Advanced Oxidation Reactions Research Articles

Green Synthesis of Graphene Acetic Acid: a Highly Effective and Versatile Carbocatalyst for Advanced Oxidation Reactions

Green Synthesis of Graphene Acetic Acid: a Highly Effective and Versatile Carbocatalyst for Advanced Oxidation Reactions

Treatment Technologies for Removal of Polyaromatic Hydrocarbon Compounds from Wastewater: A Review

Industry discharges, home effluents, and/or urban runoff can all introduce polyaromatic hydrocarbon compounds (PAHs) into a treatment center. Regrettably, due to their chemical stability and resistance to biological degradation, PAHs are regarded as organic pollutants that persist. As a consequence, PAHs have indeed been identified as a possible source of skin, lung, and bladder cancer in humans. Due to PAHs' potential to cause cancer and/or mutation, their residues in treated wastewater are now subject to stricter legal regulation. adsorption ,membrane filtration, coagulation, electrocoagulation, flocculation, advanced oxidation reactions, phytoremediation and bioremediation process are some of the techniques used to remove PAHs from wastewater. In order to reduce environmental contamination, it is important to study different treatment technologies to treat wastewater. The aim of this paper is to highlighting and discussing some of treatment technologies for removing PAHs.

Sulfur-doped activated carbon for the efficient degradation of tetracycline with persulfate: Insight into the effect of pore structure on catalytic performance.

Sulfur-doped activated carbon has proved to be a promising metal-free catalyst for persulfate (PDS) catalytic activation for the oxidation of aqueous refractory organics. Herein, sulfur-doped porous carbon (ACS) catalysts with different pore structures and doped-S contents were prepared via a template method using d(+)-glucose as the carbon source, sulfur as the sulfur source, and nano-MgO with different particle sizes as templates. Characterization results showed that the particle size of MgO significantly affects the pore structure and doped-S content of ACSs catalysts: a sample synthesized with 20 nm MgO as template (ACS-20) presented the highest content of doped-S and a mesoporous structure, which endowed it with superior adsorption and catalytic performance toward tetracycline (TC) removal. The effect of catalyst dosage, TC concentration, PDS concentration and solution pH on TC removal efficiency were evaluated. The reaction mechanism, investigated by combination of EPR, quenching experiments and LC-MS, indicated that the reactive species included HO·, SO4˙-, and 1O2, but that 1O2 played the dominant role in TC oxidation through a non-radical oxidation pathway. In addition, the reusability and regeneration properties of the ACS-20 catalyst were also studied. This work provides a promising strategy and some theoretical basis for the design and preparation of activated carbon catalysts for advanced oxidation reactions from the viewpoint of pore structure design and S-doping.

Exploring the high catalytic performances of Cu–Co–O/N-doped carbon materials toward the hydrogenation reduction and advanced oxidation reactions of 4-nitrophenol (PNP)

Cu–Co–O/N-doped carbon catalysts display excellent catalytic performances toward the hydrogenation reduction reaction of 4-nitrophenol (PNP), where a high activity parameter of 300 s−1 g−1 can be obtained when the NaBH4 : PNP molar ratio was 100 : 1.

Ultra-fast mechanochemistry reaction process: An environmentally friendly instant recycling method for spent LiFePO4 batteries

As LiFePO4 (LFP) gradually becomes the leader in the energy storage and power battery field, achieving a green and efficient industrialized recovery of Li from the stable lattice structure of LFP has become a significant requirement for driving resource and environmental sustainability. Here, a non-acid wet ultra-fast mechanochemistry reaction (UMR) instantaneous metallurgy technology is proposed, water leaching has obvious green and sustainable advantages. Including the wet mechanochemical reaction of C10H14N2Na2O8 assisted H2O2 and water leaching to deconstruct the orthorhombic olivine structure, and an innovative, detailed explanation of the mechanism of this technology is presented from the perspective of the synergy between mechanics and chemistry. The results indicate that under optimal conditions, stress energy accumulation and single-factor conditions can instantly achieve the activation process of efficiently deintercalating Li and enriching Fe in a single step within 4 mins, while still maintaining the olivine structure. Through the coupling of UMR with chelation reactions, the fastest selective recovery of 99.17 % of Li is achieved. Following filtration and precipitation, Fe and Li are ultimately recovered in the form of FePO4 and Li2CO3 precursors, respectively. Grey correlation analysis, grain flows numerical simulation, and the mechanism of chemical reactions indicate that rotation speed is the most critical factor affecting Li recovery, leading to the desorption of Fe(III) and Li+ mainly caused by the wear to the lattice structure by normal cumulative force, energy accumulation dissipation-induced advanced oxidation reactions, and chelation reactions. The non-acid USMR reported in this study offers a sustainable new pathway for the rapid extraction of Li from spent LFP for industrial purposes.

