The electro-Fenton (EF) process using iron-alginate (Fe/Alg) beads as a heterogeneous catalyst was applied to the degradation of sulfamethazine (SMT) in aqueous solution. Experiments conducted in a batch reactor at pH 3, using a carbon felt cathode and a platinum anode showed that the applied current and air flow rate significantly influenced the process. Under optimal conditions (100 mA, 0.2 L min- 1, [SMT]0 = 50 mg L-1) nearly complete SMT removal was achieved within 60 min, following pseudo-first-order kinetics (k = 0.019 min- 1) with an energy consumption of 1.6 kW h m-3. Catalyst characterization by SEM, XRD, and TGA confirmed the successful incorporation of Fe3+ ions into the alginate matrix through ionic crosslinking, resulting in enhanced structural and thermal stability. Dissolved organic carbon (DOC) monitoring revealed a continuous increase during electrolysis, reaching 95.2 mg L- 1 after 360 min for an initial SMT concentration of 50 mg L- 1 which was mainly attributed to the progressive degradation of the alginate matrix. Biodegradability assessment showed an increase in the BOD5/COD ratio from 0.014 to 0.35, indicating a partial improvement in effluent biodegradability after EF treatment. Recyclability tests demonstrated that Fe/Alg beads retained high catalytic activity over six consecutive EF cycles, achieving complete SMT removal within 60 min in each cycle. However, total iron leaching increased progressively from 0.25 mg L- 1 in the first cycle to 8.55 mg L- 1 in the sixth cycle, revealing a gradual shift from heterogeneous to homogeneous EF pathways. Overall, the results highlight that while Fe/Alg beads provide efficient and energy-effective SMT degradation, catalyst matrix stability and iron leaching remain critical factors influencing long-term process performance.

Membrane processes, including nanofiltration and reverse osmosis, are essential in water reuse due to their ability to deliver consistently high-quality treated water. However, these processes generate membrane concentrates (MC), highly pollutant-laden waste streams that present significant treatment and disposal challenges. Conventional treatment methods, while effective, often face limitations such as high operational costs, environmental risks, and inefficiencies in handling complex effluents. Anodic oxidation (AO), an advanced oxidation process, offers a promising solution for MC management. By generating reactive species, AO can efficiently degrade refractory organic pollutants, thereby improving the overall treatment effectiveness. This approach aligns with process intensification principles by enhancing energy efficiency and reducing waste discharge, as it enables the treatment and potential reuse of a stream previously considered a residual by-product from the membrane process. Therefore, this review highlights the potential of AO in enhancing water recovery and addressing sustainability challenges in MC management. Key considerations for optimizing AO performance, including operating conditions and effluent-specific parameters, are discussed to support its broader application in MC treatment and resource recovery.

Per- and polyfluoroalkyl substances (PFAS) represent an extensive class of synthetic compounds known for their persistence due to extremely stable carbon-fluorine bond, widely detected in aquifers worldwide (e.g.: PFOA 5650.2 ng/L and PFOS 203.3 ng/L, on average). Most of these compounds pose significant acute or chronic health risks. Besides this, the literature suggests that contamination by at least one PFAS is expected in all locations. Furthermore, PFAS plumes tend to be larger than those associated with hydrocarbons and volatile chlorinated organic compounds, and their remediation poses greater challenges due to limited understanding of their behavior, transformations, and remediation mechanism. Given the extent of the occurrence of these chemicals and their adverse effects, the need to develop detection and measurement techniques, in addition to remediation technologies, is evident. This review systematically examines literature published between 2014 and 2025, on Web of Science, Scopus, and Google Scholar databases, to address these limitations. It discusses the extent of PFAS contamination, their ecological effects, and the key mechanisms influencing their mobility and retention in subsurface environments. It also critically evaluates the latest advances in analytical techniques for PFAS detection and highlights emerging strategies for effective remediation in-situ, providing a base for further research and development.

