Fe3C-porous carbon derived from Fe2O3 loaded MOF-74(Zn) for the removal of high concentration BPA: The integrations of adsorptive/catalytic synergies and radical/non-radical mechanisms

A comprehensive review on advanced trends in treatment technologies for removal of Bisphenol A from aquatic media

Toxic environmental pollutants are considered to be posed a major threat to human and aquatic systems. The fast advancement of the petrochemical and chemical industries has woken up rising worries concerning the pollution of water by contaminants including phenolic Bisphenol A (BPA), an endocrine-disrupting chemical (EDC). The intermediate BPA used in synthesis of certain plastics, polycarbonate polymers, polysulfone, and epoxy resins of various polyesters. Due to potential health risks, severe toxicity, and widespread distribution, there is an urgent need to develop efficient techniques for the removal of BPA. Therefore, advance management for the active elimination of BPA prior to its release into the water sources is of serious concern. Degradation, membrane separation, adsorption, and biological treatments have been extensively examined as they are easy to operate and cost-effective for effective BPA removal. In this review, we summarized the mechanism and performance for removal of BPA by several sorbents, including natural polymers, natural inorganic minerals, porous and carbon-based materials. Comparative results revealed that composite materials and modified adsorbents have good performances for removal of BPA. Furthermore, kinetic study investigating adsorption mechanisms was also discussed. Hazardous quantities of such types of chemicals in various samples have thus been the subject of increasing concern of investigation. This review clarified the extensive literature regarding the major health effects of BPA and its advanced treatment technologies including biological treatment by natural and synthetic materials have been discussed briefly. It delivers regulation for future development and research from the aspects of materials functionalization, development of methods, and mechanism investigation that directing to stimulate developments for removal of emerging contaminants.

Enhancing enzymatic catalysis efficiency: Immobilizing laccase on HHSS for synergistic bisphenol A adsorption and biodegradation through optimized external surface utilization

Laccase, a prominent enzyme biomacromolecule, exhibits promising catalytic efficiency in degrading phenolic compounds like bisphenol A (BPA). The laccase immobilized on conventional materials frequently demonstrates restricted loading and suboptimal catalytic performance. Hence, there is a pressing need to optimized external surface utilization to enhance catalytic performance. Herein, we synthesized amino-functionalized modified silica particles with a hierarchical hollow silica spherical (HHSS) structure for laccase immobilization via crosslinking, resulting in HHSS-LE biocatalysts. Through Box-Behnken design (BBD) and response surface methodology (RSM), we achieved a remarkably high enzyme loading of up to 213.102 mg/g. The synergistic effect of adsorption by HHSS and degradation by laccase facilitated efficient removal of BPA. The HHSS-LE demonstrated superior BPA removal capabilities, with efficiencies exceeding 100 % in the 50-200 mg/L BPA concentration range. Compared to MCM-41 and solid silica spheres (SSS), HHSS showed the highest enzyme loading capacity and catalytic activity, underscoring its superior external surface utilization rate per unit mass. Remarkably, the HHSS-LE biocatalyst exhibited remarkable recyclability even after 11 successive cycles of reuse. By preparing high immobilization rate with efficient external surface utilization, this study lays the foundation for the design of universally applicable and efficient enzyme immobilization catalysts.

ZIF-67 and Biomass-Derived N, S-Codoped Activated Carbon Composite Derivative for High-Effective Removal of Hydroquinone from Water

Hydroquinone (HQ) in wastewater is of great concern, as it is harmful to human health and threatens the ecological environment. However, the existing adsorbents have low adsorption capacity for HQ. To improve the removal of HQ, N,S-codoped activated carbon-ZIF-67 (NSAC-ZIF-67@C) was synthesized in this study by in situ growth of ZIF-67 on N,S-codoped activated carbon (NSAC) and carbonization. The influence of pH, contact time, and initial concentration on the adsorption behaviors of NSAC-ZIF-67@C on HQ were investigated. Owing to the synergistic effect of abundant active sites and well-developed pore structure, the NSAC-ZIF-67@C achieved a prominent adsorption capacity of 962 mg·g-1 and can still retain high adsorption performance after 5 cycles for HQ, which is superior to that of reported other adsorbents. HQ adsorption follows the pseudo-second-order kinetics model (R2 = 0.99999) and the Freundlich isotherm model. X-ray photoelectron spectroscopy (XPS) analysis before and after adsorption as well as density functional theory (DFT) calculation results showed that pyridinic-N-termini were conducive to the π-π interactions and hydrogen-bonding interactions. Therefore, the adsorption mechanisms of NSAC-ZIF-67@C on HQ involve pore filling, electrostatic attraction, π-π interaction, and hydrogen bonding. This study is expected to provide a reference for designing highly effective adsorbents for wastewater treatment.

