Membrane Lifespan Research Articles

Permeate flux recovery and removal foulant performances of hollow fiber polyvinylidene fluoride membrane bioreactor with peroxodisulfate activated iron (II) sulfate as a chemical cleaning agent

The main challenge with membrane bioreactors is fouling, which leads to decreased flux performance and a shortened membrane lifespan. This study aims to provide a solution for the flux recovery and removal of irreversible fouling on Polyvinylidene Fluoride (PVDF) membranes without damaging their structure using sulfate radicals. Sulfate radicals are formed via peroxodisulfate precursors that are activated by Fe2+. The membrane flux recovery and irreversible fouling ratio were 88.45-99.04% and 11.60-0.96%, respectively, at operating temperatures of 298-308 K. The PVDF membrane has been tested for microfiltration and washed up to 6 times per cycle. The mechanical properties, XRD, SEM-EDX, and ATR-FTIR characterization of the PVDF membrane after washing with PDS/Fe2+ did not show a negative effect on the PVDF structure. Additionally, the results of the kinetic and thermodynamic studies showed that washing with PDS/Fe2+ inhibited the formation of fouling particles on the membrane surface. Based on this study, sulfate radical oxidants with PDS precursors activated by Fe2+ can be applied as cleaning chemicals for PVDF membranes without damaging their structures.

Cellulose and cellulose derivatives in sustainable membrane development for oil/water separation

Cellulose is a natural polymer and most abundant organic substance on Earth. Inexhaustible hydroxyl groups on the cellulose surface allow derivatives of cellulose produced. This article discusses the recent progress of cellulose and cellulose derivatives in membrane development for oil/water separation. Functional groups that are available on the cellulose and its derivatives provide modification features to improve membrane wettability. Membranes with super wetting properties possess remarkable self-cleaning abilities which in turn can enhance permeation fluxes and extend membrane lifespan. However, the role of cellulose-based membranes in oily wastewater treatments is still in its early stages. This review article emphasizes on the development and modification of cellulose-based membranes for improvement of wettability, flux and separation efficiency, and the future directions of research.

Systematic experiments and multiscale simulation calculations reveal chemical stability differences in dry/wet nanofiltration membranes

This study investigated the chemical stability differences between dry and wet nanofiltration membranes when immersed in strong acid and base environments. Systematic experimental studies were conducted on both types of nanofiltration (NF) membranes, supplemented by Molecular Dynamics (MD) simulations and Density Functional Theory (DFT) calculations. The results indicate that wet NF membranes, soaked in deionized water for a week, exhibit higher chemical stability compared to dry membranes treated only with air. Traditional air heating causes membrane pore contraction and excessive crosslinking. However, after a week of immersion in water, the polyamide (PA) layer gradually becomes a loose and well-extendable PA layer. MD simulations revealed that H+ and OH− ions possess lower diffusion coefficients and extended residence times in dry NF membranes, making them more prone to damage. Additionally, DFT calculations disclosed that the Gibbs free energy (ΔG) for amide bond hydrolysis in wet NF membranes, in the presence of water molecules, is elevated, significantly delaying their hydrolysis rate under extreme conditions. This study highlights the pivotal role of membrane wetness in the chemical durability of NF membranes and offers a novel perspective for improving membrane lifespan and efficiency.

Reviewing the potential of anaerobic membrane bioreactors in wastewater treatment