At a quarry site, the extraction of construction materials leads to heavy metal pollution in the water. A year-long study of quarry water quality located in Brittany region allowed to develop a synthetic quarry water with the characteristics: pH = 3.5 and σ = 2.0 mS cm^-1, [Al^3+] = 34 mg L^-1; [Fe^2+] = 9.4 mg L^-1; [Mn^2+] =6.0 mg L^-1 . To treat this contaminated water, an investigation of the electrocoagulation process has been made using different electrode materials (Al or Fe), at different current densities (1.3 to 13 mA cm^-1 for Al and 1.2 to 12 mA cm^-1 for Fe ) and for different electrode arrangements (monopolar or bipolar). With aluminum electrodes in monopolar configuration at 13 mA cm^-2 , removal yields of 99.9, 91.5, and 85.0 Al^3+ , Fe^2+ , and Mn^2+ , respectively. Although aluminum electrodes demonstrated similar treatment results in both monopolar and bipolar arrangements, the bipolar required more energy and electrode dissolution to remove the same amount of pollutants. For example, power consumption for Mn^2+ removal on Al electrode varied from 20.5 to 759 kWh g_Mn^2+^-1 and from 59.3 to 2597 kWh g_Mn^2+^-1 , respectively, for monopolar and bipolar arrangement. Conductivity varied in solution during electrolysis with the bipolar arrangement ( σ = 2 to 8 mS cm^-1 ). It indicated that sacrificial electrode dissolution is localized within a specific region of the reactor rather than being uniformly distributed. This study showed that aluminum electrodes outperformed iron electrodes for quarry water treatment. While monopolar and bipolar configurations achieved similar treatment outcomes, the bipolar configuration proved to be significantly more costly. In addition, the conductivity of the solution during electrolysis in a bipolar configuration can affect the dissolution of the electrode.

This article explores the benefits of electrochemical oxidation in pulsed mode, using potential, current, and power pulses. While potential and current pulse electrochemical technology has been previously studied for wastewater treatment, no study has included power pulses until now. The objective of this work is to highlight the advantages of power pulses by applying this pulse type to the electrochemical oxidation of a probe molecule, alachlor. For this aim, the influence of operating parameters and the comparison of the different pulse modes were investigated and compared to the results obtained with the electrochemical oxidation of alachlor in continuous mode. The study shows that the best results were obtained with the power pulse electrochemical oxidation with 100% alachlor degradation after 180 min and a mineralisation yield of 38.3% after 240 min. These results were better than those reported in the literature for treatments with continuous current input using platinum electrodes. This new technique could be an effective and efficient way to treat contaminated water and reduce the pressure on freshwater reserves.

At a quarry site, the extraction of construction materials leads to heavy metal pollution in the water. A year-long study of quarry water quality located in Brittany region allowed to develop a synthetic quarry water with the characteristics: pH = 3.5 and sigma = 2.0 mS cm(-1), [Al3+] = 34 mg L-1;[Fe2+] = 9.4 mg L-1;[Mn2+] = 6.0 mg L-1. To treat this contaminated water, an investigation of the electrocoagulation process has been made using different electrode materials (Al or Fe), at different current densities (1.3 to 13 mA cm(-1) for Al and 1.2 to 12 mA cm(-1) for Fe) and for different electrode arrangements (monopolar or bipolar). With aluminum electrodes in monopolar configuration at 13 mA cm(-2), removal yields of 99.9, 91.5, and 85.0% were obtained for Al3+, Fe2+, and Mn2+, respectively. Although aluminum electrodes demonstrated similar treatment results in both monopolar and bipolar arrangements, the bipolar required more energy and electrode dissolution to remove the same amount of pollutants. For example, power consumption for Mn2+ removal on Al electrode varied from 20.5 to 759 kWh g(Mn2+)(-1) and from 59.3 to 2597 kWh g(Mn2+)(-1), respectively, for monopolar and bipolar arrangement. Conductivity varied in solution during electrolysis with the bipolar arrangement (sigma = 2 to8 mS cm(-1)). It indicated that sacrificial electrode dissolution is localized within a specific region of the reactor rather than being uniformly distributed. This study showed that aluminum electrodes outperformed iron electrodes for quarry water treatment. While monopolar and bipolar configurations achieved similar treatment outcomes, the bipolar configuration proved to be significantly more costly. In addition, the conductivity of the solution during electrolysis in a bipolar configuration can affect the dissolution of the electrode. [GRAPHICS] .

