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Rationally Designed Fe2O3/GO/WO3 Z-Scheme Photocatalyst for Enhanced Solar light Photocatalytic Water Remediation
摘要： A novel ternary Fe2O3/GO/WO3 all-solid-state Z-Scheme photocatalyst was rationally designed. Structural, morphological, optical and electronic properties of the synthesized nanocomposite were investigated by XRD, SEM, TEM, UV-vis Diffuse Reflectance and Raman spectroscopy. The results revealed the successful synthesis of the nanocomposite materials. Uniquely, double absorption edges at 2.0 and 2.3 eV for Fe2O3/WO3 and triple absorption edges at 1.5, 1.8 and 2.1 eV for Fe2O3/GO/WO3 were investigated for the first time. Lower absorption band edges dominated for both Fe2O3/WO3 and Fe2O3/GO/WO3, while higher absorption edges dominated for pure nanomaterials. The enhanced interaction among GO, Fe2O3 and WO3 matrix explained the reduction in the CB energy leading to efficient electron separation and transformation and consequently improving the photocatalytic activity. The visible light photocatalytic performance of Fe2O3/GO/WO3 nanocomposites were evaluated for degradation of methylene blue (MB) and crystal violet (CV) dyes as model water pollutants. The photocatalytic activity for degradation of both dyes was found to be greatly enhanced in the presence of ternary Fe2O3/GO/WO3 nanocomposite as compared to nanocomposite systems of Fe2O3/WO3, WO3/GO and Fe2O3/GO or pure Fe2O3 and WO3 nanomaterials. The enhancement in the photocatalytic performance of ternary Fe2O3/GO/WO3 nanocomposite was proven to be due to the all-solid-state Z-Scheme in which the photogenerated electrons in the CB of photosystem I (WO3) transferred through GO mediator and recombined with the photogenerated holes in the VB of Fe2O3 (photosystem II). So that, the electron-hole pair recombination can be suppressed in both systems. Moreover, the photocatalytic activity of the best Fe2O3/GO/WO3 nanocomposite (FGW 30) has been tested for the degradation of phenol. The results show that 95.4 % of phenol was degraded in 120 minutes. Thus, this study provides an efficient green Z-Scheme photocatalyst for water remediation utilizing solar light.
关键词： solar light photocatalysis,organic dyes degradation,all-solid-state Z-Scheme,Ternary Fe2O3/GO/WO3,phenol mineralization
更新于2025-11-14 15:26:12
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Activated carbons with adsorbed cations as photocatalysts for pollutants degradation in aqueous medium
摘要： Oxidized activated carbon (AC) based on commercial coconut-shell carbon Aquacarb 607C has been prepared. This AC has micro-mesoporous structure and contains surface carboxyl and phenol/enol groups. Cu- and Co-containing ACs have been synthesized via ion-exchange in acid medium. According to potentiometric titration and XPS data, cation-exchanged forms of AC contain about 0.5% of metal ions. Such cation-containing ACs possess narrowed band gap compared oxidized AC as it is observed for doped oxides. Oxidized and cation-containing ACs have been tested as catalysts in photodegradation of dyes and phenol under UV- and visible irradiation. Initial oxidized AC is photoactive toward rhodamine B and methyl orange under UV illumination but inactive under visible light. For the first time it is shown that cation-exchanged forms of AC have enhanced activity towards rhodamine B, methyl orange and phenol in both UV and visible region. Therefore, the principal possibility of improving the photocatalytic properties of AC by introducing a minimal amount of copper and cobalt cations is shown.
