Sustainable Photovoltaic-Powered Series Electrochemical Reactors Using Nonactive Electrocatalytic Materials for Electro-Refinery in Organics and Energy Production.

The applicability of an electrochemical device with a series design and configuration, powered by photovoltaic panels, was tested as an integrated-hybrid approach for energy-efficient electrochemical green H production coupled with dye effluent upgrading. This electrochemical strategy investigated the electroconversion efficiencies of a model organic compound into carboxylic acids by applying 15, 30, and 45 mA cm, with simultaneous production of green H. Fluorine-doped lead oxide (PbO-F) and boron-doped diamond (BDD) electrodes were used as anodes in a three-compartment flow reactor, in series mode with different anodic order: setting 1 (PbO-F + BDD) and setting 2 (BDD + PbO-F).

Towards decentralized and sustainable water and wastewater treatment systems.

Achieving "sustainable management of water and sanitation for all" is a fundamental part of the Sustainable Development Goals (SDGs). Rising rates of urbanization and industrialization necessitate continual technological advancements to address existing and emerging water pollution issues related to centralized populations and industrial wastes. The articles in the Collection “Water and Wastewater Treatment Technologies” showcase salient aspects of advances in measurement and monitoring, as well as recommendations for sustainable use and management of water resources.

Reuse of sludge from photo-Fenton process and further application as a catalyst in electrochemical processes for the treatment of landfill leachate.

To evaluate the potential of sludge from solar photo-Fenton to be transformed into a catalyst for the heterogeneous electro-Fenton (EF) process, some parameters were investigated, including (i) the impact of heat treatment on catalytic activity through structural and compositional analysis of the iron species (100, 600 and 750 °C); (ii) analysis of the effect of pH and current density (j) on the decolorization and decarbonization efficiency; and (iii) the generation of high-value organic acids. The calcination of sludge to 600 and 750 °C presents changes in the multiferroic structures but does not enhance its catalytic activity, given the similarity of the treatment results of landfill leachate with the catalyst with and without calcination. The treatment of leachate via heterogeneous EF using sludge dried at 100 °C and under pH 3 achieves better results than the treatment without pH adjustment.

Electrochemical Determination of Dipyrone Using a Cold-Plasma-Treated Graphite Sheet Electrode.

The development of fast, reliable, and cost-effective techniques for pharmaceutical compound analysis is an issue of paramount importance to the pharmaceutical industry, environmental sciences, and many other applications. In this work, a low-cost graphite sheet electrode (GSE) was used as a disposable working electrode. To this purpose, the GSE surface was subjected to a cold plasma discharge using a mixture of argon and O.

Proof of Concept for the Organic Electrorefinery Technology with Actual Effluents.

This work describes results of a first proof of the concept of electrorefinery with a real waste obtained from a cashew nut factory, and it shows the effect of the current densities of both the anodic oxidation and electrochemically assisted separation processes on the performance of the system. Results obtained demonstrate that electrorefinery is a promising option to minimize the carbon fingerprint, worth studying for increasing the sustainability of the environmental remediation of wastes, because valuable species can be obtained from the destruction of pollutants and recovered within the same integrated process. They also point out that there is still a long way to reach an optimum solution for this technology, but it is worth the effort to be made.

Challenges and opportunities for large-scale applications of the electro-Fenton process.

As an electrochemical advanced oxidation process, the electro-Fenton (EF) process has gained significant importance in the treatment of wastewater and persistent organic pollutants in recent years. As recently reported in a bibliometric analysis, the number of scientific publications on EF have increased exponentially since 2002, reaching nearly 500 articles published in 2022 (Deng et al., 2022).

Diesel removal in non-aqueous phase by fibres from : kinetic, isothermal and sorption potential evaluation.

fibres have been proposed for free-phase diesel removal in case of spillage into groundwater. For this, characterizations were carried out using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FEG-SEM), wettability and contact angle measurements. Sorption oil capacity, kinetic, isothermal and recycling behaviour were evaluated.

Photocatalyzed hydrodecarboxylation of fatty acids: a prospective method to produce drop-in biofuels.

A direct and practical method for photocatalyzed hydrodecarboxylation of fatty acids is reported herein. The catalytic system consists of a commercially available acridinium salt as the photocatalyst and thiophenol as the Hydrogen Atom Transfer (HAT) co-catalyst. Results evidenced that C alkanes were obtained in yields up to 77%.

