Low Electric Potential Research Articles

Effect of Conductivity on In Situ Deactivation of Catechol-Boronate Complexation-Based Reversible Smart Adhesive.

To reduce the need for elevated electrical potential to deactivate catechol-based smart adhesive and preserve its reversibility, conductive 1-pyrenemethyl methacrylate (PyMA) was incorporated into a catechol and phenylboronic acid-containing adhesive coating immobilized on aluminum (Al) discs. Electrochemical impedance spectroscopy (EIS) indicated that incorporation of 26 mol % of PyMA reduced ionic resistance (Rs) and charge-transfer resistance (Rc) of the coating from over 22 Ω/mm2 to 5.9 and 1.2 Ω/mm2, respectively. A custom-built Johnson-Kendall-Roberts (JKR) contact mechanics test setup was used to evaluate the adhesive property of the coating with in situ applied electricity using a titanium (Ti) sphere both as a test substrate as well as the cathode for application of electricity and the Al disc as the anode. The adhesive coating demonstrated over 95% reduction in the adhesive property when electricity (1-2 V) was applied while the adhesive was in direct contact with the Ti surface. The addition of PyMA enables the deactivation of the adhesive using a voltage as low as 1 V. Both cyclic voltammetry (CV) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the formation of catechol-boronate complexation through electrochemical stimulation. Breaking the complex with an acidic buffer (pH 3) recovered the catechol for strong wet adhesion and the coating could be repeatedly deactivated and reactivated using low electrical potential for up to five cycles. Incorporation of both conductive PyMA and boronic acid as the temporary protecting group was required to achieve rapidly switchable adhesive that could be deactivated with low applied voltage.

Non-contact thin-film sheet conductance measurement based on the attenuation of low frequency electric potentials

Conductivity is a fundamental property of materials; in particular the precise quantification of electrical sheet resistance is essential for the development of electronic thin-film devices. Conventionally, resistive probes are used to perform the corresponding measurements. However, non-invasive methods are more desirable as they minimize the required sample preparation, as well as geometrical influences. Existing non-contact conductivity measurements mostly rely on the transmission of electromagnetic waves through conductive thin-films. Hence, they only characterize translucent samples at high frequencies. We present an alternative technique based on the attenuation of low frequency 10 kHz electric fields. The approach is used to quantify the field-effect induced conductivity variation of a flexible indium-gallium-zinc-oxide semiconductor film. A custom-built high-impedance electrometer is used to capacitively measure the attenuation of an alternating electric field passing through the film. The obtained data is discussed and related to the absolute conductivity with the aid of two bespoke models describing the impedance mismatch between the sample and its surroundings. The sheet conductivity is modulated and measured from 660 nS to 116 µS while conventional DC current/voltage measurements serve as a reference. Both methods show a high degree of correlation to the reference measurements. Unlike techniques based on light, the low frequency signal used here resembles quasi-static characteristics, and enables the direct measurement of DC parameters.

Vascular endothelial and smooth muscle cell galvanotactic response and differential migratory behavior

Chronic disease or injury of the vasculature impairs the functionality of vascular wall cells particularly in their ability to migrate and repair vascular surfaces. Under pathologic conditions, vascular endothelial cells (ECs) lose their non-thrombogenic properties and decrease their motility. Alternatively, vascular smooth muscle cells (SMCs) may increase motility and proliferation, leading to blood vessel luminal invasion. Current therapies to prevent subsequent blood vessel occlusion commonly mechanically injure vascular cells leading to endothelial denudation and smooth muscle cell luminal migration. Due to this dichotomous migratory behavior, a need exists for modulating vascular cell growth and migration in a more targeted manner. Here, we examine the efficacy of utilizing small direct current electric fields to influence vascular cell-specific migration (“galvanotaxis”). We designed, fabricated, and implemented an in vitro chamber for tracking vascular cell migration direction, distance, and displacement under galvanotactic influence of varying magnitude. Our results indicate that vascular ECs and SMCs have differing responses to galvanotaxis; ECs exhibit a positive correlation of anodal migration while SMCs exhibit minimal change in directional migration in relation to the electric field direction. SMCs exhibit less motility response (i.e. distance traveled in 4 h) compared to ECs, but SMCs show a significantly higher motility at low electric potentials (80 mV/cm). With further investigation and translation, galvanotaxis may be an effective solution for modulation of vascular cell-specific migration, leading to enhanced endothelialization, with coordinate reduced smooth muscle in-migration.

