Filtrate Research Articles

MXene (Ti3C2Tx)/Cellulose Acetate Mixed-Matrix Membrane Enhances Fouling Resistance and Rejection in the Crossflow Filtration Process

Obstacles in the membrane-based separation field are mainly related to membrane fouling. This study involved the synthesis and utilization of covalently crosslinked MXene/cellulose acetate mixed matrix membranes with MXene at different concentrations (CCAM-0% to CCAM-12%) for water purification applications. The membranes’ water flux, dye, and protein rejection performances were compared using dead-end (DE) and crossflow (CF) filtration. The fabricated membranes, especially CCAM-10%, exhibited high hydrophilicity, good surface roughness, significantly high water flux, high water uptake, and high porosity. A significantly higher flux was observed in CF filtration relative to DE filtration. Moreover, in CF filtration, the CCAM-10% membrane exhibited 96.60% and 99.49% rejection of methyl green (MG) and bovine serum albumin (BSA), respectively, while maintaining a flux recovery ratio of 67.30% and an irreversible fouling ratio at (Rir) of 32.70, indicating good antifouling performance. Hence, this study suggests that covalent modification of cellulose acetate membranes with MXene significantly improves the performance and fouling resistance of membranes for water filtration in CF mode relative to DE mode.

Impact of Particle Shape and Surface Group on Membrane Fouling.

Membrane fouling remains one of the most critical drawbacks in membrane filtration processes. Although the effect of various operating parameters—such as flow velocity, concentration, and foulant size—are well-studied, the impact of particle shape is not well understood. To bridge this gap, this study investigated the effect of polystyrene particle sphericity (sphere, peanut and pear) on external membrane fouling, along with the effect of particle charge (unmodified, carboxylated, and aminated). The results indicate that the non-spherical particles produce higher critical fluxes than the spherical particles (i.e., respectively 24% and 13% higher for peanut and pear), which is caused by the looser packing in the cake due to the varied particle orientations. Although higher crossflow velocities diminished the differences in the critical flux values among the particles of different surface charges, the differences among the particle shapes remained distinct. In dead-end filtration, non-spherical particles also produced lower flux declines. The shear-induced diffusion model predicts all five particle types well. The Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended DLVO (XDLVO) models were used to quantify the interaction energies, and the latter agreed with the relative critical flux trends of all of the PS particles. As for the flux decline trends, both the DLVO and XDLVO results are in good agreement.

Solvent recovery from photolithography wastes using cellulose ultrafiltration membranes

Solvent recycling and reuse are indispensable for ensuring a sustainable chemical industry and circular economy. In this study we report the fabrication of cellulose ultrafiltration membranes and their application in recovery of propylene glycol methyl ether acetate (PGMEA) used as developer solvent in SU-8 photolithography. Cellulose membranes were fabricated via alkaline hydrolysis of cellulose acetate membranes in aqueous NaOH. Membrane permeance and molecular weight cut-off (MWCO) were tuned via changing cellulose acetate concentration in precursor solution and evaporation of volatile co-solvent, acetone. MWCO of the membranes was found to be smallest in DMSO, followed by water and largest in methanol. The difference was attributed to the different hydrodynamic diameters of the probe molecules in these solvents. SU-8 rejection from its representative developer solutions in PGMEA was assessed in dead-end filtration at up to 80% permeate recovery. After the first filtration, the collected permeate was fed to the same membrane to simulate a two-stage filtration scenario. Rejection was in the range of 87%–89% in a first stage filtration and 79%–80% in a second stage, both operated at 80% permeate recovery. Recycled solvent could be used in photolithography although with some loss of pattern fidelity, possibly owing to remaining SU-8 and photoacid generator in PGMEA. • Cellulose membrane permeance and MWCO tuned between 0.40–23.3 LHM/bar and 4–15 kDa. • Permeance is via pore flow mechanism but is also affected by swelling and steric hindrance. • SU-8 can be recovered from its PGMEA solution and reused in photolithography.

