Removal Of Iron Oxides Research Articles

Effect of Surface Wettability and Pore Structure of Non-Precious Metal Catalysts on Alkaline Oxygen Reduction Reaction Activities at the Gas Diffusion Electrode

Anion exchange membrane fuel cells (AEMFC) have been attracting attention for low-cost fuel cells with a wide material selection range and facilitated oxygen reduction reaction (ORR) from lower electrode potential due to high pH.1 At the cathode, 2 moles of water are consumed in ORR, and at the anode, 4 moles of water are produced in the hydrogen oxidation reaction. Water generated at the anode is back diffused to the cathode and participates in the ORR. This imbalance of water between the cathode and the anode would make the anode and cathode vulnerable to flooding and drying, respectively. Therefore, water management of the membrane electrode assembly is important for the operation of AEMFC.2 To solve this issue, approaches such as controlling the relative humidity of H2 and O2 or modifying the electrode structure were attempted.2, 3 These approaches are mainly considered in single cells, and additional research is needed on the effect of catalyst properties on electrodes in a half-cell.Catalysts were prepared by the silica hard template method. Generally, 1 g of ordered mesoporous silica (SBA-15), which served as a hard template, was uniformly mixed with 0.87 g of 1, 10-phenanthroline, 0.65 g of FeCl3, and 3.49 g of citric acid and kept at 200 ℃ for 2 h. The red composite cooled to room temperature was carbonized in a furnace in an inert atmosphere at 900 ℃ for 3 h. Then, silica was removed using HF. To remove iron oxide and metal particles, acid leaching was performed overnight in 2 M HCl at room temperature. Afterward, heat treatment was performed again at 900 ℃ for 1 h. The obtained catalyst was named FeNC_CA, and FeNC without citric acid was prepared for comparison. GDEs of FeNC and FeNC_CA were prepared by ultrasonic spray method. Catalyst and ionomer (FAA-3; Fumasep) were dispersed in EtOH/water solution with a tip sonicator. Prepared ink was sprayed on carbon paper (Toray 060) to be 1.5 mg cm-2 of catalyst loaded.FeNC and FeNC_CA have major differences in mesopore volume to micropore volume ratio (Vmeso/Vmicro) and oxygen content. For FeNC, the ratio of mesopore volume to micropore volume was 1:1, and for FeNC_CA, the mesopore volume was 3.4 times the micropore volume. X-ray photoelectron spectroscopy showed that FeNC_CA had a 1.7 at% higher oxygen content than FeNC. The high mesopore volume and oxygen content of FeNC_CA led to high ionomer capacity and wettability when implemented as GDE. Interestingly, FeNC had 20 wt.% ionomer content in solid (catalyst+ionomer) content as an optimum, while FeNC_CA showed optimal ionomer content at 35 wt.% ionomer content (Fig. 1). This deviation was assumed to be due to the wettability of the catalyst layer and the formation of ionomer–catalyst aggregate. FeNC_CA-4 showed a flooding issue at 20 wt.% ionomer content. At 35 wt.% of FeNC, the excessive ionomer on the active site caused ion transfer hindrance. These results indicated that to implement the activity of the catalyst into an electrode, it is necessary to consider the influence of catalyst surface properties and pore structure on electrode properties.

The application of Rumex Abysinicus derived activated carbon/bentonite clay/graphene oxide/iron oxide nanocomposite for removal of chromium from aqueous solution