Phase transition and microstructures of five-dimensional charged Gauss-Bonnet-AdS black holes in the grand canonical ensemble

In this paper, we study the small-large black hole phase transition and construct the Ruppeiner geometry for the five-dimensional charged Gauss-Bonnet-AdS black hole in the grand canonical ensemble. By making use of the equal area law, we obtain the analytical coexistence curve of the small and large black holes. Then the phase diagrams are examined. We also calculate the change of the thermodynamic volume during the small-large phase transition, which indicates that there exists a sudden change among the black hole microstructures. The corresponding normalized scalar curvature of the Ruppeiner geometry is also calculated. Combing with the empirical observation of scalar curvature, we find that for low electric potential, the attractive interaction dominates among the microstructures, while a high electric potential produces repulsive interactions. In the reduced parameter space, we observe that only attractive interaction is allowed when the coexistence region is excluded. The normalized scalar curvature also admits a critical exponent 2 and a universal constant $\ensuremath{-}\frac{1}{8}$. In particular, the value of the normalized scalar curvature keeps the same along the coexistence small and large black hole curves. So in the grand canonical ensemble, the interaction can keep constant at the phase transition where the black hole microstructures change. These results disclose the intriguing microstructures for the charged AdS black hole in the Gauss-Bonnet gravity.

Electroosmotic thrusters in soft nanochannels for space propulsion

Space propulsion of electroosmotic thrusters (EOTs) with a soft charged nanochannel is investigated considering the Navier slip boundary and constant surface charge density on the walls of slit channels. The soft nanochannel is characterized by a wall-grafted ion-penetrable charged polyelectrolyte layer (PEL). The Poisson–Boltzmann equation is solved to give the electric potential distribution based on the assumption of the Debye–Hückel linearization for the low electric potential. An analytical solution of the electroosmotic velocity through the soft channel is obtained. The thrust, specific impulse, and total input power of EOTs produced by the electroosmotic flow are presented, and then, two significant physical quantities, thruster efficiency and thrust-to-power ratio, are described. It is found that these performance curves strongly depend on the slip length, surface charge density on the walls, drag coefficient, equivalent electric double layer thickness, PEL thickness, and density ratio of the PEL to the electrolyte solution layer. By analyzing and optimizing these design parameters, the simulated EOTs can deliver the thrust from 0 μN to 10 µN as well as the specific impulse from 40 s to 100 s, and the thruster efficiency up to 87.22% is realized. If more thrust control and kinetic energy are needed for different space missions, an array composed of thousands of single EOT emitters is constructed and maintains high thruster efficiency. Moreover, during mission operation, the total potential can be simply varied to optimize the performances of thrusters at any moment.

Nitrate, arsenic and fluoride removal by electrodialysis from brackish groundwater