A new insight into designing of Ni-Cu-O/N-doped carbon system for boosting peroxymonosulfate toward advanced oxidation of p-nitrophenol

Both transition metal/N-doped carbon (metal/NC) or transition metal oxide/NC materials have effective catalytic performances toward various chemical reactions. There is still a problem to be answered when designing high performance catalysts—whether metal, metal oxide or NC is more important in determining the catalytic performances. In this work, Cu-Ni-O-N-C precursors were designed by sol-gel method, and then the same precursors were heated in air to form CuO-NiO/NC materials or in N2 atmosphere to fabricate Cu-Ni/NC catalysts. X-ray photoelectron spectroscopy (XPS) measurements show that the N element only have weak intensity in the analysis result of CuO-NiO/NC material while sharp peak of N can be observed in the profile of Cu-Ni/NC catalyst. Unexpectedly, the CuO-NiO/NC materials are more effective than Cu-Ni/NC catalysts in boosting peroxymonosulfate (PMS) for oxidation of p-nitrophenol in water at room temperature, including the catalytic activity parameter and the recycling performance. This indicates that more attention should be paid to metal oxide or metal when designing metal oxide/NC or metal/NC catalysts in the advanced oxidation reaction system.

Interface-engineered cavity-structured cobalt oxide as a boosted activator for peroxymonosulfate to degrade environmental hormones in water: Structural defects and oxygen vacancies-induced enhancement

While heterogeneous cobalt (Co) catalysts are useful peroxymonosulfate (PMS) activators, the development of a heterogeneous Co-based catalyst with intriguing physicochemical properties and outstanding catalytic activities is still of great interest. Herein, a unique cavity-structured grassy-like cobalt oxide (Co3O4) (CGCO) is proposed and fabricated through two-step modifications of partial sculpting and calcination using Co-based metal organic framework (Co-MOF) as an initial precursor. The as-prepared CGCO exhibits a cavity structure covered by grassy-like outer shells, thus possessing special physicochemical properties and enriched oxygen vacancy. These features enable CGCO a much more advantageous activator than commercial Co3O4 for activating PMS, and would efficiently remove 100% of bisphenol A (BA) rapidly. The activation energy (Ea) of BA degradation by CGCO+PMS is only 31.2 kJ/mol, which is lower than the recently-reported values. The density function theory calculation is performed to investigate the degradation pathway, and the corresponding eco-toxicity is also studied to realize the environmental implication of BA by CGCO-activated PMS as the toxicities and environmental impact of BA are significantly reduced. This work provides valuable information in term of preparation strategy of cavity structured metal oxide materials, which should be propitious for the degradation of environmental hormones via advanced oxidation reactions.

Engineering a simple multisignal-output probe for measuring residual peroxymonosulfate in advanced oxidation reactions

