Highly efficient removal of bisphenol A by a novel Co-doped LaFeO3 perovskite/PMS system in salinity water

Chloride-enhanced degradation of micropollutants in natural water by the iron/biochar/peroxymonosulfate system: Role of iron(IV) and radicals

The increased occurrence and concentration of micropollutants in water supplies raise public health concerns. Advanced oxidation of micropollutants in real water sources remains challenging due to scavenging reactions involving background anions and natural organic matter. For the first time, this paper demonstrates that chloride (Cl-) accelerates the activation of peroxymonosulfate (PMS) by iron-biochar (Fe/BC) composites. Under the tested conditions, this novel system completely degraded bisphenol A (BPA), a representative micropollutant, within 1.0 min. Micropollutant degradation was investigated at different Cl- contents, PMS levels, Fe/BC doses, and solution pH. The primary reactive species involved with BPA degradation were iron(IV) (Fe(IV)), sulfate radical (SO4•-), hydroxyl radical (•OH), and reactive chlorine species (Cl•, ClO•, Cl2•-). The steady-state concentrations of these reactive species were evaluated to determine their relationships to the Cl- and PMS contents. Fe(IV) was confirmed as the dominant reactive species, with Fe(IV) concentrations increasing with Cl- content and salinity to enhance the overall BPA degradation. Importantly, BPA degradation by the Fe/BC/PMS/Cl- system was not greatly affected by background anions or natural organic matter (NOM) present in real water sources, and the system was successfully applied for five sequential cycles of BPA treatment.

Activation of peroxymonosulfate by iron tailings for degradation of tetracycline hydrochloride: Identification of active minerals and study on catalytic mechanism

Cost-effective Fe tailings were utilized to activate peroxymonosulfate (PMS) for the removal of persistent antibiotics such as tetracycline hydrochloride (TC) from water. In this study, ilmenite-containing tailings served as raw material for preparing a magnetic Fe tailings catalyst (MFT) through magnetic separation, which increased the concentration of active components. The MFT catalyst efficiently activates PMS for rapid TC degradation. It achieves a 24.05 % adsorption ratio within 20 min. Within 35 min, it achieves a 91 % degradation ratio. After six cycles, the catalyst maintained an 86 % degradation ratio despite a slight decline in adsorption. The outstanding adsorption performance of the catalyst for TC was primarily attributed to calcite and chlorite. Importantly, ilmenite, magnetite, anatase, calcite, and chlorite served as active minerals in the catalyst. Ilmenite, magnetite, chlorite, and anatase activated PMS to generate a large amount of SO4•- and O2•-, while and calcite activated PMS to produce a significant quantity of 1O2. TC underwent rapid mineralization through the action of both free and non-free radicals. A 0.5-1 mm granular catalyst maintained a 75 % degradation ratio after treating 40 L of TC wastewater, with low heavy metal ion leaching, preventing secondary pollution. This method presents a sustainable solution for water remediation and waste valorization.

Low-valent Cu doping optimizes Ruddlesden-Popper perovskite for accelerated levofloxacin removal: Enhanced Ni-dominated dual radical/nonradical pathways

Ruddlesden-Popper (R-P) perovskites have emerged as superior candidates for peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) due to their tunable electronic configurations and enhanced electron transfer kinetics. Although metal doping has been extensively studied as the most common catalyst modification strategy in PMS activation processes, systematic identification of the dominant metal species in doped systems remains lacked. In this work, copper-doped R-P perovskite (La1.2Sr0.8Ni0.7Cu0.3O4+δ, LSNC0.3) was employed to investigate the influence of B-site ion electronic environment evolution on reactive oxygen species (ROS) generation during PMS activation, with the dominant metal species being determined through combined density functional theory (DFT) calculations and characterization. LSNC0.3 demonstrated exceptional activation performance, achieving 94 % levofloxacin (LVFX) removal within 30 min (k = 0.0853 min-1), significantly surpassing undoped La1.2Sr0.8NiO4+δ (LSNO). Cu doping induced anisotropic lattice strain through synergistic Jahn-Teller distortion and B-site dual-metal redox cycling, thereby enhancing oxygen vacancies (OVs) density and enabling dual radical (•OH/•O2⁻) and non-radical (1O2/electron transfer process (ETP)) pathways. DFT calculations revealed that Cumediated downshift of Ni 3d band center (-0.266 eV) optimized PMS adsorption energy (-4.218 eV), confirming Ni's predominant role in this system. LC-MS/DFT analyses identified piperazine cleavage and quinolone oxidation as primary LVFX degradation pathways, with toxicity reduction verified by T.E.S.T. This work provides guidance for designing robust perovskite catalysts in advanced water remediation applications.

Z-Scheme MIL-88A(Fe)/LaFeO3 Heterostructured Photocatalyst: Boosting Photo-Fenton Activity for Enhanced Organic Pollutant Detoxification

A series of MIL-88A(Fe)/LaFeO3 were prepared by mechanical ball-milling method for boosted photo-Fenton ofloxacin (OFX) degradation under visible light irradiation. The optimized M160L40/photo-Fenton system accomplished complete degradation of 5.0 mg/L OFX within 10 min, attributed to synergistic enhancement of mass transfer efficiency and photogenerated carriers separation. Environmental adaptability was demonstrated through pH robustness (3.0-9.0), interference resistance to coexisting ions, and stable performance under natural sunlight in real water matrices, while 95.0% activity retention after five cycles confirmed practical durability. Mechanistic investigations combining radical trapping, ESR spectroscopy, photodeposition, and DFT calculations revealed a direct Z-scheme charge transfer pathway between MIL-88A(Fe) and LaFeO3, enabling simultaneous preservation of strong redox potentials and efficient carrier separation. Biotoxicity assessment via bacterial growth inhibition assays showed significant reduction in ecotoxicity of degradation intermediates. This work establishes a new paradigm for designing MOF/perovskite hybrid systems in advanced oxidation processes while offering mechanistic insights into Z-scheme photocatalysis for environmental remediation.