Anaerobic membrane bioreactors (AnMBRs) represent an innovative approach to wastewater treatment, combining anaerobic digestion with membrane filtration to achieve efficient organic pollutant removal and resource recovery. This review critically examines the potential of AnMBRs in wastewater treatment, highlighting their principles, advantages, challenges, recent advancements, and future prospects. AnMBRs offer several advantages over traditional aerobic treatment methods, including higher organic loading rates, reduced energy requirements, and biogas production through methane generation. However, challenges such as membrane fouling, reactor complexity, and operational costs have limited their widespread adoption. Recent advancements in membrane materials, fouling mitigation strategies, and process optimization have improved AnMBR performance and feasibility. Novel membrane materials with enhanced fouling resistance and durability have been developed, while innovative cleaning techniques and operational protocols have been implemented to mitigate membrane fouling and prolong membrane lifespan. Process optimization strategies, including reactor design modifications and operational parameter adjustments, have enhanced treatment efficiency and reduced energy consumption in AnMBRs. Future research directions in AnMBR technology focus on optimizing reactor configurations, exploring novel membrane materials and fouling control strategies, and conducting comprehensive techno-economic assessments to evaluate the environmental and economic sustainability of AnMBRs. Integration of AnMBRs with emerging technologies such as membrane distillation, forward osmosis, and bioelectrochemical systems holds promise for further enhancing treatment performance and resource recovery capabilities. Additionally, addressing knowledge gaps in membrane fouling mechanisms, microbial community dynamics, and long-term system stability is crucial for advancing AnMBR technology and facilitating its widespread implementation in wastewater treatment. Overall, AnMBRs offer significant potential for sustainable wastewater treatment, providing opportunities for organic pollutant removal, energy recovery, and resource reuse. By addressing technical challenges, optimizing process parameters, and conducting interdisciplinary research, AnMBRs can contribute to the development of efficient, cost-effective, and environmentally friendly wastewater treatment solutions, ultimately supporting the goal of achieving cleaner water resources and a more sustainable future.

Sustainability in Membrane Technology: Membrane Recycling and Fabrication Using Recycled Waste.

Membrane technology has shown a promising role in combating water scarcity, a globally faced challenge. However, the disposal of end-of-life membrane modules is problematic as the current practices include incineration and landfills as their final fate. In addition, the increase in population and lifestyle advancement have significantly enhanced waste generation, thus overwhelming landfills and exacerbating environmental repercussions and resource scarcity. These practices are neither economically nor environmentally sustainable. Recycling membranes and utilizing recycled material for their manufacturing is seen as a potential approach to address the aforementioned challenges. Depending on physiochemical conditions, the end-of-life membrane could be reutilized for similar, upgraded, and downgraded operations, thus extending the membrane lifespan while mitigating the environmental impact that occurred due to their disposal and new membrane preparation for similar purposes. Likewise, using recycled waste such as polystyrene, polyethylene terephthalate, polyvinyl chloride, tire rubber, keratin, and cellulose and their derivates for fabricating the membranes can significantly enhance environmental sustainability. This study advocates for and supports the integration of sustainability concepts into membrane technology by presenting the research carried out in this area and rigorously assessing the achieved progress. The membranes' recycling and their fabrication utilizing recycled waste materials are of special interest in this work. Furthermore, this study offers guidance for future research endeavors aimed at promoting environmental sustainability.

A novel WaveNet-GRU deep learning model for PEM fuel cells degradation prediction based on transfer learning

Precise prediction of Remaining Useful Life (RUL) within the transportation industry is essential for cost reduction and enhanced energy efficiency, focusing on extending the operational lifespan of proton exchange membrane fuel cells (PEMFCs). In pursuit of this objective, this study employs data-driven prediction methodologies centered on deep neural networks and transfer learning. The fundamental premise is that these approaches hinge on the compatibility of functional conditions across diverse datasets. Multiple strategies, amalgamating transfer learning, and deep neural networks, are introduced to forecast the PEMFC stack's behavior and its associated RUL. Network hyperparameters are optimized through Bayesian optimization, targeting root-mean-square error (RMSE) minimization in voltage predictions. The efficacy of these prediction techniques is evaluated through essential performance metrics, including the mean absolute percentage error (MAPE), RMSE, and coefficient of determination (R2), applied to both voltage predictions and RUL estimations. For the first time, a WaveNet-GRU model has been developed. Comparative assessment of models trained on 50% of the dataset underscores its supremacy. This model attains R2, RMSE, and MAPE scores of 99.1, 2.16E-4, and 0.166E-1, respectively, in predicting stack voltage. Also, RUL has increased by 21% compared to the best contemporary research. The WaveNet-GRU model demonstrates exceptional transfer learning capabilities when applied to stacks influenced by current ripples. In this context, it achieves optimal R2, RMSE, and MAPE values of 99.69, 1.37E-4, and 0.31E-1, respectively.