A sustainable solar-driven electrochemical process for reforming lignocellulosic biomass effluent into high value-added products: green hydrogen, carboxylic and vanillic acids.

There is a growing concern with waste minimization and the promotion of the circular economy. Within this framework, using membrane-equipped electrochemical systems, the electrochemical oxidation (EO) of organic compounds and simultaneous hydrogen (H) production can considerably improve the sustainability and economic viability of this process. Here, we propose an innovative-integrate electrochemical treatment strategy to maximize the economic benefits and sustainability of selectively producing organic acids and energy-saving H production from biomass platform compounds.

Sulphate-based electrochemical processes as an alternative for the remediation of a beauty salon effluent.

Beauty salons (BS) are places that deal with a wide range of cosmetics with potentially hazardous chemicals, and their effluent should be properly treated before going to the sewage system, once it represents characteristics of industrial wastewater. This work provides an extensive characterization of a BS effluent and its respective electrochemical treatment by comparing NaCl, NaSO, and NaSO as supporting electrolytes with a boron-doped diamond (BDD) as anode, applying 10 or 30 mA cm of current density (j). The inclusion of UVC irradiation was also performed but the improvements achieved in removing the organic matter were null or lower.

Ketorolac removal through photoelectrocatalysis using TiO nanotubes in water system.

Ketorolac, a highly persistent NSAID of environmental concern, was significantly removed from water (80% removal) through photoelectrocatalysis where titanium dioxide nanotubes prepared by Ti foil electrochemical anodization at 30 V were used as photoanodes. Fifteen milligrams per liter of ketorolac solutions in a 0.05 M NaSO aqueous medium was subjected to irradiation from a 365-nm light with an intensity of 1 mWcm and under an applied potential of 1.

Innovative and efficient electroanalytical approach for determining persulfate in aqueous solutions using a gold electrode.

Persulfate (PDS), peroxodisulfate, peroxydisulfate, peroxodisulfuric acid, is an oxidant that can be generated by direct oxidation of sulfate ions or indirectly via reaction with hydroxyl radicals in anodes with high oxygen overpotential. Quantitative methods for determining/quantifying PDS in the presence of other strong oxidants or other anions in eco-friendly applications do not give reliable results because of these interferents. Therefore, an additional method is needed to improve the efficacy to determine/quantify the PDS concentration in oxidative environments.

Development of recycled and miniaturized electroanalytical sensor: Probing isoniazid determination in environmental water matrices.

Surface water pollution has become relevant because growing population and intense industrial activities. Thus, to protect the environment from contamination, recently the electroanalytical sensors that require small sample volume and easy preparation have shown a prominent performance for pharmaceuticals monitoring. For this purpose, a miniaturized electrochemical platform was developed based on recycling obsolete computer integrated circuits (microchips), fitting with the ideals of green chemistry and circular economy.

Photocatalytic Hydrodecarboxylation of Fatty Acids for Drop-in Biofuels Production.

A mild, practical, and environmentally friendly method for the hydrodecarboxylation of fatty acids using an acridine-based photoredox catalyst and thiophenol was developed. C alkanes were synthesized in good to excellent yields (up to 99 %) from C10-C18 saturated fatty acids under visible light irradiation (405 nm). The developed protocol was employed for a mixture of fatty acids obtained from the hydrolysis of Licuri oil, affording a mixture of C9-C17 hydrocarbons in quantitative yield, which demonstrates the potential application of the method to produce drop-in biofuels.

Cost-effective smartphone-based method for low range chemical oxygen demand analysis.

Aiming the decentralization of monitoring policies and to facilitate the work of researchers, mainly in developing countries, the present method deals with the explanation of a simple and rapid protocol for chemical oxygen demand (COD) analysis through the use of digital smartphone devices coupled with a camera and a free app available for Android operating system that recognizes HSV (hue, saturation, value). The calibration of the method is done based on the theoretical values of potassium hydrogen phthalate for a proper and reliable build of the calibration curve by using the smartphone-based technique and the digested samples of COD. The coefficient of determination (R) attained a value upper than 0.

Decentralized environmental applications of a smartphone-based method for chemical oxygen demand and color analysis.

This study is focused on a proposal of a smartphone imaging-based quantification for providing a simple and rapid method for the analysis of chemical oxygen demand (COD) and color throughout the use of the HSV and/or RGB model in digital devices. For COD, calibration curves were done based on the theoretical values of potassium biphthalate for a proper comparison between the spectrophotometer and the smartphone techniques. The smartphone camera and application attain an average accuracy higher than the analysis in the spectrophotometer (98.

