Membrane fouling is a persistent challenge in membrane-based technologies,significantly impacting efficiency,operational costs,and system lifespan in applications like water treatment,desalination,and industrial proce...Membrane fouling is a persistent challenge in membrane-based technologies,significantly impacting efficiency,operational costs,and system lifespan in applications like water treatment,desalination,and industrial processing.Foul-ing,caused by the accumulation of particulates,organic compounds,and microorganisms,leads to reduced permeability,increased energy demands,and frequent maintenance.Traditional fouling control approaches,relying on empirical models and reactive strategies,often fail to address these issues efficiently.In this context,artificial intelligence(AI)and machine learning(ML)have emerged as innovative tools offering predictive and proactive solutions for fouling man-agement.By utilizing historical and real-time data,AI/ML techniques such as artificial neural networks,support vector machines,and ensemble models enable accurate prediction of fouling onset,identification of fouling mechanisms,and optimization of control measures.This review provides a detailed examination of the integration of AI/ML in membrane fouling prediction and mitigation,discussing advanced algorithms,the role of sensor-based monitoring,and the importance of robust datasets in enhancing predictive accuracy.Case studies highlighting successful AI/ML applications across various membrane processes are presented,demonstrating their transformative potential in improving system performance.Emerging trends,such as hybrid modeling and IoT-enabled smart systems,are explored,alongside a criti-cal analysis of research gaps and opportunities.This review emphasizes AI/ML as a cornerstone for sustainable,cost-effective membrane operations.展开更多
The use of antifouling agents is suggested to be a promising method for protecting oceanic instruments from biological contamination.We developed a novel antifouling material doped with capsaicin(CAP)as a filler and m...The use of antifouling agents is suggested to be a promising method for protecting oceanic instruments from biological contamination.We developed a novel antifouling material doped with capsaicin(CAP)as a filler and montmorillonite(MMT)as a carrier for the practical application of CTD(conductivity,temperature,depth)protection.The optimal parameters for preparing the material were established,and the obtained material achieved the maximum CAP loading capacity of 32.74%.The proposed material exhibited great release properties in acidic environments,which is beneficial for reducing bacterial attachment.Furthermore,the optimal conditions(temperature,flow rate,and pressure in the aquatic environment)for a better release rate of the material were determined through a series of simulation tests in lab.It provided good guidance and basis for practical application of the material.The CAP@MMT composite showed excellent efficiency and effectiveness in preventing the attachment of microorganisms during the four-month marine field tests.In the subsequent experiments,the great properties of the antifouling material were further confirmed by retesting the conductivity of four instruments participating in marine field tests.The measuring errors of CTD protected by the antifouling material are both within 0.01 mS/cm,which is far lower than that of the other two instruments.展开更多
As part of sewage treatment,coagulation could remove phosphorus from the effluent of the Anaerobic-Anoxic-Oxic-Anoxic(A^(2)OA)biological process.The importance in investigating the influence of coagulation on Anaerobi...As part of sewage treatment,coagulation could remove phosphorus from the effluent of the Anaerobic-Anoxic-Oxic-Anoxic(A^(2)OA)biological process.The importance in investigating the influence of coagulation on Anaerobic-Anoxic-Oxic-Anoxic Membrane Bioreactor(A^(2)OA-MBR)should be emphasized.In this study,systematic optimization of coagulation parameters for greater pollutant removal was conducted in terms of coagulant dosage,coagulation residence time and stirring hydraulic conditions.Coagulation process could remarkably remove turbidity,phosphorus,chemical oxygen demand,humic-like,protein-like and polysaccharide-like substances from secondary effluent and A^(2)OA sludge-liquid mixture.Furthermore,the influence of coagulation on membrane fouling development during the ultrafiltration of secondary effluent and A^(2)OA sludge-liquid mixture was investigated based on optimum coagulation parameters.Coagulation simultaneously reduced reversible membrane fouling and the irreversible one by 86%and 16%,respectively.According to excitation-emission matrix and attenuated total reflection-fourier transform infrared spectra,membrane fouling was primarily influenced by the cake layer,although pore fouling might be aggravated by A^(2)OA processes.Besides,the feasibility of coagulation-assisted A^(2)OA-MBRwas also assessed using hollowfibermembranes.It exhibited excellent potential in alleviatingmembrane fouling,while regular cleaning twice a day was not enough to suppress transmembrane pressure increase during direct domestic wastewater ultrafiltration.Additionally,both polysaccharide-like and protein-like foulants were vital components for membrane fouling during wastewater treatment.展开更多
Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria i...Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.展开更多
It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation...It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation but can also track the fouling process during operation.Herein,an aggregation-induced emission(AIE)-active polymer membrane was prepared by the interfacial polymerization of a cyclodextrin-based glycocluster(CD@Glucose)and a tetraphenylethylene derivative modified with boronic acid groups(TPEDB)on the surface of a polyacrylonitrile(PAN)ultrafiltration membrane.This interfacial polymerization method can be stacked layer-by-layer to regulate the hydrophilicity and pore structure of the membrane.With the increase in the number of polymer layers,the separation and antifouling properties of the membrane gradually improved.Owing to the AIE property of the crosslinking agent TPEDB,the occurrence of interfacial polymerization and the degree of fouling during membrane operation can be monitored by the fluorescence distribution and intensity.With the aggravation of membrane fouling,the fluorescence decreased gradually,but recovered after cleaning.Therefore,this AIE effect can be used for real-time monitoring of interfacial polymerization as well as membrane fouling.展开更多
Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions...Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions are critical factors influencing membrane fouling. This study aimed to investigate the simultaneous impacts of temperature and hydraulic retention time (HRT) variations on membrane fouling. Experiments were conducted at three different temperatures (18°C, 25°C, and 32°C) and HRTs (6 h, 9 h, and 15 h). The results demonstrated that increases in both temperature and HRT contributed to a reduction in membrane fouling. Additionally, a positive interaction between temperature and HRT was observed in the linear slope variation of membrane permeation, with temperature variations exerting a greater influence on membrane fouling than HRT variations. Fouling factor analysis revealed that increases in temperature and HRT led to decreased concentrations of soluble microbial products (SMP) and extracellular polymeric substances (EPS), particularly carbohydrates, in the activated sludge. Analyses of the cake layer of the membrane indicated that increasing temperature and HRT reduced EPS levels, particularly polysaccharides and proteins;altered primary protein structure;and increased the mean particle size distribution. Ultimately, these changes led to reductions in both reversible and irreversible hydraulic resistances. This study highlights the importance of optimizing operational parameters such as temperature and HRT to enhance membrane performance and treatment efficiency in MBR systems while mitigating fouling.展开更多
