Electrostatic Repulsive Forces Research Articles

Significantly enhancing enzymatic saccharification of poplar waste through the effective removal of lignin and hemicellulose by 1-butanol-Na3PO4-water treatment

Na3PO4-H2O-assisted 1-butanol pretreatment was established for changing the structure of poplar waste and improving its enzymatic efficiency. After poplar waste was pretreated at 180 °C for 60 min, 51.3 % of xylan and 52.5 % of lignin were eliminated. After the enzymatic saccharification of treated poplar waste, the yield of reducing sugars reached 75.3 %. A series of characterizations demonstrated that Na3PO4-H2O-assisted 1-butanol pretreatment altered the poplar composition with improved cellulose accessibility from 231.2 to 459.5 mg/g and reduced surface area of lignin from 384.2 to 255.3 m2/g. Molecular simulations, quantum chemical calculations and independent gradient model analysis were performed on the poplar model, and the 1-butanol-Na3PO4-H2O pretreatment resulted in the increase of electrostatic and van der Waals repulsion forces in lignin and xylan, explaining the efficient lignin and xylan removal. A comprehensive interpretation of mass balance and energy flow was applied to assess the entire pretreatment process. This eco-friendly 1-butanol-Na3PO4-H2O pretreatment effectively broken the encapsulation of cellulose by enzyme inhibitors and improve biomass pretreatment effect.

Exploration of the regulatory mechanism of pulsed electric field on the aggregation behavior of soybean protein isolates

As an emerging protein modification technology, pulsed electric field (PEF) technology in modifying soybean protein isolates (SPI) suffers from unclear mechanism and controversial changes in aggregation structure. To address these issues, the effects of PEF treatment with different electric field intensities (5–30 kV/cm) on the aggregation behavior and spatial structure of SPI were investigated. The results showed that the SPI aggregates exhibited a trend of depolymerization followed by reaggregation with the increase of PEF intensity. At 10 and 15 kV/cm, the polarization effect of PEF induced the unfolding of the tertiary structure of SPI, leading to the enhancement of the electronegativity of the side chains, and the electrostatic repulsive force between the molecules promoted the depolymerization of SPI aggregates. However, with the withdrawal of PEF, the structure of the SPI was partially reversible, resulting in a limited depolymerization effect. When the PEF intensity reached 20 kV/cm and above, SPI underwentstructure unfolding, subunit dissociation, continuous exposure of hydrophobic groups and sulfhydryl groups, and ultimately reaggregation mediated by hydrophobic interactions and disulfide bonding, resulting in the formation of high molecular weight soluble and insoluble protein aggregates. In addition, the formation of free radicals under strong electric fields (≥20 kV/cm) accelerated the oxidation of SPI and promoted the rapid formation of disulfide bonds. This study provides a theoretical basis for the targeted regulation of SPI aggregation structure by PEF.

Effect of particle size on the transport of polystyrene micro- and nanoplastic particles through quartz sand under unsaturated conditions

Micro- and nanoplastics (MNPs) are contaminants of emerging concern recently found in soil ecosystems. Their presence in terrestrial environments and their migration to aquatic environments may become a risk for the health of ecosystems and, through them, of humans. Understanding the interaction between particle properties and physicochemical and hydrodynamic factors is crucial to evaluate their fate and their potential infiltration towards groundwater. This study investigates the impact of particle size on MNPs transport through sand under unsaturated conditions. Infiltration column experiments with polystyrene MNPs ranging from 120 to 10,000 nm were conducted and supported by numerical modelling to derive reactive transport parameters. Results show a significant effect of particle size on the transport of MNPs, with higher recovery values observed for smaller particles (120 nm; 95.11%) compared to larger particles (1,000 nm; 71.44%). No breakthrough was observed for 10,000 nm particles, indicating a complete retention within the quartz sand matrix. DLVO theory confirmed the dominance of electrostatic repulsive forces between MNPs and sand grains, suggesting an unfavourable environment for MNPs to adhere to quartz sand. Consequently, particle retention in the sand matrix occurs predominantly by physical processes. Equilibrium sorption modelling reveals that larger particles (1,000 nm) tend to be immobilized in small pores throats due to straining, resulting in lower recoveries. When they are not trapped, particles tend to travel faster through preferential flows due to a size exclusion effect, evidenced by shorter arrival times at the column outlet compared to tracers. These findings highlight the influence of particle size on the transport and retention of MNPs in quartz sand under unsaturated conditions and contribute to a better understanding of their transport dynamics and environmental fate.

