The textile industry is one of the largest water consumers, with an annual usage of 79 billion cubic meters, and it is also one of the primary sources of contaminated wastewater due to its diverse production processes. Textile effluents contain recalcitrant contaminants such as dyes, toxic substances, inhibitors, surfactants, detergents, chlorinated compounds, and salts. The treatment and monitoring of these effluents are essential yet challenging due to the stable and diverse structure of the contaminants present. This study presents the results of textilewashing wastewater treatment using ozonolysis, electrocoagulation, and electro-oxidation at a laboratory scale, achieving significant reductions in physicochemical parameters: COD = 54.74 %, TOC = 74.48 %, TSS = 96.83 %, with a neutral pH of 7.71. These results comply with the criteria established by NOM-001-SEMARNAT2021, which regulates wastewater discharges into surface water bodies in Mexico. Additionally, a relationship is established between the Food and Agriculture Organization of the United Nations / World Health Organization (FAO/WHO) standards for irrigation water, the European Union - Water Framework Directive (EU-WFD), and the Iranian standard for agricultural reuse in Iran, which aims to ensure good chemical and ecological status of water bodies through strict limits on organic and inorganic pollutants. The results allow compliance with the limits set by NOM-001-SEMARNAT-2021 and reflect global efforts to improve water quality, as promoted by the FAO/ WHO, EU-WFD, and Iranian standards. Finally, based on experimental conditions, a GPS-X model of the coupled wastewater treatment system is proposed as an additional tool to optimize textile wastewater treatment and ensure compliance with international regulations.

This study evaluated the effects of electrical stimulation (ES) and biological stimulation (BS) on blueberry plants, evaluating their synergistic impact under field conditions in comparison to a control group (C) without stimulation across various growth stages. Key variables were recorded during the pre-flowering stage, including the number of flower buds, chargers, flowers, and fruit, as well as chlorophyll levels, over twelve weeks. In the fruit set and filling stage, fruit caliber, total fruit count, and yield (grams/plant) were measured over eleven weeks. Post-fruit set, characteristics such as blueberry size, color (brightness (L), hue angle, chromatic index, and color differences (∆E)), firmness, and Brix degree were evaluated. The ES + BS treatment achieved the highest cumulative yield (1383 g plant−1), followed by ES (1293 g plant−1), BS + ES (1289 g plant−1), and BS (1278 g plant−1), with the control yielding 1216 g plant−1 after eleven weeks. The control group had the highest total fruit weight (635 g plant−1), while BS treatment produced 40.26

Different ways to quantify ions in solutions require the pre-treatment of the sample and experimental measurements to be performed. This research proposes to develop an electrochemical method for ions, specifically for sodium ions, using modified surfaces by electrodeposit of Prussian Blue (PB) on carbon (C) and carbon nanotubes (CNT) to get PB-C and PB-CNT. It was observed that the PB-CNTCC modified electrode showed the highest current density compared to the bare carbon (C) and CNTC electrodes, including the modified PB-CC. For this reason, the highest detection and quantification limits were obtained using PB-CNTC with 13.1 and 43.7 mu mol L- 1, respectively. The different modified and bare electrodes were characterized by electrochemical, spectroscopically, and microscopically methods, where the electronic transference using a probe molecule showed a quasi-reversible behavior in different cases, with the PB presence by cube shape in order of the number of cycles indicating a 3D growth. Additionally, these electrodes were probed for the electrochemical detection of sodium in a synthetic aqueous media. In aqueous samples from soil extracts, these results showed that they are competitive with other analytical methods, such as flame atomic absorption, by the similarity of the sodium concentrations obtained. They look attractive for use in the field of detection of sodium. It is worth noting that this is the first time that this type of surface and electrodes have been used for sodium detection, compared to the existing ones based on the same methodology in the detection of Na+ at lower concentrations.