Membrane filtration technology has been widely utilized for microalgae harvesting due to its stability and high efficiency.However,this technology faces challenges posed by membrane fouling caused by algal cells and e...Membrane filtration technology has been widely utilized for microalgae harvesting due to its stability and high efficiency.However,this technology faces challenges posed by membrane fouling caused by algal cells and extracellular organic matter(EOM),which are significantly influenced by membrane material and pore size.This study compared the fouling behavior of polyvinylidene fluoride(PVDF)membranes and ceramic membranes with similar pore sizes(0.20 mm and 0.16 mm,respectively)during the filtration of Microcystis aeruginosa.The ceramic membrane exhibited a lower transmembrane pressure(TMP)growth rate and reduced accumulation of surface foulants compared to the PVDF membrane,indicating its greater suitability for filtering algae-laden water.Further investigations employed membranes fabricated from aluminum oxide powders with grain sizes of 1 mm,3 mm,8 mm,and 10 mm,corresponding to membrane pore sizes of 0.08 mm,0.16 mm,0.66 mm,and 0.76 mm,respectively,to assess the impact of pore size on ceramic membrane fouling.The results revealed that increasing membrane pore size significantly lowered the TMP growth rate and reduced the irreversibility of membrane fouling.The extended DerjaguineLandaueVerweyeOverbeek(XDLVO)analysis indicated that large pore sizes enhanced repulsion between the ceramic membrane and algal foulants,further alleviating membrane fouling.This investigation offers new insights into optimizing membrane material and pore size for efficient filtration of algae-laden water.展开更多
Membrane fouling is the primary resistance to the continuous production of stirred membrane reactors.This work presents a laser-enhanced high-magnification telecentric imaging system(LEHTIS),which uses a high-magnific...Membrane fouling is the primary resistance to the continuous production of stirred membrane reactors.This work presents a laser-enhanced high-magnification telecentric imaging system(LEHTIS),which uses a high-magnification telecentric lens and laser-enhanced illumination to invasively capture the motion of particles on the membrane surface or near the membrane.The problems of working distance and particle interference in the stirred membrane reactor are solved to achieve the purpose of in-situ monitoring of membrane fouling.This method is suitable for high flow rates,high solid holdup,and small particle size systems,and the dynamic motion and accumulation of particles are preliminarily analyzed.It shows that the accumulation and desorption of particles on the membrane surface are related to the physical properties of the membrane surface.There is an intermittent rotational movement in the flow field near the membrane,and it tends to stabilize over time.The filtration process can be assessed by monitoring changes in the overall velocity and acceleration of particles near the membrane.The analysis of forces acting on individual particles is compared and validated with the force balance model to correct and accurately apply it to stirred membrane reactors.The development of LEHTIS provides an effective tool for in-situ monitoring of membrane fouling and optimizing the stirred membrane reactors for industrial applications.展开更多
Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optim...Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering fouling.However,low flow velocity promotes fouling.Therefore,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation.This study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this goal.The model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and fouling.By optimizing the concentration cycle of the CCWS,water conservation and fouling control can be achieved.The model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance coefficient.Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation decrease.In periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate.Overall,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.展开更多
Fouling of landfill leachate,a biofilm formation process on the surface of the collection system,migration pipeline and treatment system causes low efficiency of leachate transportation and treatment and increases cos...Fouling of landfill leachate,a biofilm formation process on the surface of the collection system,migration pipeline and treatment system causes low efficiency of leachate transportation and treatment and increases cost for maintenance of those facilities.In addition,landfill leachate fouling might accumulate pathogens and antibiotic resistance genes(ARGs),posing threats to the environment.Characterization of the landfill leachate fouling and its associated environmental behavior is essential for the management of fouling.In this study,physicochemical and biological properties of landfill leachate fouling and the possible accumulation capacity of pathogens and ARGs were investigated in nitrification(aerobic condition)and denitrification(anaerobic condition)process during landfill leachate biological treatment,respectively.Results show that microbial(bacterial,archaeal,eukaryotic,and viral)community structure and function(carbon fixation,methanogenesis,nitrification and denitrification)differed in fouling under aerobic and anaerobic conditions,driven by the supplemental leachate water quality.Aerobic fouling had a higher abundance of nitrification and denitrification functional genes,while anaerobic fouling harbored a higher abundance of carbon fixation and methanogenesis genes.Both forms of leachate fouling had a higher abundance of pathogens and ARGs than the associated leachate,suggesting the accumulation capacity of fouling on biotic pollutants.Specifically,aerobic fouling harbored three orders of magnitude higher multidrug resistance genes mex D than its associated leachate.This finding provides fundamental knowledge on the biological properties of leachate fouling and suggests that leachate fouling might harbor significant pathogens and ARGs.展开更多
Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology.To alleviate membrane fouling,coagulation-ultrafiltration(C-UF)process using polyaluminum chloride(PACl)and PA...Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology.To alleviate membrane fouling,coagulation-ultrafiltration(C-UF)process using polyaluminum chloride(PACl)and PACl-Al_(13)with high proportion of Al_(13)O_(4)(OH)_(24)^(7+)as coagulants,respectively,were investigated at various pH conditions.Results indicated that an increase in solution pH contributed to larger floc size and looser floc structure for both PACl and PACl-Al_(13).It was conducive to the formation of more porous cake,as evidenced by mean pore area and pore area distribution of cake,leading to lower reversible fouling.Furthermore,humic acid(HA)removal presented a trend of first increasing and then decreasing with the increase of pH.The optimal HA removal was achieved at pH 6 regardless of coagulant type,suggesting that the slightest irreversible fouling should be occurred at this point.Interestingly,the irreversible fouling with PACl coagulant achieved a minimum value at pH 9,while the minimal irreversible fouling with PACl-Al_(13)was observed at pH 6.We speculated that the cake formed by PACl could further intercept HA prior to UF process at alkaline pH.Furthermore,compared with PACl,PACl-Al_(13)had a stronger charge neutralization ability,thus contributing to more compact floc structure and higher HA removal at various pH conditions.By UF fractionation measurement,higher HA removal for PACl-Al_(13)was due to higher removal of HA with molecular weight less than 50 kDa.展开更多
