Application Of Membrane Technology Research Articles

Design of microstructure for hollow fiber loose nanofiltration separation layer and its compactness-tailoring mechanism

In order to promote the application of membrane technology in the treatment of textile wastewater containing small molecule dye, fabricating a hollow fiber loose nanofiltration (LNF) with a thin and compact separation layer and deepening the understanding of compactness-tailoring mechanism in chemical crosslinking are essential. Firstly, the mechanisms of synergistic crosslinking of PEI-70K and PEI-10K, along with a weakening of the PEI hydration by ethanol, were expounded in primary crosslinking. Then, some LNF separation layers with different compactness were prepared through crosslinking with different crosslinkers to further reduce pore size, which resulted in the efficient removal (~100%) of a small molecular dye (methyl orange (MO), M = 327 g mol–1). The removal of methyl orange is mainly caused by size sieving. The relationship among the pore size, the Mw of the secondary crosslinkers, and the pore size reduction rate was interpreted by comparing the pore size reduction rate of three secondary crosslinkers with different molecular weights. In addition, the as-prepared separation layer exhibited excellent dimensional stability and solvent resistance. This paper not only provides a reference for fabricating hollow fiber LNF with better purification performance, but also shows their potential in developing solvent resistant nanofiltration

Determination of modeled costs at sewage treatment plants in the case of different sequences of treatment

Introduction. The article considers the definition of the key components of operating costs at wastewater treatment plants with a capacity of 1 to 100 thousand cubic meters per day by modeling using specialized software.
 
 Materials and methods. In the study, two technological cleaning schemes were investigated — the conventional line-up with biological aeration reactor and secondary clarifier and the scheme of biological aeration reactor with submerged membrane bioreactor for sludge separation. The other structures for the two facilities were identical. Since it was important to obtain results that could be used at real facilities, the values of concentrations of major pollutants typical for urban wastewater before treatment, as well as technological parameters of operation, were used as initial data for calculations.
 
 Results. As the results of calculations, the values of concentrations of pollutants in wastewater after treatment using both technological schemes and the values of the required volumes for the arrangement of biological treatment facilities and the area occupied by them were obtained and analyzed. Operating costs were considered in terms of electricity costs for the operation of biological treatment facilities and treatment facilities in General, as well as the specific cost of electricity for treatment 1 m3 of wastewater. In addition, the cost of purchasing membrane modules was calculated, which can be classified as operational due their replacement frequency of approximately every 7–10 years.
 
 Conclusions. The results of the study showed that application of membrane technologies at the stage of secondary treatment could have a significant potential for the reconstruction of wastewater treatment plants in conditions of increased productivity and limited opportunities for expanding the area.

Investigating Membranes Used in Gas Separation in Industry

This paper examines the membranes used in the separation of gases in industry. To date, more than 60% of the application of membrane technology in the separation of gaseous mixtures is related to the separation of nitrogen from air and the recovery of hydrogen from the gas streams of ammonia or synthesis units. These units contain clean gases free of any blocking gases and gases that affect the nature of the polymer. However, the dramatic growth of the use of membrane technology in the field of natural gas treatment, refineries and petrochemical units - which contain compressible compounds and vapors that affect the polymer network - has led to increasing attention to the stability and efficiency of polymer membranes. The flexibility of polymer chains during the manufacturing process of nanocomposite membranes is one of the most important manufacturing parameters. During the process of solvent evaporation from the film placed on the glass plate, due to the stresses caused by the shrinkage and irreversibility of the hard chains of the glass polymers, cracks are formed in the polymer-nanoparticles interface

Performance of a hybrid membrane aerated biofilm reactor (H-MBfR) for shortcut nitrification

