Three-dimensional structured electrode for electrocatalytic organic wastewater purification: Design, mechanism and role

Effects and risk assessment of halogenated bisphenol A derivatives on human follicle stimulating hormone receptor: An interdisciplinary study

Halogenated bisphenol A (BPA) derivatives are produced during disinfection treatment of drinking water or are synthesized as flame retardants (TCBPA or TBBPA). BPA is considered as an endocrine disruptor especially on human follicle-stimulating hormone receptor (FSHR). Using a global experimental approach, we assessed the effect of halogenated BPA derivatives on FSHR activity and estimated the risk of halogenated BPA derivatives to the reproductive health of exposed populations. For the first time, we show that FSHR binds halogenated BPA derivatives, at 10 nM, a concentration lower than those requires to modulate the activity of nuclear receptors and/or steroidogenesis enzymes. Indeed, bioluminescence assays show that FSHR response is lowered up to 42.36 % in the presence of BPA, up to 32.79 % by chlorinated BPA derivatives and up to 27.04 % by brominated BPA derivatives, at non-cytotoxic concentrations and without modification of basal receptor activity. Moreover, molecular docking, molecular dynamics simulations, and site-directed mutagenesis experiments demonstrate that the halogenated BPA derivatives bind the FSHR transmembrane domain reducing the signal transduction efficiency which lowers the cellular cAMP production and in fine disrupts the physiological effect of FSH. The potential reproductive health risk of exposed individuals was estimated by comparing urinary concentrations (through a collection of human biomonitoring data) with the lowest effective concentrations derived from in vitro cell assays. Our results suggest a potentially high concern for the risk of inhibition of the FSHR pathway. This global approach based on FSHR activity could enable the rapid characterization of the toxicity of halogenated BPA derivatives (or other compounds) and assess the associated risk of exposure to these halogenated BPA derivatives.

Intensive investigation of the synergistic effects between electrocatalysis and peroxymonosulfate activation for efficient organic elimination

Hybrid systems combined eletrocatalysis and Fenton-like process attract a lot of attention due their outstanding performance and unique mechanism. Here, we proposed an efficient, cost-effective, and versatile electrochemical activation (ECA) system for efficient water purification, and intensively studied the synergistic effects between electrocatalysis and peroxymonosulfate (PMS)-based advanced oxidation. The ECA system achieved complete removal of 20 ppm tetracycline hydrochloride (TCH) in 15 min, with a rate constant of 0.338 min-1. Its performance was assessed across various operational parameters (PMS dosage, pH, applied voltage, electrode interval, temperature, co-existed ions, biomass, different oxidants), demonstrating its broad applicability and stability. Excellent degradation and mineralization for other 12 kinds of refractory organic pollutants were also achieved. The outstanding performance can be attributed to the synergistic effect in the system, in which electrocatalytic reduction of dissolved oxygen generated H2O2 and O2•-, boosting the number of reactive species, such as 1O2, by interacting with PMS. Furthermore, the presence of organic matter promotes electron transfer, amplifying the system's degradation capability. These findings not only highlight the ECA system's effectiveness in organic pollutant removal but also offer insights into the underlying degradation mechanisms, paving the way for future advancements in water purification technologies.

Cu/Mn-mediated electron shuttle and high-valent metals enhance hydroxyl radicals production during the electrochemical oxidation on the CuMn-Sb-SnO2 electrode

In this work, a novel CuMn-Sb-SnO2 anode is developed by a simple, low-cost preparation process. The doping of Cu and Mn causes surface reconstruction, which optimizes its electronic structure, compared to the Sb-SnO2 anode. Experimental results demonstrate that the levofloxacin degradation kinetics constant in the CuMn-Sb-SnO2 system (0.188 min-1) was 8.5 times higher than that in the Sb-SnO2 system, which is surpassing most reported anodes. Moreover, electrochemical characterization also revealed that the CuMn-Sb-SnO2 anode possessed more active sites, higher OEP potential, and lower charge transfer resistance. Notably, electrochemical characterization and EPR experiments confirmed the formation of Cu (III), highlighting their crucial role in promoting the generation of •OH during the catalytic process. Additionally, theoretical calculations and XPS analysis revealed that Cu and Mn rely on self-mediated redox shuttles to act as "electron porters", significantly accelerating internal electron transfer between Sn and Sb to enhance the production of •OH. Furthermore, the CuMn-Sb-SnO2 anode exhibits great practicability due to its efficient degradation of various antibiotics. This study offers valuable new insights into developing novel electrodes for the efficient degradation of antibiotic wastewater.

