Membrane-based Processes Research Articles

Hydroelectric energy conversion of waste flows through hydroelectronic drag

Hydraulic energy is a key component of the global energy mix, yet there exists no practical way of harvesting it at small scales, from flows with low Reynolds number. This has triggered a search for alternative hydroelectric conversion methodologies, leading to unconventional proposals based on droplet triboelectricity, water evaporation, osmotic energy, or flow-induced ionic Coulomb drag. Yet, these approaches systematically rely on ions as intermediate charge carriers, limiting the achievable power density. Here, we predict that the kinetic energy of small-scale "waste" flows can be directly and efficiently converted into electricity thanks to the hydroelectronic drag effect, by which an ion-free liquid induces an electronic current in the solid wall along which it flows. This effect originates in the fluctuation-induced coupling between fluid motion and electron transport. We develop a nonequilibrium thermodynamic formalism to assess the efficiency of such hydroelectric energy conversion, dubbed hydronic energy. We find that hydronic energy conversion is analogous to thermoelectricity, with the efficiency being controlled by a dimensionless figure of merit. However, in contrast to its thermoelectric analogue, this figure of merit combines independently tunable parameters of the solid and the liquid, and can thus significantly exceed unity. Our findings suggest strategies for blue energy harvesting without electrochemistry, and for waste flow mitigation in membrane-based filtration processes.

Pre-ozonation coupled with forward osmosis with fertilizer as draw solution for simultaneous wastewater treatment and agricultural irrigation

Membrane-based processes have emerged as effective solutions for treating tannery wastewater. Persistent membrane fouling remains a significant obstacle to long-term operational sustainability, and residual pollutants often persist in the treated effluent. To address these challenges, we investigated an integrated ozone-forward osmosis (O3-FO) process, with a focus on evaluating the efficacy of pre-ozonation in alleviating membrane fouling, as well as exploring the possibilities of this integrated process for the reuse of tannery wastewater. Fertilizer, specifically 2 M Ca(NO3)2, served as the draw solution (DS) in this process. The findings reveal that the integrated system demonstrated remarkable pollutant retention capabilities. Notably, no metal was detected in the fertilizer. Therefore, the integrated process not only dilutes the fertilizer but also minimizes the risk of heavy metal contamination to both crops and soil. Furthermore, pre-ozonation effectively mitigated membrane fouling, resulting in an increase in membrane flux with a maximum increase of 20.98 % at 0.6 L/min. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed pre-ozonation has the most significant impact on four parameters: water flux (Jw), chemical oxygen demand (COD), fouling resistance (Rf) and oxidation reduction potential (ORP). Meanwhile, ammonium nitrogen (NH4-N) variation, dissolved organic carbon (DOC) variation and ORP played an important role in the four systems. Multi-criteria decision analysis (MCDA) showed that the 0.2 L/min O3-FO system achieved the highest score (0.66), followed by 0.6 L/min (0.53), 0.4 L/min (0.41) and 0 L/min (0.29). This research offers a theoretical framework for the synergistic integration of advanced oxidation and membrane technology in the treatment of industrial wastewater.

Pressure-induced piezoelectric response for mitigating membrane fouling in surface water treatment: Insights from continuous operation and biofouling characterization

