Oxidation Process Research Articles

Structure-based drug design of pre-clinical candidate nanopiperine: a direct target for CYP1A1 protein to mitigate hyperglycaemia and associated microbes

ABSTRACT Diabetes is attributed to an increased vulnerability to bacterial infection linked to unregulated hyperglycaemia. The present study highlights the formulation of nanoparticles with phyto-compound piperine (PIP) encapsulated within non-toxic biodegradable polymer poly-lactide co-glycolide (PLGA) which showed a variety in surface functionality, biocompatibility, and the ability to tailor an optimized release rate from its polymeric enclosure. The observations revealed that nanopiperine (NPIP) pre-treatment in mice inhibited alteration in hepatic tissue architecture and hepato-biochemical parameters in diabetes and its associated bacterial infections. NPIP also decreased the propensity of lipids to undergo an oxidation process and stabilized the membrane lipids in vivo, thereby lowering oxidative stress and preventing enzymatic activation of CYP1A1. This result is corroborated with the in silico molecular docking study where PIP binding with CYP1A1 gave −11.32 Kcal/mol dock score value. The antibacterial activity of PIP was further demonstrated by the in silico PIP and Ef-Tu protein-binding efficacy revealing −6.48 Kcal/mol score value which was coupled with the results of in vitro studies where the zone of inhibition assay with NPIP against Staphylococcus aureus and Escherichia coli. Thus, NPIP could serve as a potential drug candidate in modulating targeted proteins to inhibit the progression of hyperglycaemia and its associated microbes.

Role of the Sn-TiO2/Ti-SnO2 Heterojunction in Enhancing the Photocatalytic Oxidation of Arsenite (AsIII) through the Promotion of Charge Carrier Lifetime.

This study proposes the heterojunction photocatalyst, Sn-doped TiO2/Ti-doped SnO2 (herein named Sn1Ti1O2), as a promising alternative to pure TiO2. Sn1Ti1O2 demonstrates improved light harvesting efficiency over TiO2 by generating longer-lived electron-hole (eCB--hVB+) pairs, while also displaying a smaller band gap compared to pure TiO2. Consequently, we show that it is a promising candidate for the photocatalytic oxidation (PCO) of AsIII to the less toxic and more readily removable form AsV. Transient absorption spectroscopy (TAS) shows increased eCB--hVB+ recombination half-lives from ∼0.5 ms in TiO2 to ∼1 ms in Sn1Ti1O2. The initial transient absorption signal for Sn1Ti1O2 is twice that of pure TiO2, suggesting early time scale (pre-μs) suppression of (eCB--hVB+) recombination. Moreover, TAS showed that Sn1Ti1O2 possesses more reactive charge carriers than TiO2 under reactions with chemical scavengers. For the first time, TAS experiments were conducted using both a colorimetric indicator (molybdate) and AsIII to determine the PCO kinetics from AsIII to AsV. The TAS molybdate─AsIII experiment results indicate that the oxidation process occurs on the sub-microsecond time scale, with a notable increase in absorption at ∼700 nm, providing evidence of the formation of the AsV─molybdate blue complex. PCO experiments showed that •OH radicals played the predominant role during PCO, followed by superoxide radicals (O2•─). •OH scavengers including isopropanol, rebamipide anhydrous, and dimethyl sulfoxide (DMSO) reduce the PCO yield of AsIII to 21, 30, and 23%, respectively. While O2•─ scavengers including superoxide dismutase (SOD) and p-benzoquinone suppressed the PCO yield of AsIII to a lesser degree, with yields of 35 and 49% seen, respectively. The effects of irradiance intensity, salinity, pH, AsIII concentration, and photocatalyst mass on both the quantum efficiency (QE) and PCO kinetics were investigated. The Sn1Ti1O2 catalyst exhibited effective recyclability, validating its economical reusability. Overall, the study demonstrates the potential of the Sn1Ti1O2 heterojunction photocatalyst for the PCO of AsIII to the less toxic AsV in water treatment, showing faster oxidation kinetics and improved charge separation compared to pure TiO2 as proven by TAS.