Membrane fouling, especially that caused by microbes is the main reason restricting the application of membrane technology in wastewater treatment. In this study, shortcut nitrification (SN) of ammonia was achieved in a new hybrid membrane aerated biofilm reactor (H-MBfR) where fixed fiberfill was used as the auxiliary biofilm carrier to alleviate membrane fouling through most biomass transfer. The experiment showed that the NO2− accumulation capacity of the reactor was stable and that the NAE was greater than 80 %. The oxygen transfer efficiency reached 71.09 % because the membrane module was used to provide oxygen to the reactor. Microbial community analysis showed that the percentages of Nitrosomonas in the two biofilm-samples collected from the membrane and fiberfill were 37.47 % and 10.99 %, respectively. Microorganisms in the reactor mainly concentrated on the fiberfill, and the biomass on the surface of the membrane accounted for only 19.53 % of the total biomass. The results indicated that the addition of fiberfill effectively improved membrane fouling by reducing the biomass on the membrane surface. This research makes possible the practical application of the SN process and is an insightful method for meeting the challenge of membrane fouling.

Synthesis and Characterization of Montmorillonite Membrane for Nickel and Zink Metals Filtration in Electroplating Liquid Waste

The application of ceramic membrane technology has been applied in water treatment. The montmorillonite used was analyzed by XRD and showed typical montmorillonite peaks at 2θ 7.49o, 28.07o, 35.75 o, 40.73o, 49.14o dan 67.03o. Montmorillonite membrane was made by the process of dry pressing.PVA in montmorillonite is expected to function as a binder agent. The result variation on PVA composition 0%, 1%. 2%, 3% and 4%, show the flux value that increased with the adition of PVA composition. The montmorillonite membrane with a 4% PVA composition a result greatest flux and porosity values compared to other compositions. The resulting flux value is 1596.5679 L/m2.h and porosity 20.9477%. SEM-EDXtest result showed montmorillonite membrane is a porous membrane that is spread and evenly distributed but the resulting pore is not uniform. Montmorillonite membrane rejection of nickel metal was 55.5352% dan zink metal was 37.8614% with a 40-minute filtration process.

Highly efficient removal of organic pollutants from wastewater using a recyclable graphene oxide membrane intercalated with g-C3N4@TiO2-nanowires

Membrane fouling has been a major challenge in the practical application of membrane technology for wastewater treatment and purification. In this study, a reusable membrane composed of g-C3N4@TiO2-nanowires modified graphene oxide (GO/CN@TNWs) was successfully fabricated through electrostatic interactions and a vacuum filtration-assisted self-assembly process. The as-fabricated membrane possessed higher photocatalytic activity than the pure TNWs under simulated solar light exposure, attributing to the introduction of GO with high absorption and carrier mobility, and the synergistic effects of TNWs and CN. Furthermore, the π-π stacking interactions between GO and organic pollutant molecules contribute to the excellent enrichment efficiency of GO/CN@TNWs membrane (98.77%) toward tetracycline hydrochloride (TCH). Room-temperature ESR studies indicate that the GO/CN@TNWs membrane can generate more superoxide radical, hydroxyl radical and hole species for photocatalytic degradation. Therefore, the GO/CN@TNWs membrane may be used for TCH removal from waste water and the excellent solar-light-driven photocatalytic performance endows GO/CN@TNWs membrane absorbents with recycling abilities for the realization of large-scale wastewater purification.

A Review of Processes for Removing Antibiotics from Breeding Wastewater.

Antibiotic pollution has become an increasingly serious issue due to the extensive application of antibiotics, their resistance to removal, and the harmful effects on aquatic environments and humans. Breeding wastewater is one of the most important sources of antibiotics in the aquatic environment because of the undeveloped treatment systems in breeding farms. It is imperative to establish an effective antibiotic removal process for breeding wastewater. This paper reviews the treatment methods used to remove antibiotics from breeding wastewater. The mechanisms and removal efficiency of constructed wetlands, biological treatments, advanced oxidation processes (AOPs), membrane technology, and combined treatments are explained in detail, and the advantages and disadvantages of the various treatment methods are compared and analyzed. Constructed wetlands have high removal rates for sulfonamide (SM), tetracycline (TC), and quinolone (QN). The antibiotic removal efficiency of biological treatment methods is affected by various processes and environmental factors, whereas AOPs and combined treatment methods have better antibiotic removal effects. Although it has broad application prospects, the application of membrane technology for the treatment of antibiotics in breeding wastewater needs further research.

