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Membrane science and technology is growing rapidly worldwide and continues to play an increasingly important role in diverse fields by offering high separation efficiency with low energy consumption. Membranes have also shown great promise for “green” separation. A majority of the investigations in the field are devoted to the membrane fabrication and modification with the ultimate goals of enhancing the properties and separation performance of membranes. However, less attention has been paid to membrane life cycle management, particularly at the end of service. This is becoming very important, especially taking into account the trends toward sustainable development and carbon neutrality. On the contrary, this can be a great opportunity considering the large variety of membrane processes, especially in terms of the size and capacity of plants in operation. This work aims to highlight the prominent aspects that govern membrane life cycle management with special attention to life cycle assessment (LCA). While fabrication, application, and recycling are the three key aspects of LCA, we focus here on membrane (module) recycling at the end of life by elucidating the relevant aspects, potential criteria, and strategies that effectively contribute to the achievement of green development and sustainability goals.

Hydrogen (H2) is known for its clean energy characteristics. Its separation and purification to produce high-purity H2 is becoming essential to promoting a H2 economy. There are several technologies, such as pressure swing adsorption, membrane, and cryogenic, which can be adopted to produce high-purity H2; however, each standalone technology has its own pros and cons. Unlike standalone technology, the integration of technologies has shown significant potential for achieving high purity with a high recovery. In this study, a membrane–cryogenic process was integrated to separate H2 via the desublimation of carbon dioxide. The proposed process was designed, simulated, and optimized in Aspen Hysys. The results showed that the H2 was separated with a 99.99% purity. The energy analysis revealed a net-specific energy consumption of 2.37 kWh/kg. The exergy analysis showed that the membranes and multi-stream heat exchangers were major contributors to the exergy destruction. Furthermore, the calculated total capital investment of the proposed process was 816.2 m$. This proposed process could be beneficial for the development of a H2 economy.

Membrane separation technology for CO2 capture in pre-combustion has the advantages of easy operation, minimal land use and no pollution and is considered a reliable alternative to traditional technology. However, previous studies only focused on the H2-selective membrane (HM) or CO2-selective membrane (CM), paying little attention to the combination of different membranes. Therefore, it is hopeful to find the optimal process by considering the potential combination of H2-selective and CO2-selective membranes. For the CO2 capture process in pre-combustion, this paper presents an optimization model based on the superstructure method to determine the best membrane process. In the superstructure model, both CO2-selective and H2-selective commercial membranes are considered. In addition, the changes in optimal membrane performance and capture cost are studied when the selectivity and permeability of membrane change synchronously based on the Robeson upper bound. The results show that when the CO2 purity is 96% and the CO2 recovery rate is 90%, the combination of different membrane types achieves better results. The optimal process is the two-stage membrane process with recycling, using the combination of CM and HM in all situations, which has obvious economic advantages compared with the Selexol process. Under the condition of 96% CO2 purity and 90% CO2 recovery, the CO2 capture cost can be reduced to 11.75$/t CO2 by optimizing the process structure, operating parameters, and performance of membranes.

The skimmed goat milk was submitted to the nanofiltration process using a volume reduction factor (VRF) equal to 2. It was verified a rapid decrease of the permeate flux at a low time, with a continuous flux, caused by the reversible resistance, which is characterized by the standard and complete blocking. The combined fouling model was evaluated, including complete pore blocking and cake filtration mechanism, which described the skimmed goat milk nanofiltration behavior. For the VRF equal to 2 was determined the total solids, protein, lactose, ash, mineral fraction content, which increased successfully with the nanofiltration process. The Power Law and Herschel-Buckley models were fitting to describe the flow behavior for retentate, which presented the higher apparent viscosity. Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Symmetric flow batteries use a single electrolyte formulation instead of the usual two and offer simplified manufacture and operation, the possibility to use low-cost porous separators in place of ion-exchange membranes, and elimination of certain failure modes. Furthermore, using nonaqueous solvents in lieu of water enables exploration of redox species that support cell potentials beyond the electrochemical window of aqueous electrolytes. This thesis aims to assist in minimizing the levelized cost of storage for symmetric nonaqueous flow batteries through informed electrolyte development, materials selection, and device operation. Illustrating the large design space of flow battery electrolytes permits the definition of ``symmetric'' for the present application. A zero-dimensional model for flow batteries with porous separators is developed which incorporates self-discharge behavior. Coupling this model to technoeconomic equations reveals the basic tradeoffs inherent to using porous separators along with two promising active species approaches for symmetric flow battery electrolytes: salts of coordinated transition metal-ligand complexes and synthetically simple, soluble aromatic compounds used in a mixed electrolyte configuration. The technoeconomic analysis explores membrane cost/performance tradeoffs pertinent to symmetric systems using porous separators. Successfully implementing symmetric electrolytes of any composition requires original approaches to measurement and control of transport phenomena in the membrane due to shifts in relative contribution of different driving forces for crossover and self-discharge vs. traditional flow batteries. Real-time estimation techniques and reservoir balancing methods are developed to measure and control these convoluted phenomena. Common perceived failure modes of benchtop flow batteries and methods to deconvolute capacity fade mechanisms are discussed. The established nonaqueous redox-active species vanadium acetylacetonate is used as a representative compound to demonstrate that, counter to current literature, the primary failure mode of nonaqueous flow batteries is confined to resistance growth in the separator and not electrolyte or electrode degradation. Methods to further understand and mitigate this failure mode are discussed, and solubilities of cosolvent systems are explored to improve energy density. Iron bipyridine salts are revisited and found to succeed in symmetric flow battery operation subject to separator degradation constraints, prompting the study of more affordable counteranions.

When discharged into wastewater, pharmaceuticals and personal care products (PPCPs) become microorganic contaminants and are among the largest groups of emerging pollutants. Human, animal, and aquatic organisms’ exposures to PPCPs have linked them to an array of carcinogenic, mutagenic, and reproductive toxicity risks. For this reason, various methods are being implemented to remove them from water bodies. This report critically reviews these methods and suggests improvements to removal strategies. Biological, physical, and chemical methods such as biological degradation, adsorption, membrane filtration, and advanced electrical and chemical oxidation are the common methods used. However, these processes were not integrated into most studies to take advantage of the different mechanisms specific to each process and are synergistic in the removal of the PPCPs that differ in their physical and chemical characteristics (charge, molecular weight, hydrophobicity, hydrogen bonding, structure). In the review articles published to date, very little information is available on the use of such integrated methods for removing PPCPs. This report attempts to fill this gap with our knowledge.

Persistent pharmaceutical occurrence in different lakes and rivers usually originates from live stocks, agriculture, aquaculture, households, and hospitals. The presence of these compounds in the ecosystems leads to fatal consequences. Pharmaceuticals can threaten microorganisms in the environment, either causing its deterioration or allowing pathogens to gain resistance against antibiotics and medical treatments. These occurrences in the environment questions the ability of conventional treatment to remediate pharmaceutical wastewater.