Simultaneous nitrification and denitrification(SND)is an efficient method to remove nitrogen in municipal wastewater treatment.However,low dissolved oxygen(DO)concentrations are generally required,leading to serious m...Simultaneous nitrification and denitrification(SND)is an efficient method to remove nitrogen in municipal wastewater treatment.However,low dissolved oxygen(DO)concentrations are generally required,leading to serious membrane fouling in membrane bioreactors(MBRs).This study aimed to clarify the synergistic effect of biomass and DO on nitrogen removal and membrane fouling.To achieve this goal,four submerged MBRs equipped with ceramic membranes were operated with different biomass(mixed liquor suspended solids(MLSS))concentrations(3000 mg/L,5000 mg/L,7500 mg/L,and 12000 mg/L)under various DO concentrations(2.0 mg/L,1.0 mg/L,and 0.5 mg/L).As a result,increasing biomass in the MBRs enhanced total nitrogen(TN)removal via SND,and excellent TN removal efficiencies of 60.7%and 75.8%were obtained using the MBR with an MLSS concentration of 12000 mg/L and DO concentrations of 2.0 mg/L and 1.0 mg/L.However,a further decrease in DO deteriorated TN removal due to the inhibition of nitrification.Moreover,high MLSS concentrations were beneficial to membrane fouling control for ceramic membranes in MBRs.The lowest transmembrane pressure development rate was observed for the MBR with an MLSS concentration of 12000 mg/L.High biomass offset the adverse effect of DO decrease on membrane fouling to some extent,and improved the stability of the reactor.Therefore,biomass might be an important parameter for membrane fouling reduction in ceramic MBRs.Overall,optimal biomass and DO concentrations for TN removal were identified,providing useful information for the successful operation of MBRs with efficient TN removal and membrane fouling control.展开更多
This paper summarizes a nontoxic Anti-fouling coating utilizing capsaicin as an anti-fouling agent. The capsaicin constituent used in the coating has a rating from about 100 000 to about 1 500 000 Scoville Heat Units....This paper summarizes a nontoxic Anti-fouling coating utilizing capsaicin as an anti-fouling agent. The capsaicin constituent used in the coating has a rating from about 100 000 to about 1 500 000 Scoville Heat Units. The capsaicin is mixed with a silicon dioxide and then solubilized into a free-flowing homogeneous liquid oleoresin composition by adding a solvent to increase solubility and facilitate mixing. The oleoresin capsaicin liquid solution is mixed with a suitable corrosion resistant epoxy resin, which is then mixed with a hardening catalyst and applied to the surface to be treated.展开更多
The influence of membrane fouling on the retention of the trace organic contaminant sulfamethoxazole by a nanofiltration(NF) process was investigated.Organic fouling caused a severe flux decline possibly due to pore b...The influence of membrane fouling on the retention of the trace organic contaminant sulfamethoxazole by a nanofiltration(NF) process was investigated.Organic fouling caused a severe flux decline possibly due to pore blocking and adsorption directly after the commencement of the fouling layer development.Such membrane-foulant interactions were absent for colloidal fouling,which resulted in a more gradual flux decline.Membrane charge played a significant role in the separation process of inorganic salts,where the retention was the highest in a caustic environment(high pH) due to more swollen membrane material caused by the higher negative charge on the membrane.Organic fouling and a combination of colloidal and organic fouling led to a significant increase in the membrane negative charge.The influence of membrane fouling on solute retention was dependent on the fouling behaviour and the physicochemical properties of the model foulants,where the model foulants probably contributed to an increase in the retention of charged solutes due to enhanced electrostatic interactions.Organic fouling caused an increase in the retention of inorganic salts and sulfamethoxazole due to pore blocking.In contrast,colloidal fouling caused a decrease in the retention of inorganic salts due to cake-enhanced concentration polarisation.However,the presence of a colloidal fouling layer did not reduce the retention of sulfamethoxazole.A mixture of colloidal and organic matter improved the retention of inorganic salts.A similar conclusion can be inferred for sulfamethoxazole at pH 4 when the compound exists in a neutral form.展开更多
Biofouling is an important factor that affects bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitor...Biofouling is an important factor that affects bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cultured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53 / Lh ±1.416 / Lh in April, significantly higher than those of cleaned scallops, Le., 4.23 / Lh±2.744 / Lh. The consumption of total particulate matter by fouled scallops in April was 5.52 / Lh± 0.818 / Lh; the corresponding results for cleaned scallops are 2.49 / Lh ±0.614 / Lh Fouling increased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81/Lh ±7.699 / Lh in April, while cleaned scallops released 2.46 / Lh ±0.511 / Lh ammonia. Phosphate uptake of fouled scallops was 2.01± 0.699 / Lh and cleaned scallops released phosphate 6.01 / Lh ＋ 0.876 / Lh in April. There was not significant difference in nitrate consumption between fouled and cleaned scallops. According to the phytoplankton classification of input and output water samples, fouled scallops filtered more phytoplankton species than cleaned scallops. Therefore, this study showed that fouling contributed much to phytoplankton depletion and concentration increase of ammonia in water.展开更多
The advancement in material science and engineering technology has led to the development of antifouling(AF) coatings which are cheaper, durable, less toxic, and safe to the environment. The use of AF coatings contain...The advancement in material science and engineering technology has led to the development of antifouling(AF) coatings which are cheaper, durable, less toxic, and safe to the environment. The use of AF coatings containing tributyltin compounds was prohibited at the beginning of 2003, this necessitated the development of environmentally friendly coatings. The fouling release coating(FRC) lacks biocides and has low surface energy, low elastic modulus with smooth surface properties, hence a better release effect to fouling organisms. Several functional coatings have been recently developed based on fouling release(FR) technology to combat the effects of biofouling. Here, we provide a brief overview of innovative technologies and recent developments based on FRCs, including silicone, modified fluorinated polymer,cross-linked coatings, amphiphilic copolymer coating, hydrogel coatings, and biomimetic coatings. We also highlight the key issues and shortcomings of innovative technologies based on FRCs. This may give new insights into the future development of marine AF coatings.展开更多