MnxCo3-xO4 spinel activates peroxymonosulfate for highly effective bisphenol A degradation with ultralow catalyst and persulfate usage

Persulfates-based advanced oxidation processes are highly efficient in degrading refractory organic contaminants in wastewater. However, their practical application is often limited by the extensive consumption of catalysts and oxidants. Therefore, constructing catalysts with abundant and efficient reaction interfaces is essential for improving the efficiency of persulfate activation. In this work, we develop a novel MnxCo3-xO4 spinel with highly exposed surface active sites by etching Mn-based precursors with Co ions. This process forms sufficient interface Co-O-Mn bonds, which effectively activate peroxymonosulfate (PMS) for bisphenol A (BPA) degradation. A clear structure-activity relationship is observed between the Co/Mn content ratio and the BPA degradation rate in the MnxCo3-xO4/PMS system. Notably, Mn0.1Co2.9O4 demonstrates superior PMS activation efficiency, achieving 100 % degradation of 10 mg/L BPA within 2 minutes with 0.05 g/L catalyst and 0.05 g/L persulfate usage. Experimental analyses combined with theoretical calculations identify the interface Co-O-Mn as the active site, which plays a crucial role in accelerating PMS molecule adsorption and O-O bond activation. Additionally, the spatially adjacent Co-O-Mn sites promote redox cycling for efficient interface electron transfer during the PMS activation process. Furthermore, Zebrafish toxicity studies revealed a considerable reduction in the toxicity of the BPA treatment residue in the MnxCo3-xO4/PMS system. Overall, this work presents a novel strategy for constructing spatially adjacent redox sites in dual-metal spinel materials, offering valuable insights into reducing chemical input and advancing persulfate-based environmental remediation technology.

Optimizing Reversible Exsolution and Phase Transformation in Double Perovskite Sr2Fe1.5-xCoxMo0.5O6-δ Electrodes for High-Performance Symmetric Solid Oxide Cells

Double perovskite (DP) oxides are promising electrode materials for symmetric solid oxide cells (SSOCs) due to their excellent electrochemical activity and stability. B-site cation doping in DP oxides affects the reversibility of phase transformation and exsolution, which plays a crucial role in the catalyst recovery. Yet, few studies have been conducted on this topic. In this study, the Sr2Fe1.5-xCoxMo0.5O6-δ (CSFM, x = 0, 0.1, 0.3, 0.5) DP system demonstrates modulated exsolution and phase transformation reversibility by manipulating the oxygen vacancy concentration. The correlation between Co-doping level and oxygen vacancy concentration is investigated to optimize the exsolution and phase transformation properties. Sr2Fe1.2Co0.3Mo0.5O6-δ (3CSFM) exhibits reversible transformation between DP and Ruddlesden-Popper phases with a high density of exsolved CoFe nanoparticles under redox atmospheres. The quasi-symmetric cell with 3CSFM shows a peak power density of 1.27 W cm-2 at 850 °C in H2 fuel cell mode and a current density of 2.33 A cm-2 at 1.6 V and 800 °C in H2O electrolysis mode. The 3CSFM electrode exhibits robust stability during continuous operation for ≈700 h. These results demonstrate the significant role of B-site doping in designing DP materials capable of dynamic phase transformation in diverse environments.

Application of Biochar-Based Materials for Effective Pollutant Removal in Wastewater Treatment

With the growth of the global population and the acceleration of industrialization, the problem of water pollution has become increasingly serious, posing a major threat to the ecosystem and human health. Traditional water treatment technologies make it difficult to cope with complex pollution, so the scientific community is actively exploring new and efficient treatment methods. Biochar (BC), as a low-cost, green carbon-based material, exhibits good adsorption and catalytic properties in water treatment due to its porous structure and abundant active functional groups. However, BC's pure adsorption or catalytic capacity is limited, and researchers have dramatically enhanced its performance through modification means, such as loading metals or heteroatoms. In this paper, we systematically review the recent applications of BC and its modified materials for water treatment in adsorption, Fenton-like, electrocatalytic, photocatalytic, and sonocatalytic systems, and discuss their adsorption/catalytic mechanisms. However, most of the research in this field is at the laboratory simulation stage and still needs much improvement before it can be applied in large-scale wastewater treatment. This review improves the understanding of the pollutant adsorption/catalytic properties and mechanisms of BC-based materials, analyzes the limitations of the current studies, and investigates future directions.

Highly Efficient Activation of Peroxymonosulphate by Co and Cu Co-Doped Sawdust Biochar for Ultra-Fast Removal of Bisphenol A

The rapid, efficient, and thorough degradation of Bisphenol A (BPA) is challenging. In this study, we prepared an effective peroxymonosulphate (PMS) activation catalyst derived from sawdust containing calcium carbonate. The Co and Cu co-doped sawdust biochar (CoO/CuO@CBC) catalyst could activate PMS quickly, and the degradation rate of BPA reached 99.3% in 5 min, while the rate constant was approximately 30 times higher than in the CBC/PMS and CoCuOx/PMS systems. Moreover, the interaction between CoO, CuO, and CBC endows the CoO/CuO@CBC catalyst with excellent catalytic performance under different conditions, such as initial pH, temperature, water matrix, inorganic anions, and humic acid, which maintained fast PMS activation via the cyclic transformation of Cu and Co for BPA degradation. The results demonstrated that both the radical (•O2- and •SO4-) and non-radical (1O2) pathways participate in the degradation of BPA in the CoO/CuO@CBC/PMS system. The efficient and stable degradation over a wide range of pH, temperature, and aqueous matrices indicates the potential application of the CoO/CuO@CBC catalyst.

Insight in sulfadiazine degradation by peroxymonosulfate activated by polydopamine-derived nitrogen-doped carbon supported CoFe2O4: Co leaching inhibition and degradation enhancement

Heterogeneous catalyst-mediated sulfate radical-based advanced oxidation processes (SR-AOPs) showed excellent performance during antibiotics degradation. Spinel was a promising catalyst for SR-AOPs, but the secondary contamination due to metal ions leaching needed to be addressed. And the destruction of catalyst structure could lead to the reduction of catalytic activity and the difficulty of recovery. Thus, a novel nitrogen-doped carbon (NC)-supported CoFe2O4 (CoFe2O4@NC) was synthesized as the activator of PMS for sulfadiazine (SDZ) degradation under low Co leaching conditions. The consequences indicated that the CoFe2O4@NC/PMS system exhibited higher PMS decomposition efficiency and reaction stoichiometry efficiency than the bare CoFe2O4/PMS systems (CoFe2O4-180 and CoFe2O4-800), which in turn demonstrated a better SDZ removal performance. Under the condition of CoFe2O4@NC dosage 0.1 g/L, PMS concentration 0.5 mM, solution pH 6.8 and temperature 25°C, SDZ (20 mg/L) was almost completely degraded within 60 min. XPS analysis showed that the NC not only protected and stabilized CoFe2O4, but also provided additional active sites for PMS activation. During SDZ degradation, SO4•-, HO•, •O2- and 1O2 were involved in the reaction, among which SO4• and HO• made the main contribution. Meanwhile, CoFe2O4@NC could be recovered by magnetic separation, and showed great stability (Co leaching 0.852 mg/L) and reusability. In the fifth cycle experiment, 85.02 % SDZ degradation was obtained. Based on the detected intermediates (12 intermediates were identified) and DFT calculations, possible degradation pathways for SDZ in CoFe2O4@NC/PMS were proposed. The condensed dual descriptor indicated that the N7, N11, and C15 atoms on SDZ molecule were the main sites of electrophilic attack, which was consistent with the detected intermediates. The degradation of SDZ involved hydroxylation of NH2, cleavage of S-N and extrusion of SO2. This study explored the improvements made in NC support material to catalytic performance and resistance to dissolution of spinel, providing new insights for subsequent researches.