Size-Dependent Catalysis in Fenton-like Chemistry: From Nanoparticles to Single Atoms

State-of-the-art Fenton-like reactions are crucial in advanced oxidation processes (AOPs) for water purification. This review explores the latest advancements in heterogeneous metal-based catalysts within AOPs, covering nanoparticles (NPs), single-atom catalysts (SACs), and ultra-small atom clusters. A distinct connection between the physical properties of these catalysts, such as size, degree of unsaturation, electronic structure, and oxidation state, and their impacts on catalytic behavior and efficacy in Fenton-like reactions. In-depth comparative analysis of metal NPs and SACs is conducted focusing on how particle size variations and metal-support interactions affect oxidation species and pathways. The review highlights the cutting-edge characterization techniques and theoretical calculations, indispensable for deciphering the complex electronic and structural characteristics of active sites in downsized metal particles. Additionally, the review underscores innovative strategies for immobilizing these catalysts onto membrane surfaces, offering a solution to the inherent challenges of powdered catalysts. Recent advances in pilot-scale or engineering applications of Fenton-like-based devices are also summarized for the first time. The paper concludes by charting new research directions, emphasizing advanced catalyst design, precise identification of reactive oxygen species, and in-depth mechanistic studies. These efforts aim to enhance the application potential of nanotechnology-based AOPs in real-world wastewater treatment.

One-step growth of Cu-doped carbon dots in amino-modified carbon nanotube-modified electrodes for sensitive electrochemical detection of BPA

Copper-doped carbon dots and aminated carbon nanotubes (Cu-CDs/NH2-CNTs) nanocomposites were synthesized by a one-step growth method, and the composites were characterized for their performance. An electrochemical sensor for sensitive detection of bisphenol A (BPA) was developed for using Cu-CDs/NH2-CNTs nanocomposites modified with glassy carbon electrodes (GCE). The sensor exhibited an excellent electrochemical response to BPA in 0.2 M PBS (pH 7.0) under optimally selected conditions. The linear range of the sensor for BPA detection was 0.5-160 μM, and the detection limit (S/N = 3) was 0.13 μM. Moreover, the sensor has good interference immunity, stability and reproducibility. In addition, the feasibility of the practical application of the sensor was demonstrated by the detection of BPA in bottled drinking water and Liu Yang River water.

Facile synthesis of pyrite FeS2 on carbon spheres for high-efficiency Fenton-like reaction

Designing iron-based catalysts for Fenton-like reactions with peroxymonosulfate (PMS) as oxidants have attracted growing attentions. Herein, pyrite FeS2 supported on carbon spheres (FeS2@C) is synthesized by a facile low-temperature method. The FeS2@C/PMS system can degrade carbamazepine (CBZ) effectively in a wide pH range. Sulfate radicals (SO4·-), hydroxyl radicals (·OH), superoxide radical (O2·-), and singlet oxygen (1O2) are the responsible reactive oxygen species (ROSs) for CBZ degradation. Moreover, in the simulated fixed-bed reactor, the FeS2@C/PMS system can maintain a high CBZ removal ratio of >95% for than 8 h, exhibiting its excellent stability. The outstanding performance of FeS2@C/PMS system is attributed to the presence of carbon spheres and lattice S2-, which together promote the Fe(III)/Fe(II) redox cycle. The FeS2@C is a promising catalyst due to its facile synthesis, low cost, high efficiency, and excellent stability to activate PMS for organics degradation.

Plasma-assisted assembly of Co3O4/TiO2-NRs for photoelectrocatalytic degradation of bisphenol A in solution and muddy systems

Herein, Co3O4/TiO2-NRs electrodes with excellent photoresponse have been prepared via the plasma-assisted modification of Co3O4 on TiO2. With the combination of Co3O4 and TiO2, the composite electrode exhibited a red-shift phenomenon and the absorption of UV and visible light were enhanced to improve the light utilization efficiency. The Mott-Schottky diagram showed that a P-N heterojunction was successfully formed between Co3O4 and TiO2 on the electrode, which inhibited the recombination of electrons and holes, and had a high photocurrent density. In our photoelectrocatalysis (PEC) degradation experiments, the degradation rates of bisphenol A (BPA) by Co3O4/TiO2-NRs electrode in Na2SO4 and simulated seawater system reached 69.44 and 100%, respectively. The important role of ·O2-, ·OH, h+, and active chlorine (Cl·, HClO/ClO-, and Cl2) on the Co3O4/TiO2-NRs electrode during the degradation of BPA in simulated seawater was revealed. In addition, PEC combined with electrokinetic (EK) studies with the Co3O4/TiO2-NRs electrode were used for the degradation of BPA in muddy water, initially expanding the application scope of the PEC performance of the Co3O4/TiO2-NRs electrode for pollutants degradation, and had great potential for the subsequent treatment of muddy water pollutants.

Mechanisms of interaction between metal-organic framework-based material and persulfate in degradation of organic contaminants (OCs): Activation, reactive oxygen generation, conversion, and oxidation

Metal-organic frameworks (MOFs)-based materials have been of great public interest in persulfate (PS)-based catalytic oxidation for wastewater purification, because of their excellent performance and selectiveness in organic contaminants (OCs) removal in complex water environments. The formation, fountainhead and reaction mechanism of reactive oxygen species (ROSs) in PS-based catalytic oxidation are crucial for understanding the principles of PS activation and the degradation mechanism of OCs. In the paper, we presented the quantitative structure-activity relationship (QSAR) of MOFs-based materials for PS activation, including the relationship of structure and removal efficiency, active sites and ROSs as well as OCs. In various MOFs-based materials, there are many factors will affect their performances. We discussed how various surface modification projects affected the characteristics of MOFs-based materials used in PS activation. Moreover, we revealed the process of ROSs generation by active sites and the oxidation of OCs by ROSs from the micro level. At the end of this review, we putted forward an outlook on the development trends and faced challenges of MOFs for PS-based catalytic oxidation. Generally, this review aims to clarify the formation mechanisms of ROSs via the active sites on the MOFs and the reaction mechanism between ROSs and OCs, which is helpful for reader to better understand the QSAR in various MOFs/PS systems.