Corrosion behaviour and biofouling characteristics of mild steel in three different coastal locations in the Gulf of Mannar,India have been studied over a period of 24 months.Oyster fouling was predominant at Open sea...Corrosion behaviour and biofouling characteristics of mild steel in three different coastal locations in the Gulf of Mannar,India have been studied over a period of 24 months.Oyster fouling was predominant at Open sea-Tuticorin,while barnacle fouling was dominant at both Mandapam and Harbour-Tuticorin.The rate of corrosion for 24 months exposure period was highest at Mandapam,where fouling was minimal.The surface of the mild steel was characterized by etchings&crevices beneath the hard foulers attached on it,at all the test locations.The depth of crevice caused by hard foulers was higher at Open sea-Tuticorin followed by Harbour-Tuticorin and Mandapam.The loss in ultimate tensile strength was more in Open sea-Tuticorin than the other two locations.Corrosion behaviour of mild steel is discussed based on the variation in the biofouling assemblage at the three test locations.展开更多
Ultrafiltration(UF)has been increasingly implemented in drinking water treatment plants;however,algae and their secretions can cause severe membrane fouling and pose great challenges to UF in practice.In this study,a ...Ultrafiltration(UF)has been increasingly implemented in drinking water treatment plants;however,algae and their secretions can cause severe membrane fouling and pose great challenges to UF in practice.In this study,a simple and practical chemically enhanced backwashing(CEB)process was developed to address such issues using various cleaning reagents,including sodium hypochlorite(NaClO),sodium chloride(NaCl),sodium hydroxide(NaOH),sodium citrate,and their combinations.The results indicate that the type of chemical played a fundamental role in alleviating the hydraulically irreversible membrane fouling(HIMF),with NaClO as the best-performing reagent,followed by NaCl.Furthermore,a CEB process using a combination of NaClO with NaCl,NaOH,or sodium citrate delivered little improvement in the alleviation of membrane fouling compared with NaClO alone.The optimized dosage and dosing frequency of NaClO were 10 mg·L^(-1) two times per day.Long-term pilot-scale and full-scale experiments further verified the feasibility of the CEB process in relieving algae-derived membrane fouling.Compared with the conventional hydraulic backwashing without chemical involvement,the CEB process can effectively remove the organic foulants including biopolymers,humic substances,and proteinlike substances by means of oxidization,thereby weakening the cohesive forces between the organic foulants and the membrane surface.Therefore,the CEB process can efficiently alleviate the algae-related membrane fouling with lower chemical consumption,and is proposed as an alternative to control membrane fouling in treating the algae-containing surface water.展开更多
In this work,a conductive thin film composite forward osmosis(TFC-FO)membrane was firstly prepared via vacuum filtering MXenes nanolayer on the outer surface of polyethersulfone membrane followed by interfacial polyme...In this work,a conductive thin film composite forward osmosis(TFC-FO)membrane was firstly prepared via vacuum filtering MXenes nanolayer on the outer surface of polyethersulfone membrane followed by interfacial polymerization in the other side.Moreover,its feasibility of mitigating organic fouling under electric field was evaluated.Results indicated that the addition of MXenes greatly reduced the electric resistance of membrane from 2.1×10^(12)Ωto 46.8Ω,enhanced the membrane porosity and promoted the membrane performance in terms of the ratio of water flux to reverse salt flux.The modified TFC-FO membrane presented the optimal performance with 0.47 g/m^(2)loading amount of MXenes.Organic fouling experiments using sodium alginate(SA)and bovine serum albumin(BSA)as representative demonstrated that the introduction of MXenes could effectively enhance the anti-fouling ability of TFC-FO membrane under the electric field of 2 V.The interelectron repulsion hindered organic foulants attaching into membrane surface and thus effectively alleviated the membrane fouling.More importantly,the modified TFC-FO membrane showed good stability during the fouling experiment of 10 h.In all,our work proved that introducing MXenes into the porous layer of support is feasible to alleviate organic fouling of FO membrane.展开更多
A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and ca...A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and cake layer, was established by virtue of the interfacial polarization and the electrostatic field theory. The effect of some important parameters, such as the depth, conductivity of CPL, and cake layer, on the dielectric spectroscopy （or dielectric relaxation properties） of the UF system was discussed by the parameter sensitivity analysis and the dielectric measurement. The simulations indicate that the CPL can be created rapidly and the cake layer formation is the dynamic balance process of growth and erosion in the process of UF. The key factor affecting on the dielectric spectrum of UF system is the electrical properties of the CPL and the cake layer. In comparison to the results of dielectric measurement, the simulations indicate that the model proposed in this work is valid and reliable to some degree for describing and explaining the dielectric relaxation phenomenon in UF system. It is very important to further understand the fouling behavior of membrane surface and optimize the controlling techniques of membrane fouling in the process of UF.展开更多
文摘Membrane fouling is a persistent challenge in membrane-based technologies,significantly impacting efficiency,operational costs,and system lifespan in applications like water treatment,desalination,and industrial processing.Foul-ing,caused by the accumulation of particulates,organic compounds,and microorganisms,leads to reduced permeability,increased energy demands,and frequent maintenance.Traditional fouling control approaches,relying on empirical models and reactive strategies,often fail to address these issues efficiently.In this context,artificial intelligence(AI)and machine learning(ML)have emerged as innovative tools offering predictive and proactive solutions for fouling man-agement.By utilizing historical and real-time data,AI/ML techniques such as artificial neural networks,support vector machines,and ensemble models enable accurate prediction of fouling onset,identification of fouling mechanisms,and optimization of control measures.This review provides a detailed examination of the integration of AI/ML in membrane fouling prediction and mitigation,discussing advanced algorithms,the role of sensor-based monitoring,and the importance of robust datasets in enhancing predictive accuracy.Case studies highlighting successful AI/ML applications across various membrane processes are presented,demonstrating their transformative potential in improving system performance.Emerging trends,such as hybrid modeling and IoT-enabled smart systems,are explored,alongside a criti-cal analysis of research gaps and opportunities.This review emphasizes AI/ML as a cornerstone for sustainable,cost-effective membrane operations.
