liu e Jing Wei Zhao. "Comparative Study on the Treatment of Biologically Treated Textile Effluent by Nanofiltration and Reverse Osmosis for Water Reuse". Advanced Materials Research 441 (gennaio 2012): 584–88. http://dx.doi.org/10.4028/www.scientific.net/amr.441.584.
Testo completoAbstract (sommario):
In view of the water shortage, the increasingly severe regulations as well as the release thresholds, it is becoming increasingly necessary to reuse the textile effluents. This work concerned the treatment of textile plant effluent after conventional biological processing by membrane technology for water reuse. Desal5 DK nanofiltration (NF) membrane and BW30 reverse osmosis (RO) membrane were investigated in this study in terms of COD and color removal, salinity reduction as well as permeate flux through cross-flow permeation tests. The results showed that the Desal5 DK nanofiltration membrane exhibited higher stabilized water permeability and flux decline than the reverse osmosis membrane because of its higher porosity and tendency towards fouling. The BW30 reverse osmosis membrane reduced salinity to a great extent than the Desal5 DK nanofiltration membrane. While the nanofiltration membrane exhibited better COD removal efficiency compared to the RO membrane, possibly due to its sieving removal mechanism. The treated water with good enough quality could be recycled back into the process, thereby offering economical benefits by reducing the water consumption and wastewater treatment cost.
47
Sari, Syifa Aulia Permata, Lesta Lesta, Syarmila Syarmila, Yunilita Hanum, Zulfa Mawaddah, Jurian Jurian e Nurhadini Nurhadini. "Extra A Review of Nanofiltration Membrane Technology To Treat Water Problems". Stannum : Jurnal Sains dan Terapan Kimia 4, n. 2 (31 ottobre 2022): 74–80. http://dx.doi.org/10.33019/jstk.v4i2.2936.
Testo completoAbstract (sommario):
One of the most widely used membranes is the nanofiltration membrane, this membrane is formed from various nanomaterials, such as metal nanoparticles and metal oxides, carbon-based nanoparticles, metal organic frameworks, and micro or organic nanoparticles. Membrane separation processes are used to concentrate or fractionate liquids to produce two liquids with different compositions. This makes the nanofiltration process an alternative compared to conventional processes. The potential of nanofiltration membranes can be used in textile industry wastewater treatment, tofu liquid waste, tofu liquid waste treatment, batik wastewater testing, and groundwater management as drinking water. In addition, nanofiltration membrane technology can be used as a separator for a substance in the air, such as removal of cypermethrin, arsenic cream, concentration of lactic acid bacteria as a tasty probiotic, removal of carbosulfan, Zr-Hf separation, and can see the characterization and performance evaluation of the antifouling properties of membranes. . Based on the process, the performance of a membrane is determined by two simple factors, namely flux (permeate flow rate) and membrane selectivity.
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Liu, Lulu, Weilin Wu, Xiaogang Jin, Xiong Luo e Lili Wu. "Interfacial Polymerization on Polyethersulfone Ultrafiltration Membrane to Prepare Nanofiltration Layers for Dye Separation". Polymers 15, n. 9 (24 aprile 2023): 2018. http://dx.doi.org/10.3390/polym15092018.
Testo completoAbstract (sommario):
Nanofiltration membranes are of great significance to the treatment of dye wastewater. Interfacial polymerization is a widely used method to fabricate nanofiltration membranes. In this study, the interaction of tannic acid-assisted polyethylene polyamine (PEPA) with terephthalaldehyde (TPAL) was performed on PES ultrafiltration membranes using novel nitrogen-rich amine monomers and relatively less reactive aldehyde-based monomers. A new nanofiltration membrane ((T-P-T)/PES) was prepared by interfacial polymerization. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy were used to analyze the elemental composition, bonding state, and surface morphology of the membrane surface. The effects of the PEPA deposition time, TPAL concentration, interfacial reaction time, and curing time on the nanofiltration layer were investigated. The modified membrane, prepared under optimal conditions, showed strong dye separation ability. The permeation of the modified membrane could reach 68.68 L·m−2·h−1·bar−1, and the rejection of various dyes was above 99%. In addition, the (T-P-T)/PES membrane showed good stability during long-term dye separation.