Remaining useful life prediction of vehicle-oriented PEMFC systems based on IGWO-BP neural network under real-world traffic conditions

Accurately predicting the useful life can serve as a pivotal reference for effectively extending the lifespan of proton exchange membrane fuel cells (PEMFCs). Herein, this paper proposes a novel method that combines an improved grey wolf optimizer (IGWO) algorithm and a backpropagation (BP) neural network to predict the remaining useful life (RUL) of vehicle-oriented PEMFC systems using relative power loss rate (RPLR) as a health indicator under real-world traffic conditions. First, The Pearson correlation coefficient is used to analyze the correlation of various monitoring parameters and to verify the effectiveness of RPLR as a dynamic health indicator. Then, the IGWO-BP neural network-based prediction method is described and used to predict the RUL of PEMFC systems. Finally, the accuracy and reliability of the proposed method are validated against two separate datasets of PEMFC city buses operating under different traffic conditions. Compared with other methods, the proposed method has a relative error of less than 5 % and predicts a shorter RUL than the actual RUL. These findings illustrate that the proposed method has a high prediction accuracy and offers an early warning function, which is beneficial for practical applications.

Synergistic Effect of Ti3C2Tx MXene Nanosheets and Tannic Acid-Fe3+ Network in Constructing High-Performance Hydrogel Composite Membrane for Photothermal Membrane Distillation.

Photothermal membrane distillation (PMD) has emerged as a promising and sustainable approach for seawater desalination and wastewater purification. However, the wide application of the technique is severely impeded by low freshwater production and membrane fouling/wetting issues. Herein, we developed an advanced hydrogel-engineered membrane with simultaneously enhanced photothermal conversion capacity and desired fouling and wetting resistance for PMD. By the synergies of photothermal Ti3C2Tx MXene nanosheets and the tannic acid-Fe3+ network in the hydrogel, the membrane was endowed with excellent surface self-heating ability, yielding the highest freshwater production rate (1.71 kg m-2 h-1) and photothermal efficiency among the fabricated hydrogel composite membranes under 1 sun irradiation. Meanwhile, the PMD membrane could robustly resist oil-induced fouling and surfactant-induced wetting, significantly extending the membrane lifespan in treating contaminated saline water. Furthermore, when desalinating real seawater, the membrane exhibited superior durability with a stable vapor flux and excellent ion rejection (e.g., 99.24% for boron) for 100 h.

One-step rejuvenation for prolonging running lifespan of nanofiltration membranes

Commercial nanofiltration (NF) membranes based on polyamides may experience a decline in permeation performance after prolonged operation. The short lifespan of NF membranes will lead to waste and additional carbon emissions. Thus, rejuvenating membranes and extending their lifespan seem more meaningful than investigating new materials. In this paper, polyamide NF membranes were modified with various polyphenol monomers to improve their permeation performance. The effects of different polyphenols on pore size, surface morphology, and permeation performance of the NF membranes were thoroughly investigated. After modification with tannic acid, the NF membrane exhibits improved salt rejection while experiencing an acceptable decrease in water flux. It should be noted that the commercial NF membrane element fabricated by Koch can recover its Na2SO4 rejection from 83.0% to 94.2% and demonstrate long-term stability after rejuvenation with tannic acid. Combined with the environmental friendliness of polyphenols, this straightforward modification method has the potential for prolonging the operational lifespan of industrial NF membrane products.