基金supported by the directional Foundation of the Key Laboratory of Ocean Observation Technology,MNR(No.2021KlootB06)the National Natural Science Foundation of China(No.52271341)。
文摘The use of antifouling agents is suggested to be a promising method for protecting oceanic instruments from biological contamination.We developed a novel antifouling material doped with capsaicin(CAP)as a filler and montmorillonite(MMT)as a carrier for the practical application of CTD(conductivity,temperature,depth)protection.The optimal parameters for preparing the material were established,and the obtained material achieved the maximum CAP loading capacity of 32.74%.The proposed material exhibited great release properties in acidic environments,which is beneficial for reducing bacterial attachment.Furthermore,the optimal conditions(temperature,flow rate,and pressure in the aquatic environment)for a better release rate of the material were determined through a series of simulation tests in lab.It provided good guidance and basis for practical application of the material.The CAP@MMT composite showed excellent efficiency and effectiveness in preventing the attachment of microorganisms during the four-month marine field tests.In the subsequent experiments,the great properties of the antifouling material were further confirmed by retesting the conductivity of four instruments participating in marine field tests.The measuring errors of CTD protected by the antifouling material are both within 0.01 mS/cm,which is far lower than that of the other two instruments.
基金supported by the National Natural Science Foundation of China(Nos.52170070,52400022 and 52200088)the Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology(GDSTA)(No.SKXRC202406)+1 种基金China Postdoctoral Science Foundation(No.2023M740754)“One hundred Youth”Science and Technology Plan,Guangdong University of Technology,China(No.263113906).
文摘As part of sewage treatment,coagulation could remove phosphorus from the effluent of the Anaerobic-Anoxic-Oxic-Anoxic(A^(2)OA)biological process.The importance in investigating the influence of coagulation on Anaerobic-Anoxic-Oxic-Anoxic Membrane Bioreactor(A^(2)OA-MBR)should be emphasized.In this study,systematic optimization of coagulation parameters for greater pollutant removal was conducted in terms of coagulant dosage,coagulation residence time and stirring hydraulic conditions.Coagulation process could remarkably remove turbidity,phosphorus,chemical oxygen demand,humic-like,protein-like and polysaccharide-like substances from secondary effluent and A^(2)OA sludge-liquid mixture.Furthermore,the influence of coagulation on membrane fouling development during the ultrafiltration of secondary effluent and A^(2)OA sludge-liquid mixture was investigated based on optimum coagulation parameters.Coagulation simultaneously reduced reversible membrane fouling and the irreversible one by 86%and 16%,respectively.According to excitation-emission matrix and attenuated total reflection-fourier transform infrared spectra,membrane fouling was primarily influenced by the cake layer,although pore fouling might be aggravated by A^(2)OA processes.Besides,the feasibility of coagulation-assisted A^(2)OA-MBRwas also assessed using hollowfibermembranes.It exhibited excellent potential in alleviatingmembrane fouling,while regular cleaning twice a day was not enough to suppress transmembrane pressure increase during direct domestic wastewater ultrafiltration.Additionally,both polysaccharide-like and protein-like foulants were vital components for membrane fouling during wastewater treatment.
基金supported by the National Natural Science Foundation of China(Nos.51971032,52371048,and 52071019).
文摘Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.
基金supported by the Fundamental Research Funds for Central Universities(No.30922010811).
文摘It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation but can also track the fouling process during operation.Herein,an aggregation-induced emission(AIE)-active polymer membrane was prepared by the interfacial polymerization of a cyclodextrin-based glycocluster(CD@Glucose)and a tetraphenylethylene derivative modified with boronic acid groups(TPEDB)on the surface of a polyacrylonitrile(PAN)ultrafiltration membrane.This interfacial polymerization method can be stacked layer-by-layer to regulate the hydrophilicity and pore structure of the membrane.With the increase in the number of polymer layers,the separation and antifouling properties of the membrane gradually improved.Owing to the AIE property of the crosslinking agent TPEDB,the occurrence of interfacial polymerization and the degree of fouling during membrane operation can be monitored by the fluorescence distribution and intensity.With the aggravation of membrane fouling,the fluorescence decreased gradually,but recovered after cleaning.Therefore,this AIE effect can be used for real-time monitoring of interfacial polymerization as well as membrane fouling.
文摘Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions are critical factors influencing membrane fouling. This study aimed to investigate the simultaneous impacts of temperature and hydraulic retention time (HRT) variations on membrane fouling. Experiments were conducted at three different temperatures (18°C, 25°C, and 32°C) and HRTs (6 h, 9 h, and 15 h). The results demonstrated that increases in both temperature and HRT contributed to a reduction in membrane fouling. Additionally, a positive interaction between temperature and HRT was observed in the linear slope variation of membrane permeation, with temperature variations exerting a greater influence on membrane fouling than HRT variations. Fouling factor analysis revealed that increases in temperature and HRT led to decreased concentrations of soluble microbial products (SMP) and extracellular polymeric substances (EPS), particularly carbohydrates, in the activated sludge. Analyses of the cake layer of the membrane indicated that increasing temperature and HRT reduced EPS levels, particularly polysaccharides and proteins;altered primary protein structure;and increased the mean particle size distribution. Ultimately, these changes led to reductions in both reversible and irreversible hydraulic resistances. This study highlights the importance of optimizing operational parameters such as temperature and HRT to enhance membrane performance and treatment efficiency in MBR systems while mitigating fouling.
