Electrochemical Advanced Oxidation Processes Research Articles

Optimisation of treatment efficiency and effluent toxicity during carbamazepine degradation via electrochemical oxidation

The commercialisation of electrochemical advanced oxidation processes (eAOPs) as a method for removing recalcitrant pollutants from wastewater is currently limited due to the potential for the formation of toxic by-products. In this regard, this research comprised a comprehensive optimisation study aimed at finding a balance between minimising the toxicity effects observed via phytotoxicity assays and maximising the eAOP degradation efficiency under low energy requirements. To this end, carbamazepine (CBZ) was selected as the target pollutant in synthetic wastewater, and the operating conditions considered for optimisation were the nature of the anolyte (i.e., sulfate- or chloride-based), its concentration, and the current density applied. Together with the identification of the CBZ transformation products and their estimated toxicity based on the ECOSAR model, the optimum treatment was found to correspond to the degradation in 500mgL−1 of a sulfate-based anolyte at a current density of 10Am−2. These conditions led to the fewest and least toxic transformation products and favoured plant growth indices in phytotoxicity tests. Even if additional process improvements are required to reduce effluent toxicity, continuing such a multi-target optimisation approach can lead to innocuous electrochemical wastewater treatment.

Electrochemical reclamation of oil sands process water: Two and three-dimensional electrode configuration systems structured with different anode materials

Several studies have indicated the potential of the electrochemical advanced oxidation process in oil sands process water (OSPW) reclamation; however, the variations in different electrode configuration systems and anode materials remain elusive. This study assembled a two-dimensional electrode system (2-DES) and a packed bed electrode reactor (PBER) for OSPW reclamation, of which boron-doped diamond (BDD) (non-active anode), dimensionally stable anodes (DSA-RuO2 and DSA-IrO2) and graphite (active anodes) were selected as the anode materials, while in PBER, spherical activated carbon (SAC) was added as the third electrode. Within the 2-DES, BDD achieved over 60% removal of chemical oxygen demand (COD) due to its excellent •OH generation ability, while DSAs generated the most active chlorine and were quickly consumed by organic matter during the first 30 minutes. However, mass transfer limitation restricted the 2-DES treatment efficiency regardless of the anode materials employed, particularly resulting in limited removal of naphthenic acids (NAs). Compared to 2-DES, PBER significantly improved the OSPW treatment under identical electrolysis conditions, achieving over 91% COD and 99% NAs removal using DSA-IrO2 + SAC. Because of the contribution of the third electrode in PBER, the performance differences between various anode materials were less substantial than in the case of 2-DES. Packed SAC enhanced the mass transfer performance and generation of radical oxidants during OSPW electrolysis, improving the OSPW electrochemical treatment process. Additionally, SAC adsorbed most free chlorine from the liquid phase, avoiding the formation of halogenated organic compounds in reclaimed OSPW.

Application of biochar in electro-Fenton process: Advantages and recent advancements

The electro-Fenton (EF) process is a well-known electrochemical advanced oxidation process that produces highly active hydroxyl radicals via the externally added catalytic amount of iron catalyst and in-situ generated hydrogen peroxide. The performance of the EF process depends on the choice of catalyst and the cathode. Biochar, an economically viable carbon-rich material derived from locally available biomass, presents a promising option for both catalyst support and cathode materials. The heterogeneous EF process using biochar-based catalyst has several advantages over the conventional EF process, including enhanced efficiency, declined iron leaching, surface-predominated radical generation, and pollutant degradation even in neutral pH conditions. Moreover, biochar demonstrates the capacity to generate a significant amount of hydrogen peroxide and regenerate ferrous ions rapidly. Additionally, biochar has a high adsorption capacity for many organic pollutants and ensures the contaminants' proximity and generated reactive species when applied as supports, catalysts, or electrodes in EF and related processes. The novelty of this work lies in its comprehensive review of the significant advancements and advantages of the applications of biochar in the EF process, emphasizing its potential to revolutionize wastewater treatment methodologies.