CuFeS2/GAC particle combined with electrochemical activation of persulfates for efficient degradation of carbamazepine

Electrochemically activated persulfate is a potential advanced oxidation process due to its advantages of environmental friendliness, high efficiency, and convenient operation. An Fe-Cu-S granular activated carbon (CuFeS2/GAC, abbreviated as FCSG) particles electrode was developed and applied to degrade carbamazepine (CBZ) combined with electrochemical activation of persulfate (E-PDS-FCSG) in this work. Compared to two-dimensional electrochemical process (E-PDS), the three-dimensional (3D) E-PDS-FCSG process exhibited higher removal efficiency of CBZ and lower energy consumption. The removal efficiency of CBZ and power consumption increased by 96% and reduced by 67%, respectively. Over 98% of CBZ removal rate was reached within 25 min. Apart from the same free radicals in two-dimensional electrochemical process, both Fe2+ and Cu+ on the surface of three-dimensional particle electrodes can directly activate PDS to produce SO4•-, and the existence of S2- strengthens the circulation of Fe3+/Fe2+ and Cu2+/Cu+. Furthermore, FCSG particle electrode can not only directly enhance the activation of PDS, but also accelerate the electron transfer, and then effectively promoting reactive species generation. LC-MS analysis showed that the main degradation pathways of CBZ involved decarbonylation, deamination, dealkylation, ring opening and mineralization. Moreover, after five cycle experiments, over 80% of CBZ removal rate could be achieved, demonstrating that the E-PDS-FCSG system had excellent electrocatalytic performance and good stability. These findings indicate that FCSG is a promising material and could be used as a particle electrode for removing organic pollutants from water.

An overview of the recent advances and future prospects of three-dimensional particle electrode systems for treating wastewater

Three-dimensional (3D) electrochemical technology is considered a very effective industrial wastewater treatment method for its high treatment efficiency, high current efficiency, low energy consumption, and, especially, ability to completely mineralize nonbiodegradable organic contaminants. Particle electrodes, which are the fundamental components of 3D electrochemical technology, have multiple functions in the electrochemical reaction process. Various types of particle electrodes have been created and applied for wastewater treatment. Herein, we present a thorough analysis of the research and development of particle electrodes used for electrocatalyzing pollutants. Initially, reactor designs, factors affecting the removal efficiency of pollutants and degradation mechanisms are introduced. In particular, a detailed investigation is conducted into the selection of particle electrode materials and the roles they play in the 3D electrochemical treatment of wastewater. Subsequently, the degradation efficiency and energy consumption associated with 3D electrochemical technology for different pollutants are investigated. Finally, the directions and outlook for further studies on particle electrodes are discussed. We believe that this review will offer a useful perspective on the development and application of particle electrodes for wastewater purification.

The electrocatalytic degradation of 1,4-dioxane by Co-Bi/GAC particle electrode

Efficient degradation of industrial organic wastewater has become a significant environmental concern. Electrochemical oxidation technology is promising due to its high catalytic degradation ability. In this study, Co-Bi/GAC particle electrodes were prepared and characterized for degradation of 1,4-dioxane. The electrochemical process parameters were optimized by response surface methodology (RSM), and the influence of water quality factors on the removal rate of 1,4-dioxane was investigated. The results showed that the main influencing factors were the Co/Bi mass ratio and calcination temperature. The carrier metals, Co and Bi, existed mainly on the GAC surface as Co3O4 and Bi2O3. The removal of 1,4-dioxane was predominantly achieved through the synergistic reaction of electrode adsorption, anodic oxidation, and particle electrode oxidation, with ·OH playing a significant role as the main active free radical. Furthermore, the particle electrode was demonstrated in different acid-base conditions (pH = 3, 5, 7, 9, and 11). However, high concentrations of Cl- and NO3- hindered the degradation process, potentially participating in competitive reactions. Despite this, the particle electrode exhibited good stability after five cycles. The results provide a new perspective for constructing efficient and stable three-dimensional (3D) electrocatalytic particle electrodes to remove complex industrial wastewater.