基金supported by the National Natural Science Foundation of China(Grant No.52370035)the Natural Science Foundation of Hebei Province,China(Grant No.E2023202064)the China Postdoctoral Science Foundation(Grant No.2024M750717).
文摘Membrane filtration technology has been widely utilized for microalgae harvesting due to its stability and high efficiency.However,this technology faces challenges posed by membrane fouling caused by algal cells and extracellular organic matter(EOM),which are significantly influenced by membrane material and pore size.This study compared the fouling behavior of polyvinylidene fluoride(PVDF)membranes and ceramic membranes with similar pore sizes(0.20 mm and 0.16 mm,respectively)during the filtration of Microcystis aeruginosa.The ceramic membrane exhibited a lower transmembrane pressure(TMP)growth rate and reduced accumulation of surface foulants compared to the PVDF membrane,indicating its greater suitability for filtering algae-laden water.Further investigations employed membranes fabricated from aluminum oxide powders with grain sizes of 1 mm,3 mm,8 mm,and 10 mm,corresponding to membrane pore sizes of 0.08 mm,0.16 mm,0.66 mm,and 0.76 mm,respectively,to assess the impact of pore size on ceramic membrane fouling.The results revealed that increasing membrane pore size significantly lowered the TMP growth rate and reduced the irreversibility of membrane fouling.The extended DerjaguineLandaueVerweyeOverbeek(XDLVO)analysis indicated that large pore sizes enhanced repulsion between the ceramic membrane and algal foulants,further alleviating membrane fouling.This investigation offers new insights into optimizing membrane material and pore size for efficient filtration of algae-laden water.
基金Financial support from the National Key Research and Development Program(2022YFB3504000)the National Natural Science Foundation of China(22421003,22478391,22178345)the Youth Innovation Promotion Association CAS(Y2023012,2022045,2023052)。
文摘Membrane fouling is the primary resistance to the continuous production of stirred membrane reactors.This work presents a laser-enhanced high-magnification telecentric imaging system(LEHTIS),which uses a high-magnification telecentric lens and laser-enhanced illumination to invasively capture the motion of particles on the membrane surface or near the membrane.The problems of working distance and particle interference in the stirred membrane reactor are solved to achieve the purpose of in-situ monitoring of membrane fouling.This method is suitable for high flow rates,high solid holdup,and small particle size systems,and the dynamic motion and accumulation of particles are preliminarily analyzed.It shows that the accumulation and desorption of particles on the membrane surface are related to the physical properties of the membrane surface.There is an intermittent rotational movement in the flow field near the membrane,and it tends to stabilize over time.The filtration process can be assessed by monitoring changes in the overall velocity and acceleration of particles near the membrane.The analysis of forces acting on individual particles is compared and validated with the force balance model to correct and accurately apply it to stirred membrane reactors.The development of LEHTIS provides an effective tool for in-situ monitoring of membrane fouling and optimizing the stirred membrane reactors for industrial applications.
基金Financial support from the National Natural Science Foundation of China (22022816 and 22078358)
文摘Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering fouling.However,low flow velocity promotes fouling.Therefore,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation.This study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this goal.The model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and fouling.By optimizing the concentration cycle of the CCWS,water conservation and fouling control can be achieved.The model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance coefficient.Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation decrease.In periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate.Overall,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.
基金supported by the National Natural Science Foundation of China (Nos.52000016 and 51578642)the Major program of Science and Technology of Anhui Province (No.202103a07020016)。
文摘Fouling of landfill leachate,a biofilm formation process on the surface of the collection system,migration pipeline and treatment system causes low efficiency of leachate transportation and treatment and increases cost for maintenance of those facilities.In addition,landfill leachate fouling might accumulate pathogens and antibiotic resistance genes(ARGs),posing threats to the environment.Characterization of the landfill leachate fouling and its associated environmental behavior is essential for the management of fouling.In this study,physicochemical and biological properties of landfill leachate fouling and the possible accumulation capacity of pathogens and ARGs were investigated in nitrification(aerobic condition)and denitrification(anaerobic condition)process during landfill leachate biological treatment,respectively.Results show that microbial(bacterial,archaeal,eukaryotic,and viral)community structure and function(carbon fixation,methanogenesis,nitrification and denitrification)differed in fouling under aerobic and anaerobic conditions,driven by the supplemental leachate water quality.Aerobic fouling had a higher abundance of nitrification and denitrification functional genes,while anaerobic fouling harbored a higher abundance of carbon fixation and methanogenesis genes.Both forms of leachate fouling had a higher abundance of pathogens and ARGs than the associated leachate,suggesting the accumulation capacity of fouling on biotic pollutants.Specifically,aerobic fouling harbored three orders of magnitude higher multidrug resistance genes mex D than its associated leachate.This finding provides fundamental knowledge on the biological properties of leachate fouling and suggests that leachate fouling might harbor significant pathogens and ARGs.
基金supported by the National Natural Science Foundation of China(Nos.52100002,52200035,22076012 and51878047)the Open Project of State Key Laboratory of Urban Water Resource and Environment(No.QA202014)+4 种基金the Yangtze River Joint Research Phase II Program(No.2022-LHYJ-02-0510-02)the National Key Research and Development Program of China(No.2021YFE0100800)the Beijing Forestry University Outstanding Young Talent Cultivation Project(No.2019JQ03008)the Beijing Municipal Education Commission through the Innovative Transdisciplinary Program“Ecological Restoration Engineering”(No.GJJXK210102)the China Postdoctoral Science Foundation(No.2021M700448).