Efficient Formaldehyde Gas Sensing Performance via Promotion of Oxygen Vacancy on In-Doped LaFeO3 Nanofibers

Perovskite oxide LaFeO3(LFO) emerges as a potential candidate for formaldehyde (HCHO) detection due to its exceptional electrical conductivity and abundant active metal sites. However, the sensitivity of the LFO sensor needs to be further enhanced. Herein, a series of LaxIn1-xFeO3 (x = 1.0, 0.9, 0.8, and 0.7) nanofibers (LxIn1-xFO NFs) with different ratios of La/In were obtained via the electrospinning method followed by a calcination process. Among all these LxIn1-xFO NFs sensors, the sensor based on the L0.8In0.2FO NFs possessed the maximum response value of 18.8 to 100 ppm HCHO at the operating temperature of 180 °C, which was 4.47 times higher than that based on pristine LFO NFs (4.2). Furthermore, the L0.8In0.2FO NFs sensor also exhibited a rapid response/recovery time (2 s/22 s), exceptional repeatability, and long-term stability. This excellent gas sensing performance of the L0.8In0.2FO NFs can be attributed to the large number of oxygen vacancies induced by the replacement of the A-site La3+ by In3+, the large specific surface area, and the porous structure. This research presents an approach to enhance the HCHO gas sensing capabilities by adjusting the introduced oxygen vacancies through the doping of A-sites in perovskite oxides.

Exploring the Potentials of Chitin and Chitosan-Based Bioinks for 3D-Printing of Flexible Electronics: The Future of Sustainable Bioelectronics

Chitin and chitosan-based bioink for 3D-printed flexible electronics have tremendous potential for innovation in healthcare, agriculture, the environment, and industry. This biomaterial is suitable for 3D printing because it is highly stretchable, super-flexible, affordable, ultrathin, and lightweight. Owing to its ease of use, on-demand manufacturing, accurate and regulated deposition, and versatility with flexible and soft functional materials, 3D printing has revolutionized free-form construction and end-user customization. This study examined the potential of employing chitin and chitosan-based bioinks to build 3D-printed flexible electronic devices and optimize bioink formulation, printing parameters, and postprocessing processes to improve mechanical and electrical properties. The exploration of 3D-printed chitin and chitosan-based flexible bioelectronics will open new avenues for new flexible materials for numerous industrial applications.

Multiple interface coupling on natural tourmaline enables high-efficiency removal of antibiotic: Superior property and mechanism

Reasonably designing highly active, environmentally friendly, and cost-effective catalysts for efficient elimination of pollutants from water is desirable but challenging. Herein, an efficient heterogeneous photo-Fenton catalyst tourmaline (TM)/tungsten oxide (WO3-x) (named TW10) containing tungsten/boron/iron (W/B/Fe) synergistic active centers and 90% of cheap natural tourmaline (TM) mineral rich in Fe and B elements. The TW10 catalyst can quickly activate peroxymonosulfate (PMS) to generate massive active free radicals, which may induce the rapid and efficient degradation of tetracycline (TC). The TW10/PMS/Visible light system can effectively degrade up to 98.7% of tetracycline (TC) in actual waters (i.e. seawater, Yellow River, and Yangtze River water), and the catalytic degradation rates reach 1.65, 5.569, and 2.38 times higher than those of TM, WO3-x, and commercial P25 (Degussa, Germany), respectively. In addition, the catalyst can be recycled and reused multiple times. Electron spin resonance spectroscopy (EPR), X-ray photoelectron spectroscopy (XPS), and liquid chromatograph-mass spectrometer (LC-MS) analyses confirm that the synergistic catalytic effect of W/B/Fe sites on the TW10 catalyst accelerates the electron transfer between Fe(II) and Fe(III), as well as between W(V) and W(VI), and thus promotes the rapid degradation of TC. The catalytic reaction mechanism and degradation pathway of TC were explored. This work provides a feasible route for the design and development of new eco-friendly and efficient catalyst.

Enhanced peroxymonosulfate activation via heteroatomic doping defects of pyridinic and pyrrolic N in 2D N‑doped carbon nanosheets for BPA degradation

Understanding the role of intrinsic defects and nonmetallic heteroatom doping defects in activating peroxymonosulfate (PMS) and subsequently degrading endocrine-disrupting compounds is crucial for designing more efficient carbon catalysts. Therefore, we synthesized N-rich carbon nanosheets (NCs) through pyrolysis of a glutamic acid and melamine mixture and utilized them to activate PMS for bisphenol A (BPA) degradation. Different weight ratios of the above mixtures were allowed for manipulating NCs' defect level and N configuration. The reaction rate constant (k) was significantly positively correlated with the pyridinic and pyrrolic N content, and negatively and weakly positively correlated with graphite N and intrinsic defects, respectively. These findings suggest pyridinic and pyrrolic N, rather than graphitic N and intrinsic defects, enhance PMS activation to generate reactive oxygen species (specifically O•-2 and 1O2) and oxidize BPA. The NC-activated PMS system with the highest N content (17.9 atom%) demonstrated a remarkably high k (0.127 min-1) using minimal concentrations of PMS (0.4 mM) and NC (0.15 g/L), highlighting the system's efficiency. Excess halide anions led to significantly increased k with only a limited formation of trichloromethane (disinfection byproducts) in presence of 100 mM Cl-. This study offers novel perspectives on identifying catalytic sites within N-doped carbonaceous materials.

Insight into cobalt substitution in LaFeO3-based catalyst for enhanced activation of peracetic acid: Reactive species and catalytic mechanism

In this study, a hollow sphere-like Co-modified LaFeO3 perovskite catalyst (LFC73O) was developed for peracetic acid (PAA) activation to degrade sulfamethoxazole (SMX). Results indicated that the constructed heterogeneous system achieved a 99.7% abatement of SMX within 30 min, exhibiting preferable degradation performance. Chemical quenching experiments, probe experiments, and EPR techniques were adopted to elucidate the involved mechanism. It was revealed that the superior synergistic effect of electron transfer and oxygen defects in the LFC73O/PAA system enhanced the oxidation ability of PAA. The Co atoms doped into LaFeO3 as the main active site with the original Fe atoms as an auxiliary site exhibited high activity to mediate PAA activation via the Co(III)/Co(II) cycle, generating carbon-centered radicals (RO·) including CH3C(O)O· and CH3C(O)OO·. The oxygen vacancies induced by cobalt substitution also served as reaction sites, facilitating the dissociation of PAA and production of ROS. Furthermore, the degradation pathways were postulated by DFT calculation and intermediates identification, demonstrating that the electron-rich sites of SMX molecules such as amino group, aromatic ring, and S-N bond, were more susceptible to oxidation by reactive species. This study offers a novel perspective on developing catalysts with the coexistence of multiple active units for PAA activation in environmental remediation.

