Simultaneous Oxidation Research Articles

The oxidation behavior and corrosion mechanism of SiC matrix ceramics in a high temperature wet air environment

The oxidation behavior and corrosion mechanism of SiC ceramics were investigated at high temperatures ranging from 1000 ℃ to 1200 ℃ in wet environments (75 % water/25 % air). The results demonstrate the formation of protective SiO2 layers, which effectively inhibit further oxidation at 1000 ℃ and 1100 ℃. However, simultaneous oxidation and water vapor corrosion occur at 1200 ℃, leading to substantial weight loss and the development of numerous porous layers that can reach up to 30 μm after 10 h oxidation. The YAG phases in the SiC ceramics react with SiO2 to generate Y2Si2O7, Y2SiO5, and/or Al2Si2O7 phases during oxidation process, which exhibit enhanced corrosion resistance under wet environments.

Regioselective Electrooxidative [3+2] Annulation between Indole and Aniline Derivatives to Construct Functionalized Indolo[2,3-b]indoles.

A protocol for the electrooxidative [3+2] annulation to generate indolo[2,3-b]indoles in an undivided cell is reported. It exhibits good yields with excellent regioselectivities and tolerates various functional groups without external chemical oxidants. Cyclic voltammetry and density functional theory calculations indicate that the [3+2] annulation is initiated by the simultaneous anodic oxidation of indole and aniline derivatives, and the step to determine the rate relies on the combination of radical cations.

Comparing the abiotic removal of glyphosate by β-MnO2 and δ-MnO2 colloids: Insights into kinetics and mechanisms

Glyphosate as an effective broad-spectrum herbicide is frequently detected in various water and soil resources. Given the ubiquity of β-MnO2 and δ-MnO2 colloids in groundwater and soil, the abiotic removal of glyphosate by MnO2 colloids was investigated. β-MnO2 colloids exhibited superior glyphosate removal efficiency, up to 37%, compared to 21% for δ-MnO2 colloids at a pH of 4.0. Glyphosate removal involved simultaneous adsorption and oxidation process, identified by HRTEM, NH3-TPD, XPS, LC-MS, FTIR analyses and the occurrence of aminomethylphosphonic acid (AMPA) and Mn2+. Moreover, adsorption dominated the removal of glyphosate by two MnO2 colloids. The solution pH had a substantial effect on glyphosate removal. Co-existing ions in the solution, such as carbonate (CO32−), phosphate (Na2HPO4, NaH2PO4) and humic acid (HA), were also found to impede glyphosate removal. Phosphate, in particular, exhibited a strong competitive effect for adsorption sites on both MnO2 colloids. Of them, the removal of glyphosate by β-MnO2 colloids was more prone to occur due to its higher specific surface area, abundant oxygen vacancies, and moderate acid sites. However, δ-MnO2 colloids presented a stronger oxidation capacity than that of β-MnO2 colloids due to the quicker generation rate of Mn2+. Finally, AMPA was the same products by two MnO2 colloids in the oxidation process, revealing the degradation pathway based on the cleavage of C–N bond. Therefore, by comparing kinetics and mechanisms of glyphosate removal by β- and δ-MnO2 colloids, this study improves us better understanding for the behavior of glyphosate in the environment.

Construction of novel Cd-based coordination polymer composite with enhanced solar light driven photocatalysis toward simultaneous chlortetracycline degradation and Cr(VI) reduction

