Oxygen vacancy boosting Fenton reaction in bone scaffold towards fighting bacterial infection

Bacterial infection is a major issue after artificial bone transplantation due to the absence of antibacterial function of bone scaffold,which seriously causes the transplant failure and even amputation in severe cases.In this study,oxygen vacancy(OV)defects Fe-doped Ti O2(OV-FeTiO2)nanoparticles were synthesized by nano TiO2and Fe3O4via high-energy ball milling,which was then incorporated into polycaprolactone/polyglycolic acid(PCLGA)biodegradable polymer matrix to construct composite bone scaffold with good antibacterial activities by selective laser sintering.The results indicated that OV defects were introduced into the core/shell-structured OV-FeTiO2nanoparticles through multiple welding and breaking during the high-energy ball milling,which facilitated the adsorption of hydrogen peroxide(H2O2)in the bacterial infection microenvironment at the bone transplant site.The accumulated H2O2could amplify the Fenton reaction efficiency to induce more hydroxyl radicals(·OH),thereby resulting in more bacterial deaths through·OH-mediated oxidative damage.This antibacterial strategy had more effective broad-spectrum antibacterial properties against Gram-negative Escherichia coli(E.coli)and Gram-positive Staphylococcus aureus(S.aureus).In addition,the PCLGA/OV-FeTiO2scaffold possessed mechanical properties that match those of human cancellous bone and good biocompatibility including cell attachment,proliferation and osteogenic differentiation.

Catalytic degradation of methylene blue by Fenton like system: model to the environmental reaction

To develop more efficient chemical methods for the demineralization of organic pollutants from water bodies, which one was also mimic to the nature, a degradation of methylene blue by Fe(Ⅲ) and H 2O 2 in the absence of light instead of Fe(Ⅱ) and H 2O 2 was studied. Results showed that use of Fe (Ⅲ) is more promising than Fe(Ⅱ). The present study reflects that Fenton reaction is more efficient, in the presence of a small amount of salicylic acid is added which is a one of the priority pollutant.

Fenton法预处理合成革废水的去除研究

合成革废水中含有大量的二甲基甲酰胺(DMF)等有机污染物,对生物具有毒性危害。采用单因素试验方法,获得Fenton反应对DMF处理最佳工艺参数为pH=3、过氧化氢(H_(2)O_(2))与化学需氧量(COD_(Cr))的质量比m=6.69、H2O2与亚铁离子的摩尔比n=8及反应时间t=120 min, DMF的平均去除率达96.18%。在此基础上,利用Design-Expert软件中的响应面实验设计原理,设计三因素三水平共17组实验,进一步研究确定上述参数对Fenton法预处理合成革废水COD_(Cr)的去除效果。设计并制作针对DMF皮革废水有良好降解效果的Fenton一体化、H_(2)O_(2)和FeSO_(4)精准投加、pH精准调控的自动控制系统及集成反应设备,合成革废水的COD_(Cr)和DMF的平均去除率为71.87%和95.78%。

Magnetic field assisted Fenton reactions for the enhanced degradation of methyl blue

Magnetic field was tentatively introduced into Fenton reactions system for the degradation and discoloration of methyl blue as the represent of organic chemical dye, which was a bio-refractory organic pollutant in industry wastewater. It was found that under optimal Fenton reaction conditions, with the assistant of magnetic field in Fenton reactions, the degradation rate of methyl blue, the decomposition rate of H2O2 and the conversion rate of Fe^2＋ were accelerated, the extent of them would be improved by the increase of magnetic field intensity. Meanwhile, the mineralization of methyl blue （CODer） was improved by over 10% with magnetic field.

Different Heterogeneous Fenton Reaction Based on Foam Carrier Loaded with Photocatalysts

The effect of heterogeneous Fenton reaction was studied on methylene blue（MB） and Nitrosomonas europaea（N. europaea） cells. Four Fenton systems were prepared and compared with each other, including Nickel Foam（NF）/TiO2, NF/Bi2WO6, Ceramic foam（CM）/TiO2, and CM/Bi2WO6. The order of effect of fenton reaction ranked as NF/TiO2〉CM/TiO2〉NF/Bi2WO6〉CM/Bi2WO6. In acid or alkaline solution, the removal efficiency also decreased compared with neutral solution. With lower p H values, the nanoparticles were easier to break off from NF skeleton. Thus the synergetic effect of photocatalysis and fenton reaction can not take action. As for CM skeleton, the bond –Si-O-can bind with TiO2 or Bi2WO6. The membrane fluidity was used as an indicating parameter. After being treated by Fenton reaction, N. europaea surface was rougher than the native bacterium and the bulges on cell surface became irregular, which is attributed to change of lipopolysaccharide patches. Polarization of N. europaea cell membrane in acid medium increased more obvious than alkaline medium.