Singlet oxygen-dominated peroxymonosulfate activation by layered crednerite for organic pollutants degradation in high salinity wastewater

Advanced oxidation processes have been widely studied for organic pollutants treatment in water, but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals, especially in high salinity conditions. Here, a singlet oxygen (1O2)-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater, with layered crednerite (CuMnO2) as catalysts and peroxymonosulfate (PMS) as oxidant. Based on the experiments and density functional theory calculations, 1O2 was the dominating reactive species and the constructed Cu-O-Mn with electron-deficient Mn captured electron from PMS promoting the generation of 1O2. The rapid degradation of bisphenol A (BPA) was achieved by CuMnO2/PMS system, which was 5-fold and 21-fold higher than that in Mn2O3/PMS system and Cu2O/PMS system. The CuMnO2/PMS system shown prominent BPA removal performance under high salinity conditions, prominent PMS utilization efficiency, outstanding total organic carbon removal rate, wide range of applicable pH and good stability. This work unveiled that the 1O2-dominated non-radical process of CuMnO2/PMS system overcame the inhibitory effect of anions in high salinity conditions, which provided a promising technique to remove organic pollutants from high saline wastewater.

Sulfur-decorated Fe/C composite synthesized from MIL-88A(Fe) for peroxymonosulfate activation towards tetracycline degradation: Multiple active sites and non-radical pathway dominated mechanism

Peroxymonosulfate (PMS)-mediated advanced oxidation processes gain growing attention in degrading antibiotics (e.g., tetracycline (TC)) in wastewater for their high capacity and relatively low cost, while designing efficient catalysts for PMS activation remains a challenge. In this study, a sulfur-doped Fe/C catalyst (Fe@C-S) synthesized from iron metal-organic frameworks (Fe-MOFs) was developed for PMS activation towards TC removal. Under optimal conditions, the TC removal efficiency of Fe@C-S150/PMS system within 40 min was 91.2%. Meanwhile, the k value for Fe@C-S150/PMS system (0.2038 min-1) was 3.36-fold as high as the S-free Fe@C-based PMS system. Also, Fe@C-S150/PMS system showed high robustness in different water matrices. Further studies found that the TC degradation mechanism was mainly ascribed to the non-radical pathway (1O2 and electron transfer). Fe nanoparticles, S and CO groups on the catalyst all participated in the generation of reactive oxygen species (ROS). Besides, S species could enhance the Fe2+/Fe3+ redox cycle and accelerate the electron transfer process. This work highlights the critical role of S in enhancing the catalytic performance of Fe/C-based catalysts for PMS activation, which would provide meaningful insights into the design of high-performance PMS activators for the sustainable remediation of emerging contaminants-polluted water bodies.

Oxygen doped graphite carbon nitride as efficient metal-free catalyst for peroxymonosulfate activation: Performance, mechanism and theoretical calculation

In this study, oxygen-doped graphitic carbon nitride (g-C3N4), named O-g-C3N4, was successfully fabricated and characterized, and its performance in activating peroxymonosulfate (PMS, HSO5-) for the removal of phenol, 2,4-dichlorophenol (2,4-DCP), bisphenol A (BPA), rhodamine B (RhB), reactive brilliant blue (RBB) and acid orange 7 (AO7) was evaluated. The catalytic performance of O-g-C3N4 for AO7 removal increased by 14 times compared to g-C3N4. In the presence of 0.2 g L-1 O-g-C3N4, 3.5 mM PMS at natural pH 5.8, 96.4% of AO7 could be removed in 60 min, reduced toxicity of the treated AO7 solution was obtained, and the mineralization efficiency was 47.2% within 120 min. Density functional theory (DFT) calculations showed that the charge distribution changed after oxygen doping, and PMS was more readily adsorbed by O-g-C3N4 with the adsorption energy (Eads) of -0.855 kcal/mol than that of the pristine g-C3N4 (Eads: -0.305 kcal/mol). Mechanism investigation implied that AO7 was primarily removed by the sulfate radicals (SO4•-) and hydroxyl radicals (•OH) on the surface of O-g-C3N4, but the role of singlet oxygen (1O2) to AO7 elimination was negligible. The results of cyclic experiments and catalyst characterization after reaction confirmed the favorable catalytic activity and structural stability of O-g-C3N4 particles. Furthermore, the O-g-C3N4/PMS system was very resistant to most of the environmental impacts, and AO7 removal was still acceptable in natural water environment. This study may provide an efficient metal-free carbonaceous activator with low dosage for PMS activation to remove recalcitrant organic pollutants (ROPs).

Peroxymonosulfate activation by Fe-N-S co-doped tremella-like carbocatalyst for degradation of bisphenol A: Synergistic effect of pyridine N, Fe-Nx, thiophene S

Bisphenol A (BPA) has received increasing attention due to its long-term industrial application and persistence in environmental pollution. Iron-based carbon catalyst activation of peroxymonosulfate (PMS) shows a good prospect for effective elimination of recalcitrant contaminants in water. Herein, considering the problem about the leaching of iron ions and the optimization of heteroatoms doping, the iron, nitrogen and sulfur co-doped tremella-like carbon catalyst (Fe-NS@C) was rationally designed using very little iron, S-C₃N₄ and low-cost chitosan (CS) via the impregnation-calcination method. The as-prepared Fe-NS@C exhibited excellent performance for complete removal of BPA (20 mg/L) by activating PMS with the high kinetic constant (1.492 min^-1) in 15 min. Besides, the Fe-NS@C/PMS system not only possessed wide pH adaptation and high resistance to environmental interference, but also maintained an excellent degradation efficiency on different pollutants. Impressively, increased S-C₃N₄ doping amount modulated the contents of different N species in Fe-NS@C, and the catalytic activity of Fe-NS@C-1-x was visibly enhanced with increasing S-C₃N₄ contents, verifying pyridine N and Fe-N_x as main active sites in the system. Meanwhile, thiophene sulfur (C-S-C) as active sites played an auxiliary role. Furthermore, quenching experiment, EPR analysis and electrochemical test proved that surface-bound radicals (^·OH and SO₄^⋅-) and non-radical pathways worked in the BPA degradation (the former played a dominant role). Finally, possible BPA degradation route were proposed. This work provided a promising way to synthesize the novel Fe, N and S co-doping carbon catalyst for degrading organic pollutants with low metal leaching and high catalytic ability.