Having their cake and eat it too: Effects of different cations in reduced-salt myofibrillar protein microgel pickering emulsion under high-intensity ultrasound

Health concerns have increased the demand for low-salt emulsified meat products emulsions; however, salt-soluble myofibrillar proteins (MP) are less than optimal emulsifiers under low-salt conditions. In this study, four different cations (Na+, K+, Ca2+, and Mg2+) were added to a Pickering emulsion and high-intensity ultrasound (HIU, 20 kHz, 600 W) was used to determine the quality of the final emulsion. The divalent cation group was found to significantly (P < 0.05) improve the emulsification performance of the emulsion; in particular, the emulsion activity index and emulsion stability index of Mg2+-H group increased to 16.24 ± 1.22 m2/g and 89.66 ± 3.01%, respectively. Measurements of the particle size and zeta potential confirmed that the emulsion particle size of the Mg2+-H group decreased, and the electrostatic repulsion force increased. Based on the surface hydrophobicity and endogenous tryptophan spectra, the particle structure of the MP microgel was determined to be a more stable emulsifier. What's more, the divalent cations promoted the droplets to become evenly dispersed under high-intensity ultrasound. The micrograph confirmed this result: the divalent cation group emulsion was more uniform and stable than the monovalent cation group emulsion. Divalent cations are more suitable than monovalent cations for improving the quality of reduced-salt Pickering emulsions.

Concept of electrons pairing during the formation of covalent chemical bonds

This research studies the forces acting in an electron pair with antiparallel spins participating in forming a covalent chemical bond between atoms. The first is the force of electrostatic repulsion of electrons. The second is the gravitational attraction of these electrons. The third is the force of electromagnetic attraction between the electron pair. From calculations it follows, that the force of gravitational attraction is negligible, and therefore it is not able to withstand the force of electrostatic repulsion between electrons. However, the force of electromagnetic attraction between a pair of electrons with antiparallel spins turned out to be hundreds of times greater than the force of their electrostatic repulsion. As a result, the formation of stable electron pairs in molecular orbitals becomes possible. Thus, valence electrons of neighboring atoms interact with each other like femto-electromagnets, as a result of which a stable bond is formed between these electrons. Calculations have shown that in hydrogen molecule the force of electrostatic attraction between nuclei and paired electrons of a molecular orbital significantly exceeds the force of electrostatic repulsion of nuclei, which ensures the formation of a strong covalent chemical bond. To form covalent bonds in other molecules, the force of electrostatic attraction between the nuclei and paired electrons of the molecular orbitals must be much greater than the forces of electrostatic repulsion between both the positively charged nuclei and the negatively charged electrons of the atomic orbitals of different atoms.

Continuous Focusing of Particles by AC-Electroosmosis and Induced Dipole Interactions.

Continuous particle focusing by using microfluidics is an effective method for separating particles, cells, or droplets for analytical purposes. Previously, it was shown that an alternating current across rectangular microchannels with slightly deformed side walls results in vortex flow patterns caused by alternating current electroosmosis (AC-EOF) and could lead to particle focusing. In this work, we explore this mechanism by experimentally studying the particle focusing behavior for various fluid flow velocities through a microchannel. Since it is unlikely that the particles are kept in their focused position solely by convection, a theoretical force balance between the hydrodynamic and the induced dipole force was determined. In our experiments, it was found that there is no substantial effect of the pressure-driven fluid velocity on the particle focusing velocity within the studied range. From the theoretical force balance calculations, it was determined that while the addition of the induced dipole force can still not completely describe the experimentally observed particle focusing, the induced dipole can be strong enough to overcome the hydrodynamic force. Finally, it is hypothesized that under specific circumstances, including a repulsive electrostatic force between a particle and electrode wall can complete the theoretical particle focusing force balance. Alternative phenomena that could also play a role in particle focusing are proposed.