For the surface adsorption process, a wide range of studies have been carried out to describe the adsorption process. However, no extensive study has been carried out to investigate the pre-treatment method effect on the separation process. The purpose of the present study is to improve the performance of the membrane process in the treatment of oily wastewater. For this purpose, the effects of pre-treatment, membrane modification, and operational parameters were investigated on the microfiltration membrane system. Two methods of coagulation and surface adsorption were used as pre-treatment, and then a modified polysulfone (PSf) membrane containing TiO2 nanoparticles was applied in the microfiltration process. In order to reduce the membrane fouling and increase the permeate flux, the surface of the nanoparticle was modified. In order to check the performance of coagulation, pretreatments of polyferric sulfate (PFS) and polyferric chloride (PFC) were applied. The results showed that the Chemical Oxygen Demand (COD) reduction of 98% can be obtained using 1 g/L of PFS coagulant at pH = 6, while only 81% of COD was removed using 1 g/L PFC. It was also found that the best pH for the performance of this type of coagulant was measured as pH = 10 and the removal efficiency for 1 and 2 g/L of PFC coagulant was obtained as 96.1% and 91.7%, respectively. The results show that in the case of using a coagulant of less than 1 g/L, using PFS is more efficient than PFC; meanwhile, in more than 1 g/L of coagulant, this effect is reversed and the use of PFS will be less efficient than PFC. The performance of the PSf-TiO2 membrane fabricated by the Nonsolvent-induced phase separation (NIPS) method was investigated using modified nanoparticles with an initial size of 10 nm at different operating conditions. The results show that the permeate flux and the rejection can be increased to 563 L/h m2 and 99%, respectively, using the modified PSf membrane. The results of this paper showed that the performance of the adsorption process can be improved by using the coagulation process as a pre-treatment method.

The relationship between the solvent–solute interaction and permeation properties is fundamental in the development of the forward osmosis (FO) membrane. In this study, we report on the quantitative reproduction of the permeation flux, which has different solvent–solute interactions, through the modeled FO membrane by non-equilibrium molecular dynamics (NEMD). The interaction effect was investigated by changing the interatomic interaction between the solute and the solvent. The calculated permeation through the semi-permeable modeled FO membrane, in which the interaction between solvent and solution is equal to that between solutions, was consistent with the theoretical curve derived from the combination of the permeation flux and Van’t Hoff equations. These results validate the NEMD for the evaluation of permeation in FO. On the other hand, the permeation is much derived from the theoretical values when the interaction between the solvent and solute atoms is relatively large. However, the simulated permeation was consistent with the theoretical curve, correcting the solution concentration by the coordination number of the solvent atoms to the solute atoms. Our results imply that permeation flux through the FO membrane is significantly changed by the interaction between the solute and the solvent and can be theoretically predicted by calculating the coordination number of the solvent to the solute, which can be readily estimated by equilibrium molecular dynamics simulation.

In this study, a technical scheme of an ammonium recovery process from diluted municipal or industrial wastewaters was developed, and the main operational parameters of adsorption/desorption and air-stripping/acid-scrubbing or membrane units were examined. The proposed approach combines the removal of ammonium nitrogen by an ion-exchange mechanism on metakaolin-based geopolymers (MKGPs) followed by adsorbent regeneration. A regeneration agent was purified by the air-stripping technique or membrane technology. A ready-to-use market-grade fertilizer or industrial-grade ammonia water could be obtained as the final product. The properties and regeneration ability of MKGP, prepared from activated kaolinite clay, were compared with new geopolymer adsorbents based on papermill sludge (FS MKGP). Adsorption fixed-bed column experiments with continuously circulated regeneration solution purified by air-stripping or the membrane approach were conducted to determine the limits of the regeneration solution’s application. Sodium and potassium salts were tested as regeneration agents, and the influence of regeneration solution composition on ammonium removal and recovery rates was investigated. Based on a breakthrough curve analysis, the removal rate of ammonium N by FS MKGP was found to be 3.2 times higher than that by MKGP for actual wastewater samples. Moreover, there were substantial differences in the regeneration regime between the two adsorbents. For the air-stripping technique, a liquid-phase temperature of 45°C was minimal and enough for efficient ammonia transfer to the gaseous phase. For the membrane technique, a feed-phase temperature of 40°C was enough for removing ammonia from the regeneration solution, while no heating of a receiving phase was required.

Recycling reinjection of CO2 captured and purified from the produced gas of CO2 flooding can not only enhance oil recovery, but also realize the geological storage of CO2, so as to provide good social and economic benefit. With the operation and advancement of CO2 flooding development mode, one single CO2 capture and purification process can hardly deal with the yearly increase and large-scale variation of CO2 content in the produced gas. In order to provide support for the promotion of CO2-EOR technology oil and gas fields, to this end, this paper puts forward four schemes of multi-method CO2 capture and purification process. It includes two-stage hydramine method, one-stage membrane separation + one-stage hydramine method, two-stage membrane separation + one-stage hydramine method, one-stage membrane separation + two-stage hydramine method. And based on the working condition data of CO2 flooding in one certain oilfield, simulation was carried out by using HYSYS software. In addition, the enrichment degree of the CO2 captured and purified by means of different schemes and its energy consumption and economy were analyzed mainly. And the following research results were obtained. First, when the CO2 concentration of the produced gas is low, it is necessary to put the two-stage alcohol amine circulation process into production firstly to realize the deacidification of natural gas while purchasing some pure CO2 to mix at a certain proportion, so as to reach the required CO2 purity of reinjected gas. Second, as the CO2 concentration of the produced gas increases, it is better to use the membrane separation technology before the two-stage alcohol amine circulation process, so that the enriched and purified gas can reach the required CO2 purity of direction reinjection. In conclusion, the research results can provide engineering practical guidance for the formulation of the scheme to enrich and purify CO2 from the produced gas of CO2 flooding.

MXene,very recently emerging family of two-dimensional (2D) transition metal carbides and/or nitrides,have attracted a wide range of attention due to unique layered structure,hydrophilicity,high conductivity and catalytic activity.First,synthesis and various applications of MXene in adsorption,photocatalysis and membrane separation were summarized in this review.Then,the effects of structure control,surface modification and composite of MXene on the adsorption performance of MXene and the formation of effective heterojunction,the exposure of active crystal face and the deposition of precious metals on the catalytic performance of MXene based photocatalysts were discussed.The approaches of constructing MXene based separation membrane for separating pollutants and desalinating seawater were described in detail.Finally,the existing problems in the applications of MXene in the field of water treatment were summarized and analyzed,and the prospects of designing MXene based water treatment materials with excellent performance were put forward.

Global access to clean water and sanitation has been broadly discussed in the context of the Sustainable Development Goals adopted by the United Nations. In this context, membrane technology has been increasingly applied with great success in wastewater treatment. Considering the relevance of patent information for understanding the current status and future trends of technologies, the patent filings on membrane technology for wastewater treatment in the period from 2011 to 2019 were analyzed. This study comprised a global analysis, aimed at determining the most general aspects, and a qualitative analysis, which consisted of a careful reading of the documents to assess technological statuses and trends. From a total of 7303 patent documents found on the topic, 488 documents were selected for the qualitative analysis. China, Japan and the United States play a leading role in the development of these technologies. Companies constitute the vast majority of the applicants. The focus of the inventions turned out to be: equipment, membranes, customized equipment/processes for specific wastewaters, fouling control and cleaning, combinations of technologies and sustainability. Finally, enhancements in the operational performance of the membrane separation equipment and the development of membrane materials with increased water flow and fouling resistance are found to be key factors to broaden the application of membrane separation technology in wastewater treatment.