Interface engineering-induced perovskite/spinel LaCoO3/Co3O4 heterostructured nanocomposites for efficient peroxymonosulfate activation to degrade levofloxacin

Conventional perovskite oxides (ABO₃) tend to suffer from their inactive surfaces and limited active sites that reduce their catalytic activity and stability, while interface engineering is a facile modulating technique to boost the catalyst's inherent activity by constructing heterogeneous interfaces. In this study, perovskite/spinel LaCoO₃/Co₃O₄ nanocomposites with heterogeneous interfaces were synthesized via sol-gel and in-situ gradient etching methods to activate peroxymonosulfate (PMS) for degrading levofloxacin (LEV). LaCoO₃ on the surface was etched into spinel Co₃O₄, and LaCoO₃/Co₃O₄ nanocomposites with two crystal structures of perovskite and spinel were successfully formed. The surface-modified LaCoO₃/Co₃O₄ exhibited superior catalytic performance with a reaction rate constant more than 2 times that of the original LaCoO₃, as well as excellent pH adaptability (3-11) and reusability (more than 6 recyclings) for LEV degradation. Besides, multiple characterization techniques were carried out to find that LaCoO₃/Co₃O₄ possessed a larger specific surface area and richer oxygen vacancies after surface modification, which provided more active sites and accelerated mass transfer rate. The mechanism of reactive oxygen species involved in the reaction system was proposed that LaCoO₃/Co₃O₄ not only reacted with PMS directly to produce SO₄^•- and ^•OH but also its surface hydroxyl group helped to form the [≡Co(Ⅲ)OOSO₃]⁺ reactive complex with PMS to produce O₂^•- and ¹O₂. In addition, electrochemical experiments demonstrated that the surface electronic structure of LaCoO₃/Co₃O₄ was effectively regulated, exhibiting a faster electron transfer rate and facilitating the redox process. By detecting and identifying degradation intermediates, three degradation pathways for LEV were proposed. Our work provided profound insights into the design of efficient and long-lasting catalysts for advanced oxidation processes.

Efficient degradation of atrazine through in-situ anchoring NiCo2O4 nanosheets on biochar to activate sulfite under neutral condition

Sulfite (S(IV)) is a promising substitute for sulfate radical-based advanced oxidation processes. Here, a composite of in-situ anchoring NiCo₂O₄ nanosheets on biochar (BC) was firstly employed as a heterogeneous activator for sulfite (NiCo₂O₄@BC-sulfite) to degrade atrazine (ATZ) in the neutral environment. The synergistic coupling of BC and NiCo₂O₄ endows the resulting composite excellent catalytic activity. 82% of the degradation ratio of ATZ (1 mg/L) could be achieved within 10 min at initial concentrations of 0.6 g/L NiCo₂O₄@BC, 3.0 mmol/L sulfite in neutral environment. When further supplementing sulfite into the system at 20 min (considering the depletion of sulfite), outstanding degradation efficiency (∼ 100%) were achieved in the next 10 min without any other energy input by the NiCo₂O₄@BC-sulfite system. The features of the prepared catalysts and the effects of some key parameters on ATZ degradation were systematically examined. A strong inner-sphere complexation (Co²⁺/Ni²⁺-SO₃^2-) was explored between sulfite and the metal sites on the NiCo₂O₄@BC surface. The redox cycle of the surface metal efficiently mediated sulfite activation and triggered the series radical chain reactions. The generated radicals, in particular the surface-bound radicals were involved in ATZ degradation. High performance liquid chromatography-tandem mass spectrometry (LC-MS) technique was used to detect the degradation intermediates. Density functional theory (DFT) calculations were performed to illustrate the possible degradation pathways of ATZ. Finally, an underlying mechanism for ATZ removal was proposed. The present study offered a low-cost and sustainable catalyst for sulfite activation to remove ATZ in an environmentally friendly manner from wastewater.

Electro-enhanced activation of peroxymonosulfate by a novel perovskite-Ti4O7 composite anode with ultra-high efficiency and low energy consumption: The generation and dominant role of singlet oxygen

Traditional free radicals-dominated electrochemical advanced oxidation processes (EAOPs) and sulfate radical-based advanced oxidation processes (SR-AOPs) are limited by pH dependence and weak reusability, respectively. To overcome these shortcomings, electro-enhanced activation of peroxymonosulfate (PMS) on a novel perovskite-Ti₄O₇ composite anode (E-PTi-PMS system) was proposed. It achieved an ultra-efficient removal rate (k = 0.467 min^-1) of carbamazepine (CBZ), approximately 36 and 8 times of the E-PTi and PTi-PMS systems. Singlet oxygen (¹O₂) played a dominant role in the E-PTi-PMS system and transformed from SO₄^•-, O₂^•-, ^•OH and oxygen vacancy (V_o^••). The electric field expedited the decomposition and utilization of PMS, promoting the generation of radicals and expanding the formation pathway of ¹O₂. The E-PTi-PMS system presented superiorities over wide pH (3-10) and less dosage of PMS (1 mM), expanding the pH adaptability and reducing the cost of EAOPs. Simultaneously, the excellent reusability (30 cycles) solved the bottleneck of recycling catalysts in SR-AOPs via an ultra-low energy (0.025 kWh/m³-log). This work provides a promising alternative towards high-efficiency and low-cost treatment of polluted waters.

Highly Efficient Copper Doping LaFeO3 Perovskite for Bisphenol A Removal by Activating Peroxymonosulfate

A series of copper doping LaFeO3 perovskite (LaCuxFe1−xO3, LCFO, x = 0.1, 0.4, 0.5, 0.6, 0.9) are successfully synthesized by the sol-gel method under mild conditions. In this study, it is applied for the activation of peroxymonosulfate (PMS) for bisphenol A (BPA) removal. More than 92.6% of BPA was degraded within 30 min at 0.7 g/L of LCFO and 10.0 mM of PMS over a wide pH range with limited leaching of copper and iron ions. The physical–chemical properties of the catalysts were demonstrated by using X-ray diffraction (XRD), N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, the effects of catalyst dosage, PMS concentration, initial pH value, and inorganic anions on the LCFO/PMS system were fully investigated. Quenching experiments were performed to verify the formation of reactive oxidant species, which showed that the radical reaction and mechanisms play a great role in the catalytic degradation of BPA. The perovskite LCFO is considered a stable, easy to synthesize, and efficient catalyst for the activation of PMS for wastewater treatment.