Synergetic effect of photocatalytic oxidation plus catalytic oxidation on the performance of coconut shell fiber biochar decorated α-MnO2 under visible light towards BPA degradation

Photocatalytic technology is regarded as a promising approach for fast degradation of refractory organic pollutant in water. However, the performance of the photocatalyst can be restricted by the variation of water matrix conditions. Herein, coconut shell fiber was pyrolyzed to biochar (CSB800) and incorporated with α-MnO2 to degrade bisphenol A (BPA) in water under visible light irradiation. The prepared α-MnO2/CSB800 composites demonstrated high efficacy in degrading BPA. Specifically, 0.01 mM of BPA could be completely degraded by 0.1 g/L of MnO2/CSB800 within 45 min. It was found that the incident light could effectively trigger the separation of electron and hole in α-MnO2. The electron and hole were afterwards converted to hydroxyl radical (●OH), superoxide radical (●O2-) and non-radical singlet oxygen (1O2), which subsequently initiated the photocatalytic degradation of BPA. Additionally, α-MnO2/CSB800 could simultaneously participate the oxidative degradation pathway of BPA with its high oxidation-reduction potential. The introduction of CSB800 led to higher BPA degradation efficiency since CSB800 could accelerate the charge carrier transferring rate during BPA degradation process via either pathway. The co-existence of both photocatalytic and oxidative degradation synergy enables α-MnO2/CSB800/visible light system with high catalytic performance stability towards various water matrices. This study proposes an effective strategy to prepare easy-available photocatalysts with high and stable performance towards for addressing organic pollution issues in water.

Wood induced preparation of Fe3C decorated biochar for peroxymonosulfate activation towards bisphenol a degradation with low ion leaching

Heterogeneous iron/persulfate system suffers from the problems of high ion leaching, severe catalyst surface corrosion and low performance stability. Herein, a series of iron compound incorporated N doped biochar composite catalysts were prepared from pyrolyzing wood powder and ferric ferrocyanide mixture, which were used for bisphenol A (BPA) degradation in water through peroxymonosulfate (PMS) activation. It was found that the reducing gases released from wood powder at different pyrolysis temperature significantly affected the crystalline phase of the iron compound in the catalyst, in which pure phase iron carbide (Fe₃C) decorated N doped biochar was obtained at pyrolysis temperature of 600 °C or higher. Wood powder was introduced as both Fe₃C formation inductive agent and biochar precursor. Fe₃C/biochar exhibited optimal BPA degradation performance, in which 0.5 g/L of catalyst could completely degrade 0.05 mM BPA within 30 min. Radical, high valent iron-oxo, and non-radical species were all generated in the reaction system by both Fe₃C and N doped biochar, respectively. Moreover, the multi-valence nature of Fe in Fe₃C enabled the reaction system with remarkably reduced Fe ion leaching and negligible iron sludge production since Fe₃C could activate PMS through a heterogeneous mechanism. Having multiple active species generated for BPA degradation, the prepared catalyst also showed promising adaptability and recyclability. This study can provide a new solution for the design of iron based catalyst/PMS system for organic pollutant degradations with low ion release.

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.

Fe-Based Metal Organic Frameworks (Fe-MOFs) for Bio-Related Applications

Metal-organic frameworks (MOFs) are porous materials composed of metal ions and organic ligands. Due to their large surface area, easy modification, and good biocompatibility, MOFs are often used in bio-related fields. Fe-based metal-organic frameworks (Fe-MOFs), as important types of MOF, are favored by biomedical researchers for their advantages, such as low toxicity, good stability, high drug-loading capacity, and flexible structure. Fe-MOFs are diverse and widely used. Many new Fe-MOFs have appeared in recent years, with new modification methods and innovative design ideas, leading to the transformation of Fe-MOFs from single-mode therapy to multi-mode therapy. In this paper, the therapeutic principles, classification, characteristics, preparation methods, surface modification, and applications of Fe-MOFs in recent years are reviewed to understand the development trends and existing problems in Fe-MOFs, with the view to provide new ideas and directions for future research.

Pyrolyzed magnetic NiO/carbon-derived nanocomposite from a hierarchical nickel-based metal-organic framework with ultrahigh adsorption capacity

Herein, a simple one-pot solvothermal approach is used to create magnetic porous carbon nanocomposites which obtained from a nickel-based metal-organic framework (Ni-MOF) and examined for their ability to uptake methyl orange (MO) dye. Derived carbons with exceptional porosity and magnetic properties were created during the different pyrolysis temperatures of Ni-MOF (700, 800, and 900 °C) under a nitrogen atmosphere. The black powders were given the names CDM-700, CDM-800, and CDM-900 after they were obtained. A variety of analysis methods, including FESEM, EDS, XRD, FTIR, VSM, and N₂ adsorption-desorption were used to characterize as-prepared powders. Furthermore, adsorbent dosage, contact time, pH variation, and initial dye concentration effects was investigated. The maximum adsorption capacities were 307.38, 5976.35, 4992.39, and 2636.54 mg/g for Ni-MOF, CDM-700, CDM-800, and CDM-900, respectively, which show the ultrahigh capacity of the resulted nanocomposites compared to newest materials. The results showed that not only the crystallinity turned but also the specific surface area was increased about four times after paralyzing. The results showed that the maximum adsorption capacity of MO dye for CDM-700 was obtained at adsorbent dosage of 0.083 g/L, contact time of 60 min, feed pH of 3, and temperature of 45 °C. The Langmuir model has the best match and suggests the adsorption process as a single layer. According to the results of reaction kinetic studies using well-known models, the pseudo-second-order model (R² = 0.9989) displayed high agreement with the experimental data. The synthesized nanocomposite is introduced as a promising superadsorbent for eliminating dyes from contaminated water due to strong recycling performance up to the fifth cycle.