The co-deposition between polyphenols and amines has been demonstrated in order to prepare positively charged nanofiltration (NF) membranes for multivalent cation rejection in recent years; however, the low reactivities of the involved polyphenols usually cause a long co-deposition time and unsatisfactory rejection. Herein, a novel plant polyphenol (PG) was co-deposited with tetraethylenepentamine (TEPA) in a much shorter time period to prepare positively charged NF with high multivalent cation rejection membranes. The performance of the co-deposition membranes can be easily controlled by adjusting the mass ratio of PG and TEPA, reaction time, and pH value of the buffer solution. The optimal membrane, prepared under a polyphenol and polyamine mass ratio of 1:1, coating time of 2 h, and pH value of 8.0, shows a decent pure water permeability of 8.43 L m−2 h−1 bar−1 while maintaining a superior 96.24% MgCl2 rejection. More importantly, the universality of this method was corroborated by employing other amines with different molecular weights in the co-deposition. This work provides new insights for the preparation of high-performance positively charged NF membranes.

Lipophilization is a promising way to improve the bioavailability of flavonoids. However, the traditional enzymatic esterification methods are time-consuming, and present low yields and purity. Herein, a novel membrane-based lipophilization technology—bioinspired lipase immobilized membranes (BLIMs), including CAL-B@PES, CAL-B@PDA/PES and GA/CAL-B@PDA/PES— were fabricated to improve the antioxidant flavanone glycoside hesperidin lipophilization. Via reverse filtration, PDA coating and GA crosslinking, Candida antarctica lipase B (CAL-B) was stably immobilized on membrane to fabricate BLIMs. Among the three BLIMs, GA/CAL-B@PDA/PES had the greatest enzyme activity and enzyme loading, the strongest tolerance of changes in external environmental conditions (temperatures, pH, heating time, storage time and numbers of cycles) and the highest hesperidin esterification efficiency. Moreover, the optimal operating condition for GA/CAL-B@PDA/PES fabrication was the CAL-B concentration of 0.36 mg/mL, operation pressure of 2 bar, GA concentration of 5% and crosslinking time of 1 h. Afterwards, the hesperidin esterification process did not affect the micromorphology of BLIM, but clearly improved the BLIM permeability and esterified product efficiency. The present study reveals the fabrication mechanism of BLIMs and offers insights into the optimizing strategy that governs the membrane-based lipophilization technology process.

Máster en Ingeniería Química

The decomposition of volatile organic compounds by photocatalytic oxidation (PCO) has been widely studied. However, the technological development of this oxidative technique has to address how to handle the formation of transformation products. The work presented here investigates the original combination of a dense membrane separation process and PCO to intensify the trapping and reduction of PCO transformation products. Specific monitoring of toluene PCO transformation products, such as benzene and formaldehyde, in the outflow of both permeate and retentate compartments was proposed. The influence of operating parameters on the process, i.e., light intensity, pressure, membrane type, and catalyst mass, was also studied. The results reveal that membrane separation-PCO hybridization is particularly effective for reducing the presence of benzene and formaldehyde in the effluent treated. The benzene concentration in the outflow of the hybrid module can be reduced by a factor of 120 compared to that observed during the PCO of toluene alone.

In this work, a magnetic molecularly imprinted chitosan membrane (MMICM) was synthesized for the extraction of chlorobenzene compounds in environmental water using the membrane separation method. The optimal extraction amount for chlorobenzene (9.64 mg·L−1) was found to be a 1:2 solid to liquid ratio, with a 20 min extraction time and 35 °C extraction temperature. This method proved to be successfully applied for the separation and trace quantification of chlorobenzene compounds in environmental water, with the limit of detection (LOD) (0.0016–0.057 ng·L−1), limit of quantification (LOQ) (0.0026–0.098 ng·L−1), and the recoveries ranging (89.02–106.97%).

Nanoporous materials have attracted great attention in the fields of adsorption and membrane separation due to their remarkable nanoscale spatial effects. As an extension of inorganic porous materials, metal organic framework (MOF) has been widely used in gas-phase storage and separation, liquid-phase adsorption separation and catalytic reaction due to its large specific surface area, high porosity and adjustable pore structure. In this paper, the types of MOF are classified, and the synthesis methods and particle size control mechanism of MOF materials were compared. Among them, the advantages of solvothermal synthesis were emphatically introduced. At the same time, the problems and limitations of MOF materials in adsorption separation research were summarized systematically, and the advanced preparation technology of composite membrane based on MOF materials was prospected; the application of MOF in gas storage separation, liquid adsorption separation and membrane separation was summarized. Finally, for the preparation of composite membrane, the idea of improving the compatibility of MOF material and organic membrane by changing the synthesis method of MOF was proposed.

Nanofiltration (NF) with advantages of high efficiency and low‐cost has attracted increasing attentions in bio‐separation. However, the large‐scale application is limited by the inferior molecular selectivity, low chemical stability and serious membrane fouling. Many efforts, thus, have been devoted in NF materials design for specific applications to enhance the separation efficiency of bio‐products and increase membrane life‐time, as well as reduce the operating cost. This review summarized the recent progress of NF applications in bio‐separation, discussed various demands for NF membrane in the bio‐products purification and corresponding material innovations, finally proposed several practical suggestions for future research, which provided directions and guidance toward further product development and process industrialization.

This work was aimed at researching and developing a computer model, as well as an optimization and control algorithm for calculating pore shapes for separating membranes in separation processes. Two types of flow fluid rates through separation membranes with various pores configurations were considered. Here, the first type of pores had the form of a tortuous channel with sharp narrowing endings, which, in turn, could be assumed as “zero” wall thickness holes. The second type of pores had conical narrowing at the ends, which is closer to the real shape of the pores. As a result of the analysis of the performed calculations and models, data were obtained on the effect of the thickness of the selective layer on the performance of the membrane. In computer calculations, it was determined that the optimal volumetric porosity should be limited to 0.15, which affects the mechanical strength of the membrane. Calculations were also carried out on the Chemcad software product, which resulted in graphs of the optimal permeability of various liquids, depending on the differ curvature and pore volume of the separation membranes.

Separating carbon dioxide (CO2) from gaseous streams released into the atmosphere is becoming critical due to its greenhouse effect. Membrane technology is one of the promising technologies for CO2 capture. SAPO-34 filler was incorporated in polymeric media to synthesize mixed matrix membrane (MMM) and enhance the CO2 separation performance of this process. Despite relatively extensive experimental studies, there are limited studies that cover the modeling aspects of CO2 capture by MMMs. This research applies a special type of machine learning modeling scenario, namely, cascade neural networks (CNN), to simulate as well as compare the CO2/CH4 selectivity of a wide range of MMMs containing SAPO-34 zeolite. A combination of trial-and-error analysis and statistical accuracy monitoring has been applied to fine-tune the CNN topology. It was found that the CNN with a 4-11-1 topology has the highest accuracy for the modeling of the considered task. The designed CNN model is able to precisely predict the CO2/CH4 selectivity of seven different MMMs in a broad range of filler concentrations, pressures, and temperatures. The model predicts 118 actual measurements of CO2/CH4 selectivity with an outstanding accuracy (i.e., AARD = 2.92%, MSE = 1.55, R = 0.9964).

A key problem associated with the design of graphene oxide (GO) materials and their tuning for nanoscale separations is how specific functional groups influence the competitive adsorption of solvated ions and water at liquid/graphene interfaces. Computation accompanied by experiment shows that OH and COOH exert an influence on water adsorption properties stronger than that of O and H functional groups. The COO– anions, following COOH deprotonation, stabilize Pb(II) through strong electrostatic interactions. This suggests that, among the functional groups under study, COOH offers the best Pb(II) adsorption capacity and the ability to regenerate the sorbent through a pH swing. In line with computation, striking experimental observations revealed that a substantial increase in Pb(II) adsorption occurs with increasing pH. Our findings provide a systematic framework for controlled design and implementation of regenerable C-based sorbents used in separations and desalination.