Hydraulic Resistance and Macromolecular Structure of Aerobic and Anaerobic Mixed-Culture Extracellular Polymeric Substances Gel Layers: Opportunities and Challenges

Soluble Extracellular Polymeric Substances (sEPS) are a mixture of microbial soluble polymers produced during aerobic or anaerobic treatment of wastewater. Gel layers mainly consisting of sEPS are usually present in the fouling layers of membrane bioreactors (MBRs) and in the dynamic membranes (DMs) of dynamic membrane bioreactors (DMBRs), and their properties have not been thoroughly investigated over the years. In this study, sEPS fractions recovered from aerobic and anaerobic reactors were analyzed and tested to build-up EPS gel layers on a 0.2 µm pore size polycarbonate carrier. Dead-end filtration experiments showed that anaerobic sEPS layers, which have a low polysaccharide:protein (PS:PN) ratio, had a lower hydraulic resistance than the aerobic sEPS gel layers, which show a high PS:PN ratio. Optical Coherence Tomography (OCT) and Confocal Laser Scanning Microscopy (CLSM) analyses highlighted that both layers had similar thicknesses and 3D structural organizations. Fluorescent staining of organics and biovolume analysis revealed that for the anaerobic sEPS (low PS:PN), the abundance of proteins appears to destabilize the polysaccharide network increasing the water permeability through the layer. Additionally, the polysaccharides present in the anaerobic sEPS were mainly of the α-linked type, contributing to a more open crosslinked network within the layer, resulting in the low filtration resistance measured. The filtration characteristics observed in this study for the sEPS layers from anaerobic mixed cultures are of interest for possible future application of those layers as dynamic membranes within anaerobic reactors.

Synthesis of zirconia-ceramic composite membrane employing a low-cost precursor and evaluation its performance for separation of microbially produced silver nanoparticles

In this research, the isolated bacterium Kocuria rhizophila BR-1 was used to produce extracellular silver nanoparticles (AgNPs), which were separated by dead-end filtration method. Using electron microscopy (SEM) and particle size distribution (PSD) analysis, the synthesised AgNPs were observed to be spherical, with an average size of 48.23 nm and particle size ranging between 20 and 200 nm. The ceramic membrane support was made with low-cost precursors and coated with zirconia nanoparticles via spray pyrolysis. X-ray diffraction (XRD), surface area, contact angle, electron microscopy, particle size distribution, porosity, clean water permeability and average pore size was conducted to characterise the composite membrane (CM). The specific surface area, pore volume, and pore size distribution of the prepared zirconia particles were measured to be 22.04 m2/g, 0.083 cm3/g, and 10.9 nm, respectively. The permeability, porosity, and pore size of membrane were 1.08 × 10−7 L/m2hPa, 30% and 100 nm, respectively. Using a coated membrane and a dead-end filtration, the AgNPs were separated from their aqueous solution at distinct pressures (69–345 kPa) and solute concentrations (0.3 g/L and 0.15 g/L). The permeate flow and AgNPs rejection, at 345 kPa transmembrane pressure and 0.3 g/L feed concentration, was found to be around 32.3 L/m2h and 45%, respectively. Our findings suggest that the ceramic membrane can be used to concentrate different metallic nanoparticles from its broth.

Comparison of Selected Agro-Based Filter Media for Stormwater Quality Improvement

Polluted stormwater has become a severe problem in the environment as the runoff collecting various contaminants before discharged into water bodies, degrading the water quality and risking aquatic life. This study aims to evaluate selected agro-based filter media to treat stormwater through environmental laboratory works. These include kernel shell, coconut husk, coconut shell, durian shell, sugarcane bagasse, and pineapple leaves. The stormwater samples used were collected from a pond in Universiti Malaysia Sabah, whereas the filter column is configured through a combination of 80% of agro-based media and 20% of aggregate. Filter performance is evaluated for turbidity, pH, dissolved oxygen, biochemical oxygen demand, and ammoniacal nitrogen. Overall, the findings show the potential in utilizing agro-based media, particularly the shell-based media of CS300, KS300, and DS200. Further investigations are recommended to further study the application of agro-based media in improving the quality of stormwater.

Arsenic adsorption by low-cost laterite column: Long-term experiments and dynamic column modeling