A novel tubular membrane reactor for pure hydrogen production in the synthesis of formaldehyde by the silver catalyst process

Formaldehyde-based chemistry plays a significant role in the production of different materials. In this work, attempts have been made to revamp a silver catalyzed formaldehyde plant by applying membrane technology. The conventional silver catalyst packed bed reactor was replaced by a shell and tube membrane reactor. A steady-state one-dimensional model was applied to evaluate the performance of the proposed membrane process. The model was validated with experimental results from the plant.The effects of various parameters including reactor pressure, feed temperature, and membrane thickness on the membrane reactor were investigated. Results showed that the effect of feed temperature on production rates was negligible. The increase in pressure and decrease in membrane thickness, however, leads to increase products. The simultaneous production of 100 tonnes/day of formalin 37% (37 wt% formaldehyde in water) and 500 kg/day pure hydrogen achieved by the proposed process. Furthermore, the exiting reactor temperature can be reduced to 420 °C which is significantly lower than the conventional method (650 °C).

State-of-the-Art and Opportunities for Forward Osmosis in Sewage Concentration and Wastewater Treatment.

The application of membrane technologies for wastewater treatment to recover water and nutrients from different types of wastewater can be an effective strategy to mitigate the water shortage and provide resource recovery for sustainable development of industrialisation and urbanisation. Forward osmosis (FO), driven by the osmotic pressure difference between solutions divided by a semi-permeable membrane, has been recognised as a potential energy-efficient filtration process with a low tendency for fouling and a strong ability to filtrate highly polluted wastewater. The application of FO for wastewater treatment has received significant attention in research and attracted technological effort in recent years. In this review, we review the state-of-the-art application of FO technology for sewage concentration and wastewater treatment both as an independent treatment process and in combination with other treatment processes. We also provide an outlook of the future prospects and recommendations for the improvement of membrane performance, fouling control and system optimisation from the perspectives of membrane materials, operating condition optimisation, draw solution selection, and multiple technologies combination.

Optimization of electrodialysis unit for partial desalination: Batch and continuous operation

In recently few years, application of membrane technologies in sea water desalination is increased compared to other desalination technologies. Electrodialysis membrane technology is still limited in seawater desalination due to the high operation cost and its limitations for high salty water. Electrodialysis desalination cost is proportional to the amount of salt, which must be carried out through the membrane. Seawater desalination with high salt content of NaCl (42 g/L) was applied using IonTech electrodialysis unit. Partial desalination process was studied in two separate experiments, batch and continuous operation. Operation parameters like voltage applied, electrolyte concentration and time of desalination were studied under batch mode process. Continuous operation process was carried out to confirm the partial desalination process of electrodialysis. The limited current density is determined, 1.49 A/m2 and 1.15 A/m2 for theoretical and experimental, respectively. The specific energy consumption was calculated, 7.15 kWh/m3.

Ceramic membrane technology for water and wastewater treatment: A critical review of performance, full-scale applications, membrane fouling and prospects