Boosting hydroxyl radical generation for highly efficient electrooxidation of sulfamethazine via facile doping strategy

The one-electron water oxidation reaction (WOR) to generates hydroxyl radicals (•OH) plays a pivotal role in electrochemical advanced oxidation processes (EAOPs). In this study, we present a novel and facile strategy involving Ho-doping to regulate the electronic configuration of the conventionally nonactive PbO2 electrode. Experimental findings demonstrate that PbO2 doped with 2.4% Ho achieves the highest degradation performance of sulfamethazine (SMZ) (∼100%; kobs = 0.093 min−1) and highest •OH generation efficiency with a relatively concentration of •OH = 1.9 × 107. The doped electrodes exhibit a notable enhancement compare to the undoped electrode, which elevating SMZ degradation efficiency and •OH generation by factors of 1.45 and 3.8, respectively. Electrochemical characterization and degradation results elucidate that the modulation of electron transfer rate and oxygen evolution potential are crucial factors governing the performance of the Ho-doped PbO2 anode. Specifically, maintaining a suitably high oxygen evolution potential (OEP) enables the thermodynamically feasible production of •OH, while a relatively fast electron transfer rate ensures the generation of H2O+ (the oxidation precursor of •OH) with kinetic feasibility. Furthermore, a degradation pathway for SMZ is proposed based on the identification of transformation mechanism using density functional calculation (DFT) and the detection of intermediates via LC-MS/MS. This study provides an universal strategy for simultaneously enhancing the OEP and optimizing the electron transfer rate of an EAOP anode through the modulation of anodic electronic configuration, thereby advancing the field of efficient water treatment applications.

Electrocatalytic hydrogen peroxide generation using WO3 nanoparticle-decorated sodium niobate microcubes

The current work studies the electrocatalytic performance of NaNbO3 microcubes decorated with WO3 nanoparticles on Printex L6 at varying concentrations (1%, 3%, 5%, and 10% by weight) for H2O2 electrogeneration aiming for future use in electrochemical advanced oxidation processes for organic pollutant degradation·H2O2 electrogeneration was studied using oxygen reduction reaction (ORR) with the rotating ring-disk electrode (RRDE) technique. Electrochemical results revealed an improvement in H2O2 electrogeneration for the NaNbO3@WO3/C materials compared to that achieved with Printex L6 carbon. Notably, the 5% NaNbO3@WO3/C electrocatalyst exhibited a higher ring current for oxygen reduction reaction and promoted a 2.1-electron transfer, facilitating a higher rate of H2O2 electrogeneration through the 2-electron mechanism. Also, enhancing oxygen-containing functional groups has shown the capability to thoroughly adjust characteristics and enhance active sites, increasing H2O2 electrogeneration. These findings suggest that 5% NaNbO3@WO3/C electrocatalysts hold promise for in situ hydrogen peroxide electrogeneration.

Review on Structural Adjustment Strategies of Titanium‐Based Metal Oxide Dimensionally Stable Anodes in Electrochemical Advanced Oxidation Technology

Emerging organic pollutants and refractory pollutants in water bodies have caused severe harm to the ecological environment and human health. Electrochemical advanced oxidation processes (EAOPs) are currently one of the most effective oxidation methods to deal with refractory organic pollutants. Electrode materials serve as the most critical component in influencing the EAOP performance. Dimensionally stable anodes (DSAs) have the advantages of dimensional stability, structural diversity, chemical stability, low oxygen evolution potential and long service life, etc. Herein, several types of Ti‐based metal oxide DSAs (Ti/MOx DSAs) commonly used in EAOPs in the past 5 years, including Ti/IrO2, Ti/RuO2, Ti/PbO2, Ti/Sb–SnO2, and Ti/TiO2, are introduced. The modification methods including metal doping, composition adjustment, nanostructure construction, introduction of intermediate layers, compositing with carbon materials, and formation of 3D structures as well as the applications of these modified Ti‐based DSAs in EAOP for the rapid degradation of various organic pollutants are summarized and their advantages and current shortcomings of electrodes are pointed out. Finally, the Ti‐based DSA's current limitations and future development prospects are concluded.