Di Zhang,1,* Yafei Guo,2,* Yingli Wang2 1Department of Basic Medicine, Shanxi Medical University, Taiyuan, People’s Republic of China; 2Department of Traditional Chinese Medicine and Food Engineering, Shanxi University of Traditional Chinese Medicine, Jinzhong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Di Zhang Email zhangdi0801@live.cnIntroduction: Astragalus is a commonly used traditional Chinese medicine in China, which has been widely applied to enhance the immunomodulatory function of the body. The main bioactive components are complicated. To explore the role of the components, various techniques have been applied in Astragalus extraction. Membrane separation technique featured with green processing condition and high efficiency is of signification interest in the application of Astragalus treatment.Methods: In this study, a new ingredients group A4 was separated from Astragalus using membrane separation technique. The quantification and identification of A4 were achieved by UV-vis spectrometry and UPLC-MS measurements. Pathological approaches along with serum metabolomics were utilized to study the immunoprotective effects of the extracts and explore the underlying mechanisms on metabolic activity.Results: It was observed that A4 could promote the secretion of IL-2 and IFN-γ, stimulate the activated CD4+CD25+ and CD8+ CD25+ T lymphocytes in splenocytes and protect rat spleen to some extent. Seven crucial biomarkers that related to immunity regulations were screened out and identified through serum metabonomic analysis coupled with nuclear magnetic resonance. The enrichment analysis revealed that A4 alleviated the immune dysfunction by modulating amino acid metabolism and energy metabolism for the first time.Conclusion: The new ingredients group A4 isolated from the Astragalus membrane can reduce the immune dysfunction by regulating the amino acid metabolism and energy metabolism of rats.Keywords: Astragalus, membrane separation, immunomodulatory, serum metabolomics

Ag+ was introduced into *BEA‐type zeolite membrane by an ion‐exchange method to enhance olefin selectivity. Ag−*BEA membrane exhibited superior olefin separation performance for both ethylene/ethane and propylene/propane mixtures. Particularly, the separation factor for ethylene at 373 K reached 57 with the ethylene permeance of 1.6×10−7 mol m−2 s−1 Pa−1. Adsorption properties of olefin and paraffin were evaluated to discuss contribution of Ag+ to separation performance enhancement. A strong interaction between olefin and Ag+ in the membrane caused preferential adsorption of olefin against paraffin, leading to selective permeation of olefin. Ag−*BEA membrane also exhibited high olefin selectivities from olefin/N2 mixtures. The affinity‐based separation through Ag−*BEA membrane showed a high potential for olefin recovery and purification from various gas mixtures., Ag−*BEA membrane for olefin recovery: Ag+ was introduced into *BEA‐type zeolite membrane. We found that such a membrane exhibited superior ethylene and propylene selectivities. Ag−*BEA membrane had a high potential for olefin recovery from various gas mixtures.

In this paper, the effect of time, aeration scheme, aeration rate, and mixed liquor suspended solid (MLSS) concentration on the permeate flux in membrane bioreactors have been studied. Aeration rates of 0.5, 1.0, and 1.5 LPM were tested with MLSS concentrations of 5, 10, and 15 g/L. Furthermore, a continuous and pulsed aeration scheme (5 min on and 5 min off) was tested. The experimental data were used to develop an artificial neural network (ANN) model, which showed excellent agreement (R2 = 0.9963) with the data. The average normalized flux decreased as the MLSS concentration increased from 5 to 15 g/L and increased as the aeration rate increased from 0.5 to 1.5 LPM. No clear correlation was found between the aeration schemes and the average normalized flux. ANN weights analysis revealed the order of importance was time > aeration rate > MLSS concentration > aeration scheme. 2021 Desalination Publications. All rights reserved. Scopus

To handle the rising amount of plastic waste in the environment, new technologies are necessary to recover the value of this resource. Chemical recycling is one option to treat mixed and multi-layer plastic waste streams. Emerging technologies works e.g. with pyrolysis (via thermal or catalytic cracking) of the plastic waste streams and results in multi-material output streams. Membranes are a widely adopted and a relevant technology for bulk separations, within chemical recycling operations. Based on a different separation principle, they need less thermal energy than e.g. distillation columns. However, when it comes to their contribution to the environmental impact of the whole process chain, membranes need special attention. Compared to installed process units, such as pyrolysis and catalytic upgrading reactors, membranes have a shortened life time (non-permanent) compared to the whole process chain and need extra treatments to avoid fouling and maintain their efficiency. These points make it challenging to integrate a LCA model representing membranes within the whole LCA process model. In this paper a framework for the LCA of membranes will be presented regarding their impact in a chemical recycling process and how a shortened life time model can be integrated into a longer life LCA process model with focus on the handling of the different time scales.

Sustainable processes for purifying water, capturing carbon, producing biofuels, operating fuel cells, and performing energy-efficient industrial separations will require next-generation membranes. Solvent-less fabrication for membranes not only eliminates potential environmental issues with organic solvents, but also solves the swelling problems that occur with delicate polymer substrates. Furthermore, the activation procedures often required for synthesizing microporous materials such as metal–organic frameworks (MOFs) can be reduced when solvent-less vapor-phase approaches are employed. This perspective covers several vacuum deposition processes, including initiated chemical vapor deposition (iCVD), initiated plasma-enhanced chemical vapor deposition (iPECVD), solvent-less vapor deposition followed by in situ polymerization (SLIP), atomic layer deposition (ALD), and molecular layer deposition (MLD). These solvent-less vapor-phase methods are powerful in creating ultrathin selective layers for thin-film composite membranes and advantageous in conformally coating nanoscale pores for the precise modification of pore size and internal functionalities. The resulting membranes have shown promising performance for gas separation, nanofiltration, desalination, and water/oil separation. Further development of novel membrane materials and the scaling up of high-throughput reactors for solvent-less vapor-phase processes are necessary in order to make a real impact on the chemical industry in the future.

We analysed the effectiveness of transvaginal ultrasonographic and foetal/maternal pulse Doppler findings as predictors of labour onset within 1 week. We included 22 single normal pregnancies and evaluated the one-point and short- and long-term differences in uterine artery pulsatility index (PI), umbilical artery PI, middle cerebral artery PI (MCA-PI), peak systolic velocity, and cervical length (CL). Presence of funnelling and membrane separation over the internal cervical os was evaluated. Significant changes were observed in the one-point measurement of and short-term and long-term differences in CL, the one-point measurement of and long-term difference in MCA-PI, and the presence of membrane separation (Grade 2). In multivariate analysis, the significant predictors were short-term differences in CL (odds ratio [OR]: 5.27), long-term differences in MCA-PI (OR: 13.3), and presence of membrane separation (Grade 2) (OR: 5.38). Transvaginal ultrasonographic and foetal pulse Doppler findings were effective predictors of labour onset within 1 week., Impact statement, What is already known on this subject? Parameters reported to predict labour onset include the Bishop score, cervical length, decreased long-term cervical length, funnelling of the internal cervical os, and adrenal gland volume., What do the results of this study add?Short-term changes in cervical length, long-term changes in middle cerebral artery pulsatility index, and the presence of membrane separation Grade 2 were found to be useful predictive factors of labour onset in this study., What are the implications of these findings for clinical practice and/or further research? The prediction of labour onset enables clinicians to properly manage pregnancy and delivery considering maternal and foetal conditions.