Water scarcity and pollution are among the most pressing global challenges, exacerbated by population growth and technological advancements that deplete water resources and harm ecosystems. Novel wastewater treatment technologies are urgently needed to ensure clean water and sanitation for current and future generations. Electrochemical Advanced Oxidation Processes (EAOPs) show significant potential to address these challenges by utilizing sustainable electrode materials to generate oxidants that degrade water pollutants. Material science plays a crucial role in designing efficient, stable, and cost-effective (photo)electrocatalytic materials for wastewater treatment and resource recovery. This review critically examines recent advances in (photo)electrocatalytic materials for EAOPs, emphasizing Anodic Oxidation (AO), Electro-Fenton (EF), and Photoelectrocatalysis (PEC). The fundamentals of AO, EF, and PEC are explored, followed by a discussion on the synthesis, characterization, and applications of anodic, cathodic, and photoelectrode materials. Applications include real wastewater treatment and emerging methods for wastewater valorization, such as energy recovery and the production of value-added products. The review also highlights material intersections in AO, EF, and PEC, identifies key scientific and technological gaps, and offers research perspectives to address current bottlenecks. This work offers a comprehensive overview of material science advancements in EAOPs, aiming to guide future research and support the development of scalable systems for wastewater treatment and valorization.

Fuel theft causes hydrocarbons to be dumped on the ground by altering the tubes through which they are transported; this negatively affects the soil quality around them. Geoelectrical studies, such as resistivity studies, propose a practical and rapid technique for detecting plumes due to organic contaminants compared to laboratory chemical studies. The present work evaluated the efficiency of the electrical resistivity measurement in follow-up remediation of soil contaminated with hydrocarbons due to fuel theft actions by comparing the results obtained with those observed in the Soxhlet chemical extraction test. The treatment was carried out using electro-phytoremediation as an environmental technique in a Leptosol, with the removal of 40 % of the hydrocarbon achieved during 55 days of treatment. Performing a statistical analysis, a positive correlation coefficient greater than 0.70 was determined in all soil samples studied. This corroborated the high relationship between the electrical resistivity variables and the mass of hydrocarbons g(-1) of soil, maintaining that the soil resistivity values increase in the presence of hydrocarbon from a recent spill, which generated hydrophobicity and blocking of porous, in consequence, reduction of the ionic conduction and cationic exchange capacity of soil by the aggregation of particles. In addition to the geophysical and chemical tests, physicochemical and microbiological studies were used to support the behavior of electrical resistivity and the presence of hydrocarbon in the soil samples before and after applying electro-phytoremediation.

This work explores a novel electrochemical approach for the efficient degradation of amoxicillin (AMX), a widely used antibiotic and emerging water pollutant. This is the first time reported a system combines an IrO2-Ta2O5|Ti anode with cathodes modified using activated carbon derived from two types of waste biomass: Phragmites australis (PA) and Spergularia rubra (SR), having in mind the circular economy. This study evaluated the influence of aeration and current density on AMX degradation efficiency. Results showed that the carbon-modified cathodes enhanced the production of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction, which facilitated the generation of reactive hydroxyl radicals (center dot OH), which improve significantly the degradation rate of AMX. Under optimal conditions (aeration and 2.54 mA cm-2 current density), the system achieved complete AMX degradation within 30 min, with substantial reductions in energy consumption (0.1096 and 0.0895 kWh m-3 order-1 for PA and SR, respectively, when applying 2.54 mA cm-2) compared to conventional platinum cathodes (4.9844 kWh m-3 order-1 for Pt). Acute toxicity assays conducted with Vibrio fischeri demonstrated a significant reduction in the toxicity (measured as inhibition percentage), with values of 8.49 % and 8.79 %, respectively (vs 21.88 % of initial sample). These findings highlight the potential of integrating waste-derived carbon materials with transition metal oxide anodes for sustainable water treatment processes, offering a promising alternative to traditional electrochemical systems for the degradation of pharmaceutical contaminants supporting the sustainable development goal number six (SDG 6) focus on clean water and sanitation.

