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During the COVID 19 pandemic, the general population suffered from high degrees of stress, the consequence of which was an increase in myofascial pain syndrome. This inflammatory ailment which affects soft tissues causes pain, muscular rigidity, and modifies posture due to hyperactivity. A state of muscular ischemia leads to structural and chemical changes, and to variations in saliva’s electrical conductivity. The objective of this research was to measure the changes in pH and electrical conductivity of saliva samples, and to use these as biomarkers during therapeutical Maxillary Functional Orthopedics (Planas’ Simple Indirect Tracks and Simões Network 20). All the subjects that took part in the study evidenced changes in the beforementioned biomarkers, as well as clinical improvement of their symptoms.

Monitoring the appropriate functions of the brain is a priority when the diagnosis of neurological diseases is carried out. In this regard, there are different analytical techniques to detect neurotransmitters and other molecules with biological activity in the nervous system. Among several analytical procedures, electrochemical techniques are very important since they can be applied in situ, without loss of sensibility and/or minimal handling of samples. In addition, it is also possible to combine them with specific detectors designed on the basis of chemically-modified electrodes in order to improve detection limits by promoting molecular recognition capabilities at their surfaces, thus favoring the development of electrochemical detection in vivo by microelectrodes. In this mini-review, we will describe the major characteristics of this analytical method and its advantages for the detection of neurotransmitters (mostly dopamine) in vivo.

NiIIcyclam-modified nanoparticulate TiO2-coated ITO electrodes (ITO/TiO2//NiIIcyclam) were prepared by electropolymerization of NiIIcyclam monomers to TiO2-coated ITO electrodes (ITO/TiO2) to improve electrocatalytic urea CO(NH2)2 oxidation in alkaline aqueous solutions. A high value adding secondary effect was the collection of electrons at Pt cathodes, to simultaneously generate H2 from water reduction. NiIIcyclam-modified ITO electrodes (ITO//NiIIcyclam) were also prepared by electropolymerization of NiIIcyclam monomers to bare ITO electrodes (ITO) for comparison purposes. In the presence of the TiO2 nanoparticles, the urea mineralization on NiIIcyclam coatings was doubled (23.95% – organic carbon removal at 120 min of electrolysis) compared to those without TiO2 nanoparticles (13.02% – organic carbon removal at 120 min of electrolysis).In agreement, the faradaic efficiency for H2 generation at the Pt cathode, electrically connected to an anode having TiO2 nanoparticles (0.99 at 120 min of electrolysis), was also twice as effective than that observed when the same Pt cathode was electrically connected to an anode without TiO2 nanoparticles (0.46 at 120 min of electrolysis). The experimental results indicated that the poisoning of NiII centers (which is caused by an excessive production of CO intermediates during the urea oxidation on both NiIIcyclam-modified anodes) was strongly inhibited in the presence of the nanoparticulate TiO2|NiIIcyclam junction.A final comparison between our results and those reported in selected publications revealed that the NiIIcyclam-modified nanoparticulate TiO2-coated ITO anodes here developed, constitutes a promising electrocatalytic system for performing direct urea mineralization at a relative short electrolysis time. Furthermore, the combination of the following phenomena: (a) effective charge separation on the semiconducting ITO|nanoparticulate TiO2 junctions, (b) remarkable capabilities of the nanoporous TiO2 films for tuning the load of OH− anions demanded by the urea oxidation and, (c) outstanding capabilities of the TiO2 nanoparticles for capturing CO intermediates (at Ti3+ donor sites), successfully promoted the enhancement of the electron external transport to Pt cathodes, and consequently improved the faradaic efficiency associated to the cathodic generation of H2. Keywords: NiIIcyclam electrodeposition, Nanoparticulate TiO2 electrodes, Urea mineralization, CO intermediates inhibition, H2 electrogeneration

This work is focused on the characterization of the production of ozone, hydrogen peroxide and hydroxyl radicals (peroxone) in pressurized undivided electrochemical cells. BDD and MMO electrodes were compared as anodes and RVC, graphite and stainless steel as cathodes. Gauge pressures in the range 2–4 bar were applied. Results demonstrate the complexity in the production of oxidants in an undivided cell, allowing to propose a model of the set of reactions (both electrochemical and in the bulk) occurring in the system. A higher pressure decreases the accumulation of ozone meanwhile hydrogen peroxide production is maximized at intermediate values of pressure. Combining BDD and graphite is the best combination for enhancing the production of hydroxyl radicals for which a negligible influence of pressure was observed. These results would allow to select the proper design to maximize the efficiency in the production of each of the oxidants studied.