关键词： Cation-exchanged forms,Decolourisation and mineralization,UV and visible irradiation,Activated carbon,Photocatalytic degradation
更新于2025-09-23 15:23:52
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Sequential anaerobic and electro-Fenton processes mediated by W and Mo oxides for degradation/mineralization of azo dye methyl orange in photo assisted microbial fuel cells
摘要： The intensification of the degradation and mineralization of the azo dye methyl orange (MO) in contaminated water with simultaneous production of renewable electrical energy was achieved in photo-assisted microbial fuel cells (MFCs) operated sequentially under anaerobic - aerobic processes, in the presence of Fe(III) and W and Mo oxides catalytic species. In this novel process, the W and Mo oxides deposited on the graphite felt cathodes accelerated electron transfer and the reductive decolorization of MO. Simultaneously, the mineralization of MO and intermediate products was intensified by the production of hydroxyl radicals (HO?) produced by (i) the photoreduction of Fe(III) to Fe(II), and by (ii) the reaction of the photochemically and electrochemically produced Fe(II) with hydrogen peroxide, which was produced in-situ during the aerobic stage. Under anaerobic conditions, the reductive decolorization of MO was driven by cathodic electrons, while the partial oxidation of the intermediates proceeded through holes oxidation, producing N,N-dimethyl-p-phenylenediamine. In contrast, under aerobic conditions superoxide radicals (O2?-) were predominant to HO?, forming 4-hydroxy-N,N-dimethylaniline. In the presence of Fe(III) and under aerobic conditions, the oxidation of the intermediate products driven by HO? superseded that of O2?-, yielding phenol and amines, via the oxidation of 4-hydroxy-N,N-dimethylaniline and N,N-dimethyl-p-phenylenediamine. These sequential anaerobic and electro-Fenton processes led to the production of benzene and significantly faster oxidation reactions, compared to either the anaerobic or the aerobic operation in the presence of Fe(III). Complete degradation and mineralization (96.8 ± 3.5%) of MO (20 mg/L) with simultaneous electricity production (0.0002 kWh/kg MO) was therefore achieved with sequential anaerobic (20 min) - aerobic (100 min) operation in the presence of Fe(III) (10 mg/L). This study demonstrates an alternative and environmentally benign approach for efficient remediation of azo dye contaminated water with simultaneous production of renewable energy.
关键词： azo dye,decolorization,photo-assisted microbial fuel cells,electro-Fenton,mineralization
更新于2025-09-23 15:23:52
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Fabrication and up-conversion fluorescence property of Er<sup>3+</sup>/Yb<sup>3+</sup> co-doped Ca-Si-Ti biomaterials
摘要： This work demonstrates bulk-type up-conversion biomaterials which could be used as a bone repair material with the ability to monitor bone mineralization. Er3+/Yb3+ co-doped Ca-Si-Ti (CST3: TiO2 content is 30 mol%) bulk biomaterials were prepared via containerless processing technique in an aerodynamic levitation furnace and with subsequently heat treatment. The up-conversion fluorescence property was influenced by Yb3+ doping concentration, heat-treatment and mineralization in simulated body fluid (SBF). Optimum emission intensities were obtained for the sample with 20 mol% of Yb3+ doping concentration and heat treatment at 937 °C for 2 h. Hydroxyapatite (HAP) deposition was observed on the surface of the samples after soaking in SBF for 14 days, and the up-conversion fluorescence intensity of the samples decreased with the increase of soaking time. This indicates that Er3+/Yb3+ co-doped CST3 materials are bioactive, in which the HAP mineralization in bone repair could be monitored by measuring the intensity change of up-conversion fluorescence.
关键词： Heat treatment,Up-conversion fluorescence,Containerless processing,Mineralization,Er3+/Yb3+ co-doped Ca-Si-Ti biomaterial
更新于2025-09-23 15:23:52
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Visible light photocatalytic mineralization of bisphenol A by carbon and oxygen dual-doped graphitic carbon nitride
摘要： A facile thermal polymerization was applied to synthesize carbon and oxygen dual-doped graphitic carbon nitride (MACN) with controllable electronic band structure using malonic acid and urea as precursors. The C and O atoms substituted the sp2 N atom in graphitic carbon nitride (CN). The 1MACN (1 represented that the weight ratio of malonic acid to urea is 1% during the synthesis) with optimal band structure could decompose 15 ppm bisphenol A (BPA) within 150 min, and the mineralization rate reached to 52%. The superior photocatalytic performance of 1MACN was mainly ascribed to electronic band structure together with optical properties. On the one hand, the formation of delocalized big p bonds favored the electrons transfer after the introducing of carbon atoms. On the other hand, a positive charge density existed on the C atoms because of high electronegativity of contiguous O (3.44) that substituted N compared with C (2.55), which could attribute to high activity of MACN catalyst. The study will contribute to the further improvement of visible-light photocatalytic BPA degradation and mineralization.