Nitrate, arsenic and fluoride are some of the most hazardous elements contaminating groundwater resources. In this work, the impact of operative (flowrate, electricpotential) and water quality (salinity, contaminant feed concentration, pH) parameters on brackish water decontamination was investigated using a batch electrodialysis (ED) system. Electrodialysis at low electric potentials (5 V) was more selective toward monovalent ions, at higher potentials (>15 V) removal of all ions increased and selectivity approached one, meaning removal of all ions. Changing the flowrate from 30 to 70 L/h, increased nitrate and fluoride removal slightly, while arsenic(V) removal was maximum at 50 L/h. Rising salinity delayed removal of ions with low ionic mobility and diffusivity (i.e. fluoride, arsenic(V)). Increased feed concentration of contaminants had no impact on removal values. pH variations did not impact the nitrate, fluoride and salinity removal, yet arsenic(V) removal was greatly pH dependent. This was explained in part by lower diffusivity and higher hydration number of bi- and trivalent species of arsenic(V) at basic pH. The results of this work showed the significance of ionic characteristics (diffusivity, ionic mobility, hydration number) in ED. Nitrate concentrations satisfied guideline threshold in all experiments with concentrations below 50 mg/L. Lowest arsenic(V) concentration was 35 µg/L at the highest electric potential, 25 V. Using ionic characteristics makes separation of different ions possible, providing new opportunities for ED in environmentally friendly processes (e.g. resource recovery and zero liquid discharge).

Microwave-sintering enhanced photovoltaic conversion in polycrystalline Nd-doped BiFeO3

This work reports remarkable photovoltaic effects in the microwave-sintered lead-free perovskite (Bi0.93Nd0.07)FeO3 (B7NFO) ceramics with indium tin oxide (ITO) thin film under 405 nm blue irradiation. Maximal power conversion efficiency (PCE) ~1.2% and external quantum efficiency (EQE) ~17% can be obtained at low irradiation intensity. Optical absorption and photoluminescence emission suggest direct bandgap (Eg) in the range of 2.11–2.21 eV in B7NFO ceramics. Grain boundaries exhibit a lower electrical potential and higher electrical conductivity, and can act as conduction channels for the photo-generated charge carriers. High-resolution transmission electron microscopy (HR-TEM) suggests that field-enhanced photovoltaic effects are associated with large and highly ordered polar nano-regions (PNRs) in the matrix. Microwave-sintering process corresponds to a lower activation energy (433 kJ/mol) of grain growth than the conventional-sintering process (604 kJ/mol). This study demonstrates that the microwave-sintering process can be an effective and cost-less technique for energy-harvesting polycrystalline materials.

One-step process for the preparation of fast-response soft actuators based on electrospun hybrid hydrogel nanofibers obtained by reactive electrospinning with in situ synthesis of conjugated polymers

Soft actuators with a fast response to low electrical potentials are critical for wearables and robotics. In this work, hybrid hydrogel nanofiber mats were prepared and tested as soft actuators. Hybrid hydrogel nanofibers were produced by combining electrospinning with in situ photopolymerization of the hydrogel and polymerization of aniline during the formation of the nanofibers. The electrical conductivity of the obtained nanofibers measured by the 4-probe method reached values close to 0.01 S cm−1. Images obtained by atomic force microscopy in conductive mode (I-AFM) were also successfully acquired and proved the conductive and nanometric nature of the hybrid hydrogel nanofibers. Infrared spectra (FTIR) showed that photopolymerization of the hydrogel precursors and aniline polymerization during nanofiber formation were effectively achieved. The elastic modulus of the nanofibers was estimated from AFM nanoindentations, and values close to 10 MPa for the swollen samples were obtained. The swelling ability of the hybrid hydrogel nanofibers was evaluated by comparing AFM images of the nanofibers in dried and swollen conditions to reveal that the swelling degree is reduced by the presence of polyaniline in the nanofibers. The obtained hybrid hydrogel nanofiber mats were tested as actuators in an electrochemical cell. The application of low voltage (1 V) in a 1 MΩ cm water led to fast (2.5 mm s−1) and reversible displacement of the samples. During actuation, thin nanofiber mats could also withstand forces on the order of 80 μN that were measured by coupling the electrochemical cell to a load cell.