In order to deeply treat pharmaceutical wastewater to meet the industrial water quality standard, the membrane flux change of the comprehensive pharmaceutical wastewater treated with advanced nanofiltration and reverse osmosis was studied. The operating condition, flux and water yield rate were studied in continuous and cyclic modes. According to the change of membrane flux, the treatment and cleaning scheme suitable for industrial application of membrane separation were determined. The results show that the daily physical wash time of nanofiltration membrane is 7 minutes, the wash time of intensive acid and alkali is 90 minutes respectively, the average flux is 16.1 L/(m2·h) in continuous mode and 7.7 L/(m2·h) in cyclic mode, and the water recovery rate is 73%. The daily physical wash time of reverse osmosis membrane is 12 minutes, the wash time of intensive acid and alkali is 90 minutes respectively, the average flux is 12.8 L/(m2·h) in continuous mode and 7.2 L/(m2·h) in cycle mode, and the water recovery rate is 74%. The research on advanced membrane treatment of pharmaceutical wastewater provides a theoretical basis for the industrial application.

Biocatalytic membrane takes advantages of reaction–separation integration as well as enzyme immobilization, which has attracted increasing attentions in online detection and biomanufacturing. However, the high preparation cost, inferior comprehensive performance, and low stability limit its applications. Thus, besides enzyme immobilization, more efforts should be made in biocatalytic membrane configuration design for a specific application to enhance the synergistic effect of reaction and separation and improve its operating stability. This review summarized the recent progress on biocatalytic membrane preparation, discussed different membrane configurations for various applications, finally proposed several challenges and possible solutions, which provided directions and guides for the development and industrialization of biocatalytic membrane.

Objectives:An experimental study was conducted to investigate the membrane filtration characteristics of mixed liquor in methanogenic reactor to extend solid retention time (SRT) in food waste anaerobic digestion system. Methods:On the basis of the particle size distribution (0.5~700 µm) of the methanogenic mixed liquor, three grade membranes (MF, UF, NF) were tested in a stirred cell filtration and a plate type module. Furthermore foulants of membrane, especially UF, was investigated by SEM-EDS, FTIR, SEC. Results and Discussion:As a result UF membrane was selected for stable filtration of the liquor in terms of flux (2.51 L/m2･h･bar) and the flux recovery (100%) as well as filtration resistance (Total 7.15.E+13 m-1). Average flux was 18 L/m2･h･bar for the selected UF membrane in cross flow filtration using a flat plate module. The filtration results showed that membrane fouling was caused by gel and cake layer formed on the membrane surface and 90% of the initial flux could be recovered by physical washing. It was identified that major fouling causing materials were byproducts of carbohydrate and protein decomposition, and small amount of inorganic substance detected on the membrane surface were salt and struvite like materials. Conclusions:Based on the membrane filtration characteristics analyzed from the study, the UF membrane coupled anaerobic digestion is feasible to be applied as a novel food waste treatment system for SRT extension of the methanogenic reactor.

After the biomass pretreatment and fermentation processes, the purification step constitutes a major task in bioethanol production processes. The use of membranes provides an interesting choice to achieve high-purity bioethanol. Membrane separation processes are generally characterized by low energy requirements, but a high capital investment. Some major design aspects for membrane processes and their application to the ethanol dehydration problem are addressed in this work. The analysis includes pervaporation and vapor permeation methods, and considers using two types of membranes, A-type zeolite and amorphous silica membrane. The results identify the best combination of membrane separation method and type of membrane needed for bioethanol purification.

Yuta Saito, 1–3 Miwa Sakata, 3 Moe Kobayakawa, 3 Hiroshi Kawachi, 4 Kazunori Kawaguchi, 3 Yoshiyuki Hiki, 3 Masao Kato, 1 Mayuko Mori, 1, 3 Midori Hasegawa, 1 Norimi Ohashi, 4 Yukio Yuzawa, 1 Nobuya Kitaguchi 3 1Department of Nephrology, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan; 2Graduate School of Medical Sciences, Fujita Health University, Toyoake, Aichi, Japan; 3Faculty of Clinical Engineering, School of Medical Sciences, Fujita Health University, Toyoake, Aichi, Japan; 4Ogaki Municipal Hospital, Ogaki, Gifu, JapanCorrespondence: Nobuya Kitaguchi 4-8-17, Yuzato, Higashisumiyosi-ku, Osaka 546-0013, JapanTel/Fax +81-6-3-4392-7087Email nkitaguc@fujita-hu.ac.jpPurpose: Amyloid-β protein (Aβ) is one of the causative proteins of Alzheimer’s disease. We have been developing extracorporeal blood Aβ-removal systems as a method for enhancing Aβ clearance from the brain. We reported previously that medical adsorbents and hemodialyzers removed Aβ monomers from peripheral blood, which was associated with influx of Aβ monomers from the brain into the bloodstream. Our intent here was to develop a method to promote clearance of Aβ oligomers and to provide an estimate of the molecular size of intact Aβ oligomers in plasma.Methods: Two hollow-fiber devices with different pore sizes (Membranes A and B) were evaluated as removers of Aβ oligomers with human plasma in vitro. The concomitant removal of Aβ oligomers and monomers was investigated by using Membrane B and hexadecyl alkylated cellulose beads or polysulfone hemodialyzers. Double-filtration plasmapheresis with Membrane A was investigated as an approach for the removal of plasma Aβ oligomers in humans.Results: Aβ oligomers were effectively removed by both Membranes A and B. The increase of Aβ oligomers in plasma was observed just after the removal of plasma Aβ oligomers in humans. The intact molecular size of major Aβ oligomers in the plasma was estimated to be larger than albumin at approximately 60 kDa or more. Additionally, the concomitant removal of Aβ monomers and oligomers evoked dissociation of larger Aβ oligomers into smaller ones and monomers.Conclusion: Aβ oligomers were cleared from plasma both in vitro and in human subjects by using hollow-fiber membranes with large pores, indicating that their intact sizes were mostly larger than 60 kDa. Aβ oligomers in peripheral circulation were increased after some clearances in human. Further investigation will determine whether the Aβ oligomers detected in circulation after clearance were via influx from the brain.Keywords: Aβ, amyloid beta, oligomer, Alzheimer’s disease, blood purification, membrane separation

Lignin is a renewable and abundant source for production of bio-based chemicals and is a valuable alternative to crude oil to obtain aromatic building blocks. It is built from aromatic units with strong chemical linkages, which need to be cleaved to enable the use of the aromatic compounds in industrial applications. In addition to depolymerizing lignin, efficient fractionation and conversion of the resulting complex mixtures is an essential step in the valorization of lignin derivatives for different applications. In this work, we studied the separation of a lignin oil obtained by catalytic cleavage in supercritical ethanol (scEtOH) of technical lignin produced by means of soda pulping of wheat straw. The use of six commercial polymeric nanofiltration (NF) membranes and one in-house developed Grignard-functionalized ceramic membrane was investigated for the fractionation of a mixture of lignin derivatives. Separation by molecular weight (MW) was observed with the polymeric NP030 membrane but not with the other membranes tested. The development of a protocol using this membrane in the diafiltration mode for fractionation of crude lignin oils (CLOs) is discussed.

Petrochemical tail gases have various components and many separation methods, thus there are many possible design schemes, making it difficult to determine the optimal scheme. In this work, a graphic synthesis method was used to design a hybrid multi-input refinery gas separation process consisting of membranes, pressure swing adsorption (PSA), shallow condensation (SC), and distillation units for the production of valuable products which include H2, C2, LPG, and C5+. Ten refinery gases with different compositions were visualized and represented with vector couples in a triangular coordinate system. Firstly, according to the characteristics of the refinery gases, the feeds located in the same region of the triangular coordinate system were merged to simplify the number of input streams, then ten original input streams were combined into two mixed streams. Secondly, the optimal separation sequence was determined by using the unit selection rules of a graphic synthesis method. Thirdly, the process was simulated in UniSim Design and the process parameters were determined by sensitivity analysis. Finally, economic assessments were carried out, which led to an annual gross product profit of USD 38.62 × 106 and a payback period of less than 4 months.