Organic fouling and biofouling represents a critical challenge encountered by the membrane-based water treatment process. Herein, a piezoelectric PVDF membrane (PEM), capable of generating electrical responses to hydraulic pressure stimuli, was synthesized and employed for mitigating the fouling in surface water treatment. The surface-hydrophobilized PEM demonstrated sensitive and enhanced underwater output performance in response to increasing transmembrane pressure (TMP) during constant-flux filtration, with signals reaching up to ∼800 mV at a TMP of ∼80 kPa. This in-situ piezoelectric response significantly reduced TMP growth in both short-term (1 h) and long-term (15 days) filtration trials, demonstrating a strong capability to mitigate membrane fouling. Moreover, continuous piezoelectric stimulation effectively inhibited microbial activity and the accumulation of extracellular polymeric substances (EPS) on PEM surface, surpassing the dominant electrokinetic repulsion mechanisms observed in short-term trials. Microbial community analysis suggests that this evolution is primarily due to the targeted impact of piezoelectric stimulation on microbial metabolic behavior. The piezoelectric-induced electrical microenvironment inhibited the growth of microbes associated with high EPS production while promoting the proliferation of electrically active microbes involved in biopolymer digestion. In addition, the PEM demonstrated enhanced permeate quality throughout the filtration process, with DOC and UV254 removal rates increasing from 11.7 % and 15.6 % initially to 28.6 % and 19.5 % by the 15th day, respectively. Given the performance and self-powered capability of PEM compared to current electrified antifouling methods that require an external power supply, these attributes are anticipated to hold practical significance in developing innovative and energy-efficient strategies for mitigating both organic fouling and biofouling.

Scalable membrane-assisted ion exchange (MEM-IE) strategy for organic acid purification in biorefinery process

The transition towards a carbon-neutral society necessitates radical approaches in the bio-refinery pipeline, particularly in the production of organic acids. The current downstream process from a dilute fermentation broth is limited by the extensive use of acids and bases, along with heavy reliance on energy-intensive distillation. In this work, we propose an entirely membrane-based process to purify organic acids (e.g., gluconic acid) from a crude solution of catalytic dehydrogenation of glucose. To facilitate downstream purification, we introduce an innovative membrane-assisted ion exchange (MEM-IE) strategy, which is a scalable process that can protonate ionic compounds entirely in the solution phase. Instead of a solid ion exchange resin, a bulky yet soluble acidification agent is used to protonate the target compound, which can be easily separated via a size exclusion membrane. We selected non-toxic poly (4-styrene sulfonic acid) (H-PSS, 75 kDa) as the acidification agent to selectively protonate gluconate ions and to enable facile fractionation. The proposed MEM-IE strategy can overcome the scale-up limitation of traditional solid ion exchange resins and can be applied to many types of ionic compounds. The versatility of the proposed process was also demonstrated on formate and lactate compounds. A techno-economic evaluation using the Verberne cost model showed that the proposed process achieves an 80 % reduction in energy consumption compared to the fermentation-based process, and the return on investment (ROI) of a 330 ton-per-day plant was less than a year. The proposed membrane-based process for the purification of organic acids, particularly the MEM-IE strategy, offers a sustainable and energy-efficient downstream separation platform.

Membrane-based carbon capture for waste-to-energy: Process performance, impact, and time-efficient optimization

The energy crisis and rising waste production results in the need for more waste-to-energy solutions. However, capturing fossil-based carbon from waste incineration is crucial. The power consumption and overall impact of the carbon capture process are essential for the identification of the most suitable solution. The aim of this paper is to promote a time-efficient optimization, optimize a membrane-based post-combustion carbon capture process, and quantify its impacts on a waste-to-energy plant for various system configurations with different levels of CO2 recovery and purity. The proposed robust evaluation of the system with non-linearities resulted in the utilization of genetic algorithms with subsequent verification. Quantifying power consumption allows the comparison of different carbon capture technologies. The results confirm the importance of process optimization, show the influence of individual parameters, and quantify the disproportionate drop in power consumption with decreasing target CO2 recovery. The power consumption can be as low as 1.14 GJ/tonne of CO2 for CO2 purity of 95 % and recovery of 50 % and 1.66 GJ/tonne of CO2 for CO2 purity of 95 % and recovery of 90 %. The results also suggest that carbon neutrality can be achieved without compromising the R1 efficiency classification of energy recovery.