Advancements and Challenges in Membrane Bioreactor Technology for Industrial Wastewater Treatment

Due to its success in achieving the majority of wastewater treatment objectives, Membrane Bioreactor Technology (MBR) has replaced the Conventional Activated Sludge Process (CAS) as the leading method for treating wastewater. Nowadays, the treatment of industrial wastewater become one of the world’s major concerns, MBR technologies are used more frequently. This technology has a bright future in wastewater treatment (especially industrial wastewater). In general, this article is designed to give a general view of various aspects of an MBR, with the aim of addressing and overcoming any potential drawbacks or limitations. In this work, the fouling in MBR technology its variations and mechanisms, influencing factors are also discussed in detail. However, membrane fouling is thought to be the biggest challenge this technology faces. One of the main agents that causes the fouling of the membrane is Extracellular Polymeric Substances (EPS), which results in a decrease in filterability and a decline in membrane flux, which affects the membrane lifespan. Furthermore, it looks into how to minimize membrane fouling in MBR systems and offers biological tactics to lessen the likelihood of membrane fouling in MBR technology. Finally, this work quoted also how artificial technology might help to increase removal effectiveness and prevent filtering membrane obstruction.

Energy management for proton exchange membrane fuel cell-lithium battery hybrid power systems based on real-time prediction and optimization under multimodal information

As an emerging power source for new energy vehicles, the proton exchange membrane fuel cell-lithium battery hybrid power system still faces challenges such as difficulty in remaining life prediction and unreasonable energy allocation management. This study investigates how electrochemical surface area degradation and carbon corrosion in the catalyst layer affect the proton exchange membrane fuel cell output power. An integrated assessment system combining electrochemical surface area degradation and carbon corrosion, which could effectively evaluate degradation in the proton exchange membrane fuel cell degradation is proposed. To assess the lifespan of proton exchange membrane fuel cells, the electrochemical surface area degradation and carbon corrosion are utilized as key indicators, which in turn lead to the development of a semi-empirical model. To solve the problem of energy allocation management, this paper proposes a predictive-feedback optimization method that combines data-driven and model-driven approaches. The method includes a hybrid prediction model of a long short-term memory-convolutional neural network, an improved rapid optimization strategy of grey wolf optimizer-particle swarm optimization, and an attention-enhanced fuzzy neural network controller. The inference capability of the convolutional neural network is utilized to correct the larger prediction error of long short-term memory during short-term drastic changes, realizing the maximization of energy utilization efficiency, minimal hydrogen consumption, minimization of operation cost, and optimization objectives for information containing a wide time horizon. Tests of experiments show that the implementation of this control scheme effectively postponed the deterioration of the proton exchange membrane fuel cell-lithium battery hybrid power system, resulting in an extended lifespan.

Enhanced landfill leachate treatment performance by adsorption-assisted membrane distillation

Membrane fouling and high-strength membrane concentrate production are two limitations of membrane distillation (MD) for landfill leachate treatment. In this study, activated carbon- and biochar-based adsorption processes were integrated into a conventional MD system to overcome these limitations. The organic matter fractionations of the leachate were thoroughly investigated during the treatment. Membrane-reversible and irreversible foulants differed remarkably from the inlet leachate in the non-assisted MD system. Specifically, reversible foulants were characterized by a high abundance of humic-like fluorescent components, high-molecular-weight humic-size constituents, peptides, and unsaturated compounds. In contrast, irreversible foulants were enriched with fulvic-like fluorescent components, low-molecular-weight neutrals, unsaturated compounds, and polyphenols. The adsorption-based pre-treatment effectively removed foulant precursors from landfill leachate, with a relatively higher (20%) adsorption performance for specific biochar used in this study than for activated carbon. Compared with the non-assisted MD system, the biochar-assisted MD system showed improved performance, achieving 40% overall membrane flux recovery, 42% higher filtration fluxes, and 53% lower concentrate production. In addition, a 15% higher removal of irreversible foulants was observed as compared to the reversible foulants, which can potentially increase the membrane lifespan. This study demonstrates the effectiveness of an adsorption-assisted MD system supported by increased filtration, membrane fouling alleviation, and low-strength leachate concentrate generation.