One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically due to its indigestibility. Conventional biological and physicochemical methods for removing AMX from water are not enough to mineralize it, only it is concentrated and transferred to produce new residues that require further processing to remove the new residues.In this research, naked and modified surfaces with TiO2 nanotubes (TiO2,nt) electrophoretically modified with PbO2, IrO2, RuO2, and Ta2O5 were used to evaluate their efficiency in the electrochemical degradation of AMX in acid media (0.1 mol L− 1 H2SO4). After their comparison, Pb-Ta 50:50|TiO2,nt|Ti showed the highest removal efficiency of AMX (44.71 %) with the lowest specific energy consumption (8.69 ± 0.78 kWh Kg COD− 1), and the average instant current efficiency of 26.67 ± 9.19 %, in comparison with the others naked and modified surfaces of TiO2,nt|Ti.

Bentonite was used as model clay to evaluate the electrochemical degradation and removal of phenanthrene in clay-soils, by applying a dimensionally stable electrode. Gas chromatography couple to mass spectrometry (GC–MS) was used to identify and analyze the post-treatment greases and oils extracted from bentonite. Phenanthrene removal and the products generated by its degradation were evaluated indirectly in bentonite after the process, using physicochemical parameters such as pH, cation exchange capacity, electrical conductivity and zeta potential clay substrate. An acidic front close to the IrO2–Ta2O5|Ti anode was formed in the presence of OH free radicals. As a result, the physicochemical soil parameters changed throughout the electrochemical cell. The results show that phenantrene was removed from bentonite and degraded after 4 h of electrokinetic treatment in presence of 0.1 M NaOH.

One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically due to its indigestibility. Conventional biological and physicochemical methods for removing AMX from water are not enough to mineralize it; it is only concentrated and transferred to produce new residues that require further processing to remove the new residues. In this research, naked and modified surfaces with TiO

In this work, it is evaluated the fixation of carbon dioxide using the alkali generated in the chloralkaline process, as a new way to face the treatment of highly saline wastewater, in which it is aimed not to separate the wastewater into concentrated and diluted streams but to recover value-added products (VAPs) while contributing to minimize the carbon fingerprint of other processes. The electrolytic process is combined with a reactive absorption and with a crystallization, demonstrating the formation of pure nahcolite, hypochlorite (or chlorine) and hydrogen from the waste. Carbon dioxide is captured with a current efficiency over 90% and the energy required is around 0.65 kWh kg

The present work deals with the use of ultrafiltration as a pre-concentration stage in the electrochemical degradation of a non-polar organochlorine compound (oxyfluorfen) with boron-doped diamond (BDD) anodes. The first stage of the work consisted in evaluating the performance of a pilot scale ultrafiltration unit to concentrate a solution of a commercial formulation of oxyfluorfen (Barre®) at total recirculation mode. The ultrafiltration membrane exhibited a total rejection of oxyfluorfen, around 70% rejection of TOC and a permeate flux of 285.1 L h−1 m−2 at 4 bar and 25 °C. The rejection of oxyfluorfen is higher than expected due to the presence of surfactant compounds in the commercial formulation selected, which promotes a mechanism of micellar enhanced ultrafiltration. Next, a discontinuous ultrafiltration test was performed, maintaining this high rejection of oxyfluorfen and observing a limited contribution of fouling mechanisms, according to the adjustment of the data to fouling models. Regarding the electrochemical oxidation of the concentrate with BDD anodes, it was observed an increase in the specific power consumption from 590 kWh kg−1 for the raw solution to 882 kWh kg−1 for the concentrate. This unexpected result can be explained due to the limited rejection of the soluble fraction in the ultrafiltration stage, what produced a lower concurrence of oxidants in the electrochemical oxidation step. According to these results, it can be stated that it is worth using ultrafiltration as a concentration stage for commercial formulations of non-polar organochlorines with both high rejection and flux, although it should be combined with degradation technologies different from electrochemical oxidation.