Mechanism and security of UV driven sodium percarbonate for sulfamethoxazole degradation using DFT and metabolomic analysis

Recently, sodium percarbonate (SPC) as a solid substitute for H₂O₂ has aroused extensive attention in advanced oxidation processes. In current work, the degradation kinetics and mechanisms of antibiotic sulfamethoxazole (SMX) by ultraviolet (UV) driven SPC system were explored. The removal efficiency of SMX was enhanced as the increasing dosage of SPC. Moreover, hydroxyl radical (•OH), carbonate radical (CO₃^•-) and superoxide radical (O₂^•-) were verified to be presented by scavenger experiments and •OH, CO₃^•- exhibited a significant role in SMX degradation. Reactions mediated by these radicals were affected by anions and natural organic matters, implying that an incomplete mineralization of SMX would be ubiquitous. The screening four intermediates and transformation patterns of SMX were verified by DFT analysis. Metabolomic analysis demonstrated that a decreasing negative effect in E. coli after 24 h exposure was induced by intermediates products. In detail, SMX interfered in some key functional metabolic pathways including carbohydrate metabolism, pentose and glucuronate metabolism, nucleotide metabolism, arginine and proline metabolism, sphingolipid metabolism, which were mitigated after UV/SPC oxidation treatment, suggesting a declining environmental risk of SMX. This work provided new insights into biological impacts of SMX and its transformation products and vital guidance for SMX pollution control using UV/SPC technology.

CQDs improved the photoelectrocatalytic performance of plasma assembled WO3/TiO2-NRs for bisphenol A degradation

Carbon quantum dots (CQDs) have been supported on WO₃/TiO₂-NRs using a hydrothermal method and a novel CQDs/WO₃/TiO₂-NRs composite formed via dielectric barrier discharge. The composite electrodes were characterized using morphology, structural, optical and electrochemical analysis. The CQDs were successfully prepared on the composite electrode with the highest photocurrent density reaching 2.51 mA·cm^-2 under UV-visible light irradiation (100 mW·cm^-2) and an applied voltage of 0.6 V vs. Ag/AgCl. The CQDs/WO₃/TiO₂-NRs electrode exhibited a good degradation effect toward bisphenol A (BPA) (75.66 %) combined with the production of hydrogen (0.89 mmol) in Na₂SO₄ system after 2 h of the photoelectrocatalytic (PEC) reaction and the BPA degradation rate reached 100 % after 7 min of reaction in both simulated and real seawater. The CQDs/WO₃/TiO₂-NRs exhibited excellent stability and efficient PEC performance in which the CQDs acted as electron reservoirs to capture and promote charge separation. Our analysis of intermediates of BPA degradation indicated the possible degradation pathways that mainly formed BPA polymers in the Na₂SO₄ system or chlorinated compounds in the high chloride salt system.

A Comparison Study between Wood Flour and Its Derived Biochar for the Enhancement of the Peroxydisulfate Activation Capability of Fe3O4

In this study, both wood flour (WF) and wood flour-derived biochar (WFB) were used as supports for Fe3O4 to activate peroxydisulfate (PDS). The role of different carriers was investigated emphatically from the aspects of catalyst properties, the degradation kinetics of bisphenol A (BPA), the effects of important parameters, and the generation of reactive oxygen species (ROS). Results showed that both WF and WFB could serve as good support for Fe3O4, which could control the release of iron into solution and increase the specific surface areas (SSAs). The WFB/Fe3O4 had stronger PDS activation capability than WF/Fe3O4 mainly due to the larger SSA of WFB/Fe3O4 and the PDS activation ability of WFB. Both radical species (•OH and SO4•−) and non-radical pathways, including 1O2 and high-valent iron-oxo species, contributed to the degradation of BPA in the WFB/Fe3O4–PDS process. Moreover, the WFB/Fe3O4 catalyst also showed stronger ability to control the iron release, better reusability, and higher BPA mineralization efficiency than WF/Fe3O4.

Removal of pharmaceutical and personal care products (PPCPs) by MOF-derived carbons: A review

Nowadays, the increasing demand for pharmaceuticals and personal care products (PPCPs) has resulted in the uncontrolled release of large amounts of PPCPs into the environment, which poses a great challenge to the existing wastewater treatment technologies. Therefore, novel materials for efficient treatment of PPCPs need to be developed urgently. MOF-derived carbons (MDCs), have many advantages such as high mechanical strength, excellent water stability, large specific surface area, excellent electron transfer capability, and environmental friendliness. These advantages give MDCs an excellent ability to remove PPCPs. In this review, the effects of different substances on the properties and functions of MDCs are discussed. In addition, representative applications of MDCs and composites for the removal of PPCPs in the field of adsorption and catalysis are summarized. Finally, the future challenges of MDCs and composites are foreseen.