Arsenic (As) contamination of drinking water supplies is a major concern in many countries due to its large concentration in groundwater and high toxicity. In this study, batch adsorption experiments on a natural laterite adsorbent from Vietnam (NLTT) were firstly conducted, followed by four column adsorption experiments using NLTT working with synthetic water under different experimental conditions (initial arsenate As(V) concentration: 0.1 and 0.5 mg/L; bed height: 0.15 and 0.41 m). Results from the batch equilibrium adsorption study show that all three models - Sips, Langmuir, and Freundlich - fitted the experimental data very well. The Sips and Langmuir maximum adsorption capacities were 0.76 mg/g and 0.58 mg/g, respectively. At an As(V) concentration of 0.5 mg/L, adsorption breakthrough occurred at 28 h and 122 h for column heights of 0.15 m and 0.41 m, respectively. When As(V) concentration fell to 0.1 mg/L, the breakthrough times rose to 144 h and 240 h, respectively. A linear driving force approximation (LDFA) model incorporating the Sips equation was calibrated with data from the equilibrium and kinetic adsorption experiments and one column adsorption experiment (initial concentration: 0.1 mg/L; bed height: 0.15 m). The LDFA model with the calibrated model coefficients could predict the breakthrough curves and adsorption time in the three other column experiments and four household column filters used to treat As contaminated groundwater in Vietnam. The study revealed that application potential for NLTT in column adsorption studies and field trials to remove As(V) is significant despite this study having limited data. Subsequently, refining the model based on simulation of results is cost-effective, saves time and effort, and negates the need for multiple experiments to optimize filter conditions.

Anti-fouling performance investigation of micron-submicron hierarchical structure PVDF membranes in water-in-oil emulsion separation

Membrane technology was widely used in the field of oil-water separation. In the process of water-in-oil emulsion treatment, surface contamination of hydrophobic and lipophilic membranes was a difficult problem. Therefore, the effect of hydrophobic membrane surface micro-rough structure on oil-water separation performance and its anti-fouling behavior has been investigated as a major focus of current research. Superhydrophobic-superoleophilic polyvinylidene fluoride (PVDF) membranes with micron-submicron hierarchical structure were prepared by combining thermally induced phase separation (TIPS) with rolling embossing. The influence of the roller temperature on the structure and performance of the membrane were discussed. The best achieved superhydrophobicity with a high water contact angle (WCA) of 154.8° and rolling angle (SA) of 1.9°, which was similar with lotus-effect. Meanwhile, the N2 flux was 197 L m−2 s−1 and LEP was 4.08 bar. Besides, the tensile strength of PVDF membrane was 1.89 MPa. The embossed membrane showed good lipophilicity, and the residence time of kerosene on the membrane surface was only 0.14 s. PVDF membranes with lotus leaf effect showed excellent demulsification performance and high recyclability in water in oil emulsion. The oil flux and rejection rate were 1258 L m−2 h−1 and 99.14%, respectively. In the separation experiment of PVDF membranes in diesel emulsion containing inorganic pollutant CaCO3, the results showed that the anti-fouling effect of PVDF membranes by cross-flow filtration method was obviously better than that by dead-end filtration method. When the operating temperature and pressure were 0.1 MPa and 45 °C, respectively, embossed membrane showed relatively excellent separation performance in cross-flow filtration. This study provided some guidance for the anti-fouling performance of roughened surface superhydrophobic-superoelophilicity membrane in oil-water separation experiment.

Hydrothermal synthesis and electrochemical characterization of novel zeolite membranes supported on flat porous clay-based microfiltration system and its application of heavy metals removal of synthetic wastewaters

The present work describes the synthesis and characterization of a zeolite type LTA-clay composite membrane on pre-existing locally organized aluminosilicate in clay support and its application to the removal of heavy metals. X-ray diffraction reveals that the natural clay consists essentially of quartz, kaolinite, illite, dolomite, and calcite phases. Flat discs, membrane supports are prepared by uniaxial pressing of natural clay with 160 ≤ Ф < 250 μm as optimal grain size mixed with 3% w/w activated carbon as porogen agent. Membrane supports are consolidated by sintering to final temperatures of 1000 °C. Zeolite Linde type A (LTA) is deposited on the clay supports using the hydrothermal method. Nitrogen adsorption analysis of the support using Brunauer–Emmett–Teller (BET) theory showed pores with 35.5 nm, which is narrowed to 14.2 nm after zeolite-A deposition. X-ray analysis of the composite membrane (MZA) reveals the growth of new diffraction peaks characteristic of zeolite-A. Prior to water filtration analysis of the MZA composite membrane, the pzc is found to be 9.8 using the titration method. The efficiency of the MZA composite membrane is evaluated by filtration tests of solutions containing heavy metals using a flow loop developed specifically for dead-end filtration. The retention of heavy metals studied follows the order Pb 2+ > Al 3+ > Co 2+ > Cd 2+ > Zn 2+ with 99.7, 99, 89.5, 88.3 and 81.8 retention percent, respectively. The retention mechanism seems to be controlled by the charge of the membrane's surface, which is demonstrated using the linear wave anodic stripping voltammetry (LWASV). • Composite membrane (MZA) is prepared from a natural clay and deposited zeolite A. • Pores' structures and surface properties of the MZA affect the filtration performance. • Pre-existing locally organized aluminosilicate in the clay support enhances the crystallinity of zeolite A. • Selectivity of the MZA towards filtered ions is investigated by linear wave anodic stripping voltammetry. • Retention of heavy metals on MZA reaches 99.7%, 99%, 89.5%, 88.3%, 81.8% for Pb 2+ , Al 3+ , Co 2+ , Cd 2+ and Zn 2+ respectively.