Membrane-based oil–water separation has shown huge potential as a remedy to challenge oily wastewater with ease and low energy consumption compared to conventional purification techniques. A set of new composite ceramic membranes was fabricated to separate surfactant-stabilized oil/water (O/W) emulsion. Carbide-derived carbon (CDC) was functionalized by 3-aminopropyltriethoxy silane (APTES) and subsequently deposited on a ceramic alumina support and impregnated with piperazine as an additional amine. The APTES functionalized CDC-loaded membrane was then crosslinked using terephthalyol chloride (TPC). Different loadings of functionalized CDC (50 mg, 100 mg and 200 mg) were employed on the ceramic support resulting in three versions of ceramic membranes (M-50, M-100 and M-200). The fabricated membranes were thoroughly characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Attenuated total teflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Energy dispersive x-ray spectroscopy (EDX) and elemental mapping. The highest permeate flux of 76.05 LMH (L m−2 h−1) at 1 bar using 67.5 ppm oil-in-water emulsion (as feed) was achieved by the M-50 membrane, while an oil separation efficiency of >99% was achieved by using the M-200 membrane. The tested emulsions and their respective permeates were also characterized by optical microscopy to validate the O/W separation performance of the best membrane (M-100). The effect of feed concentration and pressure on permeate flux and oil–water separation efficiency was also studied. A long-term stability test revealed that the M-100 membrane retained its performance for 720 min of continuous operation with a minor decrease in permeate flux, but the O/W separation efficiency remained intact.

Wastewater is produced by numerous dyes producing and dye consuming industries in their process activities especially the textile industry. These effluents become toxic and harmful to the living things and the environment if not properly treated before being discharged to the environment. In recent decades dye wastewater has been becomes a growing water pollution problem because it is one of the most difficult to treat. To put an end to this problem, viable, efficient, and sustainable method of treatment of dye wastewater and color removal needs to be established. Several research papers have been done over the years on various treatment method of dye wastewater with evolving options; this paper is to bring together both the conventional and new methods. Some of the conventional and new methods researched over the years include activated sludge, coagulation, adsorption, membrane separation processes and electrochemical process etc. Although there is currently no uniform standard or method of treatment universally adopted, many countries have put in place allowable limits of composition of dischargeable wastewater. This paper seeks to explore which methods are highly efficient, produces manageable and recyclable waste and a combination/hybrid treatment option of these methods to achieve maximum color removal.

Carbon capture has been an important topic of the twenty-first century because of the elevating carbon dioxide (CO2) levels in the atmosphere. CO2 in the atmosphere is above 420 parts per million (ppm) as of 2022, 70 ppm higher than 50 years ago. Carbon capture research and development has mostly been centered around higher concentration flue gas streams. For example, flue gas streams from steel and cement industries have been largely ignored due to lower associated CO2 concentrations and higher capture and processing costs. Capture technologies such as solvent-based, adsorption-based, cryogenic distillation, and pressure-swing adsorption are under research, but many suffer from higher costs and life cycle impacts. Membrane-based capture processes are considered cost-effective and environmentally friendly alternatives. Over the past three decades, our research group at Idaho National Laboratory has led the development of several polyphosphazene polymer chemistries and has demonstrated their selectivity for CO2 over nitrogen (N2). Poly[bis((2-methoxyethoxy)ethoxy)phosphazene] (MEEP) has shown the highest selectivity. A comprehensive life cycle assessment (LCA) was performed to determine the life cycle feasibility of the MEEP polymer material compared to other CO2-selective membranes and separation processes. The MEEP-based membrane processes emit at least 42% less equivalent CO2 than Pebax-based membrane processes. Similarly, MEEP-based membrane processes produce 34–72% less CO2 than conventional separation processes. In all studied categories, MEEP-based membranes report lower emissions than Pebax-based membranes and conventional separation processes.

Metal-organic framework (MOF) membranes have demonstrated high efficiency for CO2 capture due to their wide range of pore sizes, high surface area, high porosity, and open metal sites. In this work, we propose a multi-scale design framework of MOF-based membrane separation for CO2/CH4 mixture via integration of molecular simulation, machine learning, and process modelling and simulation. The GCMC and MD molecular simulation is first used to evaluate adsorption isotherms, isosteric adsorption heat, self-diffusivity, activation energy, permeability, and selectivity of a MOF-based membrane (e.g., IRMOF-1) for CO2/CH4 separation at different operating conditions. It is found that the simulated isotherms at 298 K are consistent with experimental results. CO2 permeability can range from 4.090 × 104 to 3.818 × 105 barrer with variation in operating conditions. The same phenomenon is also reflected in the selectivity. We then establish prediction models of adsorption capacity and self-diffusivity using machine learning methods such as artificial neural network (ANN), which are used to calculate the permeability. The mean squared error is 0.0086, and the coefficient of determination is 0.9822. The proposed ANN models are integrated with the tanks-in-series model of a hollow fiber membrane separation process, which is simulated using the finite volume method. Three case studies illustrate the feasibility and superiority of the proposed integrated framework.

The widely used dyes in the pharmaceutical, chemical, and medical industries have brought about an intensive concern for the sustainable development of the environment. Membrane separation offers a versatile method for classified recycling and the reuse of residual components. In this work, polyimide membranes were synthesized via the polymerization of 4,4′-(hexafluor-isopropylidene) diphthalic anhydride and 1,4-bis (4-aminophenoxy) benzene diamine. The organic solvent nanofiltration membrane was prepared by casting onto a glass plate and precipitating in the non-solvent phase. The properties of the membranes were recorded by FTIR, 1HNMR, TGA, and GPC. The molecular simulations were carried out to analyze the affinity between the membrane and different solvents. The membrane was used in the removal of Rose Bengal, methyl blue, Victoria blue B, and crystal violet from methanol. The effects of the feed liquid concentration, operating pressure, swelling degree, organic solvent resistance, and long-term running on the membrane performance were studied. Results showed that membranes prepared in this work demonstrated high solvent permeation and dye rejection due to the sieving effect and solvent affinity. For methyl blue, the solvent performance achieved a permeability of 2.18 L∙m−2∙h−1∙bar−1 corresponding to a rejection ratio of 94.2%. Furthermore, the membrane exhibited good stability over 60 h of continued testing. These results recommend a potential strategy in the development of a suitable monomer to prepare a polyimide membrane for dye separation.

PEGylated proteins are usually purified using chromatographic methods, which are limited in terms of both speed and scalability. In this paper, we describe a microfiltration membrane-based hybrid method for purifying PEGylated proteins. Polyethylene glycol (or PEG) is a lower critical solution temperature polymer which undergoes phase transition in the presence of a lyotropic salt and forms micelle-like structures which are several microns in size. In the proposed hybrid method, the PEGylated proteins are first converted to their micellar form by the addition of a lyotropic salt (1.65 M ammonium sulfate). While the micelles are retained using a microfiltration membrane, soluble impurities such as the unmodified protein are washed out through the membrane. The PEGylated proteins thus retained by the membrane are recovered by solubilizing them by removing the lyotropic salt. Further, by precisely controlling the salt removal, the different PEGylated forms of the protein, i.e., mono-PEGylated and di-PEGylated forms, are fractionated from each other. Hybrid separation using two different types of microfiltration membrane devices, i.e., a stirred cell and a tangential flow filtration device, are examined in this paper. The membrane-based hybrid method for purifying PEGylated proteins is both fast and scalable.