Modulating the electron structure of Co-3d in Co3O4-x/WO2.72 for boosting peroxymonosulfate activation and degradation of sulfamerazine: Roles of high-valence W and rich oxygen vacancies

Sulfate radical (SO₄^•-)-based heterogonous advanced oxidation processes (AOPs) show promising potential to degrade emerging contaminants, however, regulating the electron structure of a catalyst to promote its catalytic activity is challenging. Herein, a hybrid that consists of Co₃O_4-x nanocrystals decorated on urchin-like WO_2.72 (Co₃O_4-x/WO_2.72) with high-valence W and rich oxygen vacancies (OVs) used to modulate the electronic structure of Co-3d was prepared. The Co₃O_4-x/WO_2.72 that developed exhibited high catalytic activity, activating peroxymonosulfate (PMS), and degrading sulfamerazine (SMR). With the use of Co₃O_4-x/WO_2.72, 100 % degradation of SMR was achieved within 2 min, at a pH of 7, with the reaction rate constant k₁ = 3.09 min^-1. Both characterizations and density functional theory (DFT) calculations confirmed the formation of OVs and the promotion of catalytic activity. The introduction of WO_2.72 greatly regulated the electronic structure of Co₃O_4-x. Specifically, the introduction of high-valence W enabled the Co-3d band centre to be closer to the Fermi level and enhanced electrons (e^-) transfer ability, while the introduction of OVs-Co in Co₃O_4-x promoted the activity of electrons in the Co-3d orbital and the subsequent catalytic reaction. The reactive oxygen species (ROS) were identified as •OH, SO₄^•-, and singlet oxygen (¹O₂) by quenching experiments and electron spin resonance (EPR) analysis. The DFT calculation using the Fukui index indicated the reactive sites in SMR were available for an electrophilic attack, and three degradation pathways were proposed.

Coupling the effect of Co and Mo on peroxymonosulfate activation for the removal of organic pollutants

Although heterogeneous cobalt-based catalysts have been widely studied and used in SO₄^•- based advanced oxidation processes, the efficiencies were still not high enough due to the limiting step of Co(III)/Co(II) cycle in the system. In this study, a bimetallic oxide composed of Co and Mo was designed and used for enhancing the performance of peroxymonosulfate activation on organic pollutants removal. The CoMoO₄ nanorods exhibited superior catalytic activity for methylene blue (MB) degradation than Co₃O₄, MoO₃, and their mechanical mixture, which was attributed to the synergetic effect between Co and Mo. CoMoO₄ nanorods were able to efficiently degrade MB under a wide pH range of 3-11 and could maintain high efficiency in 5 cycles with less leakage of metal ions. Moreover, CoMoO₄ nanorods displayed broad spectrum applicability to the different water matrix and a variety of pollutants such as phenol and Congo red. The Co(II) was proved to be the main active site of the catalyst, while Mo played an important role in promoting the Co(III)/Co(II) cycle. Surface free radicals are the main active species in the degradation process. This work provides new insights into the design of cobalt-based bimetallic catalyst and the improvement on PMS activation.

Oxygen-Deficient Engineering for Perovskite Oxides in the Application of AOPs: Regulation, Detection, and Reduction Mechanism

A perovskite catalyst combined with various advanced oxidation processes (AOPs) to treat organic wastewater attracted extensive attention. The physical and chemical catalytic properties of perovskite were largely related to oxygen vacancies (OVs). In this paper, the recent advances in the regulation of OVs in perovskite for enhancing the functionality of the catalyst was reviewed, such as substitution, doping, heat treatment, wet-chemical redox reaction, exsolution, and etching. The techniques of detecting the OVs were also reviewed. An insight was provided into the OVs of perovskite and reduction mechanism in AOPs in this review, which is helpful for the reader to better understand the methods of regulating and detecting OVs in various AOPs.

Core-shell magnetic CFO@COF composites toward peroxymonosulfate activation for degradation of sulfamethoxazole from aqueous solution: A comparative study and mechanistic consideration

A core-shell covalent organic framework encapsulated Co1.2Fe1.8O4 magnetic particles (CFO@COF) was designed and prepared successfully to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) degradation. It displays amazing catalytic reactivity since the unique interior structure and synergistic effect between COF shell and CFO core, reaching 99.8% removal of SMX (10 mg/L) within 30 min and 90.8% TOC removal. The synergy between bimetals vests high reactivity to CFO core. And the outer COF shell can stabilize the CFO core under intricate reaction conditions to restrain the leaching of Co ions (decreased from 0.75 to 0.25 mg/L). Further investigation compared the activation mechanism in two different system, CFO/PMS system and CFO@COF/PMS system. The result showed that the radical mechanism controlled by SO4⋅- guided the SMX degradation in CFO/PMS system whereas the 1O2 played a pivotal role in CFO@COF/PMS system called non-radical leading. The influences of various factors on degradation experiments and SMX degradation pathway were also studied. Most importantly, risk assessment in CFO@COF/PMS/SMX system was estimated via "ecological structure activity relationships". In most case, the toxicities of intermediates were lower than the initial samples, which confirmed the effectiveness of CFO@COF/PMS/SMX system in the reduction of toxicity of SMX.

Non-radical-dominated catalytic degradation of methylene blue by magnetic CoMoO4/CoFe2O4 composite peroxymonosulfate activators

In this study, magnetic CoMoO₄/CoFe₂O₄ (CMO/CFO) nanospheres with a core-shell structure were synthesized via two-step hydrothermal methods. The obtained particles were employed as catalysts to activate peroxymonosulfate (PMS) and degrade methylene blue (MB). The physico-chemical characterizations of the synthesized CMO/CFO showed that the CMO shell contributed to the enhancement of redox conversion and the increase in the concentration of oxygen vacancies (OVs). By examining reactive oxygen species (ROS) in the CMO/CFO/PMS system, the MB degradation was dominated by a non-radical pathway, and ¹O₂ was identified as the most abundant ROS. Besides, the CMO/CFO exhibited faster reaction kinetics than the pristine CFO. Moreover, the magnetic properties guaranteed the recycling and reuse of CMO/CFO, and the removal rate of MB was maintained at ∼94% after continuous use five times. Both the tolerance to SO₄^2-and the wide pH range where the material is applicable make it a promising catalyst for dyeing wastewater treatment.

Spent LiFePO4: An old but vigorous peroxymonosulfate activator for degradation of organic pollutants in water

Iron-based catalysts have been demonstrated to activate peroxymonosulfate (PMS) to generate reactive radicals, which is however limited by their complex preparation process, high costs and inefficiency for practical applications. Herein we obtain spent LiFePO₄ (SLFP), with powerful catalytic capacity by a simple one-step treatment of the retired LiFePO₄ cathode material, for PMS activation to decontaminate organic pollutants. Lithium defects and oxygen vacancies in SLFP play critical roles for PMS utilization, further confirmed by density functional theory (DFT) calculations. SLFP materials rapidly adsorb PMS, and the surface PMS is activated by Fe(II) to generate radicals, with ^•OH playing a major role for the degradation of organics after multi-step reactions. The SLFP/PMS process is finally validated for ability to remove organic contaminants and potential environmental application.