Coordination polymers (CPs) can be easily functionalized to prepare composite materials to improve their properties. In this study, we report the designed of iron-modified Cd-based coordination polymer composite (Fe@Cd-CP) and photocatalytic activity in removal of antibiotic contaminant and heavy metal. The two-dimensional (2D) layered {[Cd(4-padpe)(1,3-BDC)]⋅H2O}n (Cd-CP) was firstly synthesized by hydrothermal method. Interestingly, the introduction of iron significantly improved photocatalytic performance compared with the pristine Cd-CP. The Fe@Cd-CP composites were applied as bi-functional photocatalysts for simultaneous oxidation of chlortetracycline (CTC) and reduction of Cr(VI) under sunlight irradiation. Based on the detailed experiments, the enhanced photocatalytic performance could be mainly explained by the introduction of iron, resulting in enhanced the harvesting ability of visible light and facilitated the photogenerated electrons and holes separation. Besides, the results clearly displayed that the Fe@Cd-CP composite had good stability and reutilization. The free radical scavenging experiments revealed that ·OH, ·O2-, and h+ jointly participated in the oxidation degradation CTC and the photogenerated electrons took part in the reduction of Cr(VI). Our work proposed a functional strategy for constructing Cd-CP based photocatalyst for environmental remediation.

Quantifying the interfacial tension of adsorbed droplets on electrified interfaces

HypothesisThis paper develops a new measurement method to answer the question: How does one measure the interfacial tension of adsorbed droplets? ExperimentsThis measurement is based on the placement of a bubble at a water|organic interface. To prove the concept, a bubble was formed by pipetting gas below the water|1,2-dichloroethane interface. Our values agree well with previous reports. We then extended the measurement modality to a more difficult system: quantifying interfacial tension of 1,2-dichloroethane droplets adsorbed onto conductors. Carbon dioxide was generated in the aqueous phase from the electro-oxidation of oxalate. Given carbon dioxide’s solubility in 1,2-dichloroethane, it partitions, a bubble nucleates, and the bubble can be seen by microscopy when driving the simultaneous oxidation of tris(bipyridine)ruthenium (II), a molecule that will interact with CO2.−. and provide light through electrochemiluminescence. We can quantify the interfacial tension of adsorbed droplets, a measurement very difficult performed with more usual techniques, by tracking the growth of the bubble and quantifying the bubble size at the time the bubble breaks through the aqueous|1,2-dichloroethane interface. FindingsWe found that the interfacial tension of nanoliter 1,2-dichloroethane droplets adsorbed to an electrified interface in water, which was previously immeasurable with current techniques, was one order of magnitude less than the bulk system.

Effect of synergistic action of anodising and graphene on the mechanical properties of fibre-reinforced metal laminates

Fibre reinforced metal laminates (FMLs) are widely used in various fields due to their excellent properties. However, the weak interlayer properties of FMLs limit their applications. In this paper, the interlayer properties of FMLs are enhanced by anodising the 2024-T3 aluminium alloy layer in FMLs or by epoxy matrix modification of graphene nanoplatelets (GNPs). The effect of both synergistic impacts on the interlayer properties of most FMLs is investigated. The FMLs were manufactured using the wet lay-up technique using 2024-T3 aluminium alloy, E51 epoxy and EW100 glass fibre. The results showed that the type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of FMLs after anodic oxidation treatment were increased by 406.4%, 10.3%, 18.3%, 42.6% and 28.3%, respectively, compared with those of pure FMLs. The type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of the GNPs-modified FMLs matrix were increased by 280.4%, 3.7%, 6.8%, 34.5% and 19.1%, respectively, compared with those of pure FMLs. Moreover, the synergistic effect of FMLs indicates that the simultaneous anodic oxidation and GNPs modification of FMLs can lead to the best mechanical properties of FMLs. Microscopic images and schematics illustrate the toughening mechanism of anodising and GNPs, including the enhancement of aluminium/resin interface and fibre/resin interface and the enhancement of resin matrix properties.

Tandem Fields Facilitating Directional Carrier Migration in Van der Waals Heterojunction for Efficient Overall Piezo-Synthesis of H2O2.