This prospective study assessed a hybrid process that combines ozonation with anodic oxidation (AO/O3) with two boron-doped diamond (BDD) electrodes to treat a model aqueous solution containing 30 ppm of alachlor at pH 5 in a phosphate buffer. An innovative monophasic configuration, operated batch-wise, in which an ozone-stock solution was injected at t0 in the electrochemical reactor, was proposed in order to avoid introduction of ozone-enriched gas bubbles. The alachlor parent molecule was almost entirely degraded within around 150 min of reaction time by anodic oxidation alone, whatever the applied current intensity (200, 500 and 800 mA). The mineralization efficiency varied from 50% at 200 mA to 80% at 800 mA after 120 min. The results emphasized that the anodic oxidation was a diffusion-controlled process. Addition of ozone at a low ozone dose of 1.9-2.3 mol of ozone per mol of alachlor allowed to decrease the ozone half-life time 2.7 times with the hybrid process compared to ozonation alone. This faster ozone consumption was concomitant with an enhanced alachlor degradation rate, with a corresponding half-life time around two-times lower. However, owing to the low ozone dose applied and the short ozone lifetime in solution (around 25-30 min), similar mineralization efficiencies were noticed for both AO/O3 and AO processes. Thus, the application of pulse ozone-stock solution re-injections every 20 min to prolong the ozone exposure was assessed to overcome this limitation. However, the effect on the mineralization rate remained small, even if it allows to enhance even more the alachlor parent molecule degradation rate. The low influence of the hybrid process on the mineralization rate was attributed to the production of aliphatic fatty acids by-products that are poorly reactive with hydroxyl radicals, and whose the degradation by AO is the rate limiting step.

Food coloring has become one of the main sources of water pollution. Brilliant blue (BB) is one of the dyes used in the food industry. Heterogeneous photocatalysis is increasingly used to decontaminate polluted water from food industries. The objective of this paper was to treat this pollution using a photoreactor at the laboratory (batch) and pilot scales. The photodegradation of the brilliant blue dye, chosen as a model of pollutant, was performed at room temperature in an aqueous solution of titanium dioxide supported on cellulosic paper in the presence of an external UV lamp. The surface morphology of this photoactive tissue was characterized by SEM and FTIR. The performances of two geometric configurations were examined (batch reactor and annular recirculation reactor) in accordance with degradation and pollutant mineralization. The performance of the photocatalytic system was optimized by a parametric study to improve the impact of the different parameters on the efficiency of the degradation process, namely the initial concentration of the pollutant, the TiO2 cycle, the pH of the solution with the recirculating reactor, and the flow rate. The results showed 98% degradation of brilliant blue at the laboratory scale and 93.3% and 75% at the pilot flow rates of 800 and 200 L·h−1, respectively. The supported semiconductor showed good photodegradation ability during BB decomposition, showing that photocatalysis is a promising technique for water purification.

Iodinated X-ray contrast media (ICM) as emerging micropollutants have attracted considerable attention in recent years due to their high detected concentration in water systems. It results in environmental issues partly due to the formation of toxic by-products during the disinfection process in water treatment. Consequently, various approaches have been investigated by researchers in order to achieve ICM total mineralization. This review discusses the different methods that have been used to degrade them, with special attention to the mineralization yield and to the nature of formed by-products. The problem of pollution by ICM is discussed in the first part dedicated to the presence of ICM in the environment and its consequences. In the second part, the processes for ICM treatment including biological treatment, advanced oxidation/reductive processes, and coupled processes are reviewed in detail. The main results and mechanisms involved in each approach are described, and by-products identified during the different treatments are listed. Moreover, based on their efficiency and their cost-effectiveness, the prospects and process developments of ICM treatment are discussed.