This work focuses on the evaluation of the electrochemical dewatering of sludge obtained in the coagulation of wastes polluted with oxyfluorfen. To do this, sludge samples were treated, aiming not only to reduce the sludge volume, but also to facilitate the degradation of oxyfluorfen contained in the cake via electrolysis with a boron-doped diamond anode. Results show that water can be effectively recovered through three sequential stages. First, a gravity-driven stage, that can recover around 60% of initial volume and where no oxyfluorfen is dragged. Then, a second stage that involves the application of pressure and which accounts for the recuperation of an additional 25% of the total volume of the water removed and in which oxyfluorfen also remained in the cake. Finally, an electrochemical stage, which involves the application of electricity with increasing electric fields (1.0, 2.0, 4.0, and 16.0 V cm−1), accounting for the recovery of the rest of water released and where an electrolytic degradation of oxyfluorfen is obtained, whose extension depends on the electrode configuration used in the electro-dewatering cell. This electrode configuration also influences the retention or loss of oxyfluorfen from the cake, being the optimum choice the placement of the cathode downstream, next to the outlet of the dewatering cell.

In-doped SnO2 (ITO) cathodes bearing Ag, Cu and bimetallic Ag/Cu nanoparticulate arrays (cathode systems ITO//Ag, ITO//Cu and ITO//Ag/Cu, respectively) were prepared by a potentiostatic double-pulse technique and employed for studying the multi-step charge-transfer kinetics of CO2 electrochemical reduction (CO2ER) in propylene carbonate solution. Our results demonstrated, on one hand, that the current exchange density of the rate-determining step (rds) for the CO2 electrochemical reduction (io,rds) depends, predominantly, on the values achieved by the outer-Helmholtz plane (OHP) potential (ΔψOHP,rds) on the three cathode systems here explored. Furthermore, these results showed that a large ΔψOHP,rds (−647 mV) promoted a large io,rds (1.09 × 10−2 A⋅ cm−2) for CO2 reduction at the cathode system ITO//Cu, whereas a small ΔψOHP,rds (−168 mV) produced a small io,rds (2.05 × 10−4 A⋅ cm−2) for CO2 reduction at the cathode system ITO//Ag. In contrast, intermediate values of ΔψOHP,rds and io,rds (−333 mV, 1.09 × 10−3 A⋅ cm−2) were found for CO2 reduction on the cathode system ITO//Ag/Cu, demonstrating that the individual electrocatalytic properties of Ag and Cu can be coupled in a bimetallic array to intentionally tune the CO2ER rate in nonaqueous solvents having low proton availability.

In this study, the removal of PAHs from a clay-based soil, using electrokinetic remediation, was explored. The experiments used phenanthrene-spiked bentonite as a simplified model representative of a Vertisol soil polluted by hydrocarbons. Experiments were performed using a 1-D cell where 80 cm3 of phenanthrene-spiked bentonite was subjected to electrokinetic remediation using a constant current density. The results obtained from these experiments were compared with those predicted by a mathematical model based on a Nernst-Plank equation for the description of electromigration, electroosmosis and diffusion. Although significant electro-osmotic flow was observed, comparison between the experimental and predicted results indicated that the removal of phenanthrene was experimentally faster than predicted by the model. The greatest differences were found in the soil regions closer to the anode. To account for this behavior a first-order reaction in the aqueous phase in the regions closer to the anode was postulated and introduced into the model as the observed sink for phenanthrene. Under these conditions, much better agreement was observed between the experimental and model results.