Optimizing cleaning strategies for biofouling in reverse osmosis membrane systems: A comparative study using a self-formed instrument

Membrane biofouling poses a serious challenge in reverse osmosis (RO) plants used for water recovery, which cannot be addressed by traditional chlorine-based cleaning agents. To accommodate this problem and enhance membrane performance while maintaining high-quality water production, various cleaning strategies have been applied. It remains however challenging to identify optimal cleaning agents, as tests require discontinuation of production to evaluate the effect. This study introduces a self-formed instrument that mimics industrial RO plants on a small scale to compare the cleaning agents in a fast, affordable and feasible approach. The setup was demonstrated using three cells operating in parallel and a thorough comparison of these. Specifically, the online cleaning efficiency of a typical biofouling cleaner, a solution of NaOH/sodium dodecyl sulfate (SDS), and the commonly used non-oxidizing biocide, 2,2-dibromo-3-nitrilopropionamide, were compared to validate the system performance when fed with membrane bioreactor effluent. The effectiveness of the cleaning process was evaluated using a combination of hydrodynamic operation and membrane autopsy to estimate the biofoulant amount and composition. During a 7-day operating period, it was observed that treated membranes demonstrated higher flux rates compared to untreated membranes. The normalized flux increased more than double in the membrane after it had been cleaned with NaOH/SDS solution. CLSM analysis clearly showed the distinct effects of the two cleaning solutions on the amount and spatial structure of the biofilm layer. Cleaning with DBNPA was able to reduce the load of living bacteria, but not necessarily remove the biofilm components completely. Comparative analyses of membranes revealed that NaOH/SDS exhibited the highest cleaning efficiency during the online cleaning operation mode. This benchmark highlights the versatility of the system, which can be assembled at relevant sites and assist in the identification of efficient and eco-friendly agents that promote the lifespan of membranes. With the distribution of this instrument, it will be possible to accelerate the investigation of multiple cleaning strategies and also analyze interactions among cleaning agents in an attempt to reduce water shortage.

Enhanced conductivity behavior of titanium-based bipolar plate oxide films through microalloying: First-principles calculations and experimental investigations

Presently, the formation of oxide films on the surface of Ti-based bipolar plates results in decreased electrical conductivity. This limitation frequently curtails the operational lifespan of proton exchange membrane fuel cells (PEMFCs). In this study, we engineered Ti alloy bipolar plate materials using an elemental screening process and validated their performance through experimentation. The elemental screening results identified eight elements, specifically Ni, Cr, Mo, Ta, W, Fe, Co, and Zn, as promising candidates for bipolar plate materials. Among these, Mo exhibited a pronounced affinity for incorporation into the TiO2 oxide film. Conductivity measurements of passivated bipolar plates indicated that the Ti–Mo alloy displayed excellent electrical conductivity (1.699 × 1020 Ω m−1). Notably, the introduction of Mo (with an energy level of 1.64 eV) significantly reduced the band gap of the oxide film. Importantly, even after continuous potential oxidation for 10,000 s, the interfacial contact resistance (ICR) of Ti-0.35Mo (9.80 mΩ cm2) remained below the threshold set by the American DOE standard (ICR <10 mΩ cm2). Consequently, this research successfully devised a bipolar plate material utilizing a Ti–Mo alloy and proposed an innovative strategy for improving the conductivity of oxide films in bipolar plate materials via an elemental screening approach.