Process design and optimization of membrane-based CO2 capture process with experimental performance data for a steam methane reforming hydrogen plant and a coal-fired power plant

Membrane-based separation is one of the promising next-generation carbon capture technologies. High degrees of freedom in process design for multi-stage membrane networks, make it difficult to fully understand the impact of network configuration on the economics of capture and separation performance. Furthermore, the optimality in process design is heavily influenced by the levels of membrane performance and the characteristics of feed gas. Membrane model utilized for the study is validated and tuned with 183 experimental data measured at various operating conditions, having 2.45 % of overall prediction error. The superstructure-based framework for the optimization of multi-stage membrane networks is used, with which design interactions between network configurations, flue gas characteristics and membrane performance are systematically investigated. Techno-economic analysis is embedded in the optimization framework, which performs rigorous trade-off between capital and operating costs, as well as allows simultaneous determination of optimal process network configuration and operating variables. Flue gas streams emitted from a coal-fired power plant and a steam methane reforming hydrogen production plant are selected as CO2 capture sources for the analysis of flue gas characteristics. Case study shows capture cost ranged from 30.2 $/tCO2 to 79.9 $/tCO2, depending on the network configuration and design specifications, and clearly improves our techno-economic understanding on the network configuration of membrane capture process. In addition, cryogenic-hybridized membrane capture process is examined and the optimal level of enriched CO2 stream concentration between membrane capture and cryogenic distillation processes is determined. Study suggests how network configuration of membrane capture process can impact capture cost.

Integration of deep eutectic solvent with adsorption and membrane-based processes for CO2 capture: An innovative approach

CO2 capture strategies have been implemented to address climate change by reducing CO2 emissions from large-scale sources such as fossil fuel power plants and natural gas upgrading. Deep eutectic solvents (DESs) are a new class of green solvents with good CO2 affinity, simple synthesis steps, inexpensive raw materials, non-toxic and non-volatile properties. For these reasons, they are a promising platform for CO2 capture applications and have tremendous untapped potential to enhance the performance of the adsorption and membrane-based separation processes. Unlike existing reviews which have focused on the functionalities of DESs, as well as the physicochemical and CO2 solubility properties of DESs, this mini-review discusses the integration of DESs with adsorption and membrane processes to evaluate their CO2 separation performance. Moreover, simulation and computational studies on DES-based systems, including confinement in porous solids and membranes, are discussed. Finally, perspectives on developing DES-based adsorbents and DES-based membranes for the CO2 separation field are presented. This review provides insight into the potential of integrating DESs with CO2 capture technologies to enhance the performance of hybrid systems in relation to standalone approaches.

Application of Online Flow Cytometry for Early Biofouling Detection in Reverse Osmosis Membrane Systems.

Biofouling poses a significant challenge to reverse osmosis (RO) membrane systems, necessitating timely detection for effective control. This study evaluated the efficacy of flow cytometry (FCM) for early biofilm detection in comparison to conventional system performance indicators. Feed channel pressure drop and total cell concentration in the Membrane Fouling Simulator (MFS) flowcell cross-flow outlet water were monitored over time as early biofouling indicators. The results demonstrated the potential of increased bacterial cell concentration in cross-flow outlet water as a reliable indicator of biofouling development on the membrane. Water outlet monitoring enabled faster biofouling detection compared to feed channel pressure drop. Membrane autopsy confirmed biofilm presence prior to the pressure drop increase, highlighting the advantage of early detection in implementing corrective measures. Timely intervention reduces operational costs and energy consumption in membrane-based processes.

Jet-assisted membrane filtration and design application: A model for fouling removal area estimation

Membrane fouling remains a significant challenge in desalination and other membrane-based filtration processes. This study presents a novel force-balance model to accurately estimate the de-fouling area in jet-assisted filtration for in-situ fouling control. The model includes various design parameters, such as initial jet velocity, nozzle diameter, impinging angle, membrane pore size, membrane resistance, and permeate flux. The validation showed a strong correlation between theoretical predictions and experimental observations, with an R2 value of 0.97, indicating high predictive accuracy. Additionally, an empirical formula and design automation tools were developed to facilitate the configuration of jet filtration modules, enabling practical application of the findings. As a demonstration, the arrangement of multiple jets in a hollow fiber membrane module was optimized using the model, significantly improving microalgae filtration performance. The optimized jet configuration enhanced permeate flux by 236 % and reduced the specific energy consumption by 67 % compared to conventional setups. This research offers a framework for extending the application of jet-based fouling mitigation and cleaning in various membrane filtration systems, providing substantial improvements in efficiency and operational sustainability.