Rapid industrialization has significantly boosted economic growth but has also introduced severe environmental challenges, particularly in water pollution. This study evaluates the effectiveness of a nanocomposite composed of Rumex Abyssinicus Activated Carbon/Acid Activated Bentonite Clay/Graphene Oxide, and Iron Oxide (RAAC/AABC/GO/Fe3O4) for chromium removal from aqueous solutions. The preparation of the nanocomposite involved precise methods, and its characterization was performed using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, and the point of zero charge (pHpzc). Batch adsorption experiments were designed using Design Expert software with a central composite design under response surface methodology. The factors investigated included pH (3, 6, and 9), initial Cr (VI) concentration (40, 70, and 100 mg/L), adsorbent dose (0.5, 0.75, 1 g/200 mL), and contact time (60, 90, and 120 min). Adsorption isotherms were analyzed using nonlinearized Langmuir, Freundlich, and Temkin models, while pseudo-first-order and pseudo-second-order models were applied to adsorption kinetics. Characterization revealed a pHpzc of 8.25, a porous and heterogeneous surface (SEM), diverse functional groups (FTIR), an amorphous structure (XRD), and a significant surface area of 1201.23 m2/g (BET). The highest removal efficiency of 99.91% was achieved at pH 6, with an initial Cr (VI) concentration of 70 mg/L, a 90 min contact time, and an adsorbent dose of 1 g/200 mL. Optimization of the adsorption process identified optimal parameters as pH 5.84, initial Cr (VI) concentration of 88.94 mg/L, contact time of 60 min, and adsorbent dose of 0.52 g/200 mL. The Langmuir isotherm model, with an R2 value of 0.92836, best described the adsorption process, indicating a monolayer adsorption mechanism. The pseudo-second-order kinetics model provided the best fit with an R2 value of 0.988. Overall, the nanocomposite demonstrates significant potential as a cost-effective and environmentally friendly solution for chromium removal from wastewater.

Recovery of filler material from mining waste: Techno-economic, and kinetic study

This paper emphasizes the recovery of filler materials from bauxite mining waste by leaching iron oxides (Fe2O3). A combination of oxalic acid and hydrochloric acid is employed synergistically to facilitate the removal of iron oxides (Fe2O3) via the leaching process. Through optimization of the leaching process for iron oxide, it was determined that employing 2 M HCl along with 0.5 M oxalic acid at a temperature of 70°C for 240 minutes yielded a maximum iron removal efficiency of 64.32%. The resulting leached product met the standards outlined by the Bureau of Indian Standards (BIS) for utilization as a filler material. Kinetic investigation utilizing the shrinking core model revealed that the iron leaching process was primarily governed by a reaction step characterized by an activation energy (E) of 17.02 kJ/mol. Economic analysis indicated a return on investment of 523.65%, underscoring the profitability of the process for producing filler material from mining waste, which has the potential to generate substantial profits in the long run.

Гидроуголь на основе шрота подсолнечника, модифицированного оксидом железа, для удаления ионов свинца из водных растворов: кинетика сорбции

The article proposes a method for producing a hybrid sorption material based on renewable plant raw materials from agricultural production, synthesized by hydrothermal carbonization (HTC), the structure of which is modified by particles of iron and/or iron oxides. The authors obtained a series of samples and assessed the effect of high-temperature carbonization and subsequent alkaline activation on the sorption capacity of materials. Determination of physico-chemical properties was carried out using IR spectroscopy, X-ray diffractometry and thermogravimetry. X-ray diffraction patterns of the samples showed the presence of an α-cellulose crystal lattice and a Fe3O4 or γ-Fe2O3 crystallographic plane. As a result of carbonization, the α-cellulose phase is destroyed and iron oxides are partially reduced. Alkaline activation leads to more serious destruction of the plant base and complete restoration of the iron phase. The materials sorption capacity was assessed by heavy metal ions (lead) adsorption from model aqueous solutions. Confined adsorption kinetic studies were carried out to determine the sorption time and adsorption mechanism. The sorption capacity of the initial HTC material for Pb2+ was ~132 mg/g at a contact time of 30 min. For carbonated and activated hydrochar, the capacity was 66.8 and 99.2 mg/g, respectively. The adsorption kinetics of Pb2+ ions was described using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. It has been shown that sorption occurs predominantly due to the chemical interaction of metal ions with functional groups of sorbents with a partial contribution from mixed-diffusion absorption. Thus, the article proves the effectiveness of using hydrochar based on plant raw materials, modified with magnetic iron particles, in the processes of liquid-phase removal of inorganic pollutants.