Colloidal dispersion nanogels for in-situ fluid diversion

This paper presents the results of CDG nano gel based sandpack flooding, IFT and rheology laboratory measurements. CDGs viscosity had an inverse relation with shear rate, and rheological curve stays invariant after 7 days regardless of NP concentration. Increment of crosslinker concentration had an inverse relation with CDG's viscosity due to colloid collapse (e.g., increase of coil number). Addition of TiO2 NP to Colloidal Dispersion Gels resulted in an increased rheological stability, reduced Interfacial Tension, increased Zeta Potential and increment in RF/RRF values. The critical concentration of NP in CDG was determined. The pseudoplastic behavior, low thermochemical destruction and 35% decrease of IFT in liquid/air interface had been observed. Presence of NPs increased Zeta potential of colloid by 43% as well. RF/RRF values were 173% and 59% more than base CDG solution, respectively. We proposed the kinetic mechanism of colloidal dispersed gels gelation in the presence of TiO2 nanoparticles. Above NP critical concentration, the anionicity of colloid was reduced as a result of diffusive layer shrinkage and the low electrical potential of polymer coils. Moreover, free TiO2 NP becomes available and acts as a bridge between different polymer coils. As a result, attractive forces overtop repulsive forces due to zeta potential scale down; therefore the unstable colloids occur.

Unsteady solute dispersion by electrokinetic flow in a polyelectrolyte layer-grafted rectangular microchannel with wall absorption

The dispersion of a neutral solute band by electrokinetic flow in polyelectrolyte layer (PEL)-grafted rectangular/slit microchannels is theoretically studied. The flow is assumed to be both steady and fully developed and a first-order irreversible reaction is considered at the wall to account for probable surface adsorption of solutes. Considering low electric potentials, analytical solutions are obtained for electric potential, fluid velocity and solute concentration. Special solutions are also obtained for the case without wall adsorption. To track the dispersion properties of the solute band, the generalized dispersion model is adopted by considering the exchange, the convection and the dispersion coefficients. The solutions developed are validated by comparing the results with the predictions of finite-element-based numerical simulations. Even though the solutions can take any form of initial solute concentration into account, the results are presented by considering a solute band of rectangular shape. The results reveal that, while the short-term transport coefficients are strongly affected by the initial concentration profile, the long-term values are not dependent upon the initial conditions. In addition, it is shown that the mass transport coefficients are strong functions of the channel aspect ratio; hence, approximating a rectangular geometry by the space between two parallel plates may lead to considerable errors in the estimation of mass transport characteristics. This is particularly important for the dispersion coefficient for which the long-term values for a slit microchannel are quite different from those for a rectangular channel of very high aspect ratio. It is also illustrated that the exchange and convection coefficients increase on increasing the Damkohler number, whereas the opposite is true for the dispersion coefficient. The convection and dispersion coefficients are generally increasing functions of the PEL fixed charge density and the PEL thickness and decreasing functions of the PEL friction coefficient. Last but not least, a thicker electric double layer is found to provide a larger degree of solute dispersion, which is the opposite of that observed in a microchannel with bare walls.

Theoretical analysis of particle size re-distribution due to Ostwald ripening in the fuel cell catalyst layer

AbstractThe limited durability of hydrogen fuel cells is one of the main obstacles in their wider adoption as a clean alternative technology for small scale electricity production. The Ostwald ripening of catalyst material is recognized as one of the main unavoidable degradation processes deteriorating the fuel cell performance and shortening its lifetime. The paper systematically studies how the modeling approach towards the electrochemically driven Ostwald ripening in the fuel cell catalyst differs from the classical diffusion driven models and highlights how these differences affect the resulting evolution of particle size distribution. At moderately low electric potential, root-law growth of mean particle size is observed with linear relation between mean particle size and standard deviation of particle size distribution, similar to Lifshitz-Slyozov-Wagner theory, but with broader and less skewed distribution. In case of high electric potential, rapid particle growth regime is observed and qualitatively described by redeposition of platinum from a highly oversaturated solution, revealing the deficiencies of the existing platinum degradation models at describing the Ostwald ripening in the fuel cells at high electric potentials. Several improvements to the established models of platinum degradation in fuel cell catalysts are proposed, aimed at better description of the diffusion processes involved in particle growth due to Ostwald ripening.