A Novel and Convenient Assay for the Determination of OH Produced by Fenton Reaction

A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52V vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.

Fenton体系的优化及其对酪蛋白的氧化作用

酪蛋白是乳与乳粉中的主要蛋白组分,在加工和贮藏过程中会发生氧化反应从而影响产品的品质。研究Fenton体系诱导的酪蛋白氧化后化学及结构特性的变化。首先对Fenton体系中Fe2+浓度、抗坏血酸(ascorbic acid,Asc)浓度、H2O2浓度进行了优化,以酪蛋白为靶分子,采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳研究了Fenton体系主要成分以及体系的温度和时间对酪蛋白氧化程度的影响;并进一步研究了氧化后酪蛋白的溶解性、变性程度、总巯基含量及羰基含量的变化。结果表明:当Fenton体系中Fe2+浓度为0.8 mmol/L,EDTANa2浓度为1 mmol/L,H2O2浓度为10 mmol/L,Asc浓度为0.8 mmol/L,酪蛋白质量浓度为5 mg/mL,37℃条件下加热4 h时,酪蛋白氧化程度最明显。随着Fe2+浓度、Asc浓度、H2O2浓度、氧化温度的升高和氧化时间的延长,酪蛋白4个组分条带的密度均逐渐减小,并在相应的高分子区域出现逐渐致密的新条带;但随着酪蛋白质量浓度的升高,酪蛋白条带的变化减小。酪蛋白氧化后,其溶解度和巯基含量显著降低,变性程度和羰基含量显著升高。综上所述,酪蛋白氧化后发生蛋白交联和氨基酸功能基团变化,导致蛋白的变性程度增大以及溶解度下降。

沼渣生物炭基Fenton催化剂的制备及其高效降解吡虫啉农药废水的研究

以废弃物沼渣和含铁剩余污泥为原料,采用一步热解法制备沼渣生物炭基Fenton催化剂(以下简称催化剂),构建了非均相Fenton反应体系处理含吡虫啉模拟废水,考察了H_(2)O_(2)和催化剂用量对吡虫啉去除率的影响。结果表明,非均相Fenton反应体系中,H_(2)O_(2)最佳投加量为0.50 g/L,催化剂最佳投加量为1.00 g/L,室温下反应120 min后吡虫啉去除率可达99%左右。与传统Fenton氧化系统相比,非均相Fenton体系可有效缓解铁泥的产生,具有更宽的pH适用范围,催化剂重复利用性好,金属离子溶出较少,具有“以废治废”和经济环保等特点,为废弃物沼渣的回收利用和农药废水高效处理提供了新思路,具有较好的应用前景。

Enhanced Fenton,photo-Fenton and peroxidase-like activity and stability over Fe_3O_4/g-C_3N_4 nanocomposites

We prepared the Fe3O4/g‐C3N4nanoparticles(NPs)through a simple electrostatic self‐assembly method with a3:97weight ratio to investigate their Fenton,photo‐Fenton and oxidative functionalities besides photocatalytic functionality.We observed an improvement of the Fenton and photo‐Fenton activities of the Fe3O4/g‐C3N4nanocomposites.This improvement was attributed to efficient charge transfer between Fe3O4and g‐C3N4at the heterojunctions,inhibition of electron‐hole recombination,a high surface area,and stabilization of Fe3O4against leaching by the hydrophobic g‐C3N4.The obtained NPs showed a higher degradation potential for rhodamine B(RhB)dye than those of Fe3O4and g‐C3N4.As compared to photocatalysis,the efficiency of RhB degradation in the Fenton and photo‐Fenton reactions was increased by20%and90%,respectively.Additionally,the horseradish peroxidase(HRP)activity of the prepared nanomaterials was studied with3,3,5,5‐tetramethylbenzidinedihydrochloride(TMB)as a substrate.Dopamine oxidation was also examined.Results indicate that Fe3O4/g‐C3N4nanocomposites offers more efficient degradation of RhB dye in a photo‐Fenton system compared with regular photocatalytic degradation,which requires a long time.Our study also confirmed that Fe3O4/g‐C3N4nanocomposites can be used as a potential material for mimicking HRP owing to its high affinity for TMB.These findings suggest good potential for applications in biosensing and as a catalyst in oxidation reactions.