In view of the increasing scarcity of water resources and the imperative to develop processes with minimal environmental impact, there is a pressing need to focus on the design of water treatment methods characterized by reduced energy consumption and heightened process efficiency. In this vein, the present short review aims to provide a critical assessment of electrochemical technologies for environmental applications, with particular emphasis on reactor configuration's role in the elimination of persistent organic pollutants and the effectiveness of disinfection systems. To underscore the search for processes aligned with sustainability objectives, specific attention has been directed towards comparing conventional configurations with microfluidic devices. Conventional configurations prove effective for the objectives described in this review, achieving removals exceeding 90% of a wide range of persistent contaminants and reductions greater than 6-log for fecal coliforms, Pseudomonas aeruginosa, helminth eggs, among others. Compared to traditional configurations, microfluidic designs have demonstrated notable advantages, including reduced energy consumption (3- to 20-fold), and heightened mass transfer rates. Specifically, designs that combine a micrometric interelectrode distance with a flow-through configuration or vigorous mixing (electromixing configuration) exhibit high potential for the development of more efficient electrochemical systems compared to conventional devices. In light of the superior performance exhibited by these electrochemical devices, it is evident that continued research in the realm of environmental electrochemistry is paramount for fostering sustainability in the coming years, particularly in alignment with the UN's Sustainable Development Goals (especially SDG 6).

This article presents the imposition of a direct current electric field in the presence of seeds and plants of Zea mays L., to rehabilitate soils contaminated with hydrocarbons at a pilot level, and its influence on some physical and chemical properties of the soil, such as pH, electrical conductivity, organic matter content in the soil, enzymatic activity, bulk density, apparent density, porosity, cation exchange capacity, and soluble cations such as potassium, sodium, and calcium. For this reason, the edaphological characterization was carried out before and after an electro-phytoremediation process of soils contaminated with hydrocarbons, using an IrO2-Ta2O5|Ti anode and a titanium cathode, applying a constant electric field of 0.2 V/cm for 4 h to maize seeds and stimulating their germination. After one week, an electric field of 0.1 V/cm for 8 h was applied to the maize seeds every day for 42 days to stimulate the growth of maize plants. This study demonstrated the removal of hydrocarbons by electro-phytoremediation. The applied electric field increases seed germination and plant growth of Zea mays L. These results were obtained with the different transport phenomena that develop when using the electric field in the soil Vertisol pelic understudy at a pilot level.

The circular economy policy enables the use of waste as an input to generate value repeatedly or at least to have the opportunity to be used a second time to extract valuable substances such as metals, dyes, hydrogen, phosphorus, nitrogen, nutrients, and fertilizers. For this reason, the present paper discusses approaches to valorizing wastewater, communal production, and agricultural wastes. In particular, techniques are considered to valorize biomass, lignin-containing residues, wastewater with a high organic content, sewage sludge, oily sludge, mine tailings, fly ashes, and iron production wastes. The procedures evaluated include biological processes, microbial fuel cells, electrokinetics, electro-demulsification, electrodialysis, and the Fenton process; their rational application promotes the reuse of different chemical and biological compounds to eventually supply some economic sectors with raw materials in a sustainable manner, solve the problem of pollution in the environment, and generate power at the same time. Of particular and emerging interest is the valorization of iron wastes, which serves to obtain low-cost catalysts for wastewater treatment processes. Additionally, the correct characterization of the chemical composition of wastes and determination of their final use allows better results and less time to valorize any wastes considered.

Cu2ZnSnS4 (CZTS) was synthesized following hot injection method and the process was optimized by varying temperature conditions. Four samples at different temperatures viz., 200, 250, 300 and 350°C were prepared and analyzed using different characterization techniques. Based on the correlation between XRD, Raman and XPS, we conclude that the formation of ZnS and SnS2 occurs at 3500C but at 2000C there is no breakdown of the complex as per XRD. According to Raman and XPS analysis, as the temperature rises, the bonds between the metals become weaker, which is visibly seen in Raman and XPS due to the minor peaks of copper sulfide. Scanning electron microscopic analysis confirmed nanometric particles which increase in size with temperature. The photocatalytic evaluation showed that CZTS synthesized at 2000C performed efficiently in the removal of the two colorants, methylene blue and Rhodamine 6G, achieving 92.80% and 90.65%, respectively. The photocatalytic degradation efficiencies decreased at higher temperatures due to bigger sized CZTS particles as confirmed by SEM results. Computational simulations confirm that CZTS has a highly negative energy -25,764 Ry, confirming its structural stability and higher covalent than ionic character.