Application of perovskite oxides and their composites for degrading organic pollutants from wastewater using advanced oxidation processes: Review of the recent progress

In the recent years, perovskite oxides are gaining an increasing amount of attention owing to their unique traits such as tunable electronic structures, flexible composition, and eco-friendly properties. In contrast, their catalytic performance is not satisfactory, which hinders real wastewater remediation. To overcome this shortcoming, various strategies are developed to design new perovskite oxide-based materials to enhance their catalytic activities in advanced oxidation process (AOPs). This review article is to provide overview of basic principle and different methods of AOPs, while the strategies to design novel perovskite oxide-based composites for enhancing the catalytic activities in AOPs have been highlighted. Moreover, the recent progress of their synthesis and applications in wastewater remediation (pertaining to the period 2016-2022) was described, and the related mechanisms were thoroughly discussed. This review article helps scientists to have a clear outlook on the selection and design of new effective perovskite oxide-based materials for the application of AOPs. At the end of the review, perspective on the challenges and future research directions are discussed.

Activation of persulfate by LaFe1-xCoxO3 perovskite catalysts for the degradation of phenolics: Effect of synthetic method and metal substitution

The presence of resistant organic pollutants in environmental substrates requires the development and finding of novel decontamination methods. Advanced oxidation processes are among the most effective methods used for degradation of these pollutants through their oxidation and degradation into non-toxic and harmless, for the environment, final products. Ιn this research, a series of perovskites of ABO₃-type, with La and Fe and/or Co in A and B positions respectively, LaFe_1-xCo_xO₃ (x = 0, 0.25, 0.5, 0.75, 1), were synthesized with two different methods, a soft template method using anionic surfactant and by glycine combustion method and studied for their catalytic activity towards the degradation of phenolic compounds, a major class of environmental pollutants, through persulfate activation. The catalytic activity depended both by the B metal ion of perovskites and their ratio as well as by the synthesis method. LaCoO₃ prepared with the anionic surfactant method, showed the highest catalytic activity with a rate constant of 0.024 min^-1. Furthermore, the synthesis method also influenced the stability of perovskites as metal leaching studies showed that perovskites synthesized with the anionic surfactant showed greater stability. Quenching experiments were also used in order to shed light on the catalytic activation mechanism of persulfate for the degradation of phenolics. Overall, the results showed that the synthesis method can significantly affect the catalytic activity of the materials and their stability since the same materials synthesized with different methods show significantly different catalytic properties.

Photo-Fenton Degradation of Ciprofloxacin by Novel Graphene Quantum Dots/α-FeOOH Nanocomposites for the Production of Safe Drinking Water from Surface Water

In the current work, novel graphene quantum dots (GQDs)-doped goethite (α-FeOOH) nanocomposites (GQDs/α-FeOOH) were prepared by following a feasible hydrolysis method and applied for ciprofloxacin (CIP) removal. Results showed that the CIP degradation efficiency was significant (93.73%, 0.0566 min−1) in the GQDs/α-FeOOH + H2O2 + Vis system using much lower amounts of H2O2 (0.50 mM), which is 3.9 times the α-FeOOH + H2O2 + Vis system. It was found that •OH, O2•−, and 1O2 were mainly responsible for CIP degradation in the GQDs/α-FeOOH photo-Fenton system. GQDs/α-FeOOH demonstrated broad-spectrum UV–vis-IR responsiveness in the degradation of ciprofloxacin as a function of the doping of GQDs. Additionally, GQDs/α-FeOOH showed outstanding durability (recyclability up to 3 cycles with a lower iron leaking amount, 0.020 mg L−1), a broad range of application pH, and a pretty acceptable catalytic efficacy in a variety of surface water matrices. Overall, GQDs/α-FeOOH have been shown to be an effective photocatalyst for the remediation of emerging contaminants via the workable exploitation of solar energy.

Performance of a Three-Dimensional Electrochemical Reactor (3DER) on Bisphenol A Degradation

This study constructed a three-dimensional electrochemical reactor (3DER) using meshed stainless steel sheets and titanic magnetite particles (TMP) to investigate bisphenol A (BPA) degradation through the synergistic action of electrical current and TMP. We examined some TMP characteristics, such as particle size, specific surface areas, X-ray diffraction, surface imaging, elemental constituents, and electrical resistivity. It was found that TMP was a micron-level material with excellent electrical conductivity, and it could be regarded as a magnetite-based material comprising Fe(II) and Fe(III). The single-factor experiment determined the optimal conditions for BPA removal in 3DER, specifically by introducing 200 ml of BPA-simulated wastewater (10 mg L⁻¹) into 3DER. At the initial pH of 9.00, current and electrodes gap of 300 mA and 15 mm, respectively, and adding 1 ml of 0.5 M potassium peroxymonosulfate and 1 g TMP, > 98% of BPA was removed after 55 min of electrochemical reaction. In addition, liquid chromatography–mass spectrometry identified the intermediates formed during the BPA treatment, showing two possible pathways for BPA degradation. The final degradation intermediates were chain organics with simple molecular structures. This research provided an understanding of the potential application of 3DER for BPA removal in water.

Modulating anion defect in La0.6Sr0.4Co0.8Fe0.2O3-δ for enhanced catalytic performance on peroxymonosulfate activation: Importance of hydrated electrons and metal-oxygen covalency

Perovskite oxides are promising catalysts in peroxymonosulfate (PMS) activation for wastewater treatment, attributed to their flexible structures. In this study, halogen anion (F^- or Cl^-) was doped in La_0.6Sr_0.4Co_0.8Fe_0.2O_3-δ (LSCF) for PMS activation, showing that appropriate anion doping enhances the catalytic performances. La_0.6Sr_0.4Co_0.8Fe_0.2O_2.75-δCl_0.25 (LSCFCl_0.25) exhibits a superior catalytic activity to pristine LSCF and La_0.6Sr_0.4Co_0.8Fe_0.2O_2.75-δF_0.25 (LSCFF_0.25), attributed to the strong surface acidity, sufficient oxygen vacancies, and improved B-site metal-oxygen bonding. The rich acidic sites favor PMS adsorption on the catalyst surface. The sufficient hydrated electrons (e_aq^-) in the oxygen vacancies participated in the generation of free radicals (SO₄^•- and O₂^•-) and singlet oxygen (¹O₂). The enlarged B-site metal-oxygen covalency could boost the electron transfer between PMS and Co^(III)/Fe^(III), and thus accelerate the redox reaction. SO₄^•- and ¹O₂ are the dominating species for the degradation. This study deepens the catalytic mechanism and uncovers the active sites of perovskite catalysts for PMS activation, providing an inspiring modification strategy to improve the catalytic performances.