Insights into the Removal of Organic Contaminants by Co-CeO2 Nanocatalysts via CaCO3 Activation: Performance, Kinetic, and Mechanism.

The advanced oxidation process based on S(IV) has garnered increasing attention, owing to its efficiency in degrading contaminants. Here, a cobalt-doped cerium oxide catalyst (Co-CeO2) was employed to activate calcium sulfite (CaSO3) for imidacloprid degradation. The Co-CeO2 catalyst was characterized by using SEM, BET, XRD, and XPS techniques to analyze its structural and chemical properties. XPS analysis revealed the presence of Co0, Co2+, and Co3+ species in the Co-CeO2 catalyst. Compared to the CeO2/CaSO3 system, the Co-CeO2/CaSO3 system significantly enhanced the degradation rate of imidacloprid from 5.00% to 94.01%. Scavenging experiments, in conjunction with electron paramagnetic resonance spectroscopy, identified hydroxyl radicals (•OH), sulfate radicals (SO4•-), superoxide radicals (O2•-), sulfite radicals (SO3•-), and singlet oxygen (1O2) as the primary reactive species responsible for the degradation of imidacloprid within the Co-CeO2/CaSO3 system. Density functional theory calculation analysis was employed to investigate the specific sites of imidacloprid attacked by reactive oxygen species, proposing four potential degradation pathways. Furthermore, the Ecological Structure Activity Relationships (ECOSAR) program predicted a significant diminution in the toxicity of intermediate products compared to imidacloprid. Even after five cycles, Co-CeO2 maintained an excellent removal efficiency of 86.35%.

Hydrogen Production from Wastewater Degradation on a Rotating Hole-Arranged Boron-Doped Diamond Anode

An electrochemical system using a rotating hole-arranged boron-doped diamond (HABDD) film anode was designed for wastewater degradation. Meanwhile, in a reciprocal process, a foam nickel (FNi) cathode was employed for hydrogen evolution using the ions liberated from the HABDD. The HABDD was custom-made using an MWCVD device and characterized by SEM, Raman and electrochemical measurement. Some wastewater was tested on the HABDD anode to examine its electrochemical performance. The efficiency of the electrochemical system was evaluated by COD removal rate and hydrogen production yields. The influence of the rotating and flowing rates of the electrolyte on electrochemical performance was discussed. The rotating HABDD with dynamic three-dimensional flowing paths provided a high mass transfer, which promoted the overall performance of the wastewater mineralization. Meanwhile, the ions released from the anode to the cathode improved the hydrogen generation performance on the cathode. The hydrogen production efficiency in relation to the electrochemical oxidation process was studied in terms of the COD change and treatment time.

Revealing the Overlooked Catalytic Ability of γ-Al2O3: Efficient Activation of Peroxymonosulfate for Enhanced Water Treatment.

Activated alumina (γ-Al2O3) is one of the few nanomaterials manufactured at a ton-scale and successfully implemented in large-scale water treatment. Yet its role in advanced oxidation processes (AOPs) has primarily been limited to functioning as an inert carrier due to its inherently nonredox nature. This study, for the first time, presents the highly efficient capability of γ-Al2O3 to activate peroxymonosulfate (PMS) for selectively eliminating electron-rich organic pollutants in the presence of Cl-. Through experimental and theoretical analysis, we revealed that γ-Al2O3, characterized by uniquely strong Lewis acid sites, enabled robust inner-sphere complexation between PMS and Al(III) sites, triggering the oxidation of Cl- to free chlorine through a distinctive, low-energy-barrier Eley-Rideal pathway. Such a unique pathway resulted in a 42.7-fold increase in free chlorine generation, culminating in a remarkable 145.9-fold enhancement in the degradation of carbamazepine (CBZ) compared with the case without γ-Al2O3. Furthermore, this catalyst exhibited high oxidant utilization efficiency, stable performance in real-world environmental matrices, and sustained long-term activation for over 1206 bed volumes (BV) with a CBZ removal rate exceeding 90% in fixed-bed experiments. These favorable features render γ-Al2O3 an extremely promising nanomaterial for sustainable water treatment initiatives.