Demonstration of a real-time maximum power point tracker for salt gradient osmotic power systems

Clean energy is needed to sustainably power our economies and communities. Salt gradients, which are available in marine ecosystems as well as from the brine of engineered desalination systems, are a renewable source of energy. Membrane-based osmotic power processes have been proposed for converting the free energy of mixing seawater and diluted water to useful mechanical work. It has been shown that during osmosis, the applied mechanical load as well as the circulation rates of diluted feed and concentrated draw through the membrane module have a significant impact of transport dynamics, including polarization and friction. Therefore, to maximize performance of this process, it is necessary to carefully adjust these operating conditions. Using modelling and simulation, our group has previously shown that it is possible to coordinate the control of these key operating variables in order to maximize net power output. In this work, we report on our efforts to experimentally demonstrate the concept of real-time maximum power point tracking for a salt gradient osmotic power system. The transient response of a laboratory scale osmotic system is characterized, showing water permeate flux, pressure losses, and power output in response to step changes in applied pressure and to feed and draw circulation rates. A “perturb and observe” feedback algorithm and control strategy are implemented and as a result, the real-time net power output of the osmotic power system is shown to more than double relative to baseline conditions. Such real-time control strategies have broad applications to a variety of membrane processes and can be customized to track selected performance metrics.

Treatment of wastewater from oil palm industry in Malaysia using polyvinylidene fluoride-bentonite hollow fiber membranes via membrane distillation system

Membrane distillation (MD) is gaining increasing recognition within membrane-based processes for palm oil mill effluent (POME) treatment. This study aims to alter the physicochemical characteristics of polyvinylidene fluoride (PVDF) membranes through the incorporation of bentonite (B) at varying weight concentrations (ranging from 0.25 wt% to 1.0 wt%). Characterization was conducted to evaluate changes in morphology, thermal stability, surface characteristics and wetting properties of the resulting membranes. The resulting membranes were also tested using direct contact membrane distillation (DCMD) with POME as the feed solution, aiming to generate high-purity water. Results indicated that the PVDF-0.3B and PVDF-0.5B membranes achieved the highest water vapor flux. The finger-like structure and macrovoids present in these membranes aid in minimizing mass resistance during vapor transport and enhancing permeate flux. All membranes demonstrated exceptional performance in removing contaminants, eliminating total dissolved solids (TDS) and achieving over 99% rejection of chemical oxygen demand (COD), nitrate nitrogen (NN), color, and turbidity from the feed solution. The permeate water analysis showed that the PVDF-0.3B membrane had superior removal efficiency and met the standards set by the local Department of Environment (DOE). The PVDF-0.3B membrane was chosen as the preferred option because of its consistent flux and high removal efficiency. This study demonstrated that incorporating bentonite into PVDF membranes significantly enhanced their properties and performance for POME treatment.

Photocatalytic nanohybrid UV-light-driven PVDF/GO-NiFe@SiO2 membrane coupled with bentonite adsorption and ozonation process for a sustainable textile wastewater treatment

The textile industries face significant environmental challenges due to the presence of complex pollutant dyes in its wastewater, making it one of the world's major sources of industrial water pollution. Numerous studies have been employed to overcome this problem, including physical, chemical, and biological treatments. However, most of those methods still suffered to achieve higher dye removal performance. This study provides new insight regarding textile wastewater treatment containing indigo red as the main colorant by carrying out a hybrid process combining bentonite adsorption, ozonation, and photocatalytic membrane filtration. For the membrane, we propose a modified polyvinylidene fluoride (PVDF) membrane incorporated with graphene oxide (GO) and nickel-iron doped silica (NiFe@SiO2) photocatalyst, which is named PVDF/GO-NiFe@SiO2 membrane. The membrane was employed under different sets of filtrations (dark and under ultraviolet irradiation) to treat natural dye wastewater from textile industry effluent. Further improvement was achieved when UV light irradiation was subjected to the process. This sequential adsorption-ozonation-membrane process under UV exposure exhibited improved dye removal from 55.11 % to 97.22 %. The results show that the proposed hybrid process successfully improved the membranes' antifouling behavior, thus boosting the membranes' performance and durability. From a broader perspective, our work promotes new insights for the integration of other physical, chemical, and biological treatment methods to improve the performance and durability of membrane-based processes, particularly for dye wastewater treatment.