Surfaces modified with transition metals oxides, specifically iridium, ruthenium, and tantalum, as IrO2/Ta2O5||Ti and RuO2/Ta2O5||Ti, function as electrocatalysts in oxygen evolution. In addition, they favor the electrochemical oxidation of organic compounds by their low overpotential for the oxygen evolution reaction of oxygen, high electrical conductivity, and corrosion resistance. There are various physicochemical techniques for their characterization. Electrochemical Impedance Spectroscopy (EIS) allows their electrochemical characterization by applying a small potential perturbation, at a given frequency and amplitude, to an electrochemical cell to subsequently evaluate current response, which is stable, linear, causal, and with a finite value electrochemical systems are very effective. The impedance can be interpreted using an equivalent circuit formed by resistors, capacitances, and inductors, which must conform to the result obtained experimentally, as they relate to the elements of the Bisquert #2 and Gerischer models to MO2/Ta2O5 (M = Ir or Ru). The Electrochemical-Chemical-Electrochemical reaction mechanism for hydroxyl radical generation favors the electrochemical reaction when used in advanced oxidation processes. IrO2/Ta2O5||Ti and RuO2/Ta2O5||Ti electrodes display good stability and overpotential characteristics for O2 evolution, leading to high production of radicals ·OH via electrochemical reactions in acidic aqueous solutions by inhibiting intermediaries (·OH)IrVO2 and (·OH)RuVO2 to remove organic compounds in these aqueous solutions.

Mesostructured PbO2/TiO2 materials were synthesized to perform electrocatalysis (as electrooxidation, EO) and photoelectrocatalysis for removing diclofenac (DCF), 15 ppm concentration in 0.1 M NaSO4 solutions, at different pH conditions (3.0, 6.0 and 9.0) by applying 30 mA cm-2. Titania nanotubes (TiO2NTs)-based materials were prepared to synthetize with a massive PbO2 deposit on this support to obtain TiO2NTs/PbO2 and a TiO2NTs: PbO2 material consisting in a dispersed PbO2 deposit on TiO2-NTs that allowed the formation of a hetero-structured surface of combined composition (TiO2 and PbO2). Organics removal (DCF and byproducts) was monitored through UV-vis spectrophotometry and high-performance liquid chromatography (HPLC) during degradation tests. TiO2NTs/PbO2 electrode was tested in both processes, removing DCF at neutral and alkaline solution conditions in EO while an unimportant photoactivity was registered at this material. Conversely, TiO2NTs:PbO2 was used as electrocatalytic material in EO experiments, achieving more than 50% of DCF removal at pH 6.0 by applying 30 mA cm-2. Also, for first time, the synergic effect was investigated when it was exposed to UV irradiation in photoelectrocatalytic experiments, enhancing its efficacy (⁓more than 20%) to remove DCF from a solution with 15 ppm over performance removals achieved (56%) when EO was applied under similar conditions. Chemical Oxygen Demand (COD) analyses showed that significantly higher DCF degradation is reached under photoelectrocatalysis, since COD values decrease a 76% against a 42% decrease achieved with electrocatalysis. Scavenging experiments showed a significant participation on the pharmaceutical oxidation process through the generation of photoholes (h+), hydroxyl radicals and sulfate-based oxidants.

Hemodialysis is an extracorporeal kidney replacement procedure to remove impurities or waste products from the blood that is used in the treatment of kidney failure. During this process, large amounts of water are used, which, lacking control, end up in sewage systems, potentially flushing high levels of organic and inorganic contaminants into the receiver's aqua biota. This research considered the treatment of synthetic hemodialysis water under acid and basic conditions. To better simulate the presence of organic compounds, 10 mg L-1 of amoxicillin, an antibiotic commonly present in wastewater from clinics and hospitals, was added. Laboratory and pilot tests were performed using coupled electrocoagulation and electro-oxidation. During electrocoagulation, the use of stainless steel and aluminum, as sacrificial anodes, were compared in acidic and basic pH. The stainless steel rod anode and a titanium mesh cathode were used during electrocoagulation in acidic conditions at a field strength of 3.0 V which was applied for 60 min. After electrocoagulation, the solution obtained was filtered to separate precipitates. The supernatant was then treated with electro-oxidation using an IrO2-Ta2O5|Ti anode and the titanium mesh cathode while applying 10 mA for 120 min. Wear of the stainless steel anode was identified by scanning electron microscopy and microanalysis. Removal of organic compounds including amoxicillin was significant. These results were confirmed by decreased contaminant concentration found by diode coupled chromatography detection. In the final analysis this coupled treatment system completely eliminated amoxicillin and significantly reduced entrained salts.