Advanced oxidation process (AOP) for the decontamination of stainless steel plates was evaluated using IrO2–Ta2O5|Ti and boron doped diamond (BDD) as the potential anode materials for removing radioactive U-238 from contaminated stainless steel components. Decontamination of non-compactable radioactive wastes, such as tools and equipment, aims to reduce the volume of waste that must be further conditioned and stored. The technical viability of the application of electrochemical techniques, such as AOP, in the decontamination of non-compactable radioactive stainless steel (containing uranium) waste materials, was studied in this work. To better understand the viability of this process, initial tests were performed with stainless steel plates coated with WO3, to simulate a work piece contaminated by a radioactive compound, to determine the best conditions of pH, electrolyte support, distance between the electrodes and the cell potential for the removal of tungsten, and subsequently, uranium, by AOP. Stainless steel coated by WO3, as cathode while using IrO2–Ta2O5|Ti or BDD anodes were studied to obtain the highest generation of ·OH radicals over the shortest time. In subsequent AOP testing, using the optimal experimental conditions found for the removal of WO3, stainless steels coated with the radioactive contaminant UO2(NO3)2 studies were performed to evaluate the viability of the radioactive decontamination process. Efficiencies of uranium removal of greater than 90% were obtained in 1 h while maintaining pH = 1, a cell potential of 2.4 V and distance between anode/cathode electrodes of 1 cm.

In this work, it is evaluated the fixation of carbon dioxide using the alkali generated in the chloralkaline process, as a new way to face the treatment of highly saline wastewater, in which it is aimed not to separate the wastewater into concentrated and diluted streams but to recover value-added products (VAPs) while contributing to minimize the carbon fingerprint of other processes. The electrolytic process is combined with a reactive absorption and with a crystallization, demonstrating the formation of pure nahcolite, hypochlorite (or chlorine) and hydrogen from the waste. Carbon dioxide is captured with a current efficiency over 90% and the energy required is around 0.65 kWh kg−1, which is very promising from the view point of sustainability, considering that the system can be easily powered with green energies.

Titanium dioxide nanotubes (TiO2-Nts) array morphology and its high specific surface area provide a suitable substrate for PbO2 electrodeposition. PbO2 was effectively dispersed on the whole nanotubes surface, including both their walls and mouths (electrocatalyst of the type: Ti/TiO2-Nts::PbO2). Scanning electron microscopy and EDS microanalyses showed that PbO2 grows from the bottom to the surface of the nanotubes, firstly covering their walls. A simple growth mechanism previously proposed was confirmed by electrochemical methods. Cyclic voltammetry characterization of Ti/TiO2-Nts::PbO2 electrodes (2 cm2 geometric area) allowed to obtain the double layer capacitances that were directly related to PbO2 electroactive area, indicating that it grows inversely with deposition time. Also, electrocatalytic features (high oxygen evolution overpotential, open-edge morphologies and larger network structures to PbO2 crystals formed) depend on the PbO2 dispersion as well as electrodeposition time. Their electrooxidation properties were tested for electrolysis of 15 ppm methyl red (MR) and 50 ppm p-nitrophenol (PNP) acidic aqueous solutions at a current density of 30 mA cm− 2. Results clearly showed the effect of PbO2 deposition time on the electrocatalytic area and on the electrooxidation of PNP and MR. That is, Ti/TiO2-Nts::PbO2 with the shortest electrodeposition time has the highest surface and active area, efficiently degrading MR (100% of discoloration and 90% of organic removal) and PNP (90% of concentration removal after 3.5 h) in solutions. HPLC analyses of the final samples showed that carboxylic acids are the main remnant of electrooxidation.

The quantification of actinides in aqueous solutions involves complex and expensive separation processes. Electrochemical methods have been widely used for the quick and accurate identification and quantification of organic and inorganic compounds directly or indirectly. Therefore, this work proposes the use of modified graphite with phthalocyanine for electrochemical detection and quantification of Th, U, Pu, Am, and Cm, in aqueous media by cyclic voltammetry. The electrodes were characterized by Raman and infrared spectroscopy, and the cyclic voltammetry data were modeled with Aoki’s model. The detection limits (DL) and the quantification limits (QL) reached by the electrochemical detection of these actinides were of the order of ppt. Aoki’s model fitted perfectly with the experimental data. The functionalization of graphite electrodes promotes the formation of phthalic anhydride, and the phthalocyanine is anchored on the epoxy groups of the graphite. The electrochemical detection process of these actinides is indirect. This electrochemical detector is cheap and disposable and can be an alternative for an initial characterization of actinides in liquid waste.