Recent Advances for Wastewater Treatment on Polyvinylidene Fluoride-Based Membrane: A Review

The development of scalable membrane-based separation processes has attracted considerable interest on laboratory and industrial scales. Polyvinylidene fluoride (PVDF) is one of the most widely used fluoropolymer materials for membrane fabrication due to its excellent mechanical strength, good thermal stability and chemical resistance as well as aging resistance. However, the hydrophobic nature of PVDF has resulted in serious membrane fouling during the filtration process. From the past decade, the embedment of hydrophilic materials in/on PVDF-based membranes can significantly alter the membrane’s morphology and surface properties. Therefore, based on most articles retrieved from Web of Science, Scopus, Google Scholar, etc., this article provides the overview of the recent development of PVDF-based membranes during the recent several decades. The detailed information regarding PVDF as a polymer material as well as the main challenge in the development of PVDF-based membranes with better performance was summarised. Moreover, the factors influencing membrane fouling including surface hydrophilicity, roughness and charge are also addressed. Then, the PVDF-based membrane preparation and its recent modification via the blending method were discussed. Finally, the overview and future perspective of PVDF-based membrane development are reviewed. Overall, it can be concluded that PVDF-based membranes have great potential for further advances towards the development of membrane technologies for the future.

Lithium aluminium titanium phosphate based ceramic composite membrane for selective lithium-ion separation via a scalable membrane-based electrodialysis process

The escalating global demand for lithium necessitates efficient extraction methods, particularly from natural sources such as brine. Herein, we report a novel, thin, and dense functionalised composite ceramic membrane that is employed in conjunction with electrodialysis technology for selective lithium extraction from salt lakes. This membrane exhibits high mechanical strength, low ionic impedance, and high lithium conductivity. The thin functional layer, ~20 μm-thick NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) superionic conductor material, is deposited on high-strength and porous alumina membrane via a facile dip-coating method, providing structural stability for the composite membrane. The preparation and sintering processes of LATP-Al2O3 ceramic composite membrane were systematically studied and precisely controlled to improve its morphology and performance. A membrane-based electrodialysis set-up was designed specifically for lithium extraction demonstrated the remarkable performance of the composite-LATP membrane in separating lithium from magnesium-lithium solutions with a high Mg/Li ratio. The LATP composite membrane effectively reduced the Mg/Li ratio from 40 to 2.1 after three-stage electrodialysis. Moreover, the Li+ recovery reached 77.15% from the feed solution with an estimated power consumption of ~47.6 kWh per 1 kg of lithium carbonate. These findings have significant implications for the development of low-cost and environmentally friendly inorganic membrane separation technologies, which are important for promoting technological innovation in the lithium industry chain.

Greening the production of polymeric submicron particles by membrane-based manufacturing processes: A comparative analysis

The production of polymeric particles is the subject of extensive research in various fields and the interest in this area extends to the development of new sustainable production processes. The use of membrane technology has enabled the redesign of many traditional production processes with enormous impact in terms of product quality, reduction of energy consumption, high efficiency, productivity and reproducibility. In the present work, two alternative methodologies for the production of polycaprolactone (PCL) particles based on the use of membrane processes were investigated: i) membrane emulsification (ME) combined with solvent diffusion and ii) membrane nanoprecipitation (MN). ME/solvent diffusion is a widely applied technique for the production of microparticles, but its use for nanosized particles is still limited. On the other hand, MN is currently being investigated for its potentiality in the production of nanoparticles.In the present work, the performance of the two processes is compared in terms of: i) product quality (highly monodisperse particles in the nanometers range of size, ii) maximum productivity (expressed as mass of particles produced over time) under mild operating conditions (reduced mechanical stress), iii) environmental impact (assessed on the basis of the metrics established by the Green Aspiration Level (GAL)).