Hemodialysis Wastewater Treatment via Electrocoagulation and Electro-Oxidation: Modular Pilot-Level Modeling and Simulation

Hemodialysis treatment in specialized clinics within the same hospital significantly impacts environmental water health due to contaminated wastewater. The issues observed included changes in electrical conductivity, the presence of dangerous bacterial loads, toxicity from heavy metals, total cyanide content, and helminth parasite eggs. The level of damage is dependent on the patient's health under treatment. This research will use a modular system that employs electrocoagulation and electro-oxidation processes at the laboratory and pilot levels to treat hemodialysis wastewater using synthetically prepared and real samples extracted from local clinics. The results showed that these hybrid systems improved various physicochemical parameters. Specifically, decreases in electrical conductivity of 49 %, total suspended solids of 27-100 %, chemical oxygen demand of 49 %, biochemical oxygen demand of 49 %, and cation and anion loading were observed at 96-100 % and pH 8.13 UpH in accordance with the established standards. With these results and the experimental conditions used, the proposed treatment system was modeled using the GPS-X program, and it was concluded that the modular system used and the electrocoagulation/electro-oxidation/activated carbon configuration is suitable for treating wastewater from hemodialysis and that scaling up this process to facilities that have dialysate machines more advanced than those considered in this work is possible.

Detection and treatment of mono and polycyclic aromatic hydrocarbon pollutants in aqueous environments based on electrochemical technology: recent advances

Mono and polycyclic aromatic hydrocarbons are widely distributed and severely pollute the aqueous environment due to natural and human activities, particularly human activity. It is crucial to identify and address them in order to reduce the dangers and threats they pose to biological processes and ecosystems. In the fields of sensor detection and water treatment, electrochemistry plays a crucial role as a trustworthy and environmentally friendly technology. In order to accomplish trace detection while enhancing detection accuracy and precision, researchers have created and studied sensors using a range of materials based on electrochemical processes, and their results have demonstrated good performance. One cannot overlook the challenges associated with treating aromatic pollutants, including mono and polycyclic. Much work has been done and good progress has been achieved in order to address these challenges. This study discusses the mono and polycyclic aromatic hydrocarbon sensor detection and electrochemical treatment technologies for contaminants in the aqueous environment. Additionally mentioned are the sources, distribution, risks, hazards, and problems in the removal of pollutants. The obstacles to be overcome and the future development plans of the field are then suggested by summarizing and assessing the research findings of the researchers.

Highly efficient visible-light driven dye degradation via 0D BiVO4 nanoparticles/2D BiOCl nanosheets p-n heterojunctions

The construction of hybrid heterojunction photocatalysts is an effective strategy to improve the utilization of photogenerated carriers and photocatalytic activity. To enhance the separation distance of photogenerated carriers and accelerate the effective separation at the heterojunction of the interface, a unique 0D-2D hierarchical nanostructured p-n heterojunction was successfully fabricated in this work. BiOCl (BOC) nanosheets (p-type) were in situ grown on BiVO4 (BVO) nanoparticles (n-type) using the microemulsion-calcination method for highly efficient visible-light-driven organic dye degradation. Compared with pure BVO (the degradation rate of rhodamine B (RhB): about 32.0% in 55 min, the mineralization rate: 24.9% in 120 min), the RhB degradation rate can reach about 99.5% in 55 min and the mineralization rate of 62.1% in 120 min by utilizing BVO/25%BOC heterojunction photocatalyst under visible light irradiation. Various characterizations demonstrate that the formation of BVO/BOC p-n heterojunction greatly facilitates photogenerated carriers separation efficiency. Meanwhile, the results of the scavenging experiments and electron spin resonance tests indicate that ·O2- and h+ are the prominent active species for Rh B degradation. In addition, possible degradation pathways for Rh B were proposed using LC-MS tests. This work proves that building low dimensional p-n heterojunction photocatalysts is a promising strategy for developing photocatalysts with high efficiency.