文摘Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology.To alleviate membrane fouling,coagulation-ultrafiltration(C-UF)process using polyaluminum chloride(PACl)and PACl-Al_(13)with high proportion of Al_(13)O_(4)(OH)_(24)^(7+)as coagulants,respectively,were investigated at various pH conditions.Results indicated that an increase in solution pH contributed to larger floc size and looser floc structure for both PACl and PACl-Al_(13).It was conducive to the formation of more porous cake,as evidenced by mean pore area and pore area distribution of cake,leading to lower reversible fouling.Furthermore,humic acid(HA)removal presented a trend of first increasing and then decreasing with the increase of pH.The optimal HA removal was achieved at pH 6 regardless of coagulant type,suggesting that the slightest irreversible fouling should be occurred at this point.Interestingly,the irreversible fouling with PACl coagulant achieved a minimum value at pH 9,while the minimal irreversible fouling with PACl-Al_(13)was observed at pH 6.We speculated that the cake formed by PACl could further intercept HA prior to UF process at alkaline pH.Furthermore,compared with PACl,PACl-Al_(13)had a stronger charge neutralization ability,thus contributing to more compact floc structure and higher HA removal at various pH conditions.By UF fractionation measurement,higher HA removal for PACl-Al_(13)was due to higher removal of HA with molecular weight less than 50 kDa.
基金supported by the National Natural Science Foundation of China(Grant No.51978232)the Natural Science Foundation of Tianjin City(Grant No.19JCJQJC63000)+1 种基金the Natural Science Foundation of Hebei Province(Grant No.E2019202012)the Science and Technology Project of Hebei Education Department of China(Grant No.QN2019022).
文摘Simultaneous nitrification and denitrification(SND)is an efficient method to remove nitrogen in municipal wastewater treatment.However,low dissolved oxygen(DO)concentrations are generally required,leading to serious membrane fouling in membrane bioreactors(MBRs).This study aimed to clarify the synergistic effect of biomass and DO on nitrogen removal and membrane fouling.To achieve this goal,four submerged MBRs equipped with ceramic membranes were operated with different biomass(mixed liquor suspended solids(MLSS))concentrations(3000 mg/L,5000 mg/L,7500 mg/L,and 12000 mg/L)under various DO concentrations(2.0 mg/L,1.0 mg/L,and 0.5 mg/L).As a result,increasing biomass in the MBRs enhanced total nitrogen(TN)removal via SND,and excellent TN removal efficiencies of 60.7%and 75.8%were obtained using the MBR with an MLSS concentration of 12000 mg/L and DO concentrations of 2.0 mg/L and 1.0 mg/L.However,a further decrease in DO deteriorated TN removal due to the inhibition of nitrification.Moreover,high MLSS concentrations were beneficial to membrane fouling control for ceramic membranes in MBRs.The lowest transmembrane pressure development rate was observed for the MBR with an MLSS concentration of 12000 mg/L.High biomass offset the adverse effect of DO decrease on membrane fouling to some extent,and improved the stability of the reactor.Therefore,biomass might be an important parameter for membrane fouling reduction in ceramic MBRs.Overall,optimal biomass and DO concentrations for TN removal were identified,providing useful information for the successful operation of MBRs with efficient TN removal and membrane fouling control.
文摘This paper summarizes a nontoxic Anti-fouling coating utilizing capsaicin as an anti-fouling agent. The capsaicin constituent used in the coating has a rating from about 100 000 to about 1 500 000 Scoville Heat Units. The capsaicin is mixed with a silicon dioxide and then solubilized into a free-flowing homogeneous liquid oleoresin composition by adding a solvent to increase solubility and facilitate mixing. The oleoresin capsaicin liquid solution is mixed with a suitable corrosion resistant epoxy resin, which is then mixed with a hardening catalyst and applied to the surface to be treated.
基金Project (No. DP0985389) supported by the Australian Research Council
文摘The influence of membrane fouling on the retention of the trace organic contaminant sulfamethoxazole by a nanofiltration(NF) process was investigated.Organic fouling caused a severe flux decline possibly due to pore blocking and adsorption directly after the commencement of the fouling layer development.Such membrane-foulant interactions were absent for colloidal fouling,which resulted in a more gradual flux decline.Membrane charge played a significant role in the separation process of inorganic salts,where the retention was the highest in a caustic environment(high pH) due to more swollen membrane material caused by the higher negative charge on the membrane.Organic fouling and a combination of colloidal and organic fouling led to a significant increase in the membrane negative charge.The influence of membrane fouling on solute retention was dependent on the fouling behaviour and the physicochemical properties of the model foulants,where the model foulants probably contributed to an increase in the retention of charged solutes due to enhanced electrostatic interactions.Organic fouling caused an increase in the retention of inorganic salts and sulfamethoxazole due to pore blocking.In contrast,colloidal fouling caused a decrease in the retention of inorganic salts due to cake-enhanced concentration polarisation.However,the presence of a colloidal fouling layer did not reduce the retention of sulfamethoxazole.A mixture of colloidal and organic matter improved the retention of inorganic salts.A similar conclusion can be inferred for sulfamethoxazole at pH 4 when the compound exists in a neutral form.
基金supported by National Science Foundation of Huaihai Institute of Technology (No. KQ07102)Open Project Program of the Key Laboratory of Marine Bio-resources Sustainable Utilization, SCSIO, CAS (No. KK09001)
文摘Biofouling is an important factor that affects bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cultured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53 / Lh ±1.416 / Lh in April, significantly higher than those of cleaned scallops, Le., 4.23 / Lh±2.744 / Lh. The consumption of total particulate matter by fouled scallops in April was 5.52 / Lh± 0.818 / Lh; the corresponding results for cleaned scallops are 2.49 / Lh ±0.614 / Lh Fouling increased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81/Lh ±7.699 / Lh in April, while cleaned scallops released 2.46 / Lh ±0.511 / Lh ammonia. Phosphate uptake of fouled scallops was 2.01± 0.699 / Lh and cleaned scallops released phosphate 6.01 / Lh ＋ 0.876 / Lh in April. There was not significant difference in nitrate consumption between fouled and cleaned scallops. According to the phytoplankton classification of input and output water samples, fouled scallops filtered more phytoplankton species than cleaned scallops. Therefore, this study showed that fouling contributed much to phytoplankton depletion and concentration increase of ammonia in water.