Hemodialysis is an extracorporeal kidney replacement procedure to remove impurities or waste products from the blood used to treat kidney failure. During this process, large amounts of water are used, which, lacking control, end up in sewage systems, potentially flushing high levels of organic and inorganic contaminants into the receiver’s aqua biota. In recent years, a hybrid electrocoagulation (EC) and electro-oxidation (EO) process in sequential or simultaneous coupling has been used for the treatment of wastewater. This research considered synthetic water from hemodialysis under acid and basic conditions. To better simulate the presence of organic compounds, 10 mg L-1 of amoxicillin (AMX), an antibiotic commonly present in wastewater from clinics and hospitals, was added. Laboratory and pilot tests were performed using coupled EC and EO. They used stainless-steel (SS-304) and aluminum (Al-6061) as sacrificial anodes that were compared in acidic and basic pH during EC. The SS-304 rod anode and a titanium (Ti) mesh cathode were used during EC in acidic conditions at a field strength of 3.0 V, which was applied for 60 min. After EC, the solution obtained was filtered to separate precipitates. The supernatant was then treated with EO using an IrO2-Ta2O5|Ti (70:30) anode and the Ti mesh cathode while applying 10 mA for 120 min. The wear of the SS-304 anode was identified by scanning electron microscopy (SEM) and microanalysis (EDS). Removal of organic compounds, including AMX, was significant. This result was confirmed by decreased concentration found by diode coupled chromatography (UPLC-UV-Vis) detection. In conclusion, combining EC and EO in a sequential arrangement for the treatment of hemodialysis wastewater was carried out. EC was performed using a cylindrical SS-304 bar electrode (f = 0.8 cm) as an anode and a concentric Ti mesh as the counter electrode. A 3.0 V cell potential was maintained over one hour of electrolysis in acidic pH (pH = 5.06, s = 227 mS cm-1). This treatment yielded a removal efficiency of 86 ± 1.25 % of AMX contaminate (pH = 8.21, s = 217.26 mS cm-1, i = 11.36 mA, E = 0.568 kWh m-3). After EC, it was necessary to include a filtration or separation process to remove the Fe(OH)3 and [AMX-cation-AMX] sludge generated (2.3 g). This separation employed a settler. Subsequently, the supernatant was placed in an EO cell to remove residual organic compounds as AMX. It used a similar cell arrangement as in EC but changed the anode to IrO2-Ta2O5|Ti (70:30) (f = 0.5 cm) to perform the EO of the pharmaceutical product. During this step, the team achieved an overall removal efficiency of AMX of 100 % (pH = 8.14, s = 179.83 mS cm-1, E = 500 kWh m-3). EO was performed using a continuous 10 mA cell current for 2 h. EO generated reaction products ADP 1, ADP 2, and ADP 3. Additionally, this process decreased the content of ‘salty’ cations: Na+, K+, Ca2+, and Mg2+, while generating Cl2 gas at the electrode.