关键词： BPA mineralization,Carbon-oxygen dual-doping,Visible-light photocatalytic,Graphitic carbon nitride
更新于2025-09-23 15:23:52
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Synthesis and Characterization of ZnO-ZrO <sub/>2</sub> Nanocomposites for Photocatalytic Degradation and Mineralization of Phenol
摘要： ZnO-ZrO2 nanocomposites using zinc (II) acetylacetonate and different ZnO contents (13, 25, 50, and 75% mol) were synthesized through sol-gel method. The synthesis process was strongly related to nanocomposite properties especially on their structural composition. The obtained ZnO-ZrO2 nanomaterials presented tetragonal crystalline structure for zirconia whereas hexagonal one was formed in ZnO. Raman spectroscopy and XRD patterns confirmed the formation of tetragonal zirconia whereas inhibition of monoclinic structure was observed. Addition of ZnO affected the pore size distribution of the composite, and the measured specific surface areas were from 10 m2/g (for pure ZnO) to 46 m2/g (pristine ZrO2). Eg values of ZrO2 were modified by ZnO addition, since calculated values using Kubelka-Munk's function varied from 4.73 to 3.76 eV. The morphology and size of the nanomaterials investigated by electron microscopy showed formation of nanorods for ZnO with sizes ranging from 50 nm to 300 nm while zirconia was formed by smaller particles (less than 50 nm). The main advantage of using the nanocomposite for photocatalytic degradation of phenol was the mineralization degree, since 75ZnO-ZrO2 nanocomposite surpassed mineralization reached by pure ZnO and also inhibited formation of undesirable intermediates.
关键词： sol-gel method,UV-A irradiation,phenol mineralization,photocatalytic degradation,ZnO-ZrO2 nanocomposites
更新于2025-09-23 15:22:29
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Oxidative Degradation of Tannic Acid in Aqueous Solution by UV/S2O82? and UV/H2O2/Fe2+ Processes: A Comparative Study
摘要： Tannic acid (TA) is a major pollutant present in the wastewater generated from vegetable tanneries process and food processing. This work studied TA degradation by two advanced oxidation processes (APOs): UV irradiation at the wavelength of 254 nm in the presence of hydrogen peroxide (H2O2) and ferrous iron (photo-Fenton) and in the presence of potassium persulfate. The in?uence of certain experimental parameters such as K2S2O8, H2O2, Fe2+, and TA concentrations, initial pH and temperature was evaluated in order to obtain the highest ef?ciency in terms of aromatics (decay in UV absorbance at 276 nm) and TOC removals. Chemical oxidation of TA (0.1 mM) by UV/persulfate achieved 96.32% of aromatics removal and 54.41% of TOC removal under optimized conditions of pH = 9 and 53.10 mM of K2S2O8 after 60 min. The treatment of TA by photo-Fenton process successfully led to almost complete aromatics removal (99.32%) and high TOC removal (94.27%) from aqueous solutions containing 0.1 mM of TA at natural pH = 3 using 29.4 mM of H2O2 and 0.18 mM of Fe2+ at 25 ?C after 120 min. More ef?cient degradation of TA by photo-Fenton process than UV/persulfate was obtained, which con?rms that hydroxyl radicals are more powerful oxidants than sulfate radicals. The complete removal of organic pollution from natural waters can be accomplished by direct chemical oxidation via hydroxyl radicals generated from photocatalytic decomposition of H2O2.