In this research, the membrane separation process was used to separate helium from methane gas. In order to do this, computational fluid dynamics (CFD) was used, and the effect of process parameters on the performance of the membrane separation process was studied by this method. To simulate the hydrodynamics of flow in the channel, the Navier-Stokes equation was used, and the Maxwell-Stefan equation was applied to simulate the mass transfer phenomenon. In addition, Fick’s law was utilized to simulate mass transfer in the membrane domain. The impacts of significant parameters such as feed pressure, feed flow rate, and feed concentration on parameters such as He/CH4 separation factor, methane and helium membrane flux and helium mole fraction in permeate stream were studied. The results of the simulation indicated that the feed pressure of 10 bar, feed flow rate of 120 cm3 min–1, and feed mole fraction of 0.0254 had the best membrane performance in He/CH4 separation. This work is licensed under a Creative Commons Attribution 4.0 International License.

Orientador: Prof. Dr. Eduardo Lucas Subtil Coorientadora: Profa. Dra. Camila Clementina Arantes Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Santo André, 2022. O reator anaeróbio de fluxo ascendente de manta de lodo (UASB) é um marco no tratamento de efluentes, porém, usualmente requer pós-tratamento para atender padrões de emissão ou produção de água de reúso. Coagulantes naturais tem grande potencial para tratar efluentes anaeróbios com menor impacto ambiental, enquanto a adoção de módulos externos com membranas de microfiltração (MF) e ultrafiltração (UF) tem sido cada vez mais frequentes para seu pós-tratamento. Porém, a comparação técnica e econômica destas tecnologias não é realizada com frequência. Outra possibilidade é a pré-adição de coagulantes ao sistema de membranas, no entanto pesquisas avaliando este emprego dos coagulantes naturais são raras. Nesse contexto, o objetivo deste trabalho foi investigar e comparar sistemas de coagulação, floculação e sedimentação com coagulantes a base de tanino e de alumínio à sistemas de filtração por membranas com diferentes tamanhos de poro (MF e UF) para tratamento de efluente de reator UASB, avaliando-se também a adição de coagulantes a um sistema de UF. Tanino modificado por reação de Mannich (TANm) e cloreto de polialumínio (PACl) comerciais, em dosagens de 10 a 500 mg/L de princípio ativo, foram usados em ensaios de jar test, onde o TANm afetou menos o pH, consumiu menos alcalinidade e produziu menos lodo comparado ao PACl, porém este atingiu maior remoção de turbidez (89-97%), DQO (70-72%) e fósforo (65-98%) na faixa de dosagem de 25 a 100 mg/L. Os ensaios de filtração foram feitos em célula teste simulando filtração tangencial, com excelente remoção de turbidez (96%) e matéria orgânica (69-72%) com MF e UF. Obteve-se maior fluxo de operação e menor resistência do fouling com MF, apesar de maior decaimento do fluxo. Na avaliação econômica, os custos operacionais foram maiores para os sistemas de coagulação devido ao custo dos coagulantes e da disposição do lodo, sendo MF o sistema de menor custo, com tempo de retorno estimado para o investimento (payback simples) de 1,0 a 0,3 ano. Para o sistema de filtração por membranas com adição coagulantes, doses de 10, 25 e 40 mg/L de princípio ativo foram empregadas, com adição à célula teste após mistura rápida. Ensaios de fluxo limitante, filtrabilidade da amostra e reversibilidade do fouling foram feitos e indicaram aumento dos valores de fluxo limitante e redução do decaimento do fluxo e da resistência específica da camada de torta com uso de coagulantes, com maior produção de permeado, mas com aumento do fouling irreversível. Remoção de poluentes foi similar para os sistemas avaliados, exceto por alguns parâmetros de matéria orgânica e turbidez, além de remoção de fósforo com PACl. Na avaliação econômica, os coagulantes foram capazes de reduzir a área de membrana requerida para o tratamento, reduzindo custos com trocas de membrana e limpeza química, mas o custo de sua adição é elevado. O sistema sem coagulantes apresentou menor custo total e o payback simples foi de 1,3 a 0,4 ano. Recomendam-se ensaios futuros em escalas maiores e avaliação de parâmetros pertinentes adicionais para produção de água de reúso. The upflow anaerobic sludge blanket reactor (UASB) is a milestone in wastewater treatment, but it usually requires post-treatment in order to attend discharge standards or reuse water production. Natural coagulants have great potential for anaerobic effluent treatment with lesser environmental impact, while the adoption of microfiltration (MF) and ultrafiltration (UF) external membrane modules has been increasingly frequent for this post-treatment. However, technical and economical comparison of these technologies is not frequently realized. Another possibility is the pre-addition of coagulants to the membrane system, but researches evaluating this use of natural coagulants are rare. In this context, the objective of this work was to investigate and compare coagulation, flocculation and sedimentation with tannin-based and Al-based coagulants with membrane filtration systems with different pore size (MF and UF) for treatment of UASB effluent, and the adding of coagulants in a UF system was also evaluated. Commercial tannin modified by Mannich reaction (TANm) and polyaluminum chloride (PACl), in active principle dosages of 10-500 mg/L were used in jar test assays, where TANm affected less the pH, consumed less alkalinity and produced less sludge compared to PACl, but this reached higher turbidity (89-97%), COD (70-72%) and phosphorus (65-98%) in dosage interval of 25 to 100 mg/L. Filtration assays were made in a test cell simulating crossflow filtration, with excellent turbidity (96%) and COD (69-72%) removal with MF and UF. Higher operational flux and lesser fouling resistance were obtained with MF, despite higher flux decay. Economical evaluation showed that operational costs were higher for coagulation systems due to coagulants and sludge disposal costs, with MF being the system with lowest cost, with estimated return time for investment (simple payback) from 1.0 to 0.3 year. For membrane filtration systems with coagulant addition, active principle dosages of 10, 25 and 40 mg/L were employed, with addition to the test cell after rapid mixing. Critical flux, filterability and fouling reversibility assays were performed and indicated higher critical flux, less flux decay and specific cake layer resistance with use of coagulants, with higher permeate production, but with increase in irreversible fouling. Pollutant removal was similar for the evaluated systems, except for a few organic matter parameters and turbidity, beyond additional phosphorus removal with PACl. In the economic evaluation, coagulants were capable of reducing required membrane area for treatment, reducing membrane exchange and chemical cleaning costs, but its addition cost is high too. The system without coagulants presented the lesser total cost and the simple payback was from 1.3 to 0.4 year. Future trials with upscaling are recommended and evaluation of additional relevant parameters for reuse water production.