Real-time in situ monitoring as a tool for comparison of electrochemical advanced oxidation processes for the decolourisation of azo and indigoid dyes.

The widespread use of synthetic dyes has led to the release of substantial amounts of dye-contaminated wastewater, posing significant environmental and health concerns. This study focuses on the use of anodic and electrochemically activated persulfate oxidation for the degradation of organic contaminants. Specifically, the structural variations of nine dyes in the indigoid and azo families, and their impact on the efficiency of electrochemical oxidation were analysed. An in situ continuous monitoring apparatus with a UV-visible detector was employed to collect data in real-time. The electrochemically activated persulfate system demonstrated higher efficiency compared to the anodic oxidation approach. In both systems the efficiency of decolourisation was highly dependent on the structure of the pollutant. Electron-withdrawing substituents in direct conjugation with the chromophore, bulky auxochromes, and extended aromatic systems significantly decreased the decolourisation efficiency. Conversely, changing the location of electron-withdrawing groups and adding electron-donating substituents increased the decolourisation efficiency, even overcoming the detrimental effects of bulky groups and extended conjugation. This type of systematic structural comparison study is essential for highlighting the interconnected nature of pollutant structure and degradation speed so that efficient electrochemical oxidation systems can be designed for the treatment of genuine wastewater effluent containing more than one pollutant.

Microwave-assisted oxidation of naphthenic acids in aqueous phase

Naphthenic acids (NAs) in oil sands processing wastewater (OSPW) pose a significant environmental risk. This study investigates the effectiveness of three oxidants, hydrogen peroxide (H2O2), persulfate (PS), and percarbonate (PC), in degrading synthetic OSPW containing a commercial mixture of NAs (50 mg/L) via microwave-assisted oxidation catalyzed by graphite (500 mg/L). Initial experiments using stoichiometric oxidant doses revealed that PC led to NAs’ carboxylation, increasing Total Organic Carbon (TOC). H2O2 was only effective at acidic pH (pH: 3), while PS achieved high mineralization (>85 %) in all cases, whilst decreasing the pH to 2.Although PS efficiently mineralized NAs, it generates sulfate, increasing salinity and hindering water reuse or discharge. To address this, a sequential oxidation process was proposed. Firstly PS was employed to initiate degradation and decrease pH, followed by H2O2 for further purification. A combined dose of 30% stoichiometric PS and 70% stoichiometric H2O2 was selected to treat OSPW in both ultrapure and brackish water matrices. The microwave-assisted PS-H2O2 process demonstrated significant potential, achieving 74% TOC removal in 20 min. Furthermore, toxicity assessments using Artemia salina confirmed a reduction in NAs' toxicity after treatment.

Research on the oxidation process of micro-boron below the melting point temperature

The ignition and combustion characteristics of boron and the energy release rate of boron-based fuel are closely related to the surface oxide layer of boron. To understand the oxidation process of boron below its melting point, the slow oxidation process of boron under different temperature and humidity storage conditions and the fast oxidation process under high-temperature conditions were investigated. The results indicate that the surface oxide layer mainly comprises boron (B), boron suboxides (BxOy), and boron trioxide (B2O3). When the degree of oxidation is low, BxOy and B are the main components. After deep oxidation, BxOy almost disappeared. The thickness and composition of the surface oxide layer vary with changes in environmental temperature, humidity, and aging time. The effect of temperature increase on the growth rate of the oxide layer thickness is significantly greater than that of moisture. With the prolongation of boron aging treatment time, the onset, end, and maximum weight gain rate temperatures of the boron thermal oxidation process all slightly decrease. As the ambient temperature increases, the formation of the oxide layer transitions from a unidirectional diffusion mechanism of oxygen into the interior of boron particles to a bidirectional diffusion mechanism of molten oxide and oxygen.