Ion selectivity by charged spherical cavities and investigation of intersection point for average cavity density versus electric potential (a DFT study)

Ion separation and ion selectivity inside spherical cavities are studied within the framework of the density functional theory. Results show that, at lower electric potentials and depending on cavity size, counter ions accumulate at the wall to form a shell around the co ions that prefer to aggregate in the middle of the cavity. This gives rise to the formation of separated phases of co ions and counter ions inside the spherical cavity. Depending on cavity size, these phases convert to a nearly single phase of counter ions with increasing electric potential. In this situation, small spherical cavities could be exploited as a counter ion selector tool. Our study also shows that counter ion selectivity readily occurs at lower, rather than higher, concentrations of electrolytes. For electrolytes with monovalent co ions, the (+1: −1) electrolytes exhibit a better selectivity than the (+1: −2) ones at low electric potentials. Also the selective counter ion adsorption occurs at lower electric potential when the difference between size of counter ions and co ions becomes larger. The observed selectivity is the result of confinement effect, electrostatic interaction, and excluded volume. Our study of the average cavity density versus electric potential shows an intersection for different plots related to cavities of different sizes. This intersection point reveals two different behaviors of average cavity density with cavity size on the two sides of the intersection point. In other words, average cavity density increases (decreases) with cavity size for those electric potentials which are lower (higher) than that of the intersection point but it becomes independent of cavity size for the electric potential of the intersection point.

Solvent-free ionic silica nanofluids: Smart lubrication materials exhibiting remarkable responsiveness to weak electrical stimuli

Solvent-free ionic nanofluids (NFs) are promising smart lubrication materials due to their remarkable stimuli responsiveness to an external electric field. In this study, four kinds of silica (SiO2) NFs with diverse corona molecule structures were successfully synthesized. Effects of NFs’ structures on their physic-chemical properties and lubricity were investigated. In particular, nanostructures of the tribofilms were comprehensively characterized for shedding light on lubricating mechanisms of the NFs. Our results demonstrate that the newly synthesized NFs exhibit excellent lubrication performance and their lubricity displays remarkable electrical responsiveness. Applying even a rather low electrical potential, e.g. 1.5 V, gives rise to significant and immediate friction reduction. Moreover, lubricity and electrical responsiveness of the NFs are closely dependent on structures of the corona layers. Interestingly, our work provides direct evidence that feeding NFs onto the friction zone expedites growth of a robust tribofilm consisting mainly of SiO2 nanoparticles and tribochemical products. This work opens up new opportunities for tuning structures and functionalities of boundary layers of numerous motion components by tailoring architectures of NFs and controlling the electrical stimuli.

Turn-Off Transient of Superjunction SOI Lateral IGBTs: Mechanism and Optimization Strategy

In this paper, five types of superjunction (SJ) configurations are investigated in the silicon-on-insulator lateral insulated-gate bipolar transistor (SOI-LIGBT). technology computer aided design simulations are carried out to give insight into the mechanism for improving turn-off loss ( ${E} _{ \mathrm{\scriptscriptstyle OFF}}$ ) by adopting SJ in the drift region of SOI-LIGBT. In mechanism revealing, collector–emitter voltage rising during the inductive load turn-off is divided into two phases: slow rising phase (SRP) and rapid rising phase (RRP). It is found that the depletion accompanying with carrier extraction in the drift region and at the collector is responsible for the SRP and RRP, respectively, and accordingly, the difference of turn-off transient among the five types of SJ configurations is clarified. Moreover, reduced ${E} _{ \mathrm{\scriptscriptstyle OFF}}$ can be realized by lowering the transition voltage from SRP to RRP ( ${V} _{\text {A}}$ ). Low electric potential from the emitter side can be delivered to the collector side through the undepleted regions in P-pillar, which largely determine ${V} _{\text {A}}$ . According to the above-mentioned mechanism, an optimization strategy and a novel SJ SOI-LIGBT with composite P-pillar are proposed for the first time. The proposed SJ SOI-LIGBT achieves an ${E} _{ \mathrm{\scriptscriptstyle OFF}}~76.3$ % lower than the conventional SOI-LIGBT at ON-state voltage drop of ~1.41 V.