Preparation of VCo-MOF@MXene composite catalyst and study on its removal of ciprofloxacin by catalytically activating peroxymonosulfate: Construction of ternary system and superoxide radical pathway

The synergistic effect between transition metal active centers and the generation of multiple removal pathways has a significant impact on the catalytic activation efficiency of peroxymonosulfate. In this work, a kind of composite catalyst was prepared by growing VCo-metal-organic frameworks (VCo-MOF) in-situ on the surface of Ti3C2Tx by a solvothermal method. The morphology and structure are characterized by Transmission Electron Microscope (TEM), Energy Dispersion Spectrum (EDS), Atomic Force Microscope (AFM), etc. Response surface methodology was used to optimize the experimental conditions. Only 5 mg catalyst can be used to effectively activate PMS and remove 96.14 % ciprofloxacin (CIP, 20 mg/L) within 30 min. The removal effect of catalyst on CIP in different actual water environment was explored. In addition, the fluorescence spectrum test also verified the effective removal of ciprofloxacin. V-Co-Ti ternary system provides a wealth of active sites for CIP removal. Cyclic voltammetry (CV) and lear sweep voltammetry (LSV) tests showed the existence of the electron transfer pathway. The results of density functional theory (DFT) calculation show that VCo-MOF@Ti3C2Tx has excellent adsorption and activation ability for PMS. At the same time, the hydrophilicity of the catalyst makes PMS more inclined to react with water molecules, which promotes the formation of a unique superoxide radical path.

High performance flexible and antibacterial strain sensor based on silver‑carbon nanotubes coated cellulose/polyurethane nanofibrous membrane: Cellulose as reinforcing polymer blend and polydopamine as compatibilizer

In this study, ethyl cellulose was used as the second-phase polymer blended with polyurethane to make nanofibrous membrane as antibacterial strain sensor. The results indicated that ethyl cellulose could regulate the morphology of polyurethane through strong hydrogen bonding, which observably enhanced the nanofiber uniformity of polyurethane. Furthermore, rigid cellulose also remarkably improved the mechanical strength and thermal stability of the nanofibrous membrane. After being coated with silver nanoparticles and carbon nanotubes assisted by polydopamine (PDA), the membrane with outstanding bacteria inhibition performance exhibited outstanding sensitivity toward external mechanical stretching, as well as real-time motion of human body parts. The conductive composite membrane possessed sensitive and regular resistance feedback to 100 cycles of varied human motions. The cellulose in the nanofiber structure ensured the shape recovery and longtime use stability of the membrane. This study proposed a novel thinking for the construction of high performance strain sensor by rational introduction of rigid polysaccharide into the polymer matrix.

Ultrahigh-efficient BiOBr-x%La@y%CNQDs nanocomposites with enhanced generation and separation of photogenerated carriers towards bisphenol A degradation and toxicity reduction

In this study, a series of hierarchical flower-like La-doped BiOBr composites modified with carbon nitride quantum dots (BiOBr-x%La@y%CNQDs) was synthesized using a microwave solvothermal method in combination with a calcination method. It was found that La doping and CNQDs co-decorated with BiOBr showed much better photoreactivity for bisphenol A (BPA) degradation than pure BiOBr. The best degradation and mineralization efficiencies of BPA were 100% and 77% within 12 min at La and CNQDs contents of 1% and 1.25%, respectively. Various characterization results demonstrated that this synergistic effect on BiOBr-1%La@1.25%CNQDs was attributed to its improved light-harvesting properties, enhanced photogenerated electron and holes pairs separation and interfacial charge transfer. Degradation pathways were proposed based on active species analysis, identification of nine intermediates, and density functional theory (DFT) calculations. Furthermore, a bioluminescence assay of the inhibition rate of the luminescent bacterium Vibrio qinghaiensis sp. Q67 showed that BiOBr-1%La@1.25%CNQDs have superior detoxification ability. The present study provides some insight into the design of ultrahigh-efficiency nanojunction photocatalysts with a broadened photoabsorption range and improved separation efficiency of photogenerated carriers to enhance the degradation and detoxification performance of BPA.

Mechanistic and structure investigation of the KOH activation ZIF-8 derived porous carbon as metal-free for unprecedented peroxymonosulfate activation degradation of bisphenol A

The high-performance and free secondary pollution of the catalysts are the most critical issues in the peroxymonosulfate-based advanced oxidation processes (PMS-AOPs). In this research, the KOH was used to activate ZIF-8 derived carbon materials to synthesize the NC-KOH-x (x = 700, 800, 900 °C), which was an effective metal-free PMS activator. As-prepared NC-KOH-x showed significant improvement not only pore structure and BET surface area but also CO groups, and graphite N content, which were beneficial for the adsorptive and oxidative reaction. The NC-KOH-900 as an excellent metal-free carbon-catalyst exhibited considerable reactivity for bisphenol A (BPA) removal in broad pH ranges. Almost 100% of BPA was eliminated using 9 mg NC-KOH-900, 0.5 mM PMS within 60 min. Interestingly, It was found that the BPA removal efficiency by adding PMS after saturated adsorption of NC-KOH-x was better than that by adding NC-KOH-x and PMS simultaneously. Electronic paramagnetic resonance (EPR) and quenching experiments results demonstrated that the BPA degradation relied mainly on the nonradical (¹O₂) pathways and the defects (I_D/I_G), graphitic nitrogen, pyridinic nitrogen, and CO were verified as leading catalytic sites for BPA degradation via PMS activation. Finally, degradation pathways of BPA were proposed and the Toxicity Estimation Software Tool (T.E.S.T.) result implicated that the intermediates of BPA were environmentally friendly to the microorganism and recycled in the ecosystem. The outcomes of this study illustrated the NC-KOH-x owned many merits of state-of-the-art, eco-friendly, and high-performance for great potential practical application value.