Simulation of rapid sand filters to understand and design sequential iron and manganese removal using reactive transport modelling

Iron (Fe2+), manganese (Mn2+), and ammonium (NH4+) oxidation processes were studied in three single media and three dual media full-scale rapid sand filters (RSFs) using reactive transport modelling (RTM) in PHREEQC and parameter estimation using PEST. Here, we present the insights gained into the spatial distribution of Fe and Mn mineral coatings in RSFs and its influence on the oxidation sequence and rates. Fe2+ and Mn2+ oxidation predominantly occurred simultaneously in the RSFs, contrary to the expected sequential oxidation based on Gibbs free energy calculations. During backwashing, RSF grains become fully mixed, which initiates heterogeneous Mn2+ oxidation on Mn-coated grains that end up in the top layer. The resulting grains have a mixed Fe/Mn mineral coating, which is limiting heterogeneous Mn2+ oxidation due to the limited Mn mineral surface available. Mixed coatings did not seem to affect Fe2+ oxidation rates, instead oxidation rates were increasing at lower pH. We found that RSFs can be designed to spatially separate Fe2+ and Mn2+ oxidation, which results in optimal conditions for Mn2+ oxidation. The RSF needs to consist of two layers with varying density to inhibit mixing and complete Fe2+ oxidation should occur in the top layer. The developed RTM can be used to estimate the depth at which Fe2+ oxidation is complete, and thus the ideal intersection depth of the two layers. A novel perspective is provided on how mineral coating distribution in single and dual media filters influence removal rates and the sequence of oxidation, which contributes to the design of more efficient groundwater filters.

Stability Analysis of Jet Fuel-Bioethanol Blends: an Experimental Approach

Incorporating bioethanol into jet fuel blends has garnered increasing attention as a viable strategy to reduce dependence on fossil fuels and address environmental issues. This study investigates the influence of different amounts of bioethanol on the stability properties of jet fuel blends. Bioethanol addition to jet fuel causes a steady increase in its freezing point. The alteration has been attributed to the destabilizing effect caused by polar hydrogen bonds in bioethanol on the intermolecular forces. Oxidation stability analysis demonstrates a clear correlation between ethanol content and a swift decrease in pressure resistance. Although pure jet fuel is highly stable, mixes that include bioethanol show much lower stability. This decline highlights the reduced impact of bioethanol on fuel stability and oxidation processes. The simultaneous occurrence of gum formation emphasizes the need for careful formulation strategies to prevent stability problems and system complexities. Moreover, the complex influence of bioethanol on the temperature, stability, and oxidation properties of jet fuel blends highlights the importance of using accurate formulation methodologies to improve aviation fuels.

Decoration of CeO2 nanoparticles on Cu/Co bimetallic oxide and their catalytic performance

We have developed a series of Co-Cu bimetallic oxide nanocatalysts using an environmentally friendly water phase synthesis method, demonstrating significant potential in catalyzing the CO oxidation reaction. The 0.3Co3O4/0.7CuO nano-hybrid, with a feed ratio of 3:7 for Cobalt(II) chloride hexahydrate to Copper(II) chloride dihydrate, exhibited a CO catalytic oxidation T90 approximately 70 °C lower than that of a single transition metal oxide material. Building on this, we enhanced the catalysts by incorporating CeO2 nanoparticles to produce Co3O4/CuO/CeO2 oxide nanocatalysts. By varying the amount of CeO2 nanoparticles added to the 0.3Co3O4/0.7CuO catalyst, we achieved further improvement in the CO oxidation performance. Specifically, the T90 of the CO catalytic oxidation reaction for the 0.3Co3O4/0.7CuO/0.7CeO2 material was approximately 30 °C lower than that of 0.3Co3O40.7CuO. Various characterization methods, such as XRD, EDX, and in situ FT-IR, were employed to investigate the impact of different components on the CO oxidation process and the potential reaction mechanism. The results indicated that the introduction of CeO2 successfully enhanced the activity and stability of the catalysts.