Treatment of pharmaceutical wastewater containing recalcitrant compounds in a Fenton-coagulation process

The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.

Mechanism of Photo-Fenton Degradation of Ethanol and PVA

Contrast degradation experiments between ethanol and polyvinyl alcohol (PVA) were conducted during H2O2, UV/H2O2, Fenton, and Photo-Fenton processes in this study. UV/VIS spectra showed' that complexes between Fe(Ⅲ) and organics were easily formed and degraded within reaction time. Compared with ,the degradation of complex, hydroxyl radicals acted weakly in Fenton or Photo-Fenton process. Hydroxyl radi'cals involved in Photo-Fenton process were deemed to be generated from the split decomposition of H2O2, photolysis of Fe_aq^3+, and degradation of hydrated Fe(Ⅳ)-complex but not traditional Fenton reaction. Experimental evidence to support this point was presented in this paper.

Degradation of Acid Orange 7 in an Atmospheric-Pressure Plasma-Solution System(Gliding Discharge)

In this work, a plasma-solution system was applied to the degradation of Acid Orange 7 （AO？）. The effects of initial concentration and type of feed gases （air, oxygen, nitrogen or argon） were studied. As the initial concentration increased from 100 mg/L to 160 mg/L, the discolouration rate of AO7 decreased from 99.3% to 95.9%, whereas the COD removal rate decreased from 37.9% to 22.6%. Air provided the best discolouration and COD removal rates （99.3% and 3？.9%, respectively）. In the presence of a zero-valent iron （ZVI） catalyst, the AO？ COD removal rate increased to 76.4%. The degradation products were analysed by a GC-MS, revealing that the degradation of the dye molecule was initiated through the cleavage of the -N=N- bond before finally being converted to organic acids.

非均相光-Fenton技术在水处理领域的研究进展

非均相光-Fenton技术是基于传统Fenton试剂法,通过引入光照和新型催化剂实现光催化氧化和Fenton反应的协同作用,促进活性自由基(如·OH)的生成和有机物高效降解的新型高级氧化技术。综述了非均相光-Fenton体系的技术特征、关键影响因素和氧化原理,详细阐述了铁物种与二氧化钛、石墨相氮化碳、氧化石墨烯/还原氧化石墨烯、钒酸铋以及三氧化钨不同类型半导体结合的非均相光-Fenton材料的光催化氧化原理和有机物降解机制。

H_(2)O_(2) actuated molybdenum oxide nanodots:Multi-enzyme-like activities,leverage of Fenton reaction,and dual-mode sensitive detection of alendronate sodium

Unexpected benefits to the catalytic performance of materials often originate from the presence of surface defects.Here,novel Dpenicillamine modified molybdenum oxide nanodots,with abundant oxygen vacancy defects,were fabrication by a mild,simple,and cost-effective method.Ultraviolet–visible(UV–Vis)absorption spectra analysis showed that the nanodots had peroxidaselike and catalase-like activities.The reactive oxygen species were probed by electronic paramagnetic resonance technique and spectroscopic methods,demonstrating that the nanodots also had oxidase-like activity.Interestingly,the peroxidase-like activity of nanodots was synergistically enhanced in the presence of ferrous ions or ferric ions.Remarkably,less than nanomolar levels of ferrous ions were required to display this phenomenon,meaning Fenton reagent acted as leverage.Based on this,a sensitive colorimetric and fluorescent dual-mode sensor for alendronate sodium was developed.The linear ranges for colorimetric and fluorescence analysis were 0.2–2.5 and 0.2–2.0μM,with detection limits of 31.21 and 71.84 nM,correspondingly.The method has a simple large-scale material preparation process with higher sensitivity and shorter reaction time,which can inspire and enlighten the design of nanozyme sensors.

Fenton-reaction-triggered metabolism of acetaminophen for enhanced cancer therapy

Acetaminophen(APAP), a classic nonsteroidal anti-inflammatory drug(NSAID), has attracted much attention due to the overdose-induced hepatotoxicity in the past several decades. N-Acetyl-p-benzoquinone imine(NAPQI), the P450-dependent metabolism of APAP, leads to GSH depletion, protein binding, mitochondrial oxidative stress, and eventually the liver injury. Herein, we develop a Fe-based metal-organic framework(MOF) to deliver and transform acetaminophen into toxic “chemo” drug through the cascade reaction for enhanced cancer therapy. In the acidic tumor microenvironment, the Fe-based MOF collapses and releases abundant Fe ions to generate hydroxyl radicals(·OH) via Fenton reaction, subsequently catalyzing nontoxic APAP into toxic NAPQI. Meanwhile, NAPQI depletes intracellular glutathione(GSH) rapidly, leading to alleviating the antioxidant ability of cancer cells and amplifying Fenton activity. The intracellular oxidative stress and the toxic metabolite of APAP can provide a synergistic effect on antitumor activity.