The objective of this study was to develop a carbon felt impregnated with iron (III) sulfate (CF-Fe) for its use both as a cathode and reusable heterogeneous catalyst source in the Fenton reaction for the elimination of sulfamethazine (SMT). The CF-Fe cathode was characterized with Scanning electron microscopy-energy dispersive spectrometric (SEM–EDS) and X-ray diffraction (XRD). The results of morphology characterization with SEM–EDS revealed that the raw CF displayed a rod-like morphology with a clean and smooth surface. After the impregnation of CF with iron (III) sulfate, the surface of CF-Fe became rough and porous while retaining the raw CF structure well. Furthermore, some solid particles were clearly observed on the FC-Fe, suggesting that the iron species were loaded onto the CF–Fe surface, which contained 57.20

In this study, different oxidation processes UVA-365 nm (photolysis), UV–A/H 2 O 2 , UV–A/H 2 O 2 /Fe 2+ , UV–A/S 2 O 8 , and UV–A/S 2 O 8 /Fe 2+ were investigated to compare removal rates efficiencies of Oxytetracycline (OTC). The role of the initial concentration of oxidants, as well as their inhibitory threshold regarding degradation and mineralization of OTC, was investigated at different pH. It was found that the initial pH solution had an important role in the photolysis of OTC, since in alkaline solutions, the degradation rate was faster than in acidic solutions, but in terms of mineralization yield, it did not exceed 3%. The addition of oxidants (H 2 O 2 , S 2 O 8 ) had an impact on the mineralization, which reached 50% for the UV/S 2 O 8 system. To improve mineralization, ferrous ions were added to UVA/oxidants, leading to 85% mineralization. Quantification of the main radicals involved in the oxidation process can help in the understanding of the free radical mechanism and their respective contributions to the degradation of OTC. The ability of Dimethylsulfoxide (DMSO) to act as a free radical scavenger was considered in UV/H 2 O 2 and UV/H 2 O 2 /Fe 2+ systems. The hydroxyl radicals can react directly with DMSO to produce a stable intermediate, methanesulfonate. Otherwise, isopropanol, tert-butanol and 1,4, benzoquinone were used as indirect methods to catch and to quantify the main radicals generated during UV/S 2 O 8 and UV/S 2 O 8 /Fe 2+ processes. Finally, the results allowed to quantify the contributions of each radical involved in photo-oxidation for both systems, UV/H 2 O 2 and UV/ S 2 O 8 .

As it is well known that wastewater treatment is becoming a global concern, the search for advanced intensive oxidation processes with minimal waste generation for wastewater treatment remains a major challenge. In the present work, the photodegradation of Ciprofloxacin (CIP) was studied using the Dielectric-Barrier-Discharge (DBD) process. The effect of some operating parameters such as CIP initial concentration (from 1 to 6 mg/L), air flow rate (from 0 to 240 L/h) and frequency (from 350 to 600 Hz) on DBD performance in term of CIP degradation efficiency (%D) has been investigated. Here, as a major result, the CIP degradation efficiency and the mineralization yield (%M) reached >99 % and >49 %, respectively, during 60 min, under the obtained optimum experimental conditions (an initial concentration of 1 mg/L, an air flow rate of 100 L/h, a voltage of 18 kV, and a frequency of 350 Hz). It can be concluded that the DBD process exhibits an eco-friendly and great potential for aqueous CIP degradation. Moreover, the mechanisms involved in the degradation process by DBD were explained. The scavengers study revealed that degrees OH, HO2 degrees and O-2(-)degrees radicals were the basic reactive oxygen species (ROS) in CIP degradation process. Results show that in addition to ROS, the reactive nitrogen species (RNS) also play a key role in the CIP removal process. In order to get closer to the real conditions, DBD experiments were also carried out in other water matrices, tap water (TW) and synthetic pharmaceutical water (SW). Significant inhibition of CIP degradation (%D) and mineralization (%M) was observed in TW (%D = 76, %M = 33) and SW (%D = 60, %M = 10) with reference to the CIP degradation and mineralization in ultra-pure water (UPW) (%D >= 99, %M = 54), after 90 min irradiation. It showed that the presence of organic and inorganic molecules in TW and SW lowered the CIP degradation efficiency. Thus, the combined plasma-photocatalysis system, using luminous textile as photocatalyst, was performed for the CIP degradation in SW, in order to get closer to the real conditions, leading to >99 of %D and 64 of %M. Moreover, the use of combined DBD plasma-photocatalysis process significantly enhanced the CIP degradation performance if compared to each process considered separately. Overall, the combination of DBD and photocatalysis may be a promising technology for economical, efficient and environmentally friendly removal of pollutants in wastewater.