TRPV1 Promotes Periodontitis Tissue Inflammation and Oxidative Damage by Regulating STAT3 Signaling Pathway.

Periodontitis is a chronic disease affecting adult oral health. Transient receptor potential vanilloid 1 (TRPV1) expression is shown to upregulate in many inflammatory diseases. Nevertheless, its biological potential along with the molecular mechanism in periodontitis is unclear. Our study aimed to explore the biological role and underlying signaling pathway of TRPV1 in periodontitis. In the current research, human periodontal ligament stem cells (hPDLSCs) were stimulated by lipopolysaccharide (LPS) to induce inflammatory conditions invitro. Invivo, the periodontitis mouse model was built by ligating the gingival sulcus of male C57BL/6J mice. Thereafter, the proliferation, apoptosis, inflammation, and oxidative stress-related processes were assessed. We found that LPS induced apoptosis and inflammation in hPDLCs, along with oxidative stress, while simultaneously inhibiting hPDLC proliferation (p < 0.05). Notably, TRPV1 expression was elevated in LPS-treated hPDLSCs and gingival samples from patients with periodontitis. Interestingly, the increase in TRPV1 expression induced by Capsaicin, a TRPV1 agonist, inhibited cell proliferation while promoting LPS-stimulated apoptosis, inflammation, and oxidative stress in hPDLSCs (p < 0.01). In contrast, inhibition of TRPV1 expression using Capsazepine, a TRPV1 inhibitor, produced opposite effects (p < 0.01). Invivo experiments revealed that inhibition of TRPV1 attenuated ligation-induced periodontitis in mice, as evidenced by enhanced oxidative stress, inflammatory response, and elevated apoptosis (p < 0.01). Additionally, rescue assays indicated that TRPV1 promoted periodontitis-associated tissue inflammation and oxidative damage via activating the STAT3 signaling pathway (p < 0.01). Our study demonstrates that TRPV1 expression is high in periodontitis and facilitates periodontitis-associated tissue inflammation and oxidative damage by regulating STAT3 signaling pathway, which implies that TRPV1 may represent a new therapeutic target for periodontitis.

Unveiling the mechanism underlying in−situ enhancement on anammox system by sulfide: Integration of biological and isotope analysis

The in−situ utilization of sulfide to remove the nitrate produced during the anaerobic ammonium oxidation (anammox) process can avoid prolonged sludge acclimatization, facilitating the rapid initiation of coupled nitrogen removal processes. However, the understanding of in−situ enhancement on anammox system by sulfide remains unclear. Herein, sulfide (Na2S) was introduced as an additional electron donor to remove the nitrate derived from the anammox under varying sulfide/nitrogen (S/N, S2−-S/NO3–-N, molar ratio) ratios (0.004–4.375). The underlying mechanisms were elucidated by molecular biology techniques including flow cytometry, quantitative polymerase chain reaction, and 16S rRNA amplicon sequencing, alongside isotope tracer analysis. Results revealed that anammox reactors, when operated with in−situ sulfide addition, exhibited a significant enhancement in total nitrogen removal efficiency (NRE) ranging from 11.5%−41.7% (achieved 96%), with the optimal S/N ratios of 0.01−0.8. Isotope tracer analysis indicated the successful coupling of the anammox, sulfur autotrophic denitrification (SADN), and dissimilatory nitrate reduction to ammonium (DNRA) processes within the system, with their contributions to nitrogen removal being 46%−50%, 24%−30%, and 20%−22%, respectively. Moreover, a notable increase in the abundance of sulfur–oxidizing bacteria (SOB) (20%−40% increase) and DNRA bacteria (10%−20% increase) were observed. Effective collaboration was further supported by the sustained viability of microbial communities. It is speculated that the heightened presence of SOB and DNRA bacteria created a low toxicity environment by converting sulfide to biogenic sulfur, thereby promoting the well−being of anammox bacteria. However, the excessive dosage of sulfide (S/N=1.8) intensified the DNRA process (contribution>35%) and weakened the anammox process, leading to an increase in effluent NH4+-N concentration and a decline in NRE. This study confirms that the in−situ adding an appropriate amount of sulfide favors achieving complete nitrogen removal in anammox system, which provides a novel avenue to resolve the issue of the residual nitrate in anammox process.