Optimizing the removal of iron oxide from Egyptian feldspar ore

The demand for feldspar as a raw material for various industrial applications continuously increases. Feldspar is a primary raw material in manufacturing ceramics, glass, fillers, welding electrodes, and enamel. Feldspar is often associated with iron oxide, which decreases its economic value and hinders its industrial application. The present work aimed at reducing iron oxide content in Egyptian feldspar ore from the Wadi Zerabi locality. Ball milling was used for preparing feldspar feed of size -250+45µm. Carpco dry high-intensity magnetic separation followed by acid leaching processes were carried out in order to decrease the iron contamination and increase the feldspar content. A Box-Behnken statistical design was used to optimize the magnetic separation results. From a feldspar feed containing 1.40% Fe2O3, a non-magnetic concentrate of 0.25% Fe2O3 was obtained. The Fe2O3 removal reached up to 82% with a high yield as the % weight of non-magnetic feldspar reached up to 97.5%. The leaching process further reduced the iron oxide content down to 0.19 %. Also, the feldspar whiteness was improved from 65.17% in the original ore to 85.60% in the leached product.

Influence of Surface Finish on the Dry Sliding Wear and Electrochemical Corrosion Behaviour of 316L Stainless Steel

316L stainless steel is known for its high corrosion resistance and extensively being used for biomedical implants and for the fabrication of the parts in nuclear reactors, and fuel cells. In the current study, 316L stainless steel samples were grounded using different grades of surface grits (400, 1200, and mirror-finished) by mechanical polishing, and influence of surface finish on the wear and corrosion characteristics was studied. The dry sliding wear experiments were carried out on ball-on-plate setup against hardened steel ball and the corresponding friction curves were obtained and specific wear rates were measured. The wear mechanisms were identified by examining the worn-out surface using scanning electron microscope and Raman spectrometer. It was evident that the formation and removal of iron oxides is the dominant mechanism for material loss from the samples during wear tests. The higher wear resistance of the mirror-finished sample was attributed to the formation of stable chromium oxide layer on the wear track. Potentiodynamic polarization tests were performed on the samples and better corrosion resistance was observed for the mirror-finished sample.

Synthesis of Sulfur-Doped Magnetic Iron Oxides for Efficient Removal of Lead from Aqueous Solutions

Heavy metal pollution poses an environmental risk, and its efficient removal and facile separation from water remains a challenge. Magnetic iron oxide, an eco-friendly, relatively stable, and easy-separation material, has been regarded as one of the most applicable adsorbents for water treatment. However, the limited adsorption capacity has restricted its applications. Herein, sulfur-doped magnetic Fe3O4 (Sx–Fe3O4) adsorbent was fabricated using a calcination method for the efficient removal of Pb(II) from water. In contrast to undoped Fe3O4, the introduction of doped sulfur greatly enhanced the adsorption performance of S–Fe3O4 over four times, with a maximum capacity of 333.33 mg g−1, which was synthesized at 300 °C with a raw molar ratio of S–Fe of 5. Based on the structure and morphology analysis, it was demonstrated that sulfur was successfully doped into the Fe3O4 structures, which resulted in Fe3O4 with active sulfur sites accordingly contributing to the adsorption enhancement through the combination of strong soft–soft interactions between soft base sulfur and soft acid Pb(II) along with surface adsorption. Sx–Fe3O4 could maintain the adsorption performance in the presence of competing ions. Furthermore, although the sulfur doping process exhibited slight side effects on the magnetic property, magnetic Sx–Fe3O4 maintained the high separation potential. This study presented a promising strategy to enhance the adsorption performance of Fe3O4 through sulfur doping for Pb(II) removal from water.