Conventional agricultural systems can lead to degradation of the environment due to the high dependence on chemical fertilizers and pesticides; therefore, it is important to search for new technologies that help maintain the ecological balance. An example of this type of new technology is the electrofarming technique. This technology has been shown to improve the soil properties and the germination and growth processes of different types of plants. In this research, the effect of applying a low-intensity electric field using a 2D arrangement of electrodes with six modified IrO2-Ta2O5|Ti anodes around a bare Ti cathode as an in situ pilot level in 5.4 m3 of Anthrosol was determined. Electrofarming showed higher germination (59%) than farming (41%) after 18 days. This result validated the efficiency of the electrical stimulation of the seeds of cucumber in an Anthrosol with benefits on the physiological properties of cucumber plants (stem thickness, stem elongation, cotyledon length, true leaf size, root length), amount of biomass in the microbial population present in the soil (bacteria and fungi), as well as in its physicochemical properties (pH, soil organic matter, cationic exchange capacity, enzymatic activity, Ca+2, Mg+2, K+, and Na+), specifically in the area close to the anodes compared to farming.

Titanium electrodes coated with transition metal oxides are used in many applications such as the electrogeneration of hydroxyl radicals (•OH) via catalytic water oxidation. Here, we present electrochemical measurements of IrO2-Ta2O5|Ti electrodes with four different Ir:Ta ratios in the coating (100:0, 70:30, 30:70, 0:100) to better understand their electrochemical behavior. From the results, an Ir:Ta content of 70:30 reveals a homogeneous morphology, an outstanding mechanical stability, and the best generation of •OH radicals due to a cooperative enhancement of the electrocatalytic and proton (H+) transfer properties of IrO2 and Ta2O5, which are complemented by a small ohmic drop due to a junction established during the electrophoretic deposition of IrO2 and Ta2O5. The electrochemical data in this work in conjunction with density functional theory calculations provide in-depth insights into the outstanding electrocatalytic properties of the as-prepared IrO2-Ta2O5|Ti electrodes, which may have applications in environmental processes.

The effect of the application of electric fields, magnetic fields, and electric currents in plants is still limited. Some research has yielded favorable results on plant growth, but some has found inhibition of plant development. The physiological, microbiological, and edaphological characteristics of plants could be affected by imposing low-intensity electric fields using a 2D array of electrodes with six modified anodes with transition metal oxides such as IrO2-Ta2O5|Ti anodes around a naked Ti cathode. In the case of cucumber (Cucumis sativus) germination, electrofarming showed a higher percentage of germination (50%) than did conventional farming (30%), and changes in the other physiological properties of cucumber plants were also observed. The results showed that after 4 h of exposure to an electric field (0.2 V cm−1), stem thickness (6%), cotyledon length (5%), true leaf size (49%) and generated biomass (53%) were quantitatively improved; properties such as stem elongation (20%) and root length were quantitatively improved, and significantly different effects were obtained after exposure to the electric field (p In the case of microbiological characterization, after exposure to the electric field, a greater number of CFUs were obtained for bacteria and fungi, with an increase of 2× in both cases, than in the control soil. The electric field significantly increased the CFUs in the area close to the anodes compared to CFUs in the control soil. Other properties were also improved by electrofarming; in the microscopic characterization of bacteria, a higher percentage of Gram (−) bacilli was obtained along with increased percentages of soil organic matter (42%), cationic exchange capacity (6%), and enzymatic activity (47%) close to the anodes compared to results in the control soil.