Piezo-synthesis of H2O2 utilizing sustainable mechanical energy as well as earth-abundant water and oxygen is a green, cost-effective, and promising approach. However, achieving simultaneous two-electron water oxidation reaction (2e- WOR) and two-electron oxygen reduction reaction (2e- ORR) faces huge challenges due to insufficient synergistic active sites and slow/messy carrier transfer. Herein, a novel 2D/2D van der Waals heterojunction consisting of BiOIO3 and carbon nitride (BIO/CN) is elaborately designed for highly efficient overall H2O2 piezo-synthesis. Theoretical/experimental results reveal that a Z-scheme electron transfer is formed and facilitated by the tandem interfacial electric field and the bulk piezo-polarization field. On this basis, the carriers are efficiently separated while the oxidation/reduction capacity is preserved, thus providing the strong driving force for the 2e- WOR and 2e- ORR on BIO and CN, respectively. Furthermore, the kinetic and thermodynamic processes of WOR and ORR for H2O2 synthesis improve remarkably. Therefore, BIO/CN exhibits an excellent H2O2 yield of 259.8µM within 30min in pure water and air atmosphere (without any sacrificial agents and aeration). This study provides a new idea on strategically controlling electron transfer toward high-efficiency H2O2 piezo-synthesis and expands the avenue for developing effective environmental purification materials.

A Schottky heterojunction with spatially separated active sites for piezo-photocatalytic dual-channel hydrogen peroxide generation

Mechanical and solar energy-driven piezo-photocatalysis has drawn growing attention for H2O2 synthesis and related applications. However, most reported works focused on single pathway and ignored simultaneous oxygen reduction and water oxidation for H2O2 generation. Herein, Au-ZnO Schottky heterojunction is constructed for piezo-photocatalytic H2O2 synthesis via dual-channel pathway (simultaneous oxygen reduction and water oxidation). Experimental results and density functional theory calculations illustrated that the reduction and oxidation reactions predominantly take place at Au and ZnO sites, respectively. The spatially separated active sites avoid site competition, and enable a synergistic effect of oxidation and reduction. Furthermore, Au nanoparticles not only provide hot electrons via surface plasmon resonance effect, but also form Schottky junctions with ZnO to decrease the charge shielding effect. As a result, a H2O2 generation of 186 μM in pure water (30 min) is achieved by the optimal sample. This study provides a strategy for the construction of piezo-photocatalysts from the perspective of spatially separated redox sites for efficient H2O2 synthesis.

Mechanistic study of moisture corrosion of FeCr alloys in molten salts by ab-initio molecular dynamics simulations

Molten salts are promising for various energy applications including fuel and solar cells and nuclear energy. These applications face a common challenge: corrosion of structural materials by impurities such as H2O. This work employs ab-initio molecular dynamics simulations to study H2O induced corrosion of FeCr alloys in molten NaF and NaCl salts. H2O is found highly stable in both salts, with infrequent, reversible dissociation into OH− and H+ along with HF or HCl formation. The dissociation tendency correlates positively with the electronegativity and negatively with the size of halogen atoms. Accordingly, H2O reaches the salt/metal interface as a molecule before reacting with metal. Reduction of H+ is found to occur without simultaneous oxidation of specific metal atoms such as Cr, suggesting sequential instead of the commonly proposed concurrent reduction and oxidation. The reduced H atoms prefer to stay at the interface and may re-enter NaF but not NaCl, highlighting the influence of salt chemistry.

Visible light-driven molecular oxygen activation by lead-zinc smelting slag and tartaric acid for efficient organic pollutant degradation and Cr(VI) reduction

The remediation of heavy metal and organic-contaminated wastewater remains a significant concern in environmental science, necessitating the development of cost-effective and efficient treatment systems. This study focuses on the setup of a highly effective molecular oxygen (O2) activation system using lead–zinc smelting slag (LZSS) and tartaric acid (TA) under visible light. The LZSS-TA complex exhibited rapid photochemical reactions and demonstrated a remarkable capacity for O2 activation, resulting in the in situ generation of hydrogen peroxide (H2O2) and 99 % degradation of para-chloroaniline (p-CA). The formation of H2O2 occurred through a two-step single electron transfer pathway, whereby C-centered radicals (CHOHCHOHCOO−) generated within the system initiated the reduction of O2 to form O2−, as a crucial intermediate. The produced O2− is then reduced by Fe(II) to generate H2O2 via proton-coupled electron transfer (PCET) processes. Light-induced ligand-to-metal charge transfer (LMCT) process is the key to the production of C-centered radicals and Fe(II), which determines the production efficiency of H2O2 and OH. Additionally, this system enabled simultaneous oxidation of p-CA by 98 % and reduction of Cr(VI) by 100 % within 60 min. More importantly, O2 activation by TA-assisted LZSS under natural sunlight/solar irradiation could efficiently degrade p-CA in both ultrapure water (94 %) and reservoir water (92.5 %) within 210 min. This study significantly contributes to the understanding of light-driven O2 activation and lays the foundation for the design of cost-effective and efficient pollution remediation systems.