Process for recovery and value addition of silica mineral values of distinctly siliceous mining rejects

The mining and metal industries generate a variety of solid wastes from mining activities to finished products. Mining rejects of non-ferrous industries such as bauxite, manganese, gold, zinc, lead and copper mines are underutilized and low in demand as potential raw materials for metallurgical use. Largely these materials are in bulk use for landfilling and building materials without recovering relevant mineral values. Major reject materials such as jarosite, kaolinite, khondalite, alumogoethite and saprolite are rich sources of alumina and silica-bearing mineral phases with varying compositions of iron oxide as major constituents. In the present study, the chemical and mineralogy of some of these materials were assessed. The technical scope for recovering one of the low-cost mineral phases in the rejects such as silica was ascertained for the potential value addition in view of the large scope of utilization in glass, glass products, molten sand, cement, fibreglass, ceramic enamel, sandblasting, refractory and light concrete.The recovered silica was used as a low-cost precursor for making value-added nano-silicate suitable for various industrial applications. The paper discussed the significance of the chemical composition and mineralogy of the raw materials. The process steps involved in the selective beneficiation of silicate mineral phases are used for the stepwise removal of iron oxide and alumina followed by the preparation of sodium silicate. Chemical precipitation and separation of nano-silica followed by characterization of silica nano-particles by scanning electron microscopy (SEM) and inductively coupled plasma (ICP)-MS analysis was also elaborated. These SEM studies inferred that the silica particles size ranges from nanometer to micrometre depending on various factors such as acid concentration, ageing time and the nature of the precursor used. ICP-MS analysis revealed the purity of nano-silicate prepared from the reject material. The leached solution consisting of aluminium has been utilized for making alpha alumina based on the IPR-protected in-house process route to follow the concept of producing zero waste.

Optimization of acetaminophen adsorption onto biodegradable waste-derived activated carbon using response surface methodology

In this study, biodegradable waste like banana peel was used as a precursor for synthesis of activated carbon by the use of acidic chemical process. The activated carbon was impregnated with iron oxide for acetaminophen removal from water. Scanning electron microscope (SEM) analysis, X-ray diffraction (XRD) analysis and Brunauer-Emmet-Teller (BET) analysis were performed to characterize the iron oxide impregnated activated carbon. The SEM results denote the presence of macropores, while from the XRD it was evident that the synthesized activated carbon contains “Maghemite” (γ-Fe2O3) and “Magnetite” (Fe3O4). Specific surface area of 268.52 m2/g, and pore volume of 54.3 cc/g was obtained from BET results. Response Surface Methodology was used to optimize the adsorption process of aqueous solutions of acetaminophen using the following parameters: adsorbent dosage (0.5–1 g/L), pH (4–6), initial concentration of Acetaminophen (50–100 ppm) and time (60–120 min). Central Composite Design was employed to conduct a set of 31 runs and ANOVA was used to determine the priority of the parameters in the adsorption process. The optimum values of the parameters for 94.7 % removal efficiency of acetaminophen are, adsorbent dosage at 0.97 g/L, pH at 3.48, initial concentration at 58.3 ppm, and time at 120.9 min. The R2 value of the regression equation was determined to be 95.06%.

Acid pickling of carbon steel

This study reviews the possibilities of recovering the pickling waters from carbon and galvanised steel. Acid pickling with hydrochloric acid (HCl) is the most widely used chemical process to remove iron oxides from the metal surface without any significant attack on the steel itself. The acid pickling bath contains mainly ferrous chloride (FeCl2) produced by the reaction between the steel and free hydrochloric acid. However, zinc chloride (ZnCl2) is also found in the pickling of carbon steel parts prior to galvanisation, as the hooks and tools used to hang the carbon steel parts are also galvanised and reuse again polluting with Zn the pickling waters. Pickling water recovery or recycling technologies primarily seek the reuse of HCl in two ways. Partially by recovering the unreacted HCl or fully by breaking the FeCl2 bond through Pyrolysis technologies such as fluidised bed and spray roasting which in turn produces another iron oxide by-product. However, the most common by-product produced by pickling water recovery and recycling technologies is ferric chloride (FeCl3), as it is a coagulant widely used in wastewater treatment. However, if the pickling water contains ZnCl2 or other metals, the production of FeCl3 becomes unattractive and the pickling water is neutralised and deposited in landfill sites. This study also discusses a wide range of technologies capable of recovering all or part of the pickling water, including galvanic pickling water, that are usually excluded from circular economy strategies.