The study of ferromagnetism (FM) in semiconductor oxides having non-cubic crystalline structures (e.g. TiO2) is attractive due to their applications in spintronics [1]. FM can be activated in TiO2 nanomaterials by promoting oxygen vacancies (VO) located in paramagnetic defected sites Ti3+VOTi4+. In this context, the VO can induce in Ti3+-doped TiO2 structures remarkable magnetic anisotropy energy (MAE) of 6.51x106 erg/cm3, thus indicating the magnetic saturation (Ms) should be achieved by applying external magnetic fields (MFs) of ~425 gauss [2,3]. Therefore, magnetostriction can be observed in ferromagnetic TiO2 films containing Ti3+VOTi4+ sites as a phenomenon in which their dimensions and shapes are changed when they are magnetized. In this work, black dye-sensitized solar cells (BD-SSC) were prepared using TiO2 nanoparticle films enriched by Ti3+VOTi4+ sites, to gain an understanding of the effects of magnetostriction on the photovoltaic responses of BD-SSC. In this way, photocurrent density-cell potential plots were obtained for the BD-SSC in the absence and presence of MFs having intensities of 125, 250, 500, 1000, and 2000 gauss. MFs lines were parallel applied to the surface of the BD-sensitized TiO2 photoanodes. Our results indicated that the photogenerated electron transport through the dyed TiO2 photoanodes was not limited by electron transfer to I3 - anions at the electrolyte in the absence or the presence of MFs, because all the values for the open-circuit potential (-Eoc ~ 0.553±0.014 V) remain constant. On the contrary, the obtained values for the short-circuit current density Jsc and the global conversion efficiency, revealed that both parameters increased as a function of the MFs intensities, thus indicating that the magnetic lines were responsible for decreasing the degree of disorder (02 film (Jsc is proportional to Q1/ b where Q is the number of trapped electrons) [4,5]. [1] M. Stiller et al., Front. Phys., 11(2023)1124924.; [2] D. Kim et al., J. Phys.: Condens. Matter, 21(2009)195405.; [3] B. Shao et al., J. Appl. Phys., 115(2014)17A915. [4] N. Kopidakis et al., J. Phys. Chem. B, 107(2003)11307. [5] J. van de Lagemaat et al., J. Phys. Chem. B, 104(2000)4292. Acknowledgements The authors thank the National Council for Science and Technology (CONACyT) Mexico for the funding support (grants CB No. 258789 and FOINS No. 3838). JIVN thanks CONACyT for his doctoral fellowship support (grant No. 893260).

Artificial non-caloric sweeteners are non-bioassimilable substances that pass through the human body without biochemical changes. Sucralose, for instance, is 600 times sweeter than natural sucrose, so it is widely used in beverages and processed food products without regulation in many countries. Its environmental persistence of 337 days in sludge allows inferring that these substances can adversely affect the environment in the short or long term, thus classifying sucralose as an emergent pollutant. In this work, stainless steel (SS) mesh working electrodes were modified by TiO2- or C|TiO2-based nanoparticulate films (where C is carbon Vulcan). Both types of electrodes were employed as cathodes for the electro-generation of hydrogen peroxide (H2O2), which was the chemical precursor for photochemical producing •OH radicals able for sucralose degradation in a photo-Fenton system equipped with a 254 nm light source. Preparation of TiO2- and C|TiO2-based cathodes was performed by electrophoretic deposition method (EPD, 2 V/cm for 40 s) on AISI 304 SS mesh, followed by sintering at 450°C for 1h in the air. The EPD process was performed using aqueous colloidal suspensions containing wt./wt. ratios of C/TiO2 = 1/100 and 1/10, or TiO2 without C for comparison purposes. H2O2 electro-generation was carried out via Reaction 1 utilizing a two-electrode cell (3V-cell polarization) containing sucralose dissolved in a pH 2 aqueous sulfates buffer solution perpetually bubbled by air (volumetric flow rate of 17 mL/s) containing gaseous O2. In all the cases, a Ti grade 2.0 rod anode was immersed in the electrolyte medium with one of the following cathodes: SS* (polished, degreased, and heated at 450°C for 1h in the air as control electrode), SS||TiO2 and SS||C|TiO2 (wt./wt. ratios of C/TiO2 = 1/100 or 1/10). Furthermore, the cell was illuminated by a 254 nm lamp in order to continuous promotion of the photo-chemical Reaction 2. O2 + 2H+ + 2e- → H2O2 ...............(1) H2O2 254mn→ 2°OH...................... (2) Sucralose degradation efficiencies were registered based on the cathodes employed for continuous H2O2 electro-generation. Furthermore, the relative use time was also registered for each cathode. A comparison of these results reveals that when employed SS*, SS||TiO2, and SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/100) cathodes the sucralose degradation achieved efficiencies over 90% (i.e. 99.1, 96.8, and 91.3%, respectively). In contrast, SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/10) cathodes showed a sucralose degradation efficiency of only 88.6%. Furthermore, the SS||TiO2 and SS||C|TiO2 cathodes showed durability 3 times higher than for the SS* cathodes, and 1.8 times higher than for SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/10). These observations indicated that both, SS||TiO2 and SS||C|TiO2 cathodes are strong candidates for assembling more efficient photo-Fenton systems for the degradation of sucralose and other artificial sweeteners.