Owing to their high consumption for X-ray diagnose and to their rapid excretion from organism, iodinated Xray contrast media (ICM) are often found in source waters. It is a serious public health concern due to their potential to generate highly toxic disinfection by-products. Reductive deiodination of ICM is considered as a promising approach to degrade them and allows the possible recovery of iodide ions. Electrocatalytic reduction of iohexol, an ionic ICM, was performed in the presence of vitamin B12 as catalyst. Vitamin B12 was chosen owing to its catalytic activity toward dehalogenation processes and to its positive effect on biodegradation of pollutants. The conditions for electrocatalysis were optimized to favor the electrocatalytic process over the direct reduction, leading to the enhancement of the reaction kinetic and the current efficiency. A total deiodination of iohexol was achieved after 1 h of electrolysis. A biological treatment with activated sludge underlined a low decrease of the dissolved organic carbon even after electroreduction. However, the concentration of iohexol decreased and a significant biotransformation of iohexol occurred, slightly improved by the presence of vitamin B12. The identification of the main by-products after the biotransformation of iohexol highlighted the oxidation of the primary and secondary alcohols of the alkyl chains.

A 3D porous Ag-Bi electrode was developed to achieve the highly selective reduction of CO2 into formate. Ag particles were deposited on Bi coated graphite felt by galvanic displacement reaction. The selectivity of the reduction was enhanced with the Ag-Bi electrode compared with Bi coated graphite felt. The bimetallic catalytic system converted CO2 into formate with a high selectivity of 88% at -1.6 V-SCE. The highly porous structure and large surface area of the electrode facilitated the mass transport, leading to a high surface current density of 76 mA cm(-2) and a production rate of 8.1 +/- 0.4 mmol cm(-3) h(-1) (62 +/- 3 mg cm(-2) h(-1)). These results are very promising in the context of the electrochemical conversion of CO2. (C) 2021 Elsevier Ltd. All rights reserved.

Advanced oxidation processes are considered as a promising technology for the removal of persistent organic pollutants from industrial wastewaters. In particular, the heterogeneous electro-Fenton (HEF) process has several advantages such as allowing the working pH to be circumneutral or alkaline, recovering and reusing the catalyst and avoiding the release of iron in the environment as a secondary pollutant. Among different iron-containing catalysts, studies using clay-modified electrodes in HEF process are the focus in this review. Fe(III)/Fe(II) within the lattice of clay minerals can possibly serve as catalytic sites in HEF process. The description of the preparation and application of clay-modified electrodes in the degradation of model pollutants in HEF process is detailed in the review. The absence of mediators responsible for transferring electrons to structural Fe(III) and regenerating catalytic Fe(II) was considered as a milestone in the field. A comprehensive review of studies investigating the use of electron transfer mediators as well as the mechanism behind electron transfer from and to the clay mineral structure was assembled in order to uncover other milestones to be addressed in this study area.

Platform molecules were defined by the US Department of Energy, as bio-based or bio-derived chemicals whose constituting elements totally originated from biomass and could be used as building blocks for the production of commodity and refined chemicals. These chemicals can subsequently be converted into a number of high-value bio-based chemicals or materials. Today, there is a growing urge for the discovering of a cheaper and cleaner way for the environment to produce platform molecules from renewable substrate such as carbon. Succinic acid (SA) is considered as a key platform chemical since it is used as a precursor for other valuable chemicals and has aroused interest worldwide with its wide applications. This review aims at highlighting the currently available information about the mechanisms involved in the production of platform molecules, especially the SA production. In this review, the processing technologies used in the production of platform molecules are described, in addition to the information regarding the optimization of key parameters, the mechanisms of genetic engineering and finally the redox potential and purification processes which are known as alternative cost-competitive providers of fossil fuels .