文摘The advancement in material science and engineering technology has led to the development of antifouling(AF) coatings which are cheaper, durable, less toxic, and safe to the environment. The use of AF coatings containing tributyltin compounds was prohibited at the beginning of 2003, this necessitated the development of environmentally friendly coatings. The fouling release coating(FRC) lacks biocides and has low surface energy, low elastic modulus with smooth surface properties, hence a better release effect to fouling organisms. Several functional coatings have been recently developed based on fouling release(FR) technology to combat the effects of biofouling. Here, we provide a brief overview of innovative technologies and recent developments based on FRCs, including silicone, modified fluorinated polymer,cross-linked coatings, amphiphilic copolymer coating, hydrogel coatings, and biomimetic coatings. We also highlight the key issues and shortcomings of innovative technologies based on FRCs. This may give new insights into the future development of marine AF coatings.
基金Supported by the Ministry of Environment and Forests,New Delhi(Project Grant No.19-26/2003-RE)
文摘Corrosion behaviour and biofouling characteristics of mild steel in three different coastal locations in the Gulf of Mannar,India have been studied over a period of 24 months.Oyster fouling was predominant at Open sea-Tuticorin,while barnacle fouling was dominant at both Mandapam and Harbour-Tuticorin.The rate of corrosion for 24 months exposure period was highest at Mandapam,where fouling was minimal.The surface of the mild steel was characterized by etchings&crevices beneath the hard foulers attached on it,at all the test locations.The depth of crevice caused by hard foulers was higher at Open sea-Tuticorin followed by Harbour-Tuticorin and Mandapam.The loss in ultimate tensile strength was more in Open sea-Tuticorin than the other two locations.Corrosion behaviour of mild steel is discussed based on the variation in the biofouling assemblage at the three test locations.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(51778170)State Key Laboratory of Urban Water Resource and Environment(2020DX04)+1 种基金Fundamental Research Funds for the Central Universities,China Postdoctoral Science Foundation(2019M651290)Heilongjiang Postdoctoral Science Foundation(LBH-Z19153).
文摘Ultrafiltration(UF)has been increasingly implemented in drinking water treatment plants;however,algae and their secretions can cause severe membrane fouling and pose great challenges to UF in practice.In this study,a simple and practical chemically enhanced backwashing(CEB)process was developed to address such issues using various cleaning reagents,including sodium hypochlorite(NaClO),sodium chloride(NaCl),sodium hydroxide(NaOH),sodium citrate,and their combinations.The results indicate that the type of chemical played a fundamental role in alleviating the hydraulically irreversible membrane fouling(HIMF),with NaClO as the best-performing reagent,followed by NaCl.Furthermore,a CEB process using a combination of NaClO with NaCl,NaOH,or sodium citrate delivered little improvement in the alleviation of membrane fouling compared with NaClO alone.The optimized dosage and dosing frequency of NaClO were 10 mg·L^(-1) two times per day.Long-term pilot-scale and full-scale experiments further verified the feasibility of the CEB process in relieving algae-derived membrane fouling.Compared with the conventional hydraulic backwashing without chemical involvement,the CEB process can effectively remove the organic foulants including biopolymers,humic substances,and proteinlike substances by means of oxidization,thereby weakening the cohesive forces between the organic foulants and the membrane surface.Therefore,the CEB process can efficiently alleviate the algae-related membrane fouling with lower chemical consumption,and is proposed as an alternative to control membrane fouling in treating the algae-containing surface water.
基金supported by the National Natural Science Foundation of China(No.51978312)the Six Major Talent Peaks of Jiangsu Province(No.2018-JNHB-014)the Program to Cultivate Middle-aged and Young Science Leaders of Colleges and Universities of Jiangsu Province。
文摘In this work,a conductive thin film composite forward osmosis(TFC-FO)membrane was firstly prepared via vacuum filtering MXenes nanolayer on the outer surface of polyethersulfone membrane followed by interfacial polymerization in the other side.Moreover,its feasibility of mitigating organic fouling under electric field was evaluated.Results indicated that the addition of MXenes greatly reduced the electric resistance of membrane from 2.1×10^(12)Ωto 46.8Ω,enhanced the membrane porosity and promoted the membrane performance in terms of the ratio of water flux to reverse salt flux.The modified TFC-FO membrane presented the optimal performance with 0.47 g/m^(2)loading amount of MXenes.Organic fouling experiments using sodium alginate(SA)and bovine serum albumin(BSA)as representative demonstrated that the introduction of MXenes could effectively enhance the anti-fouling ability of TFC-FO membrane under the electric field of 2 V.The interelectron repulsion hindered organic foulants attaching into membrane surface and thus effectively alleviated the membrane fouling.More importantly,the modified TFC-FO membrane showed good stability during the fouling experiment of 10 h.In all,our work proved that introducing MXenes into the porous layer of support is feasible to alleviate organic fouling of FO membrane.
基金This work was supported by the Natural Science Foundation of Shandong Province of China （No.Q2007B01）.
文摘A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and cake layer, was established by virtue of the interfacial polarization and the electrostatic field theory. The effect of some important parameters, such as the depth, conductivity of CPL, and cake layer, on the dielectric spectroscopy （or dielectric relaxation properties） of the UF system was discussed by the parameter sensitivity analysis and the dielectric measurement. The simulations indicate that the CPL can be created rapidly and the cake layer formation is the dynamic balance process of growth and erosion in the process of UF. The key factor affecting on the dielectric spectrum of UF system is the electrical properties of the CPL and the cake layer. In comparison to the results of dielectric measurement, the simulations indicate that the model proposed in this work is valid and reliable to some degree for describing and explaining the dielectric relaxation phenomenon in UF system. It is very important to further understand the fouling behavior of membrane surface and optimize the controlling techniques of membrane fouling in the process of UF.