Magnetization mechanisms for non-destructive evaluation of low-carbon steels subject to early-stage low-temperature thermal oxidation

In this work, an investigation is done to identify the magnetic non-destructive testing techniques and their related magnetization mechanisms and, eventually, the associated indicators that present the most distinguishable response to changes in steel properties due to the onset and evolution of starting corrosion by thermal oxidation at low temperatures. This is found by measuring magnetic responses of Magnetic Hysteresis Cycle (MHC), Magnetic Barkhausen Noise (MBN), and Magnetic Incremental Permeability (MIP) at the early stage of corrosion. Herein, the magnetization mechanism identified by the Domain Wall Bulging (DWB) effect and represented by the indicator Δ|Z|MIP from the MIP response is ranked the most sensitive indicator by Pearson’s linear correlation coefficient (LCC). It is immediately followed by the Domain Wall’s Irreversible Motions (DWIM) represented by the MBN coercivity indicator. Both mechanisms are associated with the structure and kinetic of the magnetic domains, respectively, under low and medium magnetic excitations. The low-temperature thermal oxidation process set out the constructive effect of the oxide layer in the strain relief effect on the overall magnetic response of the corroded specimen. Discussions and conclusions are provided, as well as perspectives regarding the applicability of magnetic non-destructive testing techniques.

Feasibilty of UVC-LED/H2O2 Advanced Oxidation Processes as a Hybrid Water Treatment System Uniting Secondary Battery and Microbial Fuel Cell

An innovative hybrid water treatment system consisting of an ultraviolet C light-emitting diode sequentially connected to a secondary battery and microbial fuel cells was developed and systematically optimized via an electrochemical performance test. According to standardized bio-dosimetry, the generated ultraviolet intensity powered by a pre-charged battery was determined to be 2.3×10-1 μW cm-2. The quantified UV intensity was used in calculating the fundamental kinetic parameters for the inactivation of microbial entities and the degradation of organic pollutants during UVC-LED and UVC-LED/H2O2 treatment processes. The fluence-based first-order rate constants were 1.07 and 2.43 cm2/mJ for Escherichia coli and 0.10 and 0.18 cm2/mJ for MS-2 bacteriophage, respectively. The study detected 2.76–8.00×10−16 M hydroxyl radicals at steady-state during UVC-LED/H2O2 treatment with 0.3–1mM H2O2. The second-order rate constant for atrazine during UVC-LED/H2O2 treatment was 1.90×109M−1 s−1 according to linear regression analysis of atrazine elimination over •OH exposure. This comprehensive investigation expands the application of microbial electrochemical systems in water treatment, providing a fundamental kinetic dataset for quantifying and predicting the microbial and (persistent) organic pollutants abatement.

Tetracycline degradation for wastewater treatment based on ozone nanobubbles advanced oxidation processes (AOPs) – Focus on nanobubbles formation, degradation kinetics, mechanism and effects of water composition