Effects of heavy metals and metalloids on the biodegradation of organic contaminants

Heavy metals and metalloids (HMMs) inhibit the biodegradation of organic pollutants. The degree of inhibition depends not only on the concentration and bioavailability of HMMs but also on additional factors, such as environmental variables (e.g., inorganic components, organic matter, pH, and redox potential), the nature of the metals, and microbial species. Based on the degradation pattern and metal concentrations causing half biodegradation rate reductions (RC50s), the inhibition of biodegradation was: Hg2+, As2O3 > Cu2+, Cd2+, Pb2+, Cr3+ > Ni2+, Co2+ > Mn2+, Zn2+ > Fe3+. Four patterns were observed: inhibition increases with increasing metal concentration; low concentrations stimulate, while high concentrations inhibit; high concentrations inhibit less; and mild inhibition remains constant. In addition, metal ion mixtures have more complex inhibitory effects on the degradation of organic pollutants, which may be greater than, similar to, or less than that of individual HMMs. Finally, the inhibitory mechanism of HMMs on biodegradation is reviewed. HMMs generally have little impact on the biodegradation pathway of organic pollutants for bacterial strains. However, when pollutants are biodegraded by the community, HMMs may activate microbial populations harbouring different transformation pathways. HMMs can affect the biodegradation efficiency of organic pollutants by changing the surface properties of microbes, interfering with degradative enzymes, and interacting with general metabolism.

Recent progress of particle electrode materials in three-dimensional electrode reactor: synthesis strategy and electrocatalytic applications

With the complete promotion of a green, low-carbon, safe, and efficient economic system as well as energy system, the promotion of clean governance technology in the field of environmental governance becomes increasingly vital. Because of its low energy consumption, great efficiency, and lack of secondary pollutants, three-dimensional (3D) electrode technology is acknowledged as an environmentally beneficial and sustainable way to managing clean surroundings. The particle electrode is an essential feature of the 3D electrode reactor. This study provides an in-depth examination of the most current advancements in 3D electrode technology. The significance of 3D electrode technology is emphasized, with an emphasis on its use in a variety of sectors. Furthermore, the particle electrode synthesis approach and mechanism are summarized, providing vital insights into the actual implementation of this technology. Furthermore, by a metrological examination of the research literature in this sector, the paper expounds on the potential and obstacles in the development and popularization of future technology.

Catalytic degradation of crystal violet and methyl orange in heterogeneous Fenton-like processes

Metals-loaded (Fe3+, Cu2+ and Zn2+) activated carbons (M@AC) with different loading ratios (0.1%, 0.5%, 1%, 5% and 10%) were prepared and employed for catalytic degradation of dye model compounds (crystal violet (CV) and methyl orange (MO)) in wastewater by heterogeneous Fenton-like technique. Compared with Cu@AC and Zn@AC, 0.5% Fe3+ loaded AC (0.5Fe@AC) had better catalytic activity for dyes degradation. The effects of dyes initial concentration, catalyst dosage, pH and hydrogen peroxide (H2O2) volume on the catalytic degradation process were investigated. Cyclic performance, stability of 0.5Fe@AC and iron leaching were explored. Degradation kinetics were well fitted to the pseudo-second-order model (Langmuir-Hinshelwood). Almost complete decolorization (99.7%) of 400 mg L-1 CV was achieved after 30 min reaction under the conditions of CV volume (30 mL), catalyst dosage (0.05 g), H2O2 volume (1 mL) and pH (7.7). Decolorization of MO reached 98.2% under the same conditions. The abilities of pyrolysis char (PC) of dyeing sludge (DS) and metal loaded carbon to remove dye pollutants were compared. The intermediate products were analyzed and the possible degradation pathway was proposed. This study provided an insight into catalytic degradation of triphenylmethane- and aromatic azo-based substances, and utilization of sludge char.