• Ceramic membrane (CM) market is growing with many full-scale applications. • CM is superior to polymeric membrane–high stability & flux, long life, low fouling. • Physicochemical processes (e.g., ozonation) are effective for fouling control. • Catalytic (nano) CMs can enhance antifouling, and pollutant removal capability. • Cost analysis of CMs, fouling control & cleaning should be evaluated at full-scale. Application of ceramic membrane technology in water and wastewater is rapidly growing. Inherent advantages of ceramic membrane including chemical/thermal stability, low fouling propensity and long lifespan make ceramic membrane technology attractive, and the ceramic membrane market is expected to achieve a compound annual growth rate of 12%. Ceramic membranes could be integrated with advanced oxidation processes such as in-situ ozonation that cannot be applied in the case of polymeric membrane due to their potential degradation during long-term exposure. In addition, the hybrid-ceramic membrane processes such as ceramic membrane bioreactor are superior to polymeric counterparts due to higher flux, higher pollutant removal, lower fouling rate and higher cleaning efficiency. Although ceramic membrane has high capital cost, life-cycle costs of ceramic and polymeric plants are comparable. Notably, full-scale ceramic membrane water/wastewater treatment plants have been installed in many countries such as Japan, USA, Singapore and United Kingdom. Given the attractiveness of this technology, performance of ceramic membrane is critically reviewed with a focus on their applications in water and wastewater treatment under mild conditions. In addition, fouling mechanisms and control strategies are elucidated and are compared with polymeric membranes. Importantly, for the first time, the status of full-scale applications and market prospects of ceramic membranes are critically analysed to show their future potential. Lastly, future research directions such as development of cost-effective ceramic membranes, understanding the biofouling evolution and economic evaluation of physicochemical processes for fouling control are proposed.

RESEARCH OF METHANE PRODUCTION PROCESS FROM BIOGAS AND PYROLYSIS GAS

The article investigates the separation process of biogas and the pyrolysis gas by application of membrane technology. The urgency of the problem of purification of industrial, agricultural, distillery waste or waste water by means of biological fermentation in anaerobic conditions of organic substances is indicated. If it is not possible to biodegrade waste, use pyrolysis or gasification. Pyrolysis gas, unlike biogas, has hydrogen and carbon monoxide. The process of separating methane from leaving impurities is much more economical than the process of removing impurities to obtain methane. Although for more than a hundred years mankind has known about the principles of gas diffusion and mass transfer through polymer films. But only in the last 40 years, membranes have begun to be used on an industrial scale in gas purification. With a membrane unit, a high methane production efficiency (> 96%) can be achieved. The lack of mechanical complexity and their modular design, which allows them to scale easily to provide significant flexibility, are increasingly gaining attention from the industry. The paper was proposed setting circuit for isolating methane and its operation is described. As a result of the research carried out, graphical dependencies were obtained at the stages: absorption (volume fraction of dissolved methane from the circulation ratio of the absorber), adsorption (absorption capacity of the membrane packing over time) and regeneration (the rate of desorption of the absorber from the membrane packing versus time). Using these dependencies, it is possible to calculate the flow rate of the absorber that is used in the absorption process and to determine the number of membrane elements for the membrane apparatus.

Enhancing ultrafiltration performance by gravity-driven up-flow slow biofilter pre-treatment to remove natural organic matters and biopolymer foulants

Membrane fouling by influent biopolymers, and the formation of surface biofilms, are major obstacles to the practical application of membrane technologies. Identifying reliable and sustainable pre-treatment methods for membrane filtration remains a considerable challenge and is the subject of continuing research study worldwide. Herein, the performance of a bench-scale gravity-driven up-flow slow biofilter (GUSB) as the pre-treatment for ultrafiltration to reduce membrane fouling is presented. Dissolved organic carbon (DOC) was shown efficiently removed by the GUSB (around 80%) when treating a natural water influent. More significantly, biopolymers, with molecular weight (MW) between 20 kDa and 100 kDa, were effectively removed (62.8% reduction) and this led to a lower rate of transmembrane pressure (TMP) development by the UF membrane. Microbial diversity analysis further unraveled the function of GUSB in shaping microbes to degrade biopolymers, contributing to lower accumulation and different distribution pattern of SMP on the membrane surface. Moreover, the biofilm formed on the membrane surface after the pre-treatment of GUSB was observed to have a relative porous structure compared to the control system, which can also affect the fouling development. Long-term operation of GUSB further revealed its robust performance in reducing both natural organic matters and UF fouling propensity. This study overall has demonstrated the potential advantages of applying a GUSB to enhance UF process performance by reducing biofouling and improving effluent quality.