The extensive applications of peroxymonosulfate (PMS) in the field of environmental pollutant treatment based on advanced oxidation processes (AOPs) have prompted a high demand for advances in the probe ranging from improving their performances to strengthening their practicalities. Here, a multisignal-output probe of PMS was achieved by the unconventional application of traditional chromogenic system, 3,3′,5,5′-tetramethylbenzidine with Co2+ ions (Co2+-TMB). It works on the trace Co2+-catalyzed specific conversion of a colorless TMB into a blue oxidation product (oxTMB) with PMS as the oxidizing agent, accompanied by the enhanced absorption value of oxTMB at 652 nm and decreased fluorescence intensity of TMB at 405 nm. The change of color was directly observed. The combination of a hydrogel with a colorimetric platform favors the real-time and convenient sensing of PMS in the concentration range of 0.98 to 130.29 μM. A good linear relationship between the PMS concentration and both the absorption and fluorescence intensity was obtained with an r2 value of 0.999, and a detection limit of 0.03 μM for fluorescence and 0.11 μM for spectrometry. Such a multisignal output probe with the advantages of simplicity, convenience, high sensitivity and stability improves the reliability and practical adaptability. This study successfully applied a valuable strategy for sensing PMS, and verified its availability in detecting the residual quantity of PMS in pollutant water treated by AOPs and PMS concentrations in actual water samples with peroxydisulfate (PDS).

Magnetic mining waste based-geopolymers applied to catalytic reactions with ozone

The demand for sustainable and low-cost materials for wastewater treatment is increasing considerably. In this scenario, geopolymers have gained great interest, due to their good mechanical properties, their ability to be produced from industrial waste and their adsorbent or catalytic properties. In this study, novel magnetic mining waste based-geopolymers were produced by incorporating a residue from phosphate waste rocks, which were extensively characterized (XRD, TGA/DTA, SEM, BET, XRF, FTIR, Mössbauer, ss-NMR and XPS). The materials produced showed formation of a dense framework, even with 75% incorporation of the residue. The iron oxides and their magnetic properties remained unchanged, and their application in advanced oxidation reactions were evaluated, in particular, as catalysts in ozonation reactions. All of the geopolymers presented catalytic activity in the ozonation reaction, with catalytic ozone decomposition values of up to 2.98 min−1, which is 99 times greater than non-catalyzed reactions. Moreover, the reuse (performed in three cycles) and hot filtration-like experiments demonstrated, respectively, the regenerability and heterogeneous catalytic properties of the produced materials, showcasing the potential of these waste materials for catalytic geopolymer production. demonstrating the potential of this waste to produce catalytic geopolymers.

Dual Atoms (Fe, F) Co-Doping Inducing Electronic Structure Modulation of NiO Hollow Flower-Spheres for Enhanced Oxygen Evolution/Sulfion Oxidation Reaction Performance.

Heteroatoms Fe, F co-doped NiO hollow spheres (Fe, F-NiO) are designed, which simultaneously integrate promoted thermodynamics by electronic structure modulation with boosted reaction kinetics by nano-architectonics. Benefiting from the electronic structure co-regulation of Ni sites by introducing Fe and F atoms in NiO , as the rate-determined step (RDS), the Gibbs free energy of OH* intermediates (ΔGOH* ) for Fe, F-NiO catalyst is significantly decreased to 1.87eV for oxygen evolution reaction (OER) compared with pristine NiO (2.23eV), which reduces the energy barrier and improves the reaction activity. Besides, densities of states (DOS) result verifies the bandgap of Fe, F-NiO(100) is significantly decreased compared with pristine NiO(100), which is beneficial to promote electrons transfer efficiency in electrochemical system. Profiting by the synergistic effect, the Fe, F-NiO hollow spheres only require the overpotential of 215mV for OER at 10mA cm-2 and extraordinary durability under alkaline condition. The assembled Fe, F-NiO||Fe-Ni2 P system only needs 1.51V to reach 10mA cm-2 , also exhibits outstanding electrocatalytic durability for continuous operation. More importantly, replacing the sluggish OER by advanced sulfion oxidation reaction (SOR) not only can realize the energy saving H2 production and toxic substances degradation, but also bring additional economic benefits.