녹조오염 호소수의 수질특성과 흡착여과공정에 미치는 영향

The objectives of this study were to characterize an algae polluted-lake water using conventional variables of Trophic State Index Korea (TSIko) and to evaluate the performances of granular activated carbon (GAC) adsorption and the filtration of membrane filter (MF) using stirred dead end filtration cell on pollutants removal (COD, T-N, T-P, chlorophyll-a (chl-a), secchi disc (SD), and dissolved organic matter(DOC)) in the algae-polluted-lake water. As a result, regression analyses of log transformed seasonal Chl-a against T-P and T-N showed that variation of the Chl-a was explained by the variation of T-P(r= 0.3887) but not by T-N(r=0.2721). Consequently, The data obtained from this study suggest that one of the ways controlling the eutrophication would be a reduction of phosphorus from the watershed. Applied filtration rates during this experiment were <4.0 m/h for GAC bed and 0.5 m³/m².d for MF. Both GAC bed and GAC/MF system achieved more than 40% efficiency in removing geosmin and 2-methylisoborneol(2-MIB). The combined membrane process with GAC adsorption process was found to produce the highest quality finished water and could be proposed as one of the best available processes for removing geosmin. The increase of influent algae and DOC increased transmembrane pressure (TMP) of MF process. Membrane resistance of MF process coupled with GAC bed was lower than that MF process.

Effects of Benzalkonium Chloride Contents on Structures, Properties, and Ultrafiltration Performances of Chitosan-Based Nanocomposite Membranes.

The effects of benzalkonium chloride (BKC) contents on the structure, properties, and ultrafiltration performance of chitosan-based nanocomposite membranes containing poly(ethylene glycol) and multi-walled carbon nanotube (chitosan/BKC/PEG/CNT) were examined. The membranes were prepared by a mixing solution method and phase inversion before being characterized with microscopic techniques, tensile tests, thermogravimetric analysis, water contact angle, and porosity measurements. The performance of the nanocomposite membranes in regard to permeability (flux) and permselectivity (rejection) was examined. The results show that the incorporation of BKC produced nanocomposite membranes with smaller pore structures and improved physico-chemical properties, such as an increase in porosity and surface roughness (Ra = 45.15 to 145.35 nm and Rq = 53.69 to 167.44 nm), an enhancement in the elongation at break from 45 to 109%, and an enhancement in the mechanical strength from 31.2 to 45.8 MPa. In contrast, a decrease in the membrane hydrophilicity (water contact angle increased from 56.3 to 82.8°) and a decrease in the average substructure pore size from 32.64 to 10.08 nm were observed. The membrane rejection performances toward Bovine Serum Albumin (BSA) increased with the BKC composition in both dead-end and cross-flow filtration processes. The chitosan/BKC/PEG/CNT nanocomposite membranes have great potential in wastewater treatments for minimizing biofouling without reducing the water purification performance.

Polyvinylidene fluoride/boehmite nanocomposite membrane for effective removal of arsenate ion from water

Groundwater arsenic contamination is a serious threat that has affected the health of 130 million people globally. Long-term exposure to arsenic leads to arsenic poisoning, i.e., arsenicosis. Therefore, the development of new technology to reject arsenic from water has been increased. Polyvinylidene fluoride (PVDF) polymer possesses outstanding properties mainly as thermal stability, chemical and mechanical resistance. Boehmite, a polymorphic aluminium oxide, is an essential industrial mineral used as an adsorbent due to its ability to retain high surface area. It has a positive charge, and its surface renders it easy for compounds with negative charges to be attached by electrostatic attraction. Also, the nanoparticles have a high isoelectric value. High adsorption is expected on a higher isoelectric point value. PVDF/boehmite composite membrane was prepared using solvent casting method at room temperature. The nanoparticles were added in Al/As (w/w) ratio of 0:1, 50:1, 200:1 and 500:1. Al/As ratio of 200:1 has shown the best result in batch process, and in static adsorption study, 65% rejection of arsenate ion was achieved from 100 μg/L arsenate solution in 1 h. Flux was calculated in a dead-end filtration setup at 1 bar trans-membrane pressure. The water flux of the membranes was in the range of 62 to 270 L/m2h.