Interaction of charged magnetic nanoparticles with surfaces

The behavior of magnetic nanoparticles covering the surface with positive charges (MN), suspended in a continuous medium, was simulated by Brownian dynamics. Then, we studied the behavior of the MN in an aqueous-like suspension and their adsorption on a negatively charged surface, mimicking a mica surface. After several microseconds, particles are deposited onto the charged surface. Experimental results of ordered magnetic nanoparticles in surfaces are compared with the present simulation results of MN in two dimensions. We also demonstrate the effect of charged MN on the hexagonal structure when electrical repulsions dominate against magnetic dipole-dipole and van der Waals attractions. On one hand, the adsorption of MN on the surface depends on the electrostatic attraction force with the surface, while the surface organization of MN results from balancing electrostatic repulsion forces and magnetic attraction forces among particles. In magnetic nanoparticles simulated with a non-charged surface or weakly charged surface, dipole-dipole interactions dominate the particle-particle interactions, and the interactions between particles and a mica-like surface are conducted by van der Waals forces.

Divergent responses of aggregate breakdown by slaking to nitrogen forms in solution for contrasting soil types

Aggregate stability strongly affects many soil processes and is critical to maintain sustainable agriculture. Aggregate breakdown is controlled by the interaction between soil intrinsic properties and solution characteristics. Nitrogen fertilization including different forms is well known to influence aggregate stability; however, relative to their long-term effects, there is little recognition on the rapid response of aggregate breakdown to nitrogen solutions. This study aimed to examine the effects of nitrogen form and concentration on aggregate stability for different types of soils. Aggregate breakdown against slaking of three soil types (Phaeozem, Luvisol, and Acrisol) and three horizons (organo-mineral (A), illuvium (B), and parent material horizons (C)) was determined subjected to nitrogen solutions of three forms (CO(NH2)2, NH4+, NO3–) and five concentrations (0.05 ∼ 1.0 mol/L). Among nitrogen forms, urea solution almost had non-significant effect irrespective of soil type and horizon (p > 0.05); for NH4+ and NO3– solutions, aggregate stability showed little variations (MWD of 0.19 ∼ 0.26 mm) with electrolyte concentration for Phaeozem in B and C horizons, overall increased for Luvisol and Phaeozem in A horizon, and decreased first and then reached a steady state for Acrisol. The effects of nitrogen forms on aggregate breakdown were dependent on soil aggregation status or cementing agents (mainly organic matter, clay mineralogy). Electrolyte nitrogen solutions (NH4+ and NO3–) inhibited aggregate breakdown mainly through reducing electrostatic repulsive forces for moderately developed soils rich in swelling clays, and promoted aggregate breakdown by both weakening particle cohesion and enhancing compression pressure of entrapped air for highly developed soils rich in non-swelling clays and Fe/Al oxides. These results facilitate an improvement of fertilizer management and irrigation to improve soil quality on different soil types.

Evaluating the operational properties of concrete admixtures containing molecularly modified polycarboxylate superplasticizers

The objective of this study focused on the design and preparation of a molecularly modified polycarboxylate superplasticizer to develop concretes with enhanced engineering features. For this purpose, polyethylene glycol was chemically modified with maleic anhydride to give the mono polyethylene glycol maleate (MPEGM). Then, polycarboxylate superplasticizer comprising of isoprenyl oxy polyethylene glycol (TPEG) and acrylic acid (AA, PCE-1), and the synthesized MPEGM with TPEG and AA (PCE-2) were prepared through solution radical polymerization. Subsequently, concrete mixtures with different dosages (0, 0.1, 0.15, 0.2, 0.25, 0.3 wt%) of PCE-1 and PCE-2 were prepared. Chemical structure of the synthesized MPEGM and superplasticizers together with their copolymer composition were identified by FTIR and 1HNMR analyses. The molecular weights (Mw) and molecular weight distributions (PDI) of PCE-1 (8.74 × 104, 1.36) and PCE-2 (8.74 × 104, 2.19) were studied by GPC analysis, respectively. The zeta potential of cement particles (2.8 mV) becomes negative in the presence of 0.6 g/L of PCE-1 (− 7.8) and PCE-2 (− 9.5). This implies that electrostatic and steric hindrance forces of adsorbed superplasticizers synergistically provide a situation for appropriate dispersion of cement particles. The results of water-reducing percentage, fluidity, air content, bleeding water rate, initial and final setting times, wet density, flexural and compressive properties, and ultrasonic pulse velocity analyses exhibit significant enhancement on the features of concrete mixtures made of polycarboxylate superplasticizer. The superiority of PCE-2 to PCE-1 was connected to its adsorption-dispersibility potent induced by stronger electrostatic and steric repulsion forces, which result in quality and continuity enhancement in concretes.