Nanohybrid catalysts with porous structures for environmental remediation through photocatalytic degradation of emerging pollutants

Water supplies have been seriously challenged by new emerging pollutants, which are difficult to remove by traditional wastewater treatment. Thus, new technologies such as catalytic advanced oxidation processes have merged as suitable solutions; however, the drawbacks of typical catalysts limit their application. To overcome this issue, new materials with enhanced textural properties have been developed, showing that their porosity and chemical nature influence their potential as a catalyst. Herein, the recent progress in highly porous catalysts and their suitable deployment to effectively nano-remediate the polluted environmental matrices are reviewed in detail. First, following a brief introduction, several environmental pollutants of emerging concerns from different sectors, including pharmaceutical residues, endocrine-disrupting chemicals (EDCs), pesticides, and hazardous dyes are also introduced with relevant examples. To effectively tackle the sustainable remediation of emerging pollutants, this work also focuses on the multifunctional features of nanohybrid porous materials that act as catalysts constructs to degrade emerging pollutants. The influence of surface reactive centers, stability, bandgap energies, light absorption capacities, and pollutants adsorption capacities are also discussed. Successful examples of the employment of nanohybrid porous catalysts for the degradation of pharmaceutical pollutants, EDCs, pesticides, and hazardous dyes are summarized. Finally, some challenges faced by nanohybrid porous materials to achieve their potential application as advanced catalysts for environmental remediation have been identified and presented herein.

Stable magnetic CoZn/N-doped polyhedron with self-generating carbon nanotubes for highly efficient removal of bisphenols from complex wastewaters

Bisphenols have extensively been found in various environmental matrices and caused public concerns due to their endocrine-disrupting potential. Herein, we developed a ZIF-67@ZIF-8-derived CoZn/nitrogen-doped carbon (CoZn/NC) as a robust adsorbent for bisphenols in wastewaters. The self-generating carbon nanotubes and the open metal sites provided sufficient adsorption sites. The Co component endowed the derivative with strong magnetism facilitating its separation from water. CoZn/NC exhibited exceeding water stability in pH 3 - 12 solution and withstood water up to 15 days. The great applicability of CoZn/NC was validated with 16 real wastewaters from different sources (recoveries exceeding 97.9%). Fast adsorption kinetics were observed with removal efficiencies above 96.5% within 1 min. The adsorption isotherms were well fitted with the Langmuir model, with adsorption capacities of 222, 200, 193, and 321 mg g^-1 for bisphenol A, bisphenol F, bisphenol S, and bisphenol AF, respectively. Variations in external conditions, including pH 3 - 9, humic acid (50 mg L^-1), and NaCl (0.1 mol L^-1), had negligible impacts on the adsorption process. The characterizations and density functional theory computation demonstrated that electrostatic, hydrophobic, π - π, and cation- π interactions are the driving forces in this system. The as-prepared CoZn/NC exhibits great promise in real wastewater treatment.

Strategies for improving the catalytic activity of metal-organic frameworks and derivatives in SR-AOPs: Facing emerging environmental pollutants

As persulfate activator, Metal organic frameworks (MOFs) and derivatives are widely concerned in degradation of emerging environmental pollutants by advanced oxygen technology dominated by sulfate radical () (SR-AOPs). However, the poor stability and low catalytic efficiency limit the performance of MOFs, requiring multiple strategies to further enhance their catalytic activity. The aim of this paper is to improve the catalytic activity of MOFs and their derivatives by physical and chemical enhancement strategies. Physical enhancement strategies mainly refer to the activation strategies including thermal activation, microwave activation and photoactivation. However, the physical enhancement strategies need energy consumption and require high stability of MOFs. As a substitute, chemical enhancement strategies are more widely used and represented by optimization, modification, composites and derivatives. In addition, the identification of reactive oxygen species, active site and electron distribution are important for distinguishing radical and non-radical pathways. Finally, as a new wastewater treatment technology exploration of unknown areas in SR-AOPs could better promote the technology development.

Electro-enhanced sulfamethoxazole degradation efficiency via carbon embedding iron growing on nickel foam cathode activating peroxymonosulfate: Mechanism and degradation pathway

The combination of peroxymonosulfate (PMS) activation by hetero-catalysis and electrolysis (EC) attracted incremental concerns as an efficient antibiotics degradation method. In this work, carbon embedding iron (C@Fe) catalysts growing on nickel foam (NF) composite cathode (C@Fe/NF) was prepared via in-situsolvothermal growth and carbonization method and used to activate PMS toward sulfamethoxazole (SMX) degradation. The EC-[C@Fe/NF(II)]-PMS system exhibited an excellent PMS activation, with 100% SMX removal efficiency achieving within 30 min. Reactive oxygen species (ROS) generation and their roles in SMX degradation were confirmed by quenching experiments and electron paramagnetic resonance. It was found that singlet oxygen (¹O₂) and surface-bound radicals were responsible for SMX degradation, and ¹O₂ contributed the most. Furthermore, the possible SMX degradation pathways were proposed on the base of the detected degradation intermediates and density functional theory (DFT) calculation. Toxicity changes were also assessed by the Ecological Structure Activity Relationships (ESAR). This work provides a practicable strategy for synergistically enhancing PMS activation efficiency and promoting antibiotics removal.