Impact of polysaccharide and protein interactions on membrane fouling: Particle deposition and layer formation

Membrane fouling, which limits the application of membrane bioreactors, has received considerable research attention in recent years. In this work, filtration modeling was performed in combination with surface plasmon resonance (SPR) analysis to investigate the membrane fouling mechanism. Sodium alginate (SA) and bovine serum albumin (BSA) were used to perform dead-end filtration on hydrophilic and hydrophobic poly (vinylidene fluoride) (PVDF) membranes. The initial foulant deposition and layer formation on membranes as well as the interaction between the BSA and SA were comprehensively analyzed. Results indicated that during SA filtration, initial fouling on hydrophilic membranes were primarily attributed to the particle–membrane interactions, while the fouling on the hydrophobic membrane were dominantly caused by the interactions among SA particles. The interaction between BSA and SA led to more severe membrane fouling and hydrophobic membrane was more sensitive to it, especially in the initial filtration process. The SPR results helped clarify the in-situ deposition behavior of BSA and SA particles on the PVDF surface. Compared to SA, BSA adsorbed faster on the PVDF membrane, and specific interactions played an essential role in BSA adsorption, whereas the deposition of SA on PVDF could be easily removed by shear force. Interactions between BSA and SA could alleviate the bonding between BSA and the PVDF membrane.

Transition from pore fouling to cake filtration in high level waste dead end filtration

ABSTRACT Treatment of radioactive waste at the Hanford site is dependent upon dead end filtration to prepare feed for ion exchange. Recent testing has indicated that the filter media that will be deployed for this treatment process is susceptible to depth fouling. A model was developed to understand the transition from pore fouling to cake filtration to provide insight into the planned operations of this facility. These results indicate that an initial transition takes place during which the filter is depth fouled. However, after the majority of the pores have been plugged the filter flux is governed by cake filtration on the surface of the fouled filter.

A core–shell amidoxime electrospun nanofiber affinity membrane for rapid recovery Au (III) from water

An affinity membrane was prepared by coaxial electrospinning and amidoxime (AONFA), and it was applied to selectively recovery Au (III) from an aqueous solution. The static adsorption results showed that, when pH at 5, the maximum adsorption capacity of AONFA membrane for Au (III) was 509.3 mg·g −1 . AONFA membrane exhibit much higher affinity and selectivity towards Au (III) than other metal cations. The membrane could be regenerated effectively by mixture solution of thiourea and HCl, and the desorption ratio reached almost 100% after 4 hours desorption. The dead-end filtration results showed that, the membrane utilization efficiency and adsorption capacity can be improved by increasing the flow rate, while increasing the concentration shorted the breakthrough process and had little impact to adsorption capacity. We can flexibly adjust the flow rate and concentration according to the situation to obtain the maximum utilization efficiency of the membrane in filtration process. The dynamic adsorption capacity is higher than the static adsorption capacity. The adsorption mechanism for Au (III) is electrostatic adsorption and reduction. Thus, AONFA membrane filtration was demonstrated to be a promising method for continuous recover Au (III) from wastewater.

Hydrodynamic parameters when filtering chromium-containing wastewater through a layer of fibrous waste

It is feasible to filter low-concentration liquid waste of electroplating enterprises containing chromium compounds using filter columns loaded with fibrous aluminum-containing waste from the production of glass composites. The hydrodynamic parameters during filtration of wastewater through this material have been experimentally studied. The value of the constant in the Kozeny-Carman equation is determined for different degrees of filling of the filter volume, the total and reaction surface of the fibrous wastes are specified. A dependence for calculating head losses in the filter is proposed.

MF-NF Treatment Train for Pig Manure: Nutrient Recovery and Reuse of Product Water.