Presence of pharmaceuticals, especially antibiotics, in industrial and domestic effluents causes serious damage to the environment. Classic wastewater treatment processes, in particular conventional biological treatment methods, are not sufficient to rapidly eliminate antibiotics. Typically, Advanced Oxidation Processes (AOPs) based on activation of hydrogen peroxide, ozone or persulfate for production of particular type of radical species or singlet oxygen are used. A one of cutting-edge technologies to increase effectiveness of AOPs based on ozone are nanobubbles based processes. Thus, this paper focuses on utilization of ozone in the form of nanobubbles for degradation of tetracycline (TC). The effects of several reaction parameters, such as antibiotic concentration, ozone intake, pH, presence of salts, were investigated. This study revealed that the presence of ozone nanobubbles had a substantial positive impact on the degradation of TC. This improvement may be attributed to the enhanced mass transfer and the production of reactive radicals that occur during the collapse of the nanobubbles. Identification of radical species revealed a significant contribution of hydroxyl radicals in the degradation of the antibiotic. AOP process based on O3 nanobubbles was most (•OH) and superoxide (O2–) effective with 100 % degradation efficiency of 100 mg/L TC within 20 min at 8 mg/L concentration of ozone. Based on identified by LC-MS intermediates a degradation mechanism has been described. Degradation of TC and intermediates transformations included methylation, hydroxylation, ring-opening steps as well as cleavage of C-N bonds. This research introduces a novel technique combining nanobubbles with advanced oxidation processes (AOPs), which is anticipated to provide enhanced efficiency and environmental sustainability.

Efficient removal of 4-chlorophenol by activation of peroxymonosulfate with synthesized high-performance MnOx/CBC catalysts

Effective activation of peroxymonosulfate (PMS) is critical to remove chlorophenols (CPs) in the well-used sulfate radical advanced oxidation processes (SR-AOPs). Though manganese oxides (MnOx) have shown remarkable performance in activating PMS in SR-AOPs, the ease of agglomeration and relatively low crystallinity of MnOx can seriously decreases their activation efficiency. In this study, Camellia oleifera shell-based biochar (CBC) was employed as the support to load MnOx to prevent agglomeration, using the so-called co-precipitation approach. At the same time, low-temperature carbothermal reduction was utilized to increase crystallinity of MnOx while still maintaining promising surface structure of CBC. Using 4-chlorophenol (4-CP) as a representative for CPs, the synthesized MnOx/CBC showed high performance in activating PMS for degradation of 4-CP, with removal percentage up to 84.28%. Furthermore, the effects of roasting time, mass ratio between biochar and Mn, and roasting temperature on synthesis of MnOx/CBC were systematically investigated through the response surface methodology, and the obtained quadratic multinomial regression model can well predict the optimal synthesis condition. Finally, the underlined PMS activation mechanism by MnOx/CBC was explored, where main reactive oxygen species involved in degradation were found to be SO4•−, •OH, 1O2 and O2•−, and a possible routine was proposed. Overall, this work demonstrates the great potential of MnOx/CBC for activation of PMS for removing CPs.

Surface- and substrate-coated catalytic membrane for mitigating interference of water matrix species in intensified micropollutant confinement oxidation

The integration of advanced oxidation processes (AOPs) with membrane technology offers benefits for catalyst recovery and reducing membrane fouling. However, the application of the hybrid process could be hampered by the background species in water matrix. This study addresses this challenge by developing catalytic ceramic membranes (CCMs) with dual mechanisms to intensify acetaminophen (ACT) removal in water. The CCMs effectively activated peroxymonosulfate (PMS), achieving ACT degradation of 85% and 93% in real water matrices (reverse osmosis retentate and settled water, respectively) and 99% in MQ water. The CCMs demonstrated consistent performance across multiple operational cycles, even in the presence of humic acid (HA) (96% ACT reduction). The CCM design features Co3O4 catalytic layer on CCM surface, facilitating surface oxidation, reducing fouling, and TiO2 intermediate rejection layers serving as barrier for bulk organic pollutants, achieving 50% HA removal through rejection and 70% with 1.5mM PMS. This design facilitates catalytic degradation at the membrane surface, allowing retention and degradation of bulk organic pollutants and intermediates, while ACT permeates into CCM substrate. The surface oxidation and rejection enhanced confinement oxidation within the Co3O4-coated macropores, minimizing interference from background species. LC-QTOF analysis identified multiple degradation pathways, including hydroxylation, acetyl-amino group cleavage, side chain oxidation and benzene ring cleavage, with intermediates showing reduced toxicity. Reactive oxygen species involved in the system were identified and PMS activation mechanism was proposed. This research highlights the potential of the hybrid process, enhancing micropollutant removal by mitigating interference from background species, providing practical implications in water treatment applications.