Transparent to Black Electrochromism-The "Holy Grail" of Organic Optoelectronics.

In the rapidly developing field of conjugated polymer science, the attribute of electrochromism these materials exhibit provides for a multitude of innovative application opportunities. Featuring low electric potential driven colour change, complemented by favourable mechanical and processing properties, an array of non-emissive electrochromic device (ECD) applications lays open ahead of them. Building up from the simplest two-colour cell, multielectrochromic arrangements are being devised, taking advantage of new electrochromic materials emerging at a fast pace. The ultimate device goal encompasses full control over the intensity and spectrum of passing light, including the two extremes of complete and null transmittance. With numerous electrochromic device architectures being explored and their operating parameters constantly ameliorated to pursue this target, a summary and overview of developments in the field is presented. Discussing the attributes of reported electrochromic systems, key research points and challenges are identified, providing an outlook for this exciting topic of polymer material science.

Investigation of the Performance of Filtration-charged Particles in a Reversed Electric Field

ABSTRACT Electrical forces can be applied to enhance fabric filters’ ability to remove fine particles. To this end, we developed an experimental apparatus consisting of a conventional wire-tube particle precharger and fibrous filters positioned in a generated reversed external electric field. The charging and collection processes were separately accomplished in two stages, and we evaluated the device’s ability to filter filtration-charged particles with a diameter of ≤ 2.5 µm. This device exhibited a higher electric field strength, higher collection efficiency, lower pressure drop, and lower electric potential than conventional devices due to the positioning of the wire and grounded electrodes close to the bag and the repulsion of the charged particles by the reversed electric field. When the face velocity was 2.5 m min–1, the collection efficiency for the charged particles with the reversed electric field was 8.4% and 64.4% higher than the efficiencies for the charged and uncharged particles, respectively, without the field. The charged particles also displayed a pressure drop when the field was applied that was 10% lower and 5% higher than those of the uncharged and charged particles, respectively, when the field was absent. A negative direct current supply was necessary to direct the deposition of the charged particles, and neither a spark discharge nor a back corona was observed while using the reversed-electric-field apparatus, which, according to our results, enables the removal of filtration-charged particles at face velocities

Al-water reactivity of Al[sbnd]Mg[sbnd]Ga[sbnd]In[sbnd]Sn alloys used for hydraulic fracturing tools

In order to develop a new kind of dissolvable alloy used for hydraulic fracturing tools, a series of AlMgGaInSn alloys with different Mg contents were prepared by smelting and casting methods to investigate the effect of Mg on the reactivity of alloys with water. Their microstructures were investigated by means of XRD and SEM. The Volta potential difference (ΔVPD) of the interfacial phases with Al was measured using AFM/SKPFM. Mg forms different intermetallic compounds with low melting point metals, depending on Mg additions in alloys. Different from the formation of In3Sn phase in AlGaInSn alloys, the In3Sn phase disappears in Mg-bearing alloys. The experiments found that the reactivities of Mg-bearing alloys with water are closely related to Mg content of alloys and water temperature. The alloys react with water slowly at the beginning of reaction, following with a fast reaction. From the corrosive morphologies of alloys, the precipitation of low melting point metals from interfacial phases was observed at Al grain boundaries. The lower electric potential of interfacial phases than Al was accounted for the precipitation of low melting point metals, because the interfacial phases form micro-galvanic cells with Al when alloys contact with water. A reaction mechanism of Mg-bearing alloys with water was proposed to explain the reactivties of alloys with water.