Comparison of electrochemical advanced oxidation processes for the treatment of complex synthetic dye mixtures

Many industries use complex synthetic organic dye mixtures in their dyeing processes, producing wastewater effluents with complex dye mixtures. In this study, electrochemical advanced oxidation processes like electrochemical oxidation (ECO), ECO with electrogenerated H2O2 (ECO-H2O2), electro-Fenton (EF), and photo electro-Fenton (PEF) with UVC irradiation were compared to discolor and mineralize a mixture of Methyl Orange, Methyl Red, and Toluidine Blue O with a boron-doped diamond anode and a gas-diffusion cathode. While ECO and ECO-H2O2 required long times to achieve a complete discoloration, the dyes were quickly degraded by EF and PEF due to the oxidation with ∙OH formed from Fenton’s reaction. Almost complete mineralization was rapidly achieved by PEF for a solution with 424 mg O2 L-1 of chemical oxygen demand (COD) at a current density of 66.6 mA cm−2 due to the synergistic action of the UVC irradiation. Additionally, the treated effluent was evaluated using the DFZ (Deutsche Farb Zah) parameter for water condition, offering a new perspective and distinguishing this work from previous studies focused on electrified technologies for dye removal. The same behavior has been found for the mixture of such dyes in an industrial effluent upon PEF treatment, even showing faster discoloration and COD reduction as result of the additional removal with active chlorine formed from Cl− oxidation. Ion-exclusion HPLC analysis of the treated synthetic effluent revealed the formation of final carboxylic acids like malic, acetic, oxalic, and formic. Released nitrate, ammonia, and nitrite were detected as nitrogenated by-products from the initial N of the dyes.

Synergistically S/N self-doped biochar as a green bifunctional cathode catalyst in electrochemical degradation of organic pollutant

Biomass-derived heteroatom self-doped cathode catalysts has attracted considerable interest for electrochemical advanced oxidation processes (EAOPs) due to its high performance and sustainable synthesis. Herein, we illustrated the morphological fates of waste leaf-derived graphitic carbon (WLGC) produced from waste ginkgo leaves via pyrolysis temperature regulation and used as bifunctional cathode catalyst for simultaneous H2O2 electrochemical generation and organic pollutant degradation, discovering S/N-self-doping shown to facilitate a synergistic effect on reactive oxygen species (ROS) generation. Under the optimum temperature of 800 °C, the WLGC exhibited a H2O2 selectivity of 94.2% and tetracycline removal of 99.3% within 60 min. Density functional theory calculations and in-situ Fourier transformed infrared spectroscopy verified that graphitic N was the critical site for H2O2 generation. While pyridinic N and thiophene S were the main active sites responsible for •OH generation, N vacancies were the active sites to produce 1O2 from O2. The performance of the novel cathode for tetracycline degradation remains well under a wide pH range (3–11), maintaining excellent stability in 10 cycles. It is also industrially applicable, achieving satisfactory performance treating in real water matrices. This system facilitates both radical and non-radical degradation, offering valuable advances in the preparation of cost-effective and sustainable electrocatalysts and hold strong potentials in metal-free EAOPs for organic pollutant degradation.

Effect of the anode material, applied current and reactor configuration on the atenolol toxicity during an electrooxidation process