Thermophysical property evolution during molten regolith electrolysis

The electrolysis of lunar regolith for oxygen generation has been under investigation since before the Apollo missions. One critical and overlooked aspect in work to date has been how the composition and physical properties of the molten regolith change during electrolysis process as oxides are reduced. The regolith composition also varies across the surface of the moon, and thus the molten properties will also vary. In this work we aggregate previous empirical models for physical properties of mixtures of molten oxides spanning the possible composition ranges of the electrolyte. The physical properties most important to reactor operation are liquidus temperature, electrical conductivity, and viscosity. In this work we show that these properties vary dramatically for compositions present on the lunar surface and during electrolysis. From this model review we illustrate that the liquidus temperature and heat capacity of the melt rises during electrolysis while viscosity, electrical resistivity, and thermal conductivity increase with the removal of iron oxide and decrease with the removal of silicon oxide. This new framework provides Molten Regolith Electrolysis (MRE) system designers a more accurate method for evaluating system performance during operation. In addition to lunar applications, the models reviewed herein are applicable to those seeking to develop Molten Oxide Electrolysis (MOE) for terrestrial, carbon-free metal production. The code developed during this project has been released on github file exchange; a link is provided as supplementary material.

Leaching of Ibute-Nze kaolin iron-oxide impurity with oxalic acid process optimization of dissolution conditions using response surface methodology

The goal of this research was to remove iron oxide from Ibute-Nze kaolin by dissolving the clay mineral in an aqueous oxalic acid solution and optimizing the process. The chemical composition of the raw and modified clay was determined using x-ray fluorescence, and the morphology of the solid sample was determined using a scanning electron microscope. The best conditions for the oxalic acid leaching of iron-oxides impurity from Ibute-Nze kaolin were determined using response surface methodology based on Box-Behnken design. The studies were carried out within the following process parameter ranges: 40–90 leaching temperature; 0.075-0.355mm particle size; 1–6 mol/dm3 acid concentration; 0.02–0.12 g/cm3 kaolin sample to acid ratio and 30-240 min contact time. The characterization revealed that Ibute-Nze clay is kaolinitic in nature and calcination at 750 opens more pores for its leaching. According to the analysis of variance, a second-order polynomial regression equation provided the best fitting for the experimental data. The predicted and experimental response values were shown to be correlated (R2 = 0.9276) in the experimental runs. The following were found to be the best conditions for the leaching process variables: 83.2051 leaching temperature, 0.0827mm particle size, 3.6179mol/dm3 acid concentration; 0.0287g/cm3 kaolin to acid ratio and 217.932min reaction time. The chemical leaching process was 92.6035 per cent under these conditions, which made the clay good for industrial applications.

Removal of Iron Oxide from Indoor Air at a Subway Station Using a Vegetation Biofilter: A Case Study of Seoul, Korea

Recently, metallic particulate pollutants floating underground have been reported to negatively affect the human body. Thus, there is an urgent need for a public health policy pertaining to the air quality in subway stations. In this study, we investigated whether a vegetation biofilter is effective in reducing metal particle contaminants, especially iron oxide. After selecting a subway station, a vegetation biofilter system was installed, and samples were collected three times, at three intake areas and one exhaust area. The average weight ratio of the detected elements was calculated. The iron oxide reduction effect was evaluated using the Wilcoxon signed rank test. In the return air, C, O, and Fe were detected at 64.9, 27.3, and 5.2 wt.%, respectively; in the supply air, C, O, and Fe were detected at 67.2, 30.4, and 0.7 wt.%, respectively. The difference in the average Fe weight ratio was statistically significant. Air quality has a considerable effect on human health. We confirmed the possibility of reducing Fe in particulate matter using biofilters. However, we could not confirm whether the air quality was improved enough to not have a negative effect on the human body. This should be elucidated through follow-up studies.