Flash Reforming Pyrogenic Carbon to Graphene for Boosting Advanced Oxidation Reaction

AbstractBiomass‐derived pyrogenic carbon is attractive for advanced oxidation processes (AOPs); however, its amorphous structure limits its activation efficiency. Graphene with highly conjugated π structure possesses superior electron transport ability and thus high usefulness. However, bygone strategies are scarcely effective for reforming pyrogenic carbon to graphene. Herein, for the first time, a state‐of‐the‐art flash Joule heating (FJH) technique is showcased for reforming pyrogenic carbon to 2–5‐layer graphene. FJH current‐induced ultrahigh temperature and stress field realize instantaneous (≈10 s) regeneration of pyrogenic carbon via synchronization actions of carbonization, graphitization, and exfoliation. Meanwhile, volatilization of doped N atoms accelerates graphitization but has less of an effect on graphene configuration. Accordingly, tuned oxygen groups at the graphene edge boost peroxydisulfate (PDS) adsorption for finer initiating activation. Subsequently, 2D graphene with excellent electron utilization rate strengthens hydroxyl radical and direct electron transfer pathways in activating PDS for sulfamethoxazole (SMX) degradation. Impressively, the SMX degradation efficiency by fabricated graphene raises ≈8.9‐fold as compared with pristine pyrogenic carbon. Additionally, fabricated graphene is more efficient in PDS activation than commercial metal catalysts. Undoubtedly, this study realizes effective transformation of pyrogenic carbon to graphene for highly efficient metal‐free carbocatalyst.

Synthesis and Peroxide Activation Mechanism of Bimetallic MOF for Water Contaminant Degradation: A Review.

Metal-organic framework (MOF) materials possess a large specific surface area, high porosity, and atomically dispersed metal active sites, which confer excellent catalytic performance as peroxide (peroxodisulfate (PDS), peroxomonosulfate (PMS), and hydrogen peroxide (H2O2)) activation catalysts. However, the limited electron transfer characteristics and chemical stability of traditional monometallic MOFs restrict their catalytic performance and large-scale application in advanced oxidation reactions. Furthermore, the single-metal active site and uniform charge density distribution of monometallic MOFs result in a fixed activation reaction path of peroxide in the Fenton-like reaction process. To address these limitations, bimetallic MOFs have been developed to improve catalytic activity, stability, and reaction controllability in peroxide activation reactions. Compared with monometallic MOFs, bimetallic MOFs enhance the active site of the material, promote internal electron transfer, and even alter the activation path through the synergistic effect of bimetals. In this review, we systematically summarize the preparation methods of bimetallic MOFs and the mechanism of activating different peroxide systems. Moreover, we discuss the reaction factors that affect the process of peroxide activation. This report aims to expand the understanding of bimetallic MOF synthesis and their catalytic mechanisms in advanced oxidation processes.

Degradation of tetracyclines by peracetic acid and UV/peracetic acid: Reactive species and theoretical computations

As an environment-friendly oxidant and disinfectant, peracetic acid (PAA) and PAA based-advanced oxidation processes (AOPs) for the treatment of emerging micropollutants have raised increasing interest, owing to their ease of activation and less generation of harmful disinfection byproducts. Tetracyclines (TCs) antibiotics as a group of wide-spectrum antibiotics are frequently detected in sewage effluents, while the knowledge of PAA-based advanced oxidation reactions to remove the substrates is quite limited. In this work, we systematically investigated the kinetics and underlying transformation mechanisms of three TCs including tetracycline (TTC), oxytetracycline (OTC), and chlortetracycline (CTC) in the UV-activated PAA oxidation process. The results indicated that three TCs can be efficiently decayed by UV/PAA. The pseudo-first-order reaction rate constants (kobs) of TCs followed the order: kCTC (0.453 min−1) ≫ kTTC (0.164 min−1) > kOTC (0.158 min−1). Quenching experiments showed that the removal of CTC was mainly ascribed to the direct oxidation of PAA, while TTC and OTC were more susceptible to free radicals. The kobs values of the three TCs by PAA oxidation presented a fairly well correlation to the global nucleophilicity and the activation energies of the TC molecules, highlighting the structure-specific reactions of TCs to PAA. Based on product identification and theoretical calculation, N-demethylation and hydroxylation were proposed as the main pathways for TCs degradation by PAA non-radical oxidation. The combination of PAA and UV irradiation can further improve the degradation efficiency of TCs and contribute to reducing the diffusion and transmission of resistance genes in the environment.