Atenolol (ATL) is a beta-blocker pharmaceutical product which is excreted mainly unchanged and may represent a long-term risk for organisms present in the sea and in fresh water. Due to its low biodegradation rate, electrochemical advanced oxidation processes (EAOPs) can be used to remove this compound. In this work, ATL ecotoxicity was analyzed in the presence of sodium sulfate (Na2SO4), which is widely used as supporting electrolyte in EAOPs. Ecotoxicity values were expressed as the pollutant concentration that leads to a 50% inhibition of the root elongation of Lactuca sativa seeds in relation to the control (EC50(5 days)). The obtained values for ATL showed an EC50(5 days) of 1377 mg L−1 towards Lactuca sativa. When Na2SO4 was added, the toxicity of the sample increased but no synergy was detected between both compounds. With 2 g L−1 Na2SO4, ATL showed an EC50(5 days) of 972 mg L−1; and with 4 g L−1 Na2SO4 and higher concentrations, EC50 value for ATL was 0 mg L−1. Statistical tools were used to obtain the zones of the [ATL]-[Na2SO4] plane which are toxic towards Lactuca sativa.Solutions containing ATL and Na2SO4 were treated by electrooxidation. Two anode materials (a boron-doped diamond electrode and a microporous Sb-doped SnO2 ceramic one); three operation currents (0.4, 0.6 and 1 A); and two reactor configurations (one-compartment reactor and two-compartment reactor separated by a cation exchange membrane) were used. Lactuca sativa seeds and Vibrio fischeri bacterium tests were employed to evaluate the toxicity of the solutions before and after applying the electrooxidation process. In all the tests, the ecotoxicity of the treated sample increased. This fact is owing to the persulfate presence in the solution due to the sulfate electrochemical oxidation. Nevertheless, none of the final samples were toxic towards Vibrio fischeri because ecotoxicity values were lower than 10 TU; and, in the case of the one-compartment reactor, practically all of them were also non-toxic towards Lactuca sativa. The toxicity of the treated samples increased when using the two-compartment reactor in the presence of the BDD anode, and when the operation current was increased. This is attributed to the highest formation of persulfates. Amongst all the tests performed in this work, the lowest toxicity value (i.e., 3 TU) together with the complete mineralization and degradation degrees was achieved with the two-compartment reactor using the BDD anode and operating at 0.6 A.

The in-situ generation of ClO• by single- and dual-atom catalysis of chloride ions to degrade sulfonamide antibiotics: A DFT study

Single- (SACs) and dual-atom catalysts (DACs) are recognized as promising electrochemical materials. However, their application potential in the water treatment with the presence of chloride ions (the most common water matrice) still needs to be investigated. Thus, the first-principles calculation was used to investigate the electrocatalytic activation of Cl− and micropollutant degradation mechanisms by four kinds of metal-embedded nitrogen-doped carbon materials (M-N-C). The results show that the average Cl− adsorption energies (Eads) in different configurations follow the order of M2N6-a < M2N8 < MN4 < M2N6-b. The average Eads of SACs and DACs doped with different metal atoms follow the order of Fe < Co < Ni and Fe2 < FeNi < FeCo < CoNi ≈ Co2 < Ni2, respectively. The chlorine evolution reactions (CER) on the FeN4 and Fe2N6-a in neutral water were revealed as Cl− → *Cl → HClO* → free HClO, and HClO will rapidly generate ClO• to degrade target pollutants. The generated ClO• exhibits high reactivity towards sulfanilamide antibiotics (SAs) with the reaction rate constants of 1.78 × 108–6.86 × 109 M−1 s−1, indicating the high feasibility of ClO• in SAs purification from wastewater. This study provides mechanistic insights into the electrocatalytic generation of ClO• and its application in removing contaminants of emerging concern in M-N-C-supported electrochemical advanced oxidation processes.

Sustainable degradation of ciprofloxacin in water by the electro-peroxone process via a graphite felt electrode system