Geoelectric surveying is a useful method of non-invasive investigation (e.g.: for the purpose of space delineation or time dependant monitoring) of subsurface contaminants. The measured onsite electrical resistivity values are a function of certain soil parameters and the electric properties of the contaminant. With executing time domain field surveys before and after the remediation process its efficiency on contamination removal can be valorized. In this study we present a field case to illustrate the applicability of the geoelectric method for monitoring the efficiency of hydrocarbon removal and highlighting the problems of interpretation due to change of soil parameters and various hydrocarbon composition. Due to the side effects of electro-kinetic soil remediation process some soil parameters affecting the electrical resistivity are also changed. Therefore, when interpreting the data the of field survey one must be able to separate the geoelectric response of the remnant contamination from the changed soil parameters. The paper presents a multilevel interpretation method when the measured electrical resistivity data were correlated with the time-domain results of detailed soil sample analytics including particle size distribution, physical properties, and chemical composition. As a result we were able to separate the time domain geoelectric effects of the soil from the geoelectric response of the hydrocarbon contamination and we could correlate the electrical resistivity anomalies with the integrated effects of hydrocarbon content and changes in the soil due to the remediation treatment.

Toluene is a solvent widely used to produce paints, thinners, varnishes, and adhesives, as well as an octane rating improvement additive in gasoline. This compound can, unfortunately, be released into the environment in car exhaust fumes or when products containing toluene are used. Continuous exposure at high levels can cause permanent brain damage in animals. TiO2 nanotubes (TiO2,nt) increase the surface/volume ratio, as well as efficient electron transport, in the metallic substrate of Ti, enhancing the electrochemical degradation of organic compounds such as toluene. An anodizing procedure has been performed to synthesize TiO2 in the present work. The team varied two anodizing operating conditions: potential (10, 20, 30, 40, and 50 V) and cathode material (titanium, Ti, and stainless-steel, SS) to achieve desirable results. The synthesized electrodes were characterized by Raman spectroscopy to identify the different crystallographic phases. We identified the presence of the three typical phases of TiO2 (anatase, rutile, and brookite), mainly in the synthesized electrodes at 30 V (using Ti and SS as the cathode). More significant intensity signals were observed than those corresponding to the anatase and rutile phases. Additionally, the different electrodes were analyzed by scanning electron microscopy with microanalysis (SEM-EDX) to identify the external morphology and validate their chemical composition. The toluene was hydrolyzed in ethanol with the different synthesized electrodes (Ci = 1.0 ppm, E = 2.0 V, t = 180 min, n = 150 rpm, cathode = Ti or SS). Toluene removal was monitored by gas chromatography with detector BID (CG-BID). Results indicate that the electrodes synthesized at 30 V show the highest removal efficiencies in a minimal time. The TiO2,nt|Ti synthesized using the TiO2,nt|Ti ||Ti configuration showed a toluene removal of 94.53 % in 12 min. In contrast, for the TiO2,nt|Ti synthesized using the TiO2,nt|Ti||SS configuration showed a 100 % toluene removal achieved in 6 min. In conclusion, the best result for synthesizing the TiO2,nt|Ti reactive nanotube-rich surface was the configuration using stainless steel as the cathode (TiO2,nt|Ti||SS), applying a potential of 30 V during the 15 min anodizing treatment. This modified surface showed the highest toluene removal efficiency, 100 %, at 6 min when this VOC was dissolved in ethanol with 0.1 M KCl as the supporting electrolyte. This result is due to the anatase and rutile phases of TiO2, as verified with Raman spectroscopy. The corresponding stoichiometric relationship of two atoms of oxygen and one atom of titanium in the TiO2 nano-tubes when analyzed using SEM-EDX. After the electrolysis of toluene, the anatase phase was lost.