Evaluating the catalytic effect of Fe@FeO-modified granulated cork as an innovative heterogeneous catalyst in electro-fenton degradation of benzoquinone in different aqueous matrices.

This study investigated the potential of a novel biomass-derived cork as a suitable catalyst after its modification with Fe@FeO for in-situ application in heterogeneous electro-Fenton (HEF) process for benzoquinone (BQ) elimination from water. No attempts on the application of modified granulated cork (GC) as a suspended heterogeneous catalyst in the HEF process for water treatment have been published yet. GC was modified by sonification approach in a FeCl + NaBH solution to reduce the ferric ions to metallic iron in order to obtain Fe@FeO-modified GC (Fe@FeO/GC).

Mesostructured lead dioxide grown on titania nanotubes for diclofenac water removal through electrocatalytic and photoelectrocatalytic processes.

Mesostructured PbO/TiO materials were synthesized to perform electrocatalysis (as electrooxidation, EO) and photoelectrocatalysis for removing diclofenac (DCF), 15 ppm concentration in 0.1 M NaSO solutions, at different pH conditions (3.0, 6.

Probing the Use of Homemade Carbon Fiber Microsensor for Quantifying Caffeine in Soft Beverages.

In the development of electrochemical sensors, carbon micro-structured or micro-materials have been widely used as supports/modifiers to improve the performance of bare electrodes. In the case of carbon fibers (CFs), these carbonaceous materials have received extensive attention and their use has been proposed in a variety of fields. However, to the best of our knowledge, no attempts for electroanalytical determination of caffeine with CF microelectrode (µE) have been reported in the literature.

Photovoltaic Electrochemically Driven Degradation of Calcon Dye with Simultaneous Green Hydrogen Production.

In this study, for the first time, the production of green hydrogen gas (H) in the cathodic compartment, in concomitance with the electrochemical oxidation (EO) of an aqueous solution containing Calcon dye at the anodic compartment, was studied in a PEM-type electrochemical cell driven by a photovoltaic (PV) energy source. EO of Calcon was carried out on a Nb/BDD anode at different current densities (7.5, 15 and 30 mA cm), while a stainless steel (SS) cathode was used for green H production.

Reclamation of forward osmosis reject water containing hexavalent chromium via coupled electrochemical-physical processes.

Forward osmosis is a water separation process that uses the natural energy of osmotic pressure to separate water from dissolved solutes through a semipermeable membrane. One of the major challenges using this process is the rejection water which contains high content of pollutants, hindering its practical application. Herein, for the first time, this work introduces a coupled electrochemical-physical process including iron-electrocoagulation/filtration/sedimentation as a cost-effective treatment to the forward osmosis reject water containing hexavalent chromium to be reclaimed.

Environmental application of a cost-effective smartphone-based method for COD analysis: Applicability in the electrochemical treatment of real wastewater.

This study aims to develop a cheap method for the evaluation of quality of water or the assessment of the treatment of water by chemical oxygen demand (COD) measurements throughout the use of the HSV color model in digital devices. A free application installed on a smartphone was used for analyzing the images in which the colors were acquired before to be quantified. The proposed method was also validated by the standard and spectrophotometric methods, demonstrating that no significant statistical differences were attained (average accuracy of 97 %).

Application of electro-Fenton and photoelectro-Fenton processes for the degradation of contaminants in landfill leachate.

Worldwide, most solid waste ends its life in landfill sites, which have a significant environmental impact in several respects. In particular, rainfall over landfill sites results in the production of an aqueous leachate containing compounds having low biodegradability, high toxicity, and a high organic load. For this reason, this study aims to investigate the applicability of electro-Fenton (EF) and photoelectro-Fenton (PEF) processes as alternative for treating a local landfill effluent with high organic content (chemical oxygen demand (COD) = 2684.

An Electroanalytical Solution for the Determination of Pb in Progressive Hair Dyes Using the Cork-Graphite Sensor.

Lead is one of the most toxic metals for living organisms: once absorbed by soft tissues, it is capable of triggering various pathologies, subsequently bioaccumulating in the bones. In consideration of this, its detection and quantification in products for human consumption and use is of great interest, especially if the procedure can be carried out in an easy, reproducible and economical way. This work presents the results of the electroanalytical determination of lead in three different commercial products used as progressive hair dyes.