Electrodynamic dust shield efficiency characterisation under UV in vacuum for lunar application

Dust mitigation is one of the most crucial aspects of extraterrestrial exploration. This paper presents a series of experiments on the electrodynamic dust shield (EDS) and how UV radiation affects its efficiency on selected lunar simulants (LHS-1 and LMS-1) across a range of particle sizes, quantities, and surface materials. In this experimental study, VUV is used with a 1500 V AC electric field to mobilise the dust particles resting on either glass, Kapton, or Beta cloth inside a vacuum chamber at ∼10-6 mbar. The dust removal efficiency is characterised by two quantifying methods: weighing and solar array light transmission. The experimental results show that EDS activation under continuous UV exposure on the simulant particles improves the dust removal rate by 40 to 80 percentage points across all surfaces, with the exception of certain particle size ranges on Beta cloth. The primary force facilitating particle mobilisation was identified as the repulsive electrostatic force, enhanced by ionising mechanisms such as photoemission.

Crosslinking and Swelling Properties of pH-Responsive Poly(Ethylene Glycol)/Poly(Acrylic Acid) Interpenetrating Polymer Network Hydrogels.

This study investigates the crosslinking dynamics and swelling properties of pH-responsive poly(ethylene glycol) (PEG)/poly(acrylic acid) (PAA) interpenetrating polymer network (IPN) hydrogels. These hydrogels feature denser crosslinked networks compared to PEG single network (SN) hydrogels. Fabrication involved a two-step UV curing process: First, forming PEG-SN hydrogels using poly(ethylene glycol) diacrylate (PEGDA) through UV-induced free radical polymerization and crosslinking reactions, then immersing them in PAA solutions with two different molar ratios of acrylic acid (AA) monomer and poly(ethylene glycol) dimethacrylate (PEGDMA) crosslinker. A subsequent UV curing step created PAA networks within the pre-fabricated PEG hydrogels. The incorporation of AA with ionizable functional groups imparted pH sensitivity to the hydrogels, allowing the swelling ratio to respond to environmental pH changes. Rheological analysis showed that PEG/PAA IPN hydrogels had a higher storage modulus (G') than PEG-SN hydrogels, with PEG/PAA-IPN5 exhibiting the highest modulus. Thermal analysis via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated increased thermal stability for PEG/PAA-IPN5 compared to PEG/PAA-IPN1, due to higher crosslinking density from increased PEGDMA content. Consistent with the storage modulus trend, PEG/PAA-IPN hydrogels demonstrated superior mechanical properties compared to PEG-SN hydrogels. The tighter network structure led to reduced water uptake and a higher gel modulus in swollen IPN hydrogels, attributed to the increased density of active network strands. Below the pKa (4.3) of acrylic acid, hydrogen bonds between PEG and PAA chains caused the IPN hydrogels to contract. Above the pKa, ionization of PAA chains induced electrostatic repulsion and osmotic forces, increasing water absorption. Adjusting the crosslinking density of the PAA network enabled fine-tuning of the IPN hydrogels' properties, allowing comprehensive comparison of single network and IPN characteristics.

Enhanced assembly stability for amine-based cationic glycolipid

Glycolipids incorporating positive charges, mediated by an imidazolium cation, have shown potential for effective formulation of vesicular drug carriers, reflecting repulsive electrostatic forces, promoting the formation of nanosized assemblies and preventing unwanted Oswald ripening (Goh et al. (2019), ACS Omega 4, 17,039). Our continuous development of an assembly-based drug delivery system prompted us to investigate a pH-sensitive analogue, leading to the synthesis of a 6-amino-Guerbet glycoside. However, in contrast to the imidazolium counterpart, the amine-mediated charge increased the intermolecular cohesions, furnishing bigger assemblies instead, which further increased upon introduction of acid. Moreover, assemblies exhibited a significantly reduced positive charge density. It is concluded that strong proton-initiated hydrogen bonding between amino groups provide cohesive head group interactions overcompensating possible repulsive charge interactions. While this behavior invalidates the application of the amino-glucoside as dispersing agent for the formulation of small vesicles, it potentially paves a route towards enhanced vesicle stability.