Fe_(2)O_(3)/TiO_(2)/reduced graphene oxide-driven recycled visible-photocatalytic Fenton reactions to mineralize organic pollutants in a wide pH range

Photocatalytic Fenton reactions combined the advantages from both photocatalysis and Fenton reaction in mineralizing organic pollutants. The key problems are the efficiency and recycling stability. Herein, we reported a novel Fe_(2)O_(3)/TiO_(2)/reduced graphene oxide(FTG) nanocomposite synthesized by a facile solvothermal method. The TiO_(2)in FTG degraded organic pollutants and mineralized intermediates via photocatalysis under visible light irradiation, which could also promote Fenton reaction by accelerating Fe^(3+)-Fe^(2+)recycle. Meanwhile, the Fe_(2)O_(3)rapidly degraded organic pollutants via Fenton reactions, which also promoted photocatalysis by enhancing visible light absorbance and diminishing photoelectronhole recombination. The high distribution of TiO_(2)and Fe_(2)O_(3)on rGO, together with their strong interaction resulted in enhanced synergetic cooperation between photocatalysis and Fenton reactions, leading to the high mineralization efficiency of organic pollutants. More importantly, it could also inhibit the leaching of Fe species, leading to the long lifetime of FTG during photocatalytic Fenton reactions in a wide pH range from 3.4 to 9.2.

Self-powered electrochemical system by combining Fenton reaction and active chlorine geheration for organic contaminant treatment

Environmental deterioration,especially water pollution,is widely dispersed and could affect the quality of people's life at large.Though the sewage treatment plants are constructed to meet the demands of cities,distributed treatment units are still in request for the supplementary of centralized purification beyond the range of plants.Electrochemical degradation can reduce organic pollution to some degree,but it has to be powered.Triboelectric nanogenerator(TENG)is a newly-invented technology for low-frequency mechanical energy harvesting.Here,by integrating a rotary TENG(R-TENG)as electric power source with an electrochemical cell containing a modified graphite felt cathode for hydrogen peroxide(H2O2)along with hydroxyl radical(·OH)generation by Fenton reaction and a platinum sheet anode for active chlorine generation,a self-powered electrochemical system(SPECS)was constructed.Under the driven of mechanical energy or wind flow,such SPECS can efficiently degrade dyes after power management in neutral condition without any O2 aeration.This work not only provides a guideline for optimizing self-powered electrochemical reaction,but also displays a strategy based on the conversion from distributed mechanical energy to chemical energy for environmental remediation.

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/FeS nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater treatment.Here,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/FeS(Fe/S)nanoparticles,was synthesized by simple impregnation precursor,followed by pyrolysis.The prepared Fe/S-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the reaction.Moreover,the acid microenvironment formed by SO_(4)^(2-)group from Fe/S composite extended the pH range for Fenton reaction,and S^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation efficiency.Further,biochar can effectively promote cycling stability by limiting Fe leaching.This work may provide a general strategy for designing 3D framework biochar-based Fe/S catalysts with excellent performance for heterogeneous Fenton reactions.

Fe_(3)O_(4)@CF电极在非均相电芬顿系统中降解四环素

针对传统芬顿技术的工作pH范围较窄、增大pH值会明显降低四环素的去除率并导致二次污染的问题,采用溶剂热合成方法,将Fe_(3)O_(4)负载于碳毡(CF)电极表面,合成Fe_(3)O_(4)@CF复合电极.通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、Fourier变换红外吸收光谱(FTIR)和电化学阻抗(EIS)对材料进行表征,研究其作为电极在非均相电辅助芬顿(EF)系统中对四环素的降解性能和机理,并进行循环实验.结果表明:Fe_(3)O_(4)@CF电极在非均相电辅助芬顿体系中对四环素的降解性能最好;在室温下,经过90 min,四环素初始质量浓度为20 mg/L,初始pH=3,两电极间距离为2 cm,外加电流为50 mA,在非均相电芬顿系统中Fe_(3)O_(4)@CF电极对四环素的去除率可达96.7%;Fe_(3)O_(4)@CF电极可重复利用性良好;在非均相电芬顿系统降解四环素的过程中,·OH起主要作用,·O_(2)^(-)起辅助作用.