Tuning the micro-phase separation of the PES-g-PEG comb-like copolymer membrane for efficient CO2 separation

As a common CO2 separation membrane material, polyethylene glycol (PEG) with ether oxygen groups shows high dissolution selectivity to CO2. However, high molecular weight PEG has strong crystallinity, resulting in low gas flux, while the low molecular weight PEG has poor mechanical properties. Block copolymers containing PEG segments can address this challenge but are difficult to synthesize. In this work, a series of polyether sulfone (PES) comb-like copolymer with PEG side chains were prepared by the polycondensation followed by the thiol-ene click chemistry. By manipulating the density and length of PEG side chains (Mn = 550, 1000, 2000) to adjust the fine structure of the micro-phase separation, the gas separation performance of the PES-g-PEG membrane was optimized. The PES-g-PEG polymers have two glass transition temperatures (Tg), which are attributed to the PES main chain and PEG side chains. The Tg-PEG and Tg-PES difference (ΔTg) is highly correlated with the PEG side chain density and can be used to interpret the phase separation degree. The copolymer membrane with shorter PEG side chains achieved higher chain density and more developed micro-phase separation, which was facilitated by thermal annealing. As a result, PES A-g-PEG550 membrane shows the best gas separation performance with the CO2 permeability of 26.8 Barrer and the CO2/N2 selectivity of 27.6. The permeability variation with the microstructure of PES-g-PEG mostly relies on the side chain density rather than volume fraction or side chain molecular weight. We believe this study of the gas separation performance of the comb-like copolymer material is meaningful for the further application of membrane technology in CO2 capture and separation.

Recent Advances in MXene‐based Separation Membranes

AbstractTwo‐dimensional (2D) materials with unique atomic thickness are promising candidate for high performance separation membrane. Several 2D materials such as graphene, graphene oxide (GO), metal‐organic frameworks (MOFs), covalent frameworks (COFs), transition metal dichalcogenides (TMDCs), etc have been studied as a separation membrane due to their outstanding properties such as high mechanical strength, large surface area, good chemical and thermal stability, ease of functionalization, and hydrophilic surface. Recently, transition metal carbide also known as MXene, a new member of layered membrane family has attended significant interest in water purification, desalination, gas separation, and pervaporation. Herein, the most recent advances in 2D MXene‐based membranes from both experimental and computational aspects are reviewed. Emphasis is placed on materials' structures, properties, fabrication methods, and potential applications in membrane technology. Finally, this review closes with several recommendation and new directions in this research area.

Surface modified by green synthetic of Cu-MOF-74 to improve the anti-biofouling properties of PVDF membranes

Mitigation of membrane fouling is an important problem to be solved in the application of membrane technology. In this research, we synthesised a kind of Cu-MOF-74 by a facile and environmentally friendly method at room temperature. This kind of Cu-MOF-74 was firstly and successfully coated on poly (vinylidene fluoride) (PVDF) membranes for improving their anti-biofouling performance. The experimental results show that Cu-MOF-74 increases the hydrophilicity and roughness of the PVDF membrane surface, and the antibacterial efficiency of the modified membrane was as high as 97.7% at 4 h. Moreover, we found that the Cu-MOF-74 could sustainably release Cu2+ for one week, the maximum Cu2+ release concentration of PVDF membrane coated by 0.025 g Cu-MOF-74 reached 0.42 mg/L, and the generation of Cu2+ played a significant role in suppressing E. coli. In the meantime, this kind of Cu-MOF-74 can release OH, which will lead to the accumulation of reactive oxygen species (ROS) in bacterial cells. The ·OH can oxidise and destroy bacterial cells, which will be in favour of enhancing the anti-biofouling performance. This novel PVDF membrane surface modified by green synthetic Cu-MOF-74 has a strong antibacterial property and high application potential for water treatment.