A Study on the Roasting Process for Efficient Selective Chlorination of Ilmenite Ores

We investigated the effects of ilmenite roasting temperature on the efficiency of iron oxide removal from the obtained residue by selective chlorination. Roasting-induced phase transformations were analyzed by x-ray diffraction measurements, and the phase composition of roasted residue was shown to be determined by process conditions. The highest iron oxide removal efficiency was observed for non-roasted samples, which was ascribed to the fact that roasted samples contained hematite (Fe2O3), whereas non-roasted ones contained wustite (FeO). The kinetics of selective chlorination was fitted by two models, and the obtained results indicated that the rate-controlling step corresponded to diffusion through the TiO2 layer between the interface and ilmenite core.

Quantitative Estimation of the Changes in Soil CEC after the Removal of Organic Matter and Iron Oxides

The removal of organic matter and iron oxides could increase and decrease soil CEC in tropical and subtropical regions, but the quantitative information is insufficient so far about the change of soil CEC, the influence factors and their contribution. In this study, the subhorizon soils of 24 soil series in the tropical and subtropical China were used, pH, particle size composition, organic matter, iron oxides of these samples were measured, and also CECs were measured and compared for the original soils and after the removal of organic matter and iron oxides. The results showed that, compared with CEC of the original soil, the eliminating organic matter increased soil CEC significantly by 2.28% - 56.50% with a mean of 24.02%, but the further obliterating iron oxides decreased soil CEC significantly by 0.75% - 20.30% with a mean of 7.73%. CEC after the removal of organic matter and iron oxides had positive correlation with iron oxides (p − 0.546pH − 0.024OM + 0.053FexOy − 0.001Silt + 0.007Clay + 0.972CECoriginal (R2 was 0.923, RSME was 1.55 cmol(+)∙kg−1, p − 0.546pH − 0.024OM + 0.053FexOy − 0.001Silt + 0.007Clay + 0.972CECoriginal (R2 was 0.923, RMSE was 1.55 cmol(+)∙kg−1, p < 0.01). Further research is needed in the future as for exploring internal functional mechanism in view of soil electrochemistry and mineralogy.

Characterization and Gold Extraction of Gold-bearing Dust from Carbon-bearing Gold Concentrates

ABSTRACT Gold-bearing dust generated during the roasting process of refractory gold concentrates is valuable as secondary gold resources. In this study, the characterization of gold-bearing dust from carbon-bearing gold concentrates was determined by direct cyanidation and mineralogy research. Moreover, identification of refractoriness in the dust was determined by selective removal of minerals. Results showed that the dust belonged to refractory ores. Gold was observed to be presented as native and electrum which main associated with iron oxides. After preleaching with a 6 mol/L NaOH solution, arsenic, and carbon removal rates were 99.66% and 60.63%, respectively, and gold extraction was 58.90%, only 4.60% higher than that of direct cyanidation. After preleaching with a 15 wt.% H2SO4 solution, iron, arsenic, and carbon removal rates were 33.65%, 80.38%, and 12.60%, respectively, and gold extraction achieved 80.40%. After roasting, carbon and arsenic removal rates were 95.00% and 54.65%, respectively, and gold extraction achieved 84.52% under the optimum condition. Removal of carbonaceous matter and iron oxides could efficiently improve gold extraction, and the adverse effects of carbonaceous matter and iron oxides were the main reasons for refractoriness. Based on these results, a proper process for gold extraction from the dust was developed, and gold extraction achieved 95.50%.