A self-sufficient catalytic nanofiber evaporator for solar-driven efficient water purification through in-situ hydrogen peroxide generation

Solar-driven interfacial water evaporation (SDIWE) is an emerging technology for the production of clean water driven by inexhaustible energy source, but its application suffers from volatile organic compounds (VOCs) escaping into condensate water. Herein, a bifunctional SDIWE system integrated with Fenton process was proposed to achieve self-sufficient (not adding any additional chemicals to feed water) high-quality freshwater production from VOCs-contained wastewater through in-situ hydrogen peroxide (H2O2) generation. The hybrid SDIWE system based on AgNPs (Ag nanoparticles)@graphitic carbon nitride (g-C3N4)/beta-iron hydroxide oxide (β-FeOOH)-Polyacrylonitrile (AgG/Fe-PAN) nanofiber membrane exhibited an excellent evaporation performance (1.61 kg m-2h−1) under one sun (1 kW m−2). Significantly, in the absence of external oxidant source, the phenol removal rate in condensate water reached 98.4 ± 0.2 % due to the synergic photocatalysis technology and Fenton reaction, which was 6.1 times that of sole SDIWE (16.2 ± 0.5 %). Mechanism analysis reveals that H2O2 was effectively in-situ generated by AgNPs@g-C3N4 particles (∼18.8 μM at 4 h). Subsequently, the produced H2O2 was further activated to •OH radicals via β-FeOOH that ensures the VOCs decomposition during rapid steam generation. Meanwhile, the hybrid system not only exhibited an excellent phenol removal rate of 91.6 ± 0.6 % in wide pH ranges (1–11), but also ensured a good removal performance for various organic pollutants and excellent antibacterial properties. To sum up, the hybrid system has successfully integrated SDIWE technology with various advanced oxidation processes (AOPs), providing a novel way for the pollution-free production of high-quality clean water during the SDIWE process for water purification.

Efficient catalytic oxidation of xylose to formic acid with the oxygen vacancies of CeO2 promoted the vanadium catalysts anchored on biochar

The catalytic oxidation of carbohydrates for the preparation of formic acid (FA) is an prominent route for high-value utilisation of biomass. Reforming xylose, a biomass derivative, into FA with high efficiency is essential for the advancement of non-homogeneous V-type catalysts. Here, we present the self-assembly of V and Ce onto a cellulose pulp for the synthesis of oxygen vacancy (Ov)-rich non-homogeneous-bimetallic catalysts (5Ce-VOx/BC-600). Under the optimised conditions, 71.46 % FA was obtained, which far exceeded the catalytic performance of the single-metal catalyst. Furthermore, the 5Ce-VOx/BC-600 catalyst showed excellent stability and reusability. Kinetic studies revealed that glyceric and glycolic acids served as the pivotal intermediates, undergoing subsequent deacidification and oxidation processes to yield FA and CO2. The analysis of the catalytic mechanism indicated that the incorporation of Ce enhanced the quantity of acidic sites and the concentration of Ov in the 5Ce-VOx/BC-600 catalyst, which promoted substrate adsorption and O2 activation. Meanwhile, the catalyst showed high lattice oxygen (OL) mobility and assisted the redox cycle of V5+/V4+ to oxidise xylose to FA. Significantly, the synergistic effect of Ce, V species and Ov enhances the OL mobility of the catalysts, thus promoting the efficient oxidation of xylose. The catalytic system was further extended to the oxidation of other biomass derivatives to FA, demonstrating excellent catalytic performance.