Membrane-based fermentation enables highly selective caproic acid production from wine lees

Chain elongation is a green chemistry approach to convert organic waste or agro-industrial side-products into caproic acid. Nonetheless, such feedstocks may contain microorganisms and chemical pollutants that could deteriorate the product yield and purity. This study introduces a membrane-based fermentation process designed to isolate the caproic acid producing bacteria from these contaminants. A tubular polysiloxane (silicone) membrane submerged into a fermentor allowed the selective diffusion of ethanol and acetic acid while preventing the cross-over of bacteria and contaminants such as ions. Abiotic tests confirmed that membrane thickness, feedstock pH and flow velocity can be adjusted to independently control the diffusion of ethanol and acetic acid. Thereof, optimal ethanol:acetic acid ratios for chain elongation (6:1) were obtained from a feedstock solution with equimolar (1 M) concentrations of both. In the biotic tests, this resulted in a highly selective (>90 %) caproic acid production at a highest rate of 3.1 g/(L·d). Maintaining the pH above 6.8, thereby keeping most caproic acid in its dissociated form, prevented its back-diffusion through the membrane. Similar caproic acid productivity was achieved from diluted wine lees (1 M ethanol), amended with 1 M acetic acid. In contrast, unamended wine lees resulted in three times lower caproic acid production rate, although the product selectivity remained high (94 %). Downstream processing by acidification and phase separation yielded 6–13 mL/Lfeedstock of an oily product containing up to 784 g/L caproic acid (84.3 % purity). In conclusion, membrane-based fermentation enables highly selective caproic acid production from highly concentrated and unbalanced substrates.

Highly permeable carbon nanotube membranes for efficient surface water treatment through separation and adsorption–electrochemical regeneration

Membrane-based processes feature many advantages for surface water treatment over other technologies; however, the trade-off between membrane selectivity and permeability usually results in the failure to obtain high-quality filtrate at a high permeance. In this study, we report a highly permeable sodium alginate/glutaraldehyde cross-linked carbon nanotube (CNT/SA-GA) membrane with high adsorption ability for surface water treatment. The CNT/SA-GA membranes have a well-formed hollow fiber morphology and good conductivity of 166–261 S/m. They could reject >98 % of large-sized molecules (e.g., Alcian Blue 8GX and Congo Red) at high permeances of 137–227 L/(m2·h·bar). Moreover, they could remove ~100 % of smaller molecules (e.g., Rhodamine B (RhB)) through dynamic adsorption with a capacity of ~57.3 mg/g. Benefiting from their good conductivity, the CNT/SA-GA membranes could easily decompose the pollutants after adsorption saturation through electrochemical oxidation and then regenerated themselves. Though the switch between adsorption and electrochemical oxidation (2.0 V), the CNT/SA-GA membranes could remove ~100 % RhB at a high permeance of 342 L/(m2·h·bar), which is one order of magnitude higher than those of nanofiltration membranes. When used for surface water treatment, the CNT/SA-GA membranes exhibited a much higher TOC removal rate than commercial poly(acrylonitrile) (PAN) membranes (56.2 % vs. 7.2 %). LC-MS/MS analysis showed that many small molecules such as caffeine could be effectively removed by the CNT/SA-GA membranes. In addition, they exhibited a higher fouling resistance than PAN membranes, evidenced by their lower permeance decline ratio (10.1 % vs. 43.7 %). This study will promote the development and applications of the CNT-based membranes for water purification.