The decisive role of filtration reducers’ surface charge in affecting drilling fluid filtration performance

To elucidate the effects of filtration reducers’ surface charge on drilling fluid filtration performance, three kinds of SiO2@polymer nanoparticles with different surface charges are prepared. When these nanoparticles are added into bentonite-based drilling fluids as filtration reducers, the negatively charged nanoparticles show the best filtration reduction performance while the positively charged nanoparticles show the most inferior filtration reduction performance. Moreover, more negative charges induce better filtration reduction performance. Conversely, more positive charges induce more inferior filtration reduction performance. The filtration performance of drilling fluids is decided by the compactness of the filter cake. And the interactions among the particles in the drilling fluids play an important role in affecting the compactness of filter cake. The electrostatic attraction forces between the positively charged nanoparticles and negatively charged bentonite particles promoted the aggregation before the formation of incompact filter cake, and the electrostatic repulsion forces between the negatively charged nanoparticles and negatively charged bentonite particles slowed down the aggregation of particles to form more compact filter cakes. These findings demonstrate the decisive role of surface charge of filtration reducers, which could provide guidance for searching suitable filtration controlling additives for drilling fluids in the future.

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

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

Effect of nitrogen/oxygen ratios on surface charge distributions generated by repetitive surface dielectric barrier discharges

Studies on the dielectric surface parameters and dielectric barrier discharges (DBD) characteristics considering the influence of gases in DBD on the surface charge distribution are scarce. Thus, to overcome this research gap, this study measured the potential distributions of AC-driven surface DBD in oxygen (O2), synthetic air and nitrogen (N2) as background gases using the Pockels effect. The results showed that the patterns of the filamentary discharges generated during the positive voltage polarity phase differed depending on the O2 ratio. In addition, the electrostatic repulsion forces between the residual charge and the newly created filament were analysed from the measured potential distribution and the greatest effect was observed in air, rather than in N2 and O2. The potential distribution was transformed into a charge density distribution and compared with the discharge luminescence in air and N2. The results showed that the shape of the filament tip differed between the charge density and discharge luminescence only in the case of air, which was attributed to the effect of attachment reactions on the formation of residual charge. The measurements showed that in a surface discharge, similar to the case in a volume discharge, the photoionisation and ionisation coefficients significantly affected the geometrical properties of the discharges.

Enhancing proton transport in polyvinylidenedifluoride membranes and reducing biofouling for improved hydrogen production in microbial electrolysis cells

Hydrophilic porous membranes, exemplified by polyvinylidene fluoride (PVDF) membranes, have demonstrated significant potential for replacing ion exchange membranes in microbial electrolysis cells (MECs). Membrane fouling remains a major challenge in MECs, impeding proton transport and consequently limiting hydrogen production. This study aims to investigate a synergistic antifouling strategy for PVDF membrane through the incorporation of a coating composed of polydopamine (PDA), polyethyleneimine (PEI), and silver nanoparticles (AgNPs). The PDA-PEI-Ag@PVDF membrane not only effectively mitigates fouling through steric and electrostatic repulsion forces, but also amplifies ion transport by facilitating water diffusion and electromigration. The PDA-PEI-Ag@PVDF membrane exhibited a reduced membrane resistance of 1.01 mΩ m2 and PDA-PEI-Ag modifying PVDF membrane was found to be effective in enhancing the proton transportation of PVDF membrane. Therefore, the enhanced hydrogen production rate of 2.65 ± 0.02 m3/m3/d was achieved in PDA-PEI-Ag@PVDF-MECs.