Quantifying Charge Effects on Fouling Layer Strength and (Ir)Removability during Cross-Flow Microfiltration.

Fouling of membranes is still an important limiting factor in the application of membrane technology. Therefore, there is still a need for an in-depth understanding of which parameters affect the (ir)removability of fouling layers, as well as the mechanisms behind fouling. In this study, fluid dynamic gauging (FDG) was used to investigate the influence of charge effects between negatively charged foulant particles and cations on cake cohesive strength. Fouling cakes’ thicknesses and cohesive strengths were estimated during membrane operations, where microfiltration (MF) membranes were fouled in a feed-and-bleed cross-flow filtration system with low and highly negatively charged polystyrene–polyacrylic acid core-shell particles. In addition, an added procedure to determine the irremovability of cakes using FDG was also proposed. Comparing layers formed in the presence and absence of calcium ions revealed that layers formed without calcium ions had significantly lower cohesive strength than layers formed in the presence of calcium ions, which is explained by the bridging effect between negatively charged particles and calcium ions. Results also confirmed more cohesive cakes formed by high negative charge particles in the presence of calcium compared to lower negative charge particles. Hence, it was demonstrated that FDG can be used to assess the cohesive strength ((ir)removability) of cake layers, and to study how cake cohesive strength depends on foulant surface charge and ionic composition of the solution.

ИССЛЕДОВАНИЕ ЗАВИСИМОСТИ УДЕЛЬНОГО ВЫХОДНОГО ПОТОКА АЦЕТАТЦЕЛЛЮЛОЗНЫХ ПЛЕНОК ОТ ГРАДИЕНТА ДАВЛЕНИЯ, ТЕМПЕРАТУРЫ И КЛАССИФИКАЦИЯ ПРОЦЕССОВ МЕМБРАННОГО РАЗДЕЛЕНИЯ РАСТВОРОВ

A comparative study of the application of membrane, electromembrane and electrobaromembrane technologies for various industries in the field of wastewater treatment and technological solutions is presented. The principle of classification of membrane separation processes is formulated. The characteristic periods of the solvent transfer stimulation were determined. Based on the experimental data obtained on the permeability of the solvent through the MGA-80P and MGA-95 membranes, empirical dependences are proposed that describe the kinetic characteristics of the dependence from transmembrane pressure and temperature effects.

Prospects for the application of membrane technologies at various stages of biotechnological processes

Prospects for the application of membrane technologies at various stages of biotechnological processes

Membrane Fractionation of Protein Hydrolysates from By-Products: Recovery of Valuable Compounds from Spent Yeasts

Spent brewer’s yeast (Saccharomyces sp.), the second most generated by-product from the brewing industry, contains bioactive and nutritional compounds with high added value such as proteins (40–50%), polysaccharides, fibers and vitamins. Molecules of interest from agro-industrial by-products need to be extracted, separated, concentrated, and/or purified so that a minimum purity level is achieved, allowing its application. Enzymatic hydrolysis has been successfully used in the production of peptides and protein hydrolysates. The obtained hydrolysates require efficient downstream processes such as membrane technology, which is an important tool for the recovery of thermolabile and sensitive compounds from complex mixtures, with low energy consumption and high specificity. The integration of membrane techniques that promote the separation through sieving and charge-based mechanisms is of great interest to improve the purity of the recovered fractions. This review is specifically addressed to the application of membrane technologies for the recovery of peptides from yeast protein hydrolysates. Fundamental concepts and practical aspects relative to the ultrafiltration of agro-industrial protein hydrolysates will be described. Challenges and perspectives involving the recovery of peptides from yeast protein hydrolysates will be presented and thoroughly discussed.