A general finite element model and a new solution method were developed to simulate the permeances of Lintz Donawiz converter gas (LDG) components and the performance of a polysulfone membrane separation unit. The permeances at eight bars of CO, N2, and H2 in LDG simulated using the developed model equations employing the experimental mixed gas data were obtained by controlling the finite element numbers and comparing them with pure gas permeation data. At the optimal finite element numbers (s = 15, n = 1), the gas permeances under the mixed-gas condition were 6.3% (CO), 3.9% (N2), and 7.2% (H2) larger than those of the pure gases, On the other hand, the mixed-gas permeance of CO2 was 4.5% smaller than that of pure gas. These differences were attributed to the plasticization phenomenon of the polysulfone membrane used by CO2. The newly adopted solution method for the stiff nonlinear model functions enabled the simulation of the performance (in terms of gas recovery, concentration, and flow rate) of the first-stage membrane within two seconds under most gas flow conditions. The performance of a first-stage membrane unit separating LDG could be predicted by the developed model with a small error of

Spinach and orange by-products are well recognized for their health benefits due to the presence of natural polyphenols with antioxidant activity. Therefore, the demand to produce functional products containing polyphenols recovered from vegetables and fruits has increased in the last decade. This work aims to use the integrated membrane process for the recovery of polyphenols from spinach and orange wastes, implemented on a laboratory scale. The clarification (microfiltration and ultrafiltration, i.e., MF and UF), pre-concentration (nanofiltration, NF), and concentration (reverse osmosis, RO) of the spinach and orange extracts were performed using membrane technology. Membrane experiments were carried out by collecting 1 mL of the permeate stream after increasing the flow rate in 1 mL/min steps. The separation and concentration factors were determined by HPLC-DAD in terms of total polyphenol content and by polyphenol families: hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids. The results show that the transmembrane flux depended on the feed flow rate for MF, UF, NF, and RO techniques. For the spinach and orange matrices, MF (0.22 µm) could be used to remove suspended solids; UF membranes (30 kDa) for clarification; NF membranes (TFCS) to pre-concentrate; and RO membranes (XLE for spinach and BW30 for orange) to concentrate. A treatment sequence is proposed for the two extracts using a selective membrane train (UF, NF, and RO) to obtain polyphenol-rich streams for food, pharmaceutical, and cosmetic applications, and also to recover clean water streams.

In this study, a laminar pulsatile fluid flow was used for the separation of benzene, toluene, ethylbenzene, and xylene isomers (BTEX) from aqueous solutions. Polyether sulfone hollow fiber membrane has been applied to this process. The effects of BTEX concentration, and feedand extraction flow rates were examined. It was found that the application of the pulsatile fluid flow with the frequency of 0.5 Hz improved the separation process significantly, and the removal efficiency increased more than twice. Moreover, the results showed that BTEX separation under pulsatile fluid flow was affected by the feed flow rate, extraction flow rate, and the BTEX concentration, as well. Validerad;2022;Nivå 2;2022-11-29 (sofila);Funder: University of Sistan and Baluchestan (grant no. G1394/3); PolishNational Agency for Academic Exchange (grant no. PPN/ULM/2020/1/00014/DEC/1)

International audience; Surfactant flooding is one of the Chemical Enhanced Oil Recovery (cEOR) methods used to meet the growing demand for oil. It consists in injecting an aqueous formulation containing surfactants, whose performance, both in terms of incremental oil production and surfactant adsorption, is assessed in the laboratory with coreflood tests. Currently, coreflood effluents are collected in tubes throughout the experiment and the analyses are performed offline. Surfactants are measured in the aqueous phase by Hyamine assay or by liquid chromatography. It is noteworthy that these analyses may be difficult to carry out since the effluents may contain stable emulsions. Moreover, it is unclear whether all surfactants are in the aqueous phase, or whether they are partly trapped in the oil phase. To overcome these difficulties and quantify surfactants reliably in coreflood effluents, we have developed an online experimental setup that includes: a dilution “millifluidic” chip to transfer the surfactants in the aqueous phase, a “microfluidic” membrane-based separation device to separate oil from the aqueous phase, and an online UV–visible spectrometer to measure the surfactant concentration. This setup was successfully validated with model fluid mixtures and was evaluated on real systems. Finally, it was tested under representative conditions of coreflood experiments. The obtained results proved the efficiency of the setup to facilitate the quantification of the surfactants in the effluents which clearly improves the accuracy of the measurements.

The toxicity of heavy metals can cause water pollution and has harmful effects on human health and the environment. Various methods are used to overcome this pressing issue and each method has its own advantages and disadvantages. Membrane filtration technology such as nanofiltration (NF) produces high quality water and has a very small footprint, which results in lower energy usage. Nanofiltration is a membrane-based separation technique based on the reverse osmosis separation process developed in the 1980s. NF membranes have a pore size of 1 nm and molecular weight cut off (MWCO) of 300 to 500 Da. The properties of NF membranes are unique since the surface charge of the membranes is dependent on the functional groups of the membrane. The rejection mechanism of NF membrane is unique as it is a combination of various rejection mechanisms such as steric hindrance, electric exclusion, dielectric effect, and hydration mechanism. However, these mechanisms have not been studied in-depth due to their complexity. There are also many factors contributing to the rejection of NF membrane. Many junior researchers would face difficulty in studying NF membrane. Therefore, this paper is designed for researchers new to the field, and will briefly review the rejection mechanisms of NF membrane by both sieving and non-sieving separation processes. This mini-review aims to provide new researchers with a general understanding of the concept of the separation process of charged membranes.

Organic micropollutants (OMPs) in climate change affected natural environment such as wetlands, and engineered systems have brought serious concerns for water security and public health. These issues have increased the demand for better managing water resources and developing effective technologies for aqueous micropollutants removal. This thesis investigated these subjects through the following five sub-research projects. First, boreal peatland was used as a case study for understanding how peatland fires and droughts impacts peatland resilience. Laboratory results suggested that heating and moisture condition, coupled with peat organic hydrophobic transformations, influence peat soil hydrophobicity and the resultant water-extractable pollutant leaching, which potentially threatens peatland downstream receiving waters such as potable waters by high organic loads. Further, post-fire peat chemistry and their mechanistic relationships to leached pollutants (total organic carbon (TOC), nutrients and phenols) were elucidated through a laboratory leaching study. Increased contaminant loading was observed in post-heated peat leachates, suggesting negative effects to water treatment efficiency and an increase of treatment costs to surface waters as potable water source. Next, peat soils damaged from extreme fires and droughts were upcycled for producing high surface area, value-added porous carbons based on a rapid, facile chemical activation approach. This application had the simultaneous benefit of peatland ecological restoration, protecting downstream communities from heavy run-off, and using the sustainable damaged peats for effective environmental remediation though adsorption. Moreover, a critical review of nano-enabled composite membranes for OMP removal (size-exclusion, adsorption, charge interaction, and photo- and electro-catalysis) and their respective benefits and limitations were discussed. This work brought new perspectives for next-generation nanocomposite membranes for OMP removal. Finally, a novel, hyperbranched polyethylenimine (HPEI) crosslinked iron doped reduced graphene oxide (rGO) nanocomposite membrane was synthesized for process-intensified flow-through separation of phenolic micropollutants. Mechanisms and separation performance to phenolic micropollutant and azo dyes were investigated. Thesis Doctor of Philosophy (PhD) Climate change, industrial manufacture, and population growth have been exacerbating the global water stress. Organic micropollutants (OMPs) are potentially toxic, persistent and can exist even at trace levels, which have been increasingly discovered and identified in natural and built systems. In this research, environmental chemistry of climate-change impacted boreal peatland soils, and their mechanistic relationships to peat soil hydrophobicity, organic substance transformations, micropollutant leaching, and impacts to downstream potable water quality was investigated as a case study. Two different innovative water treatment strategies were developed for restoring peatland resilience and enhancing water resource sustainability including treating peatland phenolic micropollutants. The first approach converted shallow layer wildfire- and drought- damaged peats into value-added porous carbons for adsorption. The second approach synthesized a novel reduced graphene oxide (rGO) nanocomposite membrane for process-intensified flow-through separation. These solutions provide novel insights for source water protection and wastewater treatment in adaption to climate change.