Evaluating and predicting surfactant-induced hydrophilization of pore channels in membrane distillation

Membrane distillation (MD) processes are susceptible to membrane pore wetting, which compromises the membrane's salt rejection efficiency and deteriorates the quality of the distillate. However, current understanding of the dynamics of membrane wetting remains incomplete, and the conventional indicators used to detect post-wetting, such as conductivity and distillate flux, have limitations.We develop a theoretical model for the wetting front (l) to elucidate the adsorption of surfactant molecules and their role in the hydrophilization of commercial polyvinylidene fluoride (PVDF) membranes under various sodium dodecyl sulfate (SDS) concentrations and different membrane pore sizes. Subsequently, we utilize an in-situ impedance-based monitoring technique to quantitatively track the progression of wetting and validate our model's ability to accurately describe the relationship between the wetting front and the square root of time (l=Kt) to obtain the wetting progression coefficient K within the first 30 min of the slow wetting stage.Hence, K, through the combination of impedance measurement and modelling, offers the advancement of wetting until the critical wetting front is reached. This critical wetting front, located at the half point of the membrane thickness, signifies the occurrence of partial wetting, alerting the need for membrane cleaning to mitigate full wetting before it occurs. Additionally, the potential for membrane recoverability can be assessed by examining the variation of K after cleaning, thereby facilitating the evaluation of the effectiveness of different membrane cleaning strategies. The theoretical model and applicable parameters presented in this study contribute to the understanding and quantification of mechanisms slow wetting in surfactant-induced scenarios and provide a promising method for determining the appropriate membrane for the desired feed and the optimal membrane cleaning strategy for extending the lifespan of membranes.

Control strategy for the anode gas supply system in a proton exchange membrane fuel cell system

Stable pressure control can improve the lifespan, efficiency, and stability of proton exchange membrane fuel cell system (PEMFCs). We successfully implemented a feedforward-based proportion-integral controller (FPIC) to control the anode pressure of a 100 kW fuel cell system. The bench experimental results demonstrate that the fuel cell stack achieves a maximum efficiency of 62.3 %, while the fuel cell power generation system achieve a maximum efficiency of 53.5 %. Under the steady-state and dynamic conditions, the strategy achieves a pressure tracking control accuracy of 98.93 % and 94.47 %, respectively. To address the large overshoot phenomenon and slow response speed of the FPIC when controlling the anode pressure, we further design a second order active disturbance rejection controller (SOADRC). The simulation results show that the SOADRC exhibits higher control stability and lower overshoot than FPIC. Moreover, it demonstrates a 51.3 % increase in response speed and an 80.7 % improvement in control stability under steady-state conditions compared to FPIC. The evaluation metrics for the error integral criterion (eISE = 0.023, eITSE = 2.58, eIAE = 0.35, and eIEAE = 36.76) are lower than FPIC, which demonstrates that the SOADRC provides more precise control of anode pressure, and enhances the stability of PEMFCs.

Temporal dynamic of biofouling on the ultrafiltration membrane for wastewater reclamation and strategy for biofouling pertinence mitigation

Biofouling deteriorates water quality, increases energy consumption after long-term porous membrane filtration, and shortens membrane lifespan. However, the mechanism of long-term biofouling and corresponding effective anti-biofouling strategies used in municipal wastewater reclamation remains unclear. Herein, the biofouling mechanism was unveiled through revealing the biofouling development and temporal shifts of microbial communities, and correspondingly strategy to mitigate biofouling was proposed to improve initial anti-attachment and to reduce the extracellular matrix content. At the initial stage of biofouling, a sharp drop (68%) in the energy barrier was found according to XDLVO theory, which was attributed to the change of membrane surface due to the formation and colonization of biofilm by Dojkabacteria, Saprospiraceae, Mycobacterium with high EPS secretion capabilities. At the second stage, we demonstrated EPS-protein as the key factors as the main sources that resulted in irreversible community adhesion by Hydrogenophaga and Acinetobacter. At the maturation and aging stage, Bacilli played a vital role in the mature biofilm with fragmentation of the biofouling layer aggregates occurred. Based on the biofouling mechanism, the target anti-biofouling strategy combining PES-PDA-Ag membranes with d-tyrosine was proposed to control biofouling development at the initial and stable stages. This strategy prolonged filtration time about 129%, contributing to at least 94.1% antimicrobial properties and 1.43 times improvement in the energy barrier by disrupting the biofilm integrity to minimize membrane resistance. This finding provides an in-depth understanding of biofouling development and benefits effective and feasible biofouling control.