Excessive, unregulated usage and reckless disposal of antibiotics have led to the formation of antibiotic resistance in bacteria. Additionally, untreated or partially treated pharmaceutical effluents are discharged into water bodies. With the increasing prevalence of antibiotic resistance across the globe, previously curable diseases are becoming challenging to handle due to the advent of superbugs. It is crucial to ensure complete treatment and removal of antibiotics and pharmaceuticals before discharging them into water bodies. Conventional treatment plants are not specialized in removing such complex, emerging contaminants. The advanced oxidation process is an emerging and promising treatment strategy for the abatement of emerging contaminants such as pharmaceutical compounds. This study explores an electrochemical advanced oxidation process, viz., electro-peroxone for treating ciprofloxacin, a model antibiotic drug. The electro-peroxone system houses electrodes of graphite felt that helps form hydrogen peroxide, an oxidant, in situ. The viability of the carbon-based graphite felt system in reactive oxygen species generation and ciprofloxacin degradation is investigated. A comparison of the electro-peroxone with two benchmark processes, namely, electrolysis and ozonation, is also carried out. Electro-peroxone and ozonation are both quite promising in removing the model contaminant. The in situ generation of H2O2 and •OH is estimated. This is a one-of-a-kind study involving graphite felt as both anode and cathode and achieves an in situ generation of H2O2 of 47 mg/L in 120 min and •OH of 140 µM within 60 min of electro-peroxone. Besides, the efficacy of the system in contaminant degradation is examined at voltammetric and galvanostatic modes of operation. Ozonation and electro-peroxone processes achieved an efficiency between 97% and complete removal of ciprofloxacin in less than an hour. This novel system generates several times higher hydrogen peroxide than the existing graphite electrode system, making it more efficient in radical generation and pollutant abatement. This graphite felt-based electro-peroxone system, on further optimization and up-scaling, can be a promising strategy for abating pharmaceutical compounds and effluents.Graphical

Removal of Congo red dye by electrochemical advanced oxidation process: optimization, degradation pathways, and mineralization

The degradation of Congo red dye has been studied by electrochemical advanced oxidation process based on the generation of powerful oxidizing agents especially hydroxyl radicals ·OH. In this study, the effect of several experimental parameters, such as pH, ferrous ion concentration, electrolyte support concentration and current intensity, on the process was investigated. The experimental design of Doehlert was applied to determine the optimum conditions of three factors, namely current intensity, initial Fe2+ concentration and electrolysis time for the Congo red removal. The relationship of response to experimental variables was represented graphically by the construction of the two-dimensional iso-response contour plots and those indicated that 360 mA, 19 mM Fe2+ and 30 min reaction time were optimal under 50 mM Na2SO4 at pH 3, leading to a total Congo red degradation. A quadratic polynomial model was determined and its statistical significance was verified through the variance analysis, which indicated that the proposed model was statistically meaningful and convenient for the results prediction. The mineralization of Congo red under the obtained optimum conditions was examined and the results showed a high TOC removal rate (81.1%) after 300 min of reaction time. Finally, a plausible degradation pathway was suggested.

Electrochemical arsenite oxidation for drinking water treatment: Mechanisms, by-product formation and energy consumption

The mechanisms and by-product formation of electrochemical oxidation (EO) for As(III) oxidation in drinking water treatment using groundwater was investigated. Experiments were carried out using a flowthrough system, with an RuO2/IrO2 MMO Ti anode electrode, fed with synthetic and natural groundwater containing As(III) concentrations in a range of around 75 and 2 µg/L, respectively. Oxidation was dependent on charge dosage (CD) [C/L] and current density [A/m2], with the latter showing plateau behaviour for increasing intensity. As(III) concentrations of <0.3 µg/L were obtained, indicating oxidation of 99.9 % of influent As(III). Achieving this required a higher charge dosage for the natural groundwater (>40 C/L) compared to the oxidation in the synthetic water matrix (20 C/L), indicating reaction with natural organic matter or other compounds. As(III) oxidation in groundwater required an energy consumption of 0.09 and 0.21 kWh/m3, for current densities of 20 and 60 A/m2, respectively. At EO settings relevant for As(III) oxidation, in the 30–100 C/L CD range, the formation of anodic by-products, as trihalomethanes (THMs) (0.11–0.75 µg/L) and bromate (<0.2 µg/L) was investigated. Interestingly, concentrations of the formed by-products did not exceed strictest regulatory standards of 1 µg/L, applicable to Dutch tap water. This study showed the promising perspective of EO as electrochemical advanced oxidation process (eAOP) in drinking water treatment as alternative for the conventional use of strong oxidizing chemicals.