The aggregated biofilm dominated by Delftia tsuruhatensis enhances the removal efficiency of 2,4-dichlorophenol in a bioelectrochemical system

Bioelectrochemical system is a prospective strategy in organic-contaminated groundwater treatment, while few studies clearly distinguish the mechanisms of adsorption or biodegradation in this process, especially when dense biofilm is formed. This study employed a single chamber microbial electrolysis cell (MEC) with two three-dimensional electrodes for removing a typical organic contaminant, 2,4-dichlorophenol (DCP) from groundwater, which inoculated with anaerobic bacteria derived from sewage treatment plant. Compared with the single biodegradation system without electrodes, the three-dimensional electrodes with a high surface enabled an increase of alpha diversity of the microbial community (increased by 52.6% in Shannon index), and provided adaptive ecological niche for more bacteria. The application of weak voltage (0.6 V) furtherly optimized the microbial community structure, and promoted the aggregation of microorganisms with the formation of dense biofilm. Desorption experiment proved that the contaminants were removed from the groundwater mainly via adsorption by the biofilm rather than biodegradation, and compared with the reactor without electricity, the bioelectrochemical system increased the adsorption capacity from 50.0% to 74.5%. The aggregated bacteria on the surface of electrodes were mainly dominated by Delftia tsuruhatensis (85.0%), which could secrete extracellular polymers and has a high adsorption capacity (0.30 mg/g electrode material) for the contaminants. We found that a bioelectrochemical system with a three-dimensional electrode could stimulate the formation of dense biofilm and remove the organic contaminants as well as their possible more toxic degradation intermediates via adsorption. This study provides important guidance for applying bioelectrochemical system in groundwater or wastewater treatment.

Unveiling the spatially confined oxidation processes in reactive electrochemical membranes

Electrocatalytic oxidation offers opportunities for sustainable environmental remediation, but it is often hampered by the slow mass transfer and short lives of electro-generated radicals. Here, we achieve a four times higher kinetic constant (18.9 min-1) for the oxidation of 4-chlorophenol on the reactive electrochemical membrane by reducing the pore size from 105 to 7 μm, with the predominate mechanism shifting from hydroxyl radical oxidation to direct electron transfer. More interestingly, such an enhancement effect is largely dependent on the molecular structure and its sensitivity to the direct electron transfer process. The spatial distributions of reactant and hydroxyl radicals are visualized via multiphysics simulation, revealing the compressed diffusion layer and restricted hydroxyl radical generation in the microchannels. This study demonstrates that both the reaction kinetics and the electron transfer pathway can be effectively regulated by the spatial confinement effect, which sheds light on the design of cost-effective electrochemical platforms for water purification and chemical synthesis.

Three-Dimensional Electrochemical Sensors for Food Safety Applications

Considering the increasing concern for food safety, electrochemical methods for detecting specific ingredients in the food are currently the most efficient method due to their low cost, fast response signal, high sensitivity, and ease of use. The detection efficiency of electrochemical sensors is determined by the electrode materials' electrochemical characteristics. Among them, three-dimensional (3D) electrodes have unique advantages in electronic transfer, adsorption capacity and exposure of active sites for energy storage, novel materials, and electrochemical sensing. Therefore, this review begins by outlining the benefits and drawbacks of 3D electrodes compared to other materials before going into more detail about how 3D materials are synthesized. Next, different types of 3D electrodes are outlined together with common modification techniques for enhancing electrochemical performance. After this, a demonstration of 3D electrochemical sensors for food safety applications, such as detecting components, additives, emerging pollutants, and bacteria in food, was given. Finally, improvement measures and development directions of electrodes with 3D electrochemical sensors are discussed. We think that this review will help with the creation of new 3D electrodes and offer fresh perspectives on how to achieve extremely sensitive electrochemical detection in the area of food safety.