Green production of functionalized few-layer borophene decorated with cerium-doped iron oxide nanoparticles for repeatable hydrogen peroxide detection

Functionalized few-layer borophene (FFB) was prepared using gallnut extract and coffee waste extract as natural exfoliating and stabilizing agents in an environmentally friendly ultrasonic and high shear exfoliation. Here, a facile precipitation method was employed to grow iron oxide nanoparticles doped with cerium (Ce-FeONPs) onto the surface of FFB. This intriguing combination of materials yielded Ce-FeONPs nanoparticles that exhibited exceptional peroxidase-like activity, efficiently catalyzing the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H2O2). Additionally, the introduction of FFB contributes a reducibility effect to the catalytic oxidation of TMB, facilitating the restoration of the oxTMB to TMB. Thus, FFB-Ce-FeONPs showcase intriguing properties encompassing both oxidative and reductive characteristics, suggesting their potential as a reagent for repeated detection of H2O2. Moreover, a colorimetric sensing system enabled the liner detection of H2O2 spanning a concentration range from 0.08 to 1 mM, with a detection limit of 0.03 mM. Noteworthily, FFB-Ce-FeONPs demonstrated sustained efficacy over ten successive recycling cycles, as indicated by consistent slopes and observable color changes. In summary, this work reports the first application of nanoenzymes in repetitive H2O2 detection. Even after ten multiple cycles, the detection limit remains virtually unaltered, underscoring the robustness and enduring effectiveness of the engineered nanomaterial. The proposed simultaneous oxidation and reduction strategies for detecting H2O2 showed a commendable capability in ten cycles of H2O2 detection, thus providing a promising approach in the field of H2O2 detection.

Ultrathin Ru-CdIn2S4 nanosheets for simultaneous photocatalytic green hydrogen production and selective oxidation of furfuryl alcohol to furfural

Biomass is an important sustainable carbon source and converting biomass intermediates into value-added chemicals/fuels using a green technology is a promising sustainable pathway. Dual-functional photocatalysis can be used to “hit two birds with one stone” via the simultaneous production of hydrogen (H2) and valorisation of the biomass intermediates. CdIn2S4 (CIS) is an exciting photocatalytic material because of its high visible-light harvesting capacity. Herein, ultrathin CIS nanosheets were fabricated via a solvothermal method with in situ deposition of Ru (Ru-CIS). The photocatalytic performance of Ru-CIS toward the selective oxidation of furfuryl alcohol (FOH, a biomass intermediate), to a value-added product (Furfural, FCHO) with concurrent generation of hydrogen was investigated. Ru incorporation resulted in up to 50-fold enhancement in H2 production rate and higher FOH to FCHO conversion% and selectivity%. This enhancement was attributed to the enhanced charge separation due to the incorporated Ru species, as supported by density functional theory (DFT) calculations.