In situ acid production by organic matter induced with trace homogeneous Fenton reagent for membrane fouling control

The homogeneous Fenton process involves both coagulation and oxidation, but it requires added acidity, so it is rarely used to control membrane fouling. This work found that the pH of neutral simulated wastewater sharply declined to 4.1 after pre-treatment with 0.1 mM Fenton reagent (Fe2+:H2O2=1:1) without added acidity. This occurred mainly because the trace homogeneous Fenton reagent induced in situ acid production by organic matter in the wastewater, which supplied the acidic conditions required for the Fenton reaction and ensured that the reaction could proceed continuously. Then, oxidation during the pre-Fenton process enhanced the electrostatic repulsion forces and effectively weakened the hydrogen bonds of organic matter at the membrane surface by altering the net charge and hydroxyl content of organic matter, while coagulation caused the foulants to gather and form large aggregates. These changes diminished the deposition of foulants onto the membrane surface and resulted in a looser fouling layer, which eventually caused the membrane fouling rate to decline from 83 % to 24 % and the flux recovery rate to increase from 44 % to 98 % during 2 h of filtration. This membrane fouling mitigation ability is much superior to that of pre-H2O2, pre-Fe2+ or pre-Fe3+ processes with equivalent doses.

Negatively charged hydrochar from Aesculus indica waste: A sustainable material for enhanced Li-S batteries performance

This study presents a negatively charged hydrochar from Aesculus indica waste, employing a microwave-assisted hydrothermal carbonization (HTC) method at very low temperatures (120∼200 °C). The research shows the utilization of these negatively-charged-oxygen-containing hydrochars in lithium-sulfur (Li-S) batteries effectively mitigates polysulfide shuttling through electrostatic repulsive forces and simultaneously facilitate uniform lithium-ion transportation, leading to substantial improvement in battery performance. Through detailed investigations into the HTC reaction mechanism, the concentration of the negatively charged oxygen functional groups is tunable by controlling the carbonization process, which could further improve the enhancement effects. Furthermore, negatively-charged-oxygen-containing hydrochars were utilized as modified separator in Li-S batteries to enhance the electrochemical performance. The batteries assembled with hydrochar modified separator, has an initial discharge capacity of 1216 mAh g−1 at 0.1 C, and after 200 cycles at 1 C, its reversible discharge capacity was still 800 mAh g−1 with more than 80 % capacity retention. This research not only provides an efficient method for the utilization of waste biomass, but also offers a new approach for the preparation of negatively charged carbon for lithium-sulfur batteries.

Impact of silt chemical composition on deflocculation and coagulation of clay-rich paste

This paper investigates the impact of the chemical composition of two silts, quartz and limestone, on the deflocculation/coagulation process for poured earth application. The driving mechanisms behind the evolution of the rheological behavior after the addition of sodium hexametaphosphate are highlighted through zeta potential measurementand the chemical changes with ICP-OES and 31P MAS NMR spectroscopy. The first results show that adding sodium hexametaphosphate into the quartz silt modifies its inter-particle forces through electrostatic repulsion forces induced by the adsorption of phosphate anions onto the quartz structure. For limestone paste, the deflocculation mechanism is affected by the dissolution of the calcite. This dissolution leads to a release of Ca2+ cations and an increase in the paste's pH, reducing the paste deflocculation rate. These dissolved Ca2+ cations in the solution conduct to a partial coagulation making the delayed flocculation targeted initially with the addition of magnesium oxide less effective.

Tuning electrostatic repulsive and acid–base forces for efficient fouling mitigation in membrane filtration system

Membrane fouling caused by colloidal particles and microorganisms impose restrictions to further practical implementation of membrane separation technology. To advance the practical applications of this technology sustainably, this study explores an in-situ fouling control strategy utilizing an electrochemical membrane filtration (EMF) system. By applying varying electric potentials, the study evaluated the impact on dissolved organic matter (DOM) removal and elucidated the fouling mechanisms involved. The results indicate that increasing the potential significantly enhances the water flux of the conductive carbon membrane (CC/PVDF), with the flux at 3.0 V being 2.1 times greater than at 0 V. Moreover, this adjustment in potential significantly reduces the attachment of viable bacteria to the CC/PVDF membrane, with an applied potential greater than or equal to 2 V completely inactivating Escherichia coli (E. coli). The cohesive free energy (ΔGSWS) and extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theories suggest that imposing an external potential improved the acid–base and electrostatic repulsive forces between foulants and the membrane, as the applied potentials significantly increased the surface potential and wettability of the membrane. This EMF system not only mitigates fouling effectively but also delineates a path for enhancing membrane durability in practical applications.