Control samples of scintillation liquids - Phaeozem soil mixtures were prepared with different scintillation liquids as the support electrolyte, Install Gel® XF, (Ultima Gold AB™ and Ultima Gold XR™), to construct the polarization curves, and to select the cell potential with the highest mass transfer to remove 24Na (15 h) and 99mTc (6 h) as radiotracers from polluted Phaeozem soil. During the electrokinetic treatment (EKT), the removal of radionuclides contained in scintillation liquids absorbed in Phaeozem soil, liquid phase was characterized by Gas Chromatography coupled with a Flame Ionization Detector (GC-FID) and Fourier Transform Infrared Spectrometry (FTIR), solids by FTIR, before and after the application of cell potential. In this sense, the support electrolyte was selected based on the highest current generated (1 mA), as in the case of scintillation liquid 50% Ultima Gold XR™ + 50% Water (1:1), which was used for 6 h in the presence of a mesh and a titanium rod, as anode and cathode, respectively. Finally, the removal percentage accumulated in the liquid phase after the EKT of Phaeozem soil polluted by 99mTc was 61% close to the anode after 4 h. It was also 61% for 24Na close to cathode after 2 h, and after 4 h it was 71.8%.

In recent years, physicochemical processes such as the electrokinetic treatment (EKT) have gained acceptance as suitable alternatives to restore hydrocarbon (HC)-contaminated sites. EKT entails relatively short times, moderate operation costs and high removal efficiencies, being usually applied in heterogeneous soils with low permeability. In this work, 1D and 2D configurations, which require one sole pair of electrodes (facing each other) or six anodes around a central cathode (radial array), respectively, have been tested by employing Ti cathodes and anodes, as well as purpose-made IrO2-Ta2O5|Ti as dimensionally-stable anodes (DSA). The electrodes were partially introduced into a real Vertisol soil contaminated with heavy and intermediate fractions of HC. The distance between the cathode and each anode was of 6 cm at laboratory scale employing a 276 cm3 container with 2.2 kg of polluted soil and a 115 cm3 container with 87.8 g of polluted soil for the 2D and 1D arrays, respectively. From GC-MS analysis of fat and oil content, it has been found that the radial 2D array with one central Ti cathode and six IrO2-Ta2O5|Ti anodes performed better, reaching 58% HC removal near the anode applying 30 V and an electric field of 2.4 A cm-1. The effect of the treatment on the morphology of the anodes has been analyzed by SEM-EDX.

The purpose of geophysical electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the true resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters, such as the mineral and fluid content, porosity and degree of water saturation in the rock. Electrical resistivity surveys have been used for many decades in hydrogeological, mining and geotechnical investigations. More recently, they have been used for environmental surveys. To obtain a more accurate subsurface model than is possible with a simple 1-D model, a more complex model must be used. In a 2-D model, the resistivity values are allowed to vary in one horizontal direction (usually referred to as the x direction) but are assumed to be constant in the other horizontal (the y) direction. A more realistic model would be a fully 3-D model where the resistivity values are allowed to change in all three directions. In this research, a simulation of the cone penetration test and 2D imaging resistivity are used as tools to simulate the distribution of hydrocarbons in soil.

Soil contaminated with hydrocarbons is a current problem of great importance. These contaminants may be toxic, can retain water and block gas exchange with the atmosphere, which produces a poor-quality soil unsuitable for ecological health. Electroremediation is among the treatments for the removal of such contaminants. In this research, a pilot-level electroremediation test was applied using a circular arrangement of electrodes with a Ti cathode at the middle of the cell surrounded by six IrO 2 –Ta 2 O 5 | Ti anodes. The presence of an NaOH electrolyte helps to develop the electromigration and electro-osmosis of gasoline molecules (at 1126 mg kg −1 ) surrounded by Na + ions. The hydrocarbons are directed towards the cathode and subsequently removed in an aqueous Na + – hydrocarbon solution, and the –OH migrates to the anode. During electrokinetic treatment, the physicochemical characteristics of the soil close to either the cathode or anode and at the half-cell were evaluated during the three weeks of treatment. During that time, more than 80% of hydrocarbons were removed. Hydrocarbons removed by the electrokinetic treatment of gasoline-polluted soil were collected in a central wastewater compartment and subsequently treated with a Fenton-type advanced oxidation process. This achieved more than 70% mineralization of the hydrocarbons to CO 2 and H 2 O within 1.5 h; its low toxicity status was verified using the Deltatox ® kit test. With this approach, the residual water complied with the permissible limits of COD, pH, and electrical conductivity for being discharged into water bodies, according to Mexican norm NOM-001-SEMARNAT-1996.