Enhanced removing of cyanobacterium by NZVI coupled with H2O2: Influencing factors and removal mechanisms

AbstractAs advanced oxidation processes (AOPs) is considered to be a highly effective approach for degrading organic pollutants, the simultaneous coagulation and oxidation process by the Fenton‐like reaction of nanoscale zero‐valent iron (NZVI) and hydrogen peroxide (H2O2) is investigated to eliminate the harmful cyanobacterium Microcystis aeruginosa in this study, and the process conditions are optimized using the central composite design of response surface methodology (RSM); in addition, the removal efficiency of M. aeruginosa (in terms of chlorophyll a, Chl a) and the verifications of the antioxidant abilities, as well as extracellular organic matters (EOM) and intracellular organic matters (IOM) are investigated under the optimized conditions. Results indicate that H2O2 concentration is the key factor affecting the Chl a removal efficiency, and the maximum Chl a removal reaches 98.10% under the optimized conditions: NZVI concentration 62.82 mg L−1, H2O2 concentration 54.2 mmol L−1, pH 4.38 and rotating speed 67 rpm. The high correlation coefficient (R2 > 0.80) of analysis of variance (ANOVA) demonstrates the RSM model is extremely significant and suitable for experimental results. Moreover, the total organic carbon (TOC) and fluorescent substances (soluble cyanobacteria metabolic byproducts, aromatic proteins II, humic and fulvic acid‐like compounds) for both EOM and IOM are enhanced removal. It is speculated the removal mechanisms of the Fenton‐like process of NZVI/H2O2 for cyanobacterium belongs to the combined actions of the oxidation of Fe(II)/H2O2 and the coagulation of Fe(III), which destroy the defense system and result in the removal of M. aeruginosa.

CO2 photoreduction integrated with oxidative coupling of amines over WO3/Cu(BTC) nanocomposite

Here, we report an efficient integrated CO2 photoreduction to methanol accompanied with the simultaneous oxidation of benzyl amines to corresponding imines using quadrangular WO3 nanoplates grafted with Cu(BTC) as a photocatalyst under visible light, enabling to provide efficient use of the photogenerated electrons and holes. Under the optimized reaction conditions, the maximum yield of methanol and N-(4-methoxybenzyl)-1-(4-methoxyphenyl)methanimine was found to be 642 μmol-g−1 and 98 %, respectively. The developed integrated dual functional system comprising CO2 reduction coupled with the oxidative organic synthesis opens a new window for value chain up gradation at both ends using sustainable solar energy.

Coupled one-pot oxidative extractive desulfurization of a model fuel catalyzed by nanostructured-ZIF-67/Biomass-derived activated carbon composite

The simultaneous oxidation and extraction of refractory sulfur compounds, such as DBT, has emerged as one of the most efficient complementary procedures for the HDS process in achieving ultradeep desulfurization of fuels. In this paper, a bio-based activated carbon (AC) obtained from the waste of date palm bark has been utilized as an abundant, green, and low-cost support for synthesizing a stable metal-organic framework, zeolitic imidazolate framework-67 (ZIF-67), on its structure to reach a novel nanocomposite catalyst (AC/ZIF-67) for the removal of DBT from a model fuel through the extractive oxidative desulfurization method. The accuracy of the AC/ZIF-67 catalyst formation was comprehensively characterized using XRD, FTIR, FESEM, BET, and TGA analytical techniques. Subsequently, the newly synthesized nanocomposite catalyst was employed efficiently for removing DBT from a toluene solution, acting as a model fuel. The impact of various operating variables, i.e. catalyst dosage, the temperature of reaction, oxidant-to-sulfur (O/S) molar ratio, contact time, initial concentration of DBT, and volume of extraction solvent on the removal efficiency has been thoroughly investigated. The results revealed that employing only 25 mg of the AC/ZIF-67 catalyst could achieve a remarkably high efficiency of around 98 % after one hour oxidation of a 25 ppm DBT solution in the presence of TBHP, followed by extraction using acetonitrile. This was achieved while maintaining a constant temperature of 60 °C and an O/S ratio of 20. The obtained results confirm the potential application of ACs for supporting MOF catalysts in various catalytic processes such as desulfurization.