One-Step Fabrication of Novel Polyethersulfone-Based Composite Electrospun Nanofiber Membranes for Food Industry Wastewater Treatment

Using an environmentally friendly approach for eliminating methylene blue from an aqueous solution, the authors developed a unique electrospun nanofiber membrane made of a combination of polyethersulfone and hydroxypropyl cellulose (PES/HPC). SEM results confirmed the formation of a uniformly sized nanofiber membrane with an ultrathin diameter of 168.5 nm (for PES/HPC) and 261.5 nm (for pristine PES), which can be correlated by observing the absorption peaks in FTIR spectra and their amorphous/crystalline phases in the XRD pattern. Additionally, TGA analysis indicated that the addition of HPC plays a role in modulating their thermal stability. Moreover, the blended nanofiber membrane exhibited better mechanical strength and good hydrophilicity (measured by the contact angle). The highest adsorption capacity was achieved at a neutral pH under room temperature (259.74 mg/g), and the pseudo-second-order model was found to be accurate. In accordance with the Langmuir fitted model and MB adsorption data, it was revealed that the adsorption process occurred in a monolayer form on the membrane surface. The adsorption capacity of the MB was affected by the presence of various concentrations of NaCl (0.1–0.5 M). The satisfactory reusability of the PES/HPC nanofiber membrane was revealed for up to five cycles. According to the mechanism given for the adsorption process, the electrostatic attraction was shown to be the most dominant in increasing the adsorption capacity. Based on these findings, it can be concluded that this unique membrane may be used for wastewater treatment operations with high efficiency and performance.

Ag nanoparticles immobilized sulfonated polyethersulfone/polyethersulfone electrospun nanofiber membrane for the removal of heavy metals

In this work, Eucommia ulmoides leaf extract (EUOLstabilized silver nanoparticles (EUOL@AgNPs) incorporated sulfonated polyether sulfone (SPES)/polyethersulfone (PES) electrospun nanofiber membranes (SP ENMs) were prepared by electrospinning, and they were studied for the removal of lead (Pb(II)) and cadmium (Cd(II)) ions from aqueous solutions. The SP ENMs with various EUOL@AgNPs loadings were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscope, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle (CA) measurements. The adsorption studies showed that the adsorption of Cd(II) and Pb(II) was rapid, achieved equilibrium within 40 min and 60 min, respectively and fitted with non-linear pseudo-second-order (PSO) kinetics model. For Cd(II) and Pb(II), the Freundlich model described the adsorption isotherm better than the Langmuir isotherm model. The maximum adsorption capacity for Cd(II) and Pb(II) was 625 and 370.37 mg g⁻¹ respectively at neutral pH. Coexisting anions of fluoride, chloride, and nitrate had a negligible influence on Cd(II) removal than the Pb(II). On the other hand, the presence of silicate and phosphate considerably affected Cd(II) and Pb(II) adsorption. The recyclability, regeneration, and reusability of the fabricated EUOL@AgNPs-SP ENMs were studied and they retained their high adsorption capacity up to five cycles. The DFT measurements revealed that SP-5 ENMs exhibited the highest adsorption selectivity for Cd(II) and the measured binding energies for Cd(II), Pb(II), are 219.35 and 206.26 kcal mol⁻¹, respectively. The developed ENM adsorbent may find application for the removal of heavy metals from water.

Honeycomb-like holey Co3O4 membrane triggered peroxymonosulfate activation for rapid degradation of organic contaminants

Heterogeneous advanced oxidation processes (AOPs) are commonly employed for the degradation of recalcitrant contaminants, however, practical application of heterogeneous AOPs has been limited by their low activation efficiency and inefficient utilization of radicals. Herein, this study demonstrates for the first time that 2D honeycomb-like holey membranes assembled by Co₃O₄ nanosheets, serve as an excellent activator for peroxymonosulfate (PMS) and aid in rapid pollutant removal. The Co₃O₄ membrane achieved 100% target pollutant ranitidine removal and a membrane retention time of only ~385 ms with the degradation rate 3-5 orders of magnitude faster than that achieved by conventional heterogeneous catalysis. Ranitidine degradation was maintained at >90% for 13 h of continuous-flow operation at a high flux of 176 L m^-2 h^-1 bar^-1. Furthermore, the Co₃O₄ membrane could also effectively degrade several recalcitrant pollutants, including pharmaceutical personal care products, phenols, and dyes. SO₄^•- and •OH were identified as the primary reactive oxygen species in the Co₃O₄ membrane/PMS system, with Co providing the active site for PMS activation. This strategy of membrane-based AOP treatment offers helpful guidance for the design of other efficient heterogeneous catalytic systems and presents a novel approach to overcoming the limitations of conventional heterogeneous catalysis.

Engineered magnetic oxides nanoparticles as efficient sorbents for wastewater remediation: a review

The rapid urbanization and industrialization is causing worldwide water pollution, calling for advanced cleaning methods. For instance, pollutant adsorption on magnetic oxides is efficient and very practical due to the easy separation from solutions by an magnetic field. Here we review the synthesis and performance of magnetic oxides such as iron oxides, spinel ferrites, and perovskite oxides for water remediation. We present structural, optical, and magnetic properties. Magnetic oxides are also promising photocatalysts for the degradation of organic pollutants. Antimicrobial activities and adsorption of heavy metals and radionucleides are also discussed.

The synergistic effect of PMS activation by LaCoO3/g-C3N4 for degradation of tetracycline hydrochloride: performance, mechanism and phytotoxicity evaluation

A LaCoO3/g-C3N4 catalyst with high stability was designed and used for PMS activation to degrade TC.

Sustainable Treatment of Food Industry Wastewater Using Membrane Technology: A Short Review

Water is needed for food processing facilities to carry out a number of tasks, including moving goods, washing, processing, and cleaning operations. This causes them to produce wastewater effluent, and they are typically undesirable since it contains a high volume of suspended solids, bacteria, dyestuffs, salts, oils, fats, chemical oxygen demand and biological oxygen demand. Therefore, treatment of food industry wastewater effluent is critical in improving process conditions, socio-economic benefits and our environmental. This short review summarizes the role of available membrane technologies that have been employed for food wastewater treatment and analyse their performance. Particularly, electrospun nanofiber membrane technology is revealed as an emerging membrane science and technology area producing materials of increasing performance and effectiveness in treating wastewater. This review reveals the challenges and perspectives that will assist in treating the food industry wastewater by developing novel membrane technologies.