关键词： hydroxyl radicals,degradation,photo-fenton,mineralization,UV/persulfate,sulfate radicals,Tannic acid
更新于2025-09-23 15:22:29
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Photo-Fenton oxidative of pharmaceutical wastewater containing meropenem and ceftriaxone antibiotics: influential factors, feasibility, and biodegradability studies
摘要： The main aim of the present research, as the first study, was coupling of hydrogen peroxide (H2O2), ferrous ions (Fe2t) and UV irradiation in a photo-Fenton system to degradation two anti-biotics (e.g. meropenem and ceftriaxone) from aqueous solution. The tests were carried out at different experimental conditions namely solution pH, iron dosages, H2O2 concentrations, UV light intensities, temperatures, and initial antibiotic concentrations. The degradation rates of 99 and 96.2% were observed for respectively meropenem and ceftriaxone during 60 min treatment. Biodegradability tests illustrated that photo-Fenton system has a high performance in removing organic compounds and biodegradability enhanced remarkably after treatment.
关键词： homogeneous Fenton,mineralization,antibiotic degradation,Photo-Fenton oxidation,biodegradability
更新于2025-09-23 15:19:57
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ZnO-Bi2O3/graphitic carbon nitride photocatalytic system with H2O2-assisted enhanced degradation of Indigo carmine under visible light
摘要： Indigo carmine in aqueous solution was effectively degraded using ZnO-Bi2O3/Graphitic Carbon Nitride heterojunction structure by visible light/H2O2 system. The mechanism of photocatalytic degradation of Indigo carmine shows the responsible species for the degradation of Indigo carmine in the ZnO-Bi2O3-xC3N4/H2O2/visible light system (x = 0, 1, 2, and 3) is the hydroxyl radicals which were generated from the reaction of e? and h? with H2O2. Under optimal conditions, ZnO-Bi2O3-2C3N4/H2O2/Vis system degraded more than 93% of Indigo carmine in 180 min. Besides, the kinetic of the photocatalytic process was detailed. These results demonstrate that the ZnO-Bi2O3-2C3N4/H2O2/visible light system may become a promising approach to achieve efficient environmental remediation as an environmentally friendly oxidant.
关键词： Indigo carmine,Hydroxyl radicals,Mineralization,Photocatalyst,Degradation
更新于2025-09-19 17:15:36
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Enhanced photocatalytic degradation of ciprofloxacin by black Ti3+/N-TiO2 under visible LED light irradiation: Kinetic, energy consumption, degradation pathway, and toxicity assessment
摘要： In this work, the photocatalytic degradation of ciprofloxacin (CIP) by black Ti3+/N-TiO2 under visible LED light irradiation (b-N-TiO2/LED) was studied for the first time. Characterization of the prepared photocatalyst was performed by XRD, UV–Vis DRS, FE-SEM, EDS, HRTEM, and BET techniques. The b-N-TiO2 nanoparticles with high surface area of near 100 m2 g?1 and narrow band gap of 2.0 eV, exhibited a remarkable photocatalytic performance on the degradation (100 %) and mineralization (82 %) of CIP under visible LED light irradiation. The maximum degradation was found at reaction time = 70 min, initial CIP concentration = 0.5 mg L?1, pH = 6.7, and catalyst dosage = 0.43 g L?1. Based on the results, both the hole (h+) and hydroxyl radical (?OH) played a major role than the superoxide radical (?O2?) in CIP degradation. Although common coexisting anions in water had a slight negative effect on CIP degradation; humic acid (HA), especially in higher amounts, showed a considerable inhibitory effect on degradation process. Besides, the intermediates of CIP degradation were ultimately transformed into simple compounds. Accordingly, toxicity assessments revealed that the treatment of CIP solution by b-N-TiO2/LED process remarkably resulted in diminished toxicity compared to the untreated controls. The energy utilized in this study was far less than that used in other studies. Moreover, we found that b-N-TiO2 had desirable stability and can be reused for more than five runs of experiments. Collectively, based on our findings, the b-N-TiO2/LED process is a promising, low cost and feasible candidate can be used for degradation and mineralization of antibiotics like CIP in real water samples.
关键词： Photocatalytic degradation,Mineralization,Visible LED,Black Ti3+/N-TiO2,Reusability,Ciprofloxacin
更新于2025-09-19 17:13:59