When possible, the bioprocesses should be implemented to treat wastewater for their cost-effectiveness. However, many effluents are composed of biorecalcitrant organic pollutants, especially in industrial wastewaters. Advanced physico-chemical treatments are therefore needed to deal with these pollution levels. Electrochemical processes could be cost-effective solutions. However, the energy required to reach complete mineralization is often high. One promising combination would be to combine electrochemical processes that can remove xenobiotic compounds from effluent with biotechnologies that are able to mineralize the biodegradable fraction. Therefore, this review presents the most recent articles dealing with this combination, by mainly focusing on electrochemical advanced oxidation processes that demonstrated to have high removal efficiency for organic biorecalcitrant compounds. Additional and imperative information about the treatment strategy and the engineering aspects for the upscaling approach are also given.

The objective of this study was to improve the mineralization of metronidazole, a recalcitrant antibiotic by the development of a new combined process coupling electro-Fenton and a biological process. For biotreatment, various strategies were considered bioaugmentation, bioacclimatation and biostimulation alone or combined. So, the novelty of this strategy is to combine advanced oxidation process with advanced biological process. The conventional biotreatment with activated sludge after 120 h of culture, led to 58.1% mineralization, whereas the pure isolated strains, from activated sludge culture in the presence of metronidazole by-products, identified as Pseudomonas putida (strain A) and Achromobacter sp. (strain B), led to 37.2% and 40.1% respectively. After original acclimation of the isolated strains to electrolysis by-products, the mineralization levels reached 75.6% and 72.9% for strains A and B respectively after 120 h of culture. The results showed that the mineralization of metronidazole by-products was the most important in the case of the combination of autochthonous bioaugmentation and biostimulation, with 96.1% after 120 h of treatment. By coupling the two processes, the global treatment reached therefore a mineralization yield of 97% with a reduction in processing time of 16 days compared to previous conventional biological treatment.

The occurrence of iodine X-ray contrast media (ICM) in the environment is a global concern since they can be transformed into toxic compounds during water disinfection process. Among the different approaches that have been tested to degrade them, electroreduction offers the advantages to be selective, targeting in a cost-effective way the functional groups responsible for ICM biorecalcitrance and allowing the recovery of iodide ions. We have previously shown that total deiodination of diatrizoate, a highly biorecalcitrant ICM, did not lead to a significant enhancement of its biodegradability. In this work, the electroreduction of amido groups of diatrizoate was attempted to further improve its biodegradability. Electrolyses of diatrizoate and its deiodinated derivative, were investigated in neutral and acidic medium. A total deiodination of diatrizoate was rapidly achieved in both media along with a slower reduction of the amido groups, as shown by LC-MS/MS analysis of by-products. The biodegradability of the solutions was estimated by the evaluation of the BOD5/COD ratio. Results show that it was improved after the electroreduction performed in acidic medium. This result was confirmed by a biological treatment on activated sludge over a 21 days period, leading to mineralization yields of 46% and 68% for diatrizoate and 3,5-diacetamidobenzoic acid, respectively, after the electroreduction process.

The anaerobic fermentation of glucose and fructose was performed by Actinobacillus succinogenes 130Z in batch mode using three different volume of bioreactors (0.25, 1 and 3 L). The strategy used was the addition of MgCO3 and fumaric acid (FA) as mineral carbon and the precursor of succinic acid, respectively, in the culture media. Kinetics and yields of succinic acid (SA) production in the presence of sugars in a relevant synthetic medium were investigated. Work on the bench scale (3 L) showed the best results when compared to the small anaerobic reactor’s succinic acid yield and productivity after 96 h of fermentation. For an equal mixture of glucose and fructose used as substrate at 0.4 mol L−1 with the addition of FA as enhancer and under proven optimal conditions (pH 6.8, T = 37 °C, anaerobic condition and 1% v/v of biomass), about 0.5 mol L−1 of SA was obtained, while the theoretical production of succinic acid was 0.74 mol L−1. This concentration corresponded to an experimental yield of 0.88 (mol-C SA/mol-C sugars consumed anaerobically) and a volumetric productivity of 0.48 g-SA L−1 h−1. The succinic acid yield and concentration obtained were significant and in the order of those reported in the literature.