Enhanced oxidation of organic pollutants by regulating the interior reaction region of reactive electrochemical membranes

Reactive electrochemical membrane (REM) emerges as an attractive strategy for the elimination of refractory organic pollutants that exist in wastewater. However, the limited reaction sites in traditional REMs greatly hinder its practical application. Herein, a feed-through coating methodology was developed to realize the uniform loading of SnO2-Sb catalysts on the interior surface of a REM. The uniformly coated REM (Unif-REM) exhibited 2.4 times higher reaction kinetics (0.29 min–1) than that of surface coated REM (Surf-REM) for the degradation of 2 mM 4-chlorophenol (4-CP), rendering an energy consumption as low as 0.016 kWh gTOC–1. The fast degradation of various emerging contaminants, e.g., sulfamethoxazole (SMX), ofloxacin (OFLX), and tetracycline (TC), also confirms its superior oxidation capability. Besides, the Unif-REM exhibited good performance in generating hydroxyl radicals (•OH) and a relatively long service lifetime. The simulation of spatial current distribution demonstrates that the interior reaction region in the Unif-REM channels can be drastically extended, thereby maximizing the surface coupling of mass diffusion and electron transfer. This study offers an in-depth look at the spatially confined reactions in REM and provides a reference for the design of electrochemical systems with economically efficient water purification.

Application of electro oxidation process for treating wastewater from petrochemical with mixed metal oxide electrode

Petrochemicals require a large volume of water for their operation, which results in the production of a large volume of wastewater. Treatment of petrochemical wastewater is an important process before discharging it into the environment. This research examines the treatment of real petrochemical wastewater using the electrochemical oxidation process. Direct anodic oxidation is an effective advanced electrochemical oxidation process (AEOP), with different electrodes using a parallel plate electrochemical reactor. Four types of real wastewater were received from different petrochemical units were treated by AEOP. Real wastewater samples with chemical oxygen demand (COD) concentrations ranging from 20,450 to 52,300 mg/l. The main goal of this research is to make electrodes of Mixed Metal Oxide (MMO), which can reduce the treatment time and electricity consumption for oxidation, greater stability of the surface of the electrodes. Investigation of the rate constant kinetics shows that high COD removal efficiency can be achieved following the pseudo-second order reaction rate (R2 > 98%). When the wastewater pH is less than 5, COD removal efficiency is higher and the treatment process will be successful, which succeeded in removing 79% COD, but in alkaline wastewater, COD reduction efficiency was not satisfactory. The electricity consumption for 79% removal during 6 min was 117 kWh/m3. As a result, due to the very short time of the process (6 min), it can be used as one of the pre-treatment steps of petrochemical wastewater with acidic pH.

Step-by-step guide for electrochemical generation of highly oxidizing reactive species on BDD for beginners.

Selecting the ideal anodic potential conditions and corresponding limiting current density to generate reactive oxygen species, especially the hydroxyl radical (•OH), becomes a major challenge when venturing into advanced electrochemical oxidation processes. In this work, a step-by-step guide for the electrochemical generation of •OH on boron-doped diamond (BDD) for beginners is shown, in which the following steps are discussed: i) BDD activation (assuming it is new), ii) the electrochemical response of BDD (in electrolyte and ferri/ferro-cyanide), iii) Tafel plots using sampled current voltammetry to evaluate the overpotential region where •OH is mainly generated, iv) a study of radical entrapment in the overpotential region where •OH generation is predominant according to the Tafel plots, and v) finally, the previously found ideal conditions are applied in the electrochemical degradation of amoxicillin, and the instantaneous current efficiency and relative cost of the process are reported.

Efficient lignin depolymerization by continuous flow microreactor-assisted electrochemical advanced oxidation in water/co-solvent system

The employment of EAOP using a continuous flow microreactor for efficient lignin depolymerization under ambient conditions.