The livestock industry negatively impacts the environment by producing high organic and mineral loaded manure and wastewater. On the contrary, manure is also considered as the major focal point of resource recovery. The microfiltration (MF) process in manure treatment is well known for being the least complex and highly energy efficient. However, the major fraction of the dissolve nutrients easily bypasses the MF membranes. In this research work, we reported the efficiency of using MF–nanofiltration (NF) treatment train in a dead-end filtration system for the treatment of raw manure. The objectives were to produce nutrient rich separate streams in reduced volumes and a particle and pathogen-free product water. MF removed TSS above 98% and the COD and phosphorus (P) retention were noticed above 60 and 80%, respectively, within a reduced MF concentrate volume, which accounted for 40% of the initial feed volume. The NF of MF permeate by NF270 showed most promising results by concentrating overall 50 and 70% of the total nitrogen (TN) and potassium (K) within a reduced NF concentrate volume, which accounted for 30% of the initial MF feed volume. Finally, the MF–NF treatment train of raw pig manure could produce a particle-free product water that can be reused in farms to wash barns, to irrigate nearby cultures, or can be applied to specific fields based on the demand.

Coupling bead-milling and microfiltration for the recovery of lipids and proteins from Parachlorella kessleri: Impact of the cell disruption conditions on the separation performances

Microalgae biorefinery has become an attracting topic to fully exploit the intracellular compounds such as lipids, proteins, polysaccharides or pigments, etc. Conventionally, microalgae biorefinery involves four major operations; harvesting, cell disruption, fractionation and purification, and final product formulation. This study evaluates the possibility to recover lipids and hydrosoluble compounds from Parachlorella kessleri cultivated in starving conditions. The cell disruption by bead-milling was coupled with centrifugation and membrane filtration for the fractionation. The impact of the biomass variation and the bead-milling, centrifugation and physicochemical conditions on the compounds’ recovery into the supernatant and on the filtration performances was investigated. Three different filtration conditions were also compared: dead end, cross-flow and dynamic filtration. Finally, the best scenario allowed to recover 23% of the total lipids from initial biomass in the retentate and 9% of the sugars and 8% of the proteins from the biomass, totally soluble in the permeate.

Dehydration of fatty acid methyl ester mixtures from enzymatic biodiesel using a modified PVDF membrane

This study aimed to investigate the efficiency of microfiltration with a polymeric membrane in the dehydration of fatty acid ester mixtures. The dip-coating method was used to modify the surface of polyvinylidene fluoride (PVDF) hydrophilic membranes using silazane to render them hydrophobic. The membranes were characterized by the contact angle, Fourier-transform infrared spectroscopy (FTIR), zeta potential, field emission scanning electron microscopy (FESEM), membrane water absorption, silazane crosslinking to the membrane surface, and chemical compatibility of membranes to methanol. The microfiltration experiments were carried out in the dead-end and crossflow configurations. Membrane performance was evaluated by permeate flux values, mass reduction ratio, moisture, acidity, and glycerol content in the permeate. Mixtures with different compositions and concentrations of methyl ester, methanol, water, oleic acid, glycerol, and enzyme were used. Silazane deposition time of 60 min at 1 mg silazane/g toluene resulted in the best performance. The modification resulted in chemical and morphological changes in the membrane surface to render it hydrophobic changing its water contact angle from 0 to 94°. For dead-end and crossflow filtration configurations, the modified membranes presented the highest fluxes when compared to the unmodified control membrane, regardless of the composition of the mixtures. All biodiesel mixtures treated with the modified membrane had a decreased water content and an increased oleic acid content in the permeate. This work demonstrated that biocatalyzed fatty acid methyl esters (FAME) can be dehydrated using silazane-modified membranes, resulting in increased separation efficiency.

Real time imaging of single extracellular vesicle pH regulation in a microfluidic cross-flow filtration platform

Extracellular vesicles (EVs) are cell-derived membranous structures carrying transmembrane proteins and luminal cargo. Their complex cargo requires pH stability in EVs while traversing diverse body fluids. We used a filtration-based platform to capture and stabilize EVs based on their size and studied their pH regulation at the single EV level. Dead-end filtration facilitated EV capture in the pores of an ultrathin (100 nm thick) and nanoporous silicon nitride (NPN) membrane within a custom microfluidic device. Immobilized EVs were rapidly exposed to test solution changes driven across the backside of the membrane using tangential flow without exposing the EVs to fluid shear forces. The epithelial sodium-hydrogen exchanger, NHE1, is a ubiquitous plasma membrane protein tasked with the maintenance of cytoplasmic pH at neutrality. We show that NHE1 identified on the membrane of EVs is functional in the maintenance of pH neutrality within single vesicles. This is the first mechanistic description of EV function on the single vesicle level.