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Elmenshawy, Mohamed R., Saleh M. Shalaby, Asaad M. Armanuos, Ahmed I. Elshinnawy, Iqbal M. Mujtaba e Tamer A. Gado. "Assessing RO and NF Desalination Technologies for Irrigation-Grade Water". Processes 12, n. 9 (31 agosto 2024): 1866. http://dx.doi.org/10.3390/pr12091866.
Testo completoAbstract (sommario):
In this work, the performance of a Reverse Osmosis (RO) process using different types of reverse osmosis (RO) and nanofiltration (NF) membranes is evaluated for brackish water desalination for producing irrigation-grade water. The proposed desalination system is a single-stage system, where three types of RO and two NF membranes were examined. The different desalination systems were simulated using ROSA72 software. In order to validate the theoretical model, the results obtained from the simulation were compared to those obtained from the experiment conducted in this work. The El-Moghra aquifer of Egypt is considered the test bed due to a considerable amount of data being available for this aquifer. The El-Moghra aquifer has 79 wells, and the available water data, when checked against several quality parameters, show that none of the investigated wells are suitable for direct irrigation without treatment due to problems of salinity, the sodium adsorption ratio, and low water quality according to the irrigation water quality index values. The obtained results show that nanofiltration membranes exhibited superior energy efficiency compared to reverse osmosis membranes. However, what sets the nanofiltration membranes apart is their ability to elevate water quality in 89.9% of the total investigated wells to an acceptable level for agricultural purposes. This underscores the nanofiltration membranes as a highly effective alternative to reverse osmosis membranes, demonstrating the capability to produce water suitable for irrigation while concurrently reducing operational costs due to the lower energy consumption in nanofiltration-based systems.
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Altaibayev, Bagdat, Nessipbay Tussupbayev, Zhiger Kenzhetaev, Omirserik Baigenzhenov, Alibek Khabiyev, Zekail Tyulyubayev e Alexey Leksin. "Research on purification of tailings solutions from metal impurities at lead dust processing enterprises". Mining of Mineral Deposits 18, n. 3 (30 settembre 2024): 126–34. http://dx.doi.org/10.33271/mining18.03.126.
Testo completoAbstract (sommario):
Purpose. The research aims to develop a technology for tailings solution purification using membrane nanofiltration to reduce waste volume and enterprise costs by reusing the purified water. Methods. The research uses polyamide nanofiltration membranes on a semi-industrial plant. The nanofiltration process is conducted at a pressure of 3.5 MPa with 30% permeate yield. The chemical composition of the solutions is analyzed using atomic-absorption and chemical methods. Findings. Removal of 69% arsenic, 68.5% zinc and 95.7% iron has been achieved under optimal conditions. The purified solution with a residual sulphuric acid concentration of ~3.5 g/l can be used again for leaching lead dust. The concentrated metal solution allows for additional zinc extraction. The use of technology reduces waste volumes by more than 30% and reduces the enterprise’s recycling costs. Originality. The research proposes a new environmentally friendly nanofiltration technology for tailings solution purification that can effectively remove heavy metals and extract valuable components. This approach uniquely integrates membrane nanofiltration at an optimized pressure of 3.5 MPa, achieving high removal rates of heavy metal ions such as As³⁺, AsO4³⁻, Zn²⁺, Fe²⁺, and Fe³⁺, while reducing waste by 30% and enabling the reuse of sulfuric acid and water in the leaching process, leading to significant cost and resource savings. Practical implications. Implementation of the proposed technology at lead dust processing enterprises reduces the costs of wastewater treatment, reduces the waste volume and allows for the reuse of water and acids in the production process.