Advanced oxidative chemical recycling of carbon-fiber reinforced plastic using hydroxyl radicals and accelerated by radical initiators

We herein report a method for the chemical depolymerization of the epoxy resin present in a carbon composite through an advanced oxidation reaction using hydroxyl radicals. It was found that decomposition of the epoxy resin by the hydroxyl radicals generated from NaOCl was complete within 2 h at 100 °C and ambient pressure in an aqueous solution. The effects of different radical initiators (i.e., potassium persulfate (KPS) and 4,4′-azobis(4-cyanovaleric acid) (ACVA)) on the acceleration of hydroxyl radical generation from NaOCl were also evaluated. More specifically, the rate of hydroxyl radical formation in the presence and absence of a radical initiator was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method, and it was confirmed that the radical generation rate was increased by up to 3 times when the KPS radical initiator was employed (c.f., in the absence of an initiator). Interestingly, it was confirmed that the reaction rate constant (k) increased by up to 5.3 times when the combination of NaOCl and radical initiator KPS was applied to the recycling of carbon fiber-reinforced plastic (CFRP). In addition, X-ray photoelectron spectroscopy, Raman spectroscopy, and Field-emission scanning electron microscopy observations of the reclaimed carbon fiber demonstrated that no significant damage occurred during the reaction. This result is expected to lead to novel methods for enhancing the rate of CFRP chemical recycling processes.

Modified Polyethersulfone Ultrafiltration Membrane for Enhanced Antifouling Capacity and Dye Catalytic Degradation Efficiency

Catalytic membranes, as a combination of heterogeneous advanced oxidation and membrane technology reaction systems, have important application prospects in the treatment of dyes and other organics. In practical applications, it is still challenging to construct catalytic membranes with excellent removal efficiency and fouling mitigation. Herein, molybdenum disulfide-iron oxyhydroxide (MoS2-FeOOH) was fabricated using iron oxide and MoS2 nanoflakes, which were synthesized by the hydrothermal method. Furthermore, by changing the concentration of MoS2-FeOOH, the MoS2-FeOOH/polyethersulfone (PES) composite ultrafiltration membrane was obtained with improved hydrophilicity, permeability, and antifouling capacity. The pure water flux of the composite membrane reached 385.3 L/(m2·h), which was 1.7 times that of the blank PES membrane. Compared with the blank membrane, with the increase of MoS2-FeOOH content, the MoS2-FeOOH/PES composite membranes had better adsorption capacity and catalytic performance, and the membrane with 3.0% MoS2-FeOOH content (M4) could be achieved at a 60.2% methylene blue (MB) degradation rate. In addition, the membrane flux recovery ratio (FRR) of the composite membrane also increased from 25.6% of blank PES membrane (M0) to more than 70% after two cycles of bovine serum albumin (BSA) filtration and hydraulic cleaning. The membrane with 2.25% MoS2-FeOOH content (M3) had the best antifouling performance, with the largest FRR and the smallest irreversible ratio (Rir). Catalytic self-cleaning of the composite membrane M3 recovered 95% of the initial flux with 0.1 mol/L H2O2 cleaning. The MoS2-FeOOH/PES composite membranes with the functions of excellent rejection and antifouling capacity have a good prospect in the treatment of printing and dyeing wastewater composed of soluble dyes.

Fabrication of sulfide nanoscale zero-valent iron and heterogeneous Fenton-like degradation of 2,4-Dichlorophenol

Surface sulfidation has become a desirable technique to enhance the physicochemical properties of nanoscale zero-valent iron (NZVI) and improve the decontamination efficiency for organic pollutants. However, the macroscopic elimination performance and microscopic reaction mechanism of sulfide NZVI (SNZVI) towards organic matters remains uncovered. Herein, we fabricated SNZVI via one-step dithionite-method and applied it for heterogeneous Fenton-like elimination of 2,4-Dichlorophenol (DCP). The sulfidation technique greatly improved the stability, specific area, oxidized resistance, hydrophobicity, and functionality. The efficiency of degradation (86.3%) was approximately 7 times higher than adsorption (12.6%) under N2 condition, indicating the promising potential of SNZVI in environmental governance. Moreover, Fenton-like reaction and reactive oxygen species (ROS) were confirmed to dominate the degradation process, and the generated radicals had priority to degrade DCP rather than corroded SNZVI. Furthermore, the result of gas chromatography-mass spectrometry (GC–MS) confirmed that DCP was mainly decomposed into harmless alkanes and inorganic matters, which significantly reduced the perniciousness of DCP. Overall, this research bridged the knowledge gap between organic pollutant removal and the advanced oxidation reaction of NZVI-based materials after surface sulfidation.