Influence of the Ambient Electric Field on Measurements of the Actively Controlled Spacecraft Potential by MMS

AbstractSpace missions with sophisticated plasma instrumentation such as Magnetospheric Multiscale, which employs four satellites to explore near‐Earth space benefit from a low electric potential of the spacecraft, to improve the plasma measurements and therefore carry instruments to actively control the potential by means of ion beams. Without control, the potential varies in anticorrelation with plasma density and temperature to maintain an equilibrium between the plasma current and the one of photoelectrons produced at the surface and overcoming the potential barrier. A drawback of the controlled, almost constant potential is the difficulty to use it as convenient estimator for plasma density. This paper identifies a correlation between the spacecraft potential and the ambient electric field, both measured by double probes mounted at the end of wire booms, as the main responsible for artifacts in the potential data besides the known effect of the variable photoelectron production due to changing illumination of the surface. It is shown that the effect of density variations is too weak to explain the observed correlation with the electric field and that a correction of the artifacts can be achieved to enable the reconstruction of the uncontrolled potential and plasma density in turn. Two possible mechanisms are discussed: the asymmetry of the current‐voltage characteristic determining the probe to plasma potential and the fact that a large equipotential structure embedded in an electric field results in asymmetries of both the emission and spatial distribution of photoelectrons, which results in an increase of the spacecraft potential.

Low voltage electric potential as a driving force to hinder biofouling in self-supporting carbon nanotube membranes

This study aimed at evaluating the contribution of low voltage electric field, both alternating (AC) and direct (DC) currents, on the prevention of bacterial attachment and cell inactivation to highly electrically conductive self-supporting carbon nanotubes (CNT) membranes at conditions which encourage biofilm formation. A mutant strain of Pseudomonas putida S12 was used a model bacterium and either capacitive or resistive electrical circuits and two flow regimes, flow-through and cross-flow filtration, were studied. Major emphasis was placed on AC due to its ability of repulsing and inactivating bacteria. AC voltage at 1.5 V, 1 kHz frequency and wave pulse above offset (+0.45) with 100Ω external resistance on the ground side prevented almost completely attachment of bacteria (>98.5%) with concomitant high inactivation (95.3 ± 2.5%) in flow-through regime. AC resulted more effective than DC, both in terms of biofouling reduction compared to cathodic DC and in terms of cell inactivation compared to anodic DC. Although similar trends were observed, a net reduced extent of prevention of bacterial attachment and inactivation was observed in filtration as compared to flow-through regime, which is mainly attributed to the permeate drag force, also supported by theoretical calculations in DC in capacitive mode. Electrochemical impedance spectroscopy analysis suggests a pure resistor behavior in resistance mode compared to involvement of redox reactions in capacitance mode, as source for bacteria detachment and inactivation. Although further optimization is required, electrically polarized CNT membranes offer a viable antibiofouling strategy to hinder biofouling and simplify membrane care during filtration.

Electrochemically assisted photocatalysis: Highly efficient treatment using thermal titanium oxides doped and non-doped electrodes for water disinfection

Electrochemically assisted photocatalysis (by electronic drainage) is a highly promising method for disinfection of water. In this research, the efficiency of photolytic oxidation using UV-A radiation and electrochemically assisted photocatalysis (with electric potential of 1.5 V) was studied by using electrodes prepared by thermal treatment and doped with silver, for inactivation of Escherichia coli and Staphylococcus aureus. The Chick-Watson microorganism inactivation model was applied and the electrical energy consumption of the process was calculated. It was observed no significant inactivation of microorganisms when UV-A light or electric potential were applied separately. However, the electrochemically assisted photocatalytic process, with Ag-doped electrode completely inactivated the microbial population after 10 (E. coli) and 60 min (S. aureus). The best performing non-doped electrodes achieved 52.74% (E. coli) and 44.09% (S. aureus) inactivation rates after 60 min. Thus, electrochemically assisted photocatalytic activity was not only effective for the inactivation of microorganisms, but also notably low on electrical energy consumption during the treatment due to small current and low electric potential applied.