Microwave-assisted preparation of Ag/Fe magnetic biochar from clivia leaves for adsorbing daptomycin antibiotics

Novel clivia biochar adsorbing daptomycin (DAP) was prepared by microwave digestion–anaerobic carbonization in this work. Fe/Ag submicron particles were introduced to the biochar surface based on the reducibility of biochar to enhance its adsorption capacity. Characterization confirmed that modified biochar (AF-biochar) had a higher particle size (126 μm), larger specific surface area (521.692 m2 g−1), richer pore structure, and higher thermal stability. The effects of the main variables (e.g., the solution pH, contact time, initial DAP concentration, and temperature) were investigated during adsorption. The results showed that AF-biochar could reach the adsorption equilibrium at pH 4.8 for 85 min. Besides, the adsorption capacity was 48.25 mg g−1, and the adsorption efficiency was 96.50% when the concentration of DAP was 25 mg L−1. The pseudo-second-order kinetics (R 2 = 0.9997), Langmuir equation (R 2 = 0.9999), and thermodynamics (R 2 = 0.9631) of AF-biochar fit well, indicating that the main adsorption process of AF-biochar was spontaneous, exothermic, and monolayer. Their adsorption was analyzed by physical and chemical adsorption. The main adsorption mechanisms included the electron donor–acceptor interaction, electrostatic force interaction, Lewis acid–base interaction, and H-bond interaction.

Iron Carbon Catalyst Initiated the Generation of Active Free Radicals without Oxidants for Decontamination of Methylene Blue from Waters

In conventional oxidation technologies for treatment of contaminated waters, secondary pollution of the aqueous environment often occurs because of the additional oxidants generated during the process. To avoid this problem, Fe/NG catalyst composites without additives were developed in this study for decontamination of methylene blue (MB) from waters. The Fe/NG catalyst, composed of carbon nitride and iron chloride (FeCl3·6H2O), was prepared by high temperature pyrolysis. It is an exceptionally efficient, recoverable, and sustainable catalyst for degradation of organic matter. The morphological characteristics, chemical structure, and surface properties of the catalyst composites were investigated. The catalyst exhibited high MB removal efficiency (100%) within 30 min under ambient temperature and dark conditions. The experiments indicated that an MB degradation effect was also applicable under most acid–base conditions (pH = 2–10). The characterization results using electron spin resonance and analysis of intermediate products demonstrated that free radicals such as ·OH and ·O2− were produced from the Fe/NG composites in the heterogeneous system, which resulted in the high MB degradation efficiency. Moreover, the catalysis reaction generated reducing substances, triggering iron carbon micro-electrolysis to spontaneously develop a microcurrent, which assisted the degradation of MB. This study demonstrates the feasibility of Fe/NG catalysts that spontaneously generate active species for degrading pollutants in an aqueous environment at normal temperature, providing an attractive approach for treating organic-contaminated waters.

An efficient removal mechanism for different hydrophilic antibiotics from aquatic environments by Cu-Al-Fe-Cr quasicrystals

The work studied the adsorption properties and mechanism of Cu-Al-Fe-Cr quasicrystals (QCs) for the adsorption of ibuprofen (IBU), tedizolid phosphate (TZD), and sulbactam sodium (SAM) for the first time. The experimental results showed that quasicrystals were good adsorbents with great potential. The structure, surface morphology, and elemental composition of QCs were investigated by XPS, XRD, SEM, EDX, particle size, DSC-TG, and FTIR. The adsorption pH, kinetics, thermodynamics, and isotherms of IBU, TZD, and SAM in QCs were systematically studied. QCs had good adsorption performance for antibiotics, and the adsorption capacities of IBU, TZD, and SAM were 46.964, 49.206, and 35.292 mg g-1 at the concentration of 25 mg L-1, respectively. The surface charge and hydrophobicity of QCs were affected by changing pH, thereby affecting the adsorption performance of QCs. The main driving forces of adsorption included electrostatic force and hydrophobicity.

Waste preserved wood derived biochar catalyst for promoted peroxymonosulfate activation towards bisphenol A degradation with low metal ion release: The insight into the mechanisms

The rational disposal of waste preserved wood is of great significance since its embedded metals (Cu, As, and Cr) pose potential threat to environment and human health. In this study, a biochar catalyst derived from waste preserved wood (PWB) was prepared for the degradation of bisphenol A (BPA) via peroxymonosulfate (PMS) activation. The PWB exhibited prominent catalytic degradation capability towards BPA compared with common wood derived biochar (CWB). Further tests and analysis elucidated that both radical species (OH) and non-radical species (¹O₂) were generated by the PWB/PMS system, whereas only ¹O₂ was detected in CWB/PMS system. Specifically, the metal compounds, especially metallic Cu in the PWB activated PMS via radical pathway, and the CO groups in the biochar generated the non-radical pathway, the coexistence of which resulted in higher BPA degradation rate in PWB/PMS system. It was also demonstrated that the heavy metal ion leaching (As and Cr) in PWB/PMS system was negligible. Furthermore, the biochar could effectively inhibit the leakage of oxidized Cu ions. This study provides a novel approach to prepare high-efficient carbocatalysts for organic pollutant degradation in water, which also enables the waste preserved wood with an environmental nondestructive mode of dispatch.