Strong Pyro-Electro-Chemical Coupling of Elbaite/H2O2 System for Pyrocatalysis Dye Wastewater

Elbaite is a natural silicate mineral with a spontaneous electric field. In the current study, it was selected as a pyroelectric catalyst to promote hydrogen peroxide (H2O2) for dye decomposition due to its pyro-electro-chemical coupling. The behaviors and efficiency of the elbaite/H2O2 system in rhodamine B (RhB) degradation were systematically investigated. The results indicate that the optimal effective degradability of RhB reaches 100.0% at 4.0 g/L elbaite, 7.0 mL/L H2O2, and pH = 2.0 in the elbaite/H2O2 system. The elbaite/H2O2 system exhibits high recyclability and stability after recycling three times, reaching 94.5% of the degradation rate. The mechanisms of RhB degradation clarified that the hydroxyl radical (·OH) is the main active specie involved in catalytic degradation in the elbaite/H2O2 system. Moreover, not only does elbaite act as a pyroelectric catalyst to activate H2O2 in order to generate the primary ·OH for subsequent advanced oxidation reactions, but it also has the role of a dye sorbent. The elbaite/H2O2 system shows excellent application potential for the degradation of RhB.

Boosting Fenton-like reaction efficiency by co-construction of the adsorption and reactive sites on N/O co-doped carbon

A N/O-codoped carbon-based catalyst (N/O-C-8) designed with dual reaction sites (pyridinic N and carbonyl group) was fabricated in this work, for persulfate based advanced oxidation reaction. The pyridinic N served as the adsorption site for target molecule, via series of high resolution XPS analysis and DFT calculation. Meanwhile, the carbonyl group functioned as the persulfate activation site, to generate oxidative 1O2. Engineering and isolating the two reaction sites on catalyst surface can greatly shorten the migration distance from 1O2 to target organic molecule, resulting in good catalytic removal efficiency. As demonstrated, during a 4-hour continuous flow experiment, our catalyst showed stable and efficient removal of tetracycline, with a flow rate of 4 mL/min. The study provides keen insights into the design of effective non-metal based catalysts for practical water remediation.

Density Functional Theory Calculations for Insight into the Heterocatalyst Reactivity and Mechanism in Persulfate-Based Advanced Oxidation Reactions

Density Functional Theory Calculations for Insight into the Heterocatalyst Reactivity and Mechanism in Persulfate-Based Advanced Oxidation Reactions

Perovskite Oxide Catalysts for Advanced Oxidation Reactions

AbstractMeeting the escalating demand for clean water resources is one of the key challenges to ensure a sustainable future. Catalysis plays an important role to advance the chemical reactions required for wastewater efficient remediation. How to exploit high‐performance catalysts to boost the pivotal reaction kinetics always attracts researchers’ enthusiasm. Perovskite oxides as a novel class of functional materials can be tuned to confer compositional flexibilities and provide rich and unique structural properties. As the rising‐star material, it has been widely probed for electrocatalysis, photocatalysis, and membrane‐catalysis for energy conversion, but received less attention in water treatment. In this review, the advances of perovskite oxides for advanced oxidation processes (AOPs) in water remediation are comprehensively elaborated. A fundamental understanding of the crystal structures and properties of perovskite oxides as well as the basic principles of AOPs is firstly provided. Then, emphasis is placed on how to tune the perovskite oxides to suit various AOPs. The strategies to design novel perovskite oxides to enhance the catalytic activities in AOPs have been highlighted. It is expected that after reading this review, readers will have a clearer vision of the background, the state of the art development, and general guidelines for future directions regarding research in this area.