Anthraquinone-catalyzed H2O2 electrosynthesis coupled with an advanced oxidation process for water treatment

An anthraquinone-derived gas diffusion electrode is successfully developed for H2O2 production and an in situ electrochemical advanced oxidation process with a high performance, low power consumption, and long service life.

Cobalt single-atom catalyst as a multifunctional electrocatalyst for boosting radical generation

Electro-generated hydroxyl radicals (•OH) are of fundamental importance in electrochemical advanced oxidation processes (EAOPs). Herein, a cobalt single-atom (Co1) dispersed on N-doped carbon black (NCB) was synthesized and used forthefirsttime as a multifunctional electrocatalyst on both the anode and cathode to boost the generation of •OH. Specifically, the Co1–NCB anode electrochemically generates •OH through water oxidation reaction (WOR), whereas the Co1–NCB cathode generates hydrogen peroxide (H2O2) through oxygen reduction reaction (ORR), followed by its subsequent electrochemical/catalytic activation by Co1–NCB, which synergistically promotes the formation of •OH. In an electrochemical system with the optimized coordination structure and operating conditions, the Co1–NCB electrode-based EAOP exhibited high phenol-removal efficiency (>95%) over a wide pH range (pH = 3–9). This study provides a new strategy for maximizing radical production and suggests its application in the electrochemical oxidation of recalcitrant organic pollutants.

PFAS-Free Carbon Electrodes for Efficient Micropollutants Removal through Heterogeneous Electro-Fenton: From Material Synthesis to Module Design

Emerging micropollutants (MPs) in water bodies such as pharmaceuticals, pesticides, personal care products, and per-and poly-fluoroalkyl substances (PFAS) have posed environmental, ecological, and anthropological issues since MPs are too persistent to be degraded by conventional biological treatment. On the other hand, electrochemical advanced oxidation processes (EAOPs) have proved themselves as efficient and robust techniques to unselectively degrade MPs by forming OH radicals (•OH). Among EAOPs, electro-Fenton, or more specifically heterogeneous electro-Fenton (HEF), suggests an eco-friendly and energy-efficient treatment technique with a wide pH range for removing persistent MPs. In HEF, hydrogen peroxide (H2O2) is electrochemically produced on the cathode surface, which can react with immobilized, adjacent Fe catalysts for •OH generation. Yet, one challenge for HEF is that most of the studies have primarily focused on synthesizing Fe-containing carbons as a catalyst that suffers from several delicate preparation steps, which are time-, chemical-, and energy-consuming and lack reusability over consecutive runs [1].Additionally, these catalysts are usually powders, entailing adding polymeric binders for the immobilization of the catalyst layer on electrodes. The presence of polymeric binders, e.g., polytetrafluoroethylene (PTFE)—as PFAS-containing compounds on the electrode surface—enhances the risk of PFAS contamination during the HEF process due to mechanical wear-off or degradation under the harsh oxidative condition caused by the formation of unselective •OH. Therefore, developing PFAS-free carbon electrodes for the HEF process offering facile fabrication and good reusability with a scaling-up perspective is imperative to enable decentralized solutions for MPs removal, especially highly recalcitrant PFAS. In this work, freestanding carbons made of bio-based precursors, chitosan and sucrose, serve as electrodes for the HEF process. Chitosan is the backbone for the self-standing feature and a nitrogen-rich biopolymer, while sucrose serves as a carbon-rich compound. The mixture of chitosan and sucrose undergoes silica- and ice-templating to make a hierarchically porous carbon [2]. Bio-based carbons illustrated their capability for oxygen reduction reactions, particularly the electro-generation H2O2 [3]. As-synthesized carbons proved to remove carbamazepine and sulfamethoxazole as two persistent MPs at pH 3 and pH 7 [3]. Moreover, a novel flow-through electrolysis module equipped with as-synthesized carbons has been designed and operated to remove 20 mg/L CBZ solution at a current density of 20 mA/cm2. This module design demonstrates the ease of scaleup for a decentralized water/wastewater treatment unit to remove highly recalcitrant MPs.