Electro-responsive OCNT/PPy membrane for efficient irreversible-fouling control through electroregulation of electrostatic and fluid interaction forces

Membrane-based separation process has been proven to be a powerful strategy for low-energy-consumption and high-efficiency water purification. However, the practical application is still subjected to serious membrane fouling. In this study, an impressive approach to alleviate membrane fouling is proposed using an electro-conductive oxygenated carbon nanotube/polypyrrole (OCNT/PPy) membrane combining electrically-regulated electrostatic and fluid forces. Benefiting from the negative potential (−1.18 V vs. SCE) applied on the membrane, the electric polarization effects significantly enhance the repulsive electrostatic force on contaminant. The transmembrane pressure increases at an ignorable rate during the filtration process. Meanwhile, for accumulated irreversible membrane fouling after multi-cycle filtrations, the positive potential (+1.19 V vs. SCE) exerted on OCNT/PPy membrane can decrease the fluid resistances of backwash flow. As a result, the electrically-regulated hydraulic backwash achieves a thorough recovery rate of permeance at 99.1 %. The numerical analysis of the antifouling mechanism reveals that the mitigation of irreversible membrane fouling is mainly attributed to rapid formation of a loose cake layer under electrical assistance. Moreover, the computational fluid dynamics verifies that the reduction of water-channel resistance enhances the elimination of foulants in membrane pores. This work motivates a new thought for membrane fouling control through electroregulation of electrostatic and fluid forces at the membrane-water interface.

Sustainable fabrication of solvent resistant biodegradable cellulose membranes using green solvents

The paradigm of the polymer industry is confronting an inevitable transition from fossil-based to bio-derived sources. The membrane-based separation process, generally regarded as a sustainable technology, mostly employs fossil-based polymeric membranes. In order to become an entirely carbon–neutral technology, all of the materials and chemicals employed during membrane fabrication must be scrutinized from a sustainability perspective. In this work, we report a versatile strategy to fabricate solvent-resistant cellulose membranes using bio-derived green solvents. The thermodynamic and kinetic aspects of the membrane fabrication process were systematically investigated. It was found that well-known green solvents such as Cyrene and PolarClean were not suitable due to high dope viscosity, whereas bio-derived methyl lactate and triethyl phosphate exhibited desirable properties to yield excellent cellulose membranes. The membrane performance could be tailored from the ultrafiltration to nanofiltration range by controlling the fabrication parameters. Importantly, the thermal treatment step prior to the deacetylation reaction was necessary to improve the solute rejection profile. The cellulose membranes displayed adequate compression resistance against pressure. However, their shear resistance was insufficient compared to that of commercial membranes. Nevertheless, the prepared cellulose membranes exhibited excellent solvent resistance in strong aprotic solvents such as N-methylpyrrolidone and N,N-dimethylacetamide, potentially allowing them to enter niche membrane markets such as the organic solvent nanofiltration (OSN).

Integrating artificial intelligence modeling and membrane technologies for advanced wastewater treatment: Research progress and future perspectives

Membrane technologies have become proficient alternatives for advanced wastewater treatment, ensuring high contaminant removal and sustainable resource recovery. Despite significant progress, ongoing research efforts aim to further optimize treatment performance. Among the challenges faced, membrane fouling persists as a relevant obstacle in membrane technologies, necessitating the development of more effective mitigation strategies. Mathematical models, widely employed for predicting treatment performance, generally exhibit low accuracy and suffer from uncertainties due to the complex and variable nature of wastewater. To overcome these limitations, numerous studies have proposed artificial intelligence (AI) modeling to accurately predict membrane technologies' performance and fouling mechanisms. This approach aims to provide advanced simulations and predictions, thereby enhancing process control, optimization, and intensification.This literature review explores recent advancements in modeling membrane-based wastewater treatment processes through AI models. The analysis highlights the enormous potential of this research field in enhancing the efficiency of membrane technologies. The role of AI modeling in defining optimal operating conditions, developing effective strategies for membrane fouling mitigation, enhancing the performance of novel membrane-based technologies, and improving membrane fabrication techniques is discussed. These enhanced process optimization and control strategies driven by AI modeling ensure improved effluent quality, optimized resource consumption, and minimized operating costs. The potential contribution of this cutting-edge approach to a paradigm shift toward sustainable wastewater treatment is examined. Finally, this review outlines future perspectives, emphasizing the research challenges that require attention to overcome the current limitations hindering the integration of AI modeling in wastewater treatment plants.