APPLICATIONS AND CHALLENGES OF THE REVERSE OSMOSIS MEMBRANE PROCESS: A REVIEW

Reverse osmosis is one of the most prevalent methods of generating potable water owing to its low power usage, excellent rates of contaminant removal, simple design, large output capacity, and much cheaper initial and maintenance costs than comparable alternatives. In this review, the most important published research related to the reverse osmosis process was reviewed. It was found that the majority of reported studies were related to using the reverse osmosis process for water desalination and wastewater treatment. Research has proven that the reverse osmosis process is a very effective method for desalinating water and treating industrial effluent containing heavy metals, organics, and other pollutants. Fouling was found to be one of the greatest obstacles encountered by the reverse osmosis method in water treatment, which raises operating costs due to the need for frequent cleaning, reduces the membrane's lifespan, and reduces the permeate flux. In general, microfiltration/ultrafiltration pretreatment and backwashing were among the most effective strategies suggested by researchers to reduce fouling and ensure the longevity and proper operation of the system.

High-efficiency cleaning technology and lifespan prediction for the ceramic membrane treating secondary treated effluent.

Chemical cleaning is one of the key technical means to control membrane fouling, restore membrane flux and ensure the stable operation of membrane systems. In the experiment, the six most representative chemical cleaning agents for ceramic membranes, such as sulfuric acid (H2SO4), sodium hydroxide (NaOH), sodium hypochlorite (NaClO), ethylenediaminetetraacetic acid disodium salt (EDTA-Na2), sodium dodecyl sulfate (SDS) and nonylphenol polyoxyethylene ether (OP-10), were used as research objects. The cleaning effect of the two-step combined cleaning of chemical cleaning agents on the fouled membrane was systematically investigated. Results showed that the order of the chemical cleaning agent had a significant effect on the cleaning effect. The best chemical cleaning program was determined to be NaClO first and then SDS: the fouled ceramic membrane was soaked in NaClO solution at 0.15% for 2.5 h and further soaked in SDS solution at five times its own critical micelle concentration for 2.5 h. The predicted long-term lifespan of the ceramic membranes was 4.91 years. Scanning electron microscopy-energy spectrum analysis showed that the surface roughness of the cleaned ceramic membrane was slightly higher than that of the new membrane. The contact angle was slightly lower than that of the new membrane.

Quasi-critical condition to balance the scaling and membrane lifespan tradeoff in hypersaline water concentration

Mineral scaling is an inconvenient obstacle for membrane distillation in hypersaline wastewater concentration applications, compromising membrane lifespan to maintain high water recovery. Although various measures are devoted to alleviating mineral scaling, the uncertainty and complexity of scale characteristics make it difficult to accurately identify and effectively prevent. Herein, we systematically elucidate a practically applicable principle to balance the trade-off between mineral scaling and membrane lifespan. Through experimental demonstration and mechanism analysis, we find a consistent concentration phenomenon of hypersaline concentration in different situations. Based on the characteristics of the binding force between the primary scale crystal and the membrane, the quasi-critical concentration condition is sought to prevent the accumulation and intrusion of mineral scale. The quasi-critical condition achieves the maximum water flux on the premise of guaranteeing the membrane tolerance, and the membrane performance can be restored by undamaged physical cleaning. This report opens up an informative horizon for circumventing the inexplicable scaling explorations and develops a universal evaluation strategy to provide technical support for membrane desalination.