Efficient degradation of organic dyes using peroxymonosulfate activated by magnetic graphene oxide

Magnetic graphene oxide (MGO) was prepared and used as a catalyst to activate peroxymonosulfate (PMS) for degradation of Coomassie brilliant blue G250 (CBB). The effects of operation conditions including MGO dosage, PMS dosage and initial concentration of CBB were studied. CBB removal could reach 99.5% under optimum conditions, and high removals of 98.4–99.9% were also achieved for other organic dyes with varied structures, verifying the high efficiency and wide applicability of the MGO/PMS catalytic system. The effects of environmental factors including solution pH, inorganic ions and water matrices were also investigated. Reusability test showed that CBB removals maintained above 90% in five consecutive runs, indicating the acceptable recyclability of MGO. Based on quenching experiments, solvent exchange (H₂O to D₂O) and in situ open circuit potential (OCP) test, it was found that ˙OH, SO₄˙⁻ and high-valent iron species were responsible for the efficient degradation of CBB in the MGO/PMS system, while the contributions of O₂˙⁻, ¹O₂ and the non-radical electron-transfer pathway were limited. Furthermore, the plausible degradation pathway of CBB was proposed based on density functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS) results, and toxicity variation in the degradation process was evaluated by computerized structure–activity relationships (SARs) using green algae, daphnia, and fish as indicator species.

Efficient degradation of organic dyes with PMS and magnetic graphene oxide.

Efficient removal of emerging contaminant sulfamethoxazole in water by ozone coupled with calcium peroxide: Mechanism and toxicity assessment

Sulfamethoxazole (SMX) is a widely distributed emerging contaminant, which will bring serious harm to ecology and human health. Herein, evaluation of ozone (O₃) coupled with calcium peroxide (CaO₂) for SMX elimination was carried out. The results showed that CaO₂ could promote SMX elimination in O₃ system. The removal efficiency was improved from 65.6% to 73.9% when the CaO₂ dosage was 0.06 g L^-1. O₃ dosage of 0.55 g h^-1 was beneficial to SMX degradation. With decrease of initial SMX concentration, the removal of SMX firstly enhanced and then declined. Compared with alkaline, acidic and neutral conditions were favorable for SMX degradation. ROS including ·OH, ·O₂^- and ¹O₂ play critical role for SMX degradation. Synergetic effect could be established between O₃ and CaO₂, which encouraged formation of ·OH and accelerated SXM decomposition. The total organic carbon (TOC) and chemical oxygen demand (COD) were all declined after O₃/CaO₂ treatment. According to results of liquid chromatography-mass spectrometry (LC-MS) and references, four major pathways were proposed. The O₃/CaO₂ technology was also suitable for practical wastewater treatment. QSAR calculation and seed germination experiment showed that toxicity of the treatment solution was alleviated after O₃/CaO₂ treatment.

Critical review of natural iron-based minerals used as heterogeneous catalysts in peroxide activation processes: Characteristics, applications and mechanisms

Recently, an increasing number of works have been reported about iron-based materials applied as catalysts in peroxide activation processes to degrade pollutants in water. Iron-based catalysts include synthetic and natural iron-based materials. However, some synthetic iron-based materials are difficult to scale up in the practical applications due to high cost and serious secondary environmental pollution. In contrast, natural iron-based minerals are more available and cheaper, and also hold a great promise in peroxide activation processes for pollutant degradation. In this review, we classify different natural iron-based materials into two categories: iron oxide minerals (e.g., magnetite, hematite, and goethite,), and iron sulfide minerals (e.g., pyrite and pyrrhotite,). Their overview applications in peroxide activation processes for pollutant degradation in wastewaters are systematically summarized for the first time. Moreover, the peroxide activation mechanisms induced by natural minerals, and the influences of reaction conditions in different systems are discussed. Finally, the application prospects and existing drawbacks of natural iron-based minerals in the peroxide activation processes for wastewater treatment are proposed. We believe this review can shed light on the application of natural iron-based minerals in peroxide activation processes and present better perspectives for future researches.

The radical and non-radical oxidation mechanism of electrochemically activated persulfate process on different cathodes in divided and undivided cell

Electrochemically activated persulfate (PS) employing stainless steel (SS), carbon felt (CF) and carbon black modified CF (CB-CF) as the cathode, in the divided and undivided cell, respectively, for degradation of atrazine (ATZ) was first investigated using novel B, Co-doped TiO₂ nanotubes (B, Co-TNT) anode. In undivided cell, ATZ degradation was followed the order of CF<CB-CF<SS. The main radical for ATZ removal in SS and CF system was ^•OH, while on CB-CF cathode, it was the comprehensive contribution of ^•OH and SO₄^•-. ^•OH in SS system was more inclined to free ^•OH, while in CF and CB-CF systems it was more likely to be surface ^•OH. In divided anode cell, ^•OH was responsible for ATZ degradation in all three cathodes system. However, in divided cathode cell, ^•OH played a major role for ATZ degradation in SS cathode system. In CF and CB-CF cathode systems, the ATZ degradation was the comprehensive effect of ^•OH and SO₄^•- with the contribution of ^•OH and SO₄^•- was 91.7%, 8.3%, and 96.3%, 3.6%, respectively. The quenching studies showed that non-radical oxidation occurred in anode chamber in the presence of PS. Besides, the intermediates in divided and undivided cell were detected by LC-MS, and the possible degradation pathway was proposed.