Simultaneous catalytic oxidation of Hg0 and NO over CoxCuy metal oxides catalyst

In this work, Co3O4, CoxCuy and CuO metal oxides catalysts were synthesized by coprecipitation method and tested in catalytic oxidation of Hg0 and NO. The Co3Cu1 catalyst exhibited nearly 100% Hg0 oxidation efficiency at 100–400 ℃ and 84% NO oxidation efficiency at 250 ℃. Respectively, 1155.2 μg g−1 Hg0 adsorption capacity and 92.9 μmol g−1 NOx adsorption capacity over Co3Cu1 catalyst were measured by Hg0-TPD and NOx-TPD. The largest BET specific surface area of Co3Cu1 catalyst was obtained, reaching 26.2 m2 g−1. And H2-TPR demonstrated that the first reduction peak temperature (192 ℃) of Co3Cu1 catalyst was much lower than that of other catalysts. O2-TPD illustrated that the oxygen storage capacity and oxygen mobility ability of Co3Cu1 catalyst were higher than that of other catalysts. These results were consistent with the results of Hg0 and NO oxidation activity tests. In addition, in-situ DRIFTS spectra of NO adsorption indicated that the band at 1390 cm−1 over Co3Cu1 catalyst disappeared after the pretreatment of Hg0. And the transient experiments of Hg0 adsorption suggested that Hg0 could also be extruded from the surface of Co3Cu1 catalyst after the introduction of NO. It was speculated that there might be competitive adsorption between Hg0 and NO over Co3Cu1 catalyst. Finally, the XPS characterization demonstrated that the Oα and the redox cycle of Co3+ + Cu+ ↔ Co2+ + Cu2+ were involved in Hg0-NO simultaneous oxidation. The Co3Cu1 catalyst was an excellent candidate for Hg0-NO oxidation reaction.

Facile synthesis of Bi3O(OH)(AsO4)2 and simultaneous photocatalytic oxidation and adsorption of Sb(III) from wastewater

Antimony (Sb) decontamination in water is necessary owing to the worsening pollution which seriously threatens human life safety. Designing bismuth-based photocatalysts with hydroxyls have attracted growing interest because of the broad bandgap and enhanced separation efficiency of photogenerated electron/hole pairs. Until now, the available photocatalysis information regarding bismuth-based photocatalysts with hydroxyls has remained scarce and the contemporary report has been largely limited to Bi3O(OH)(PO4)2 (BOHP). Herein, Bi3O(OH)(AsO4)2 (BOHAs), a novel ultraviolet photocatalyst, was fabricated via the co-precipitation method for the first time, and developed to simultaneous photocatalytic oxidation and adsorption of Sb(III). The rate constant of Sb(III) removal by the BOHAs was 32.4, 3.0, and 4.3 times higher than those of BiAsO4, BOHP, and TiO2, respectively, indicating that the introduction of hydroxyls could increase the removal of Sb(III). Additionally, the crucial operational parameters affecting the adsorption performance (catalyst dosage, concentration, pH, and common anions) were investigated. The BOHAs maintained 85% antimony decontamination of the initial yield after five successive cycles of photocatalysis. The Sb(III) removal involved photocatalytic oxidation of adsorbed Sb(III) and subsequent adsorption of the yielded Sb(V). With the acquired knowledge, we successfully applied the photocatalyst for antimony removal from industrial wastewater. In addition, BOHAs could also be powerful photocatalysts in the photodegradation of organic pollutants studies of which are ongoing. It reveals an effective strategy for synthesizing bismuth-based photocatalysts with hydroxyls and enhancing pollutants’ decontamination.

Electrochemical Nanosensor for the Simultaneous Determination of Anticancer Drugs Epirubicin and Topotecan Using UiO-66-NH2/GO Nanocomposite Modified Electrode.