Characterization and Mechanisms of a New Carbonaceous Adsorbent Based on Black Liquor Loaded with Iron Oxide for Removal of Tripolyphosphate Ions

The impregnation process has successfully prepared a novel composite of iron oxide/carbon from black liquor (CA-BL/Fe) as an adsorbent for the removal of tripolyphosphate ions. Black liquor is a secondary product of the bioethanol pre-treatment process. X-ray diffraction results showed that the main iron oxide species present in the CA-BL/Fe was goethite (α-FeOOH). Interestingly, the specific surface area of CA-BL/Fe was 504 m2/g higher than that of commercial activated carbon of 356 m2/g. The adsorption performance showed that tripolyphosphate ion removal efficiency increased by increasing the adsorbent dosage, pH, and contact time. At the same time, it decreased with an increase in the initial concentration of tripolyphosphate. By controlling the environment pH value, the optimum removal efficiency of tripolyphosphate ions with CA-BL/Fe was 96.87%, with the adsorption capacity of 1.5922 mg/g for 1 h measurement. In this study, the dominant mechanisms of tripolyphosphate adsorption are electrostatic attraction and ion exchange. The result of this study is expected to be the basis for further promising adsorbent material for tripolyphosphate ion.

Improving Fly Ash Brightness with Carbon and Iron Oxide Removal

In this paper, the brightness of fly ash is improved by carbon removal by heating and iron-containing oxides removal by acid treatment using a two-step method to realize the application of fly ash as filler or coating in the future, which not only increases the range of resource utilization of fly ash, but also reduces dust pollution. The modification results show that the brightness of fly ash reaches the maximum value of 38.27% ISO (Brightness unit) after decarburization by heating at 600 °C. On this basis, the Box–Benhnken design scheme is adopted to optimize the brightening process for removing iron-containing oxides in fly ash. Finally, when the concentration of hydrochloric acid is 15%, the acid leaching time is 0.75 h, the reaction temperature is 74 °C, and the brightness of fly ash can eventually increase to 43.92% ISO.

One-Pot Synthesis of Fe/N-Doped Hollow Carbon Nanospheres with Multienzyme Mimic Activities against Inflammation.

Inflammation, including infectious and noninfectious inflammation, are a growing threat to public health worldwide. For different types of inflammation, more specific and intensified therapy is needed. Nanozymes are able to regulate levels of radical reactive oxygen species (ROS) to suppress inflammation, becoming potential anti-inflammatory agents. Herein, hollow porous carbon spheres codoped with nitrogen and iron (Fe/N-HCNs) are synthesized through a one-pot strategy, which exerted multienzyme mimicking activities, including peroxidase (POD)-, oxidase (OXD)-, catalase (CAT)-, and superoxide dismutase (SOD)-like activities. Moreover, these activities were promoted by the removal of iron oxides produced in the synthesis process. Based on the study of multienzyme activities, we designed two kinds of animal inflammatory models, bacteria-infected wound and inflammatory bowel disease, to evaluate the anti-inflammation ability of Fe/N-HCNs. The results indicated that Fe/N-HCNs could increase ROS levels through performing their POD-like activity in a weak acid environment to catalyze H2O2 against bacteria-infected wound healing, whereas Fe/N-HCNs with the capability of scavenging ROS in a neutral environment could also be unitized to treat noninfectious inflammatory bowel disease. Together, our study provided evidence that the prominent multienzyme activities of Fe/N-HCNs could be used as an anti-inflammatory alternative for both infectious and noninfectious inflammation.

S-Fe改性生物炭的制备及其活化过硫酸盐优化去除磺胺甲噁唑

S-Fe改性生物炭的制备及其活化过硫酸盐优化去除磺胺甲噁唑