In this work, UiO-66-NH2/GO nanocomposite was prepared using a simple solvothermal technique, and its structure and morphology were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). An enhanced electrochemical sensor for the detection of epirubicin (EP) was proposed, which utilized a UiO-66-NH2/GO nanocomposite-modified screen-printed graphite electrode (UiO-66-NH2/GO/SPGE). The prepared UiO-66-NH2/GO nanocomposite improved the electrochemical performance of the SPGE towards the redox reaction of EP. Under optimized experimental conditions, this sensor demonstrates a remarkable limit of detection (LOD) of 0.003 µM and a linear dynamic range from 0.008 to 200.0 µM, providing a highly capable platform for sensing EP. Furthermore, the simultaneous electro-catalytic oxidation of EP and topotecan (TP) was investigated at the UiO-66-NH2/GO/SPGE surface utilizing differential pulse voltammetry (DPV). DPV measurements revealed the presence of two distinct oxidation peaks of EP and TP, with a peak potential separation of 200 mV. Finally, the UiO-66-NH2/GO/SPGE sensor was successfully utilized for the quantitative analysis of EP and TP in pharmaceutical injection, yielding highly satisfactory results.

La-doped Al2O3/g-C3N4 /agarose aerogel for removal of As(III) via simultaneous photocatalytic oxidation and adsorption

Attributing to its ubiquitous nature, arsenic (As) is frequently detected in various waterbodies across the globe, at concentrations often exceeding the permissible limits. In view of the acute and chronic toxicity of the arsenite species (As(III)), it is highly recommended to remove As(III) from aqueous matrices. Herein, we propose a agarose-based La-doped Al2O3/g-C3N4 (LAC) aerogel as a novel adsorptive photocatalyst for removal of As(III) via the synergistic effect of adsorption and photocatalysis. While g-C3N4 could transform As(III) to As(V) through photocatalytic oxidation, La-doped Al2O3 provided strong adsorption sites for the resulting As(V). Accordingly, the combination of adsorption and photocatalytic transformation of highly toxic As(III) into less toxic As(V), followed by subsequent adsorption of the latter can be considered as a promising technique to treat arsenic-contaminated water. The as-prepared aerogel was successfully characterized via a range of state-of-the-art microscopy, spectroscopy, and surface-specific analytical techniques. The optimized aerogel demonstrated a removal efficiency of 66.5% after 300 min of UV light irradiation. Furthermore, evaluating the effects of various reactive oxygen species via free-radical quenching experiments revealed that superoxide radicles (•O2−), singlet oxygen (1O2), and holes (h+) played a role key in the photocatalytic oxidation of As(III). More importantly, the LAC aerogel was structurally resilient and can be reused over multiple cycles, without any significant loss of the desired functionalities. Based on these deliberations, the integration of g-C3N4 with La-Al2O3 in the form of aerogel can be considered as a prospective strategy for the removal of arsenic from aqueous phase.

Revealing the characteristics of coagulant and ·OH generation in the electrocoagulation coupled with E-peroxone process and comparison of the synergistic effect for water purification

Electrocoagulation (EC) coupled with E-peroxone process (ECP) offers a promising approach for simultaneous coagulation and oxidation, enhancing contaminant removal efficiency and current efficiency within a single electrochemical system. However, understanding the production characteristics of active species and their synergistic effects remains limited. This study comprehensively investigated the production of active species (i.e., ·OH and coagulant) during the ECP process and explored their synergistic effect in real water purification. Increasing current density and O3 dosage led to significant enhancements in ·OH and Alb production. The synergistic factor (β) for ·OH production ranged from 1.68 to 1.73 for lower current density and from 1.19 to 1.32 for higher current density, while β for ·OH production in ECP increased from 0.77 to 1.16–1.19 with increased O3 dosage. Besides O3 decomposition and cathodically-induced H2O2 production, alternative pathways contributed to enhanced ·OH production and synergistic effects. The Al-based coagulant facilitated the reaction with O3, initiating a chain reaction for ·OH and Alb production. Furthermore, the feasibility and synergistic effects of ECP for two water matrices (surface water and shale gas produced water) were compared. ECP exhibited superior performance for both matrices, with TOC removal exceeding 63.2 % for surface water and 87.0 % for shale gas produced water. The study provides deeper insights into the ECP process, highlighting its potential for sustainable water treatment.