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Facile synthesis of N/B double-doped Mn <sub/>2</sub> O <sub/>3</sub> and WO <sub/>3</sub> nanoparticles for dye degradation under visible light
摘要： In the present work, Nitrogen-doped and Nitrogen-Boron double doped manganese oxide (Mn2O3) and tungsten oxide (WO3) nanoparticles were synthesized using precipitation-hydrothermal method for methylene blue degradation under visible light. Materials were characterized using X-ray diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and UV-Vis spectroscopy. Results showed that N and B were successfully incorporated into the crystal lattices of Mn2O3 and WO3. XRD showed that WO3 was crystallized in the form of a monoclinic lattice, while cubic Mn2O3 was produced in the cubic form. The crystallite size was found to be decreased due to the substitution of N and B elements which reveals their roles to accelerate the crystal nucleation rate resulting in the decreased size. On the other hand, single and double doping has successfully narrowed the bandgaps of the as-synthesised metal oxide photocatalysts resulting in better absorption in the visible light. Bandgaps obtained were as follows: 3.02, 2.50, 1.73 and 1.77 eV for N-WO3 N/B-WO3, N-Mn2O3 and N/B-Mn2O3 respectively. Photocatalytic experiments showed that all as-synthesised materials exhibited a photocatalytic efficiency under visible light ≥420 nm. The degradation efficiency of MB was in the following order: N-B-co-doped metal oxides > N-doped metal oxides > metal oxides. The presence of scavenger molecules such as isopropanol (IPA), EDTA-2Na and benzoquinone inhibited MB degradation. Finally, the results showed that these materials can be reused several times without a notable decrease in efficiency.
关键词： Photocatalytic degradation,Visible light,Double-doping,Metal oxides
更新于2025-09-23 15:23:52
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Photocatalytic and antibacterial activities of <i>Paeonia emodi</i> mediated silver oxide nanoparticles
摘要： Green synthesis of nanomaterials and its verity of applications have linked chemistry, biotechnology and environmental chemistry. Green process get more attention due to its easy handling and inertness to ecosystem. The selection of green synthesis and silver oxide nanoparticles (Ag2O NPs) are purely based on its nontoxic behavior and promising activates. Eco-friendly process was applied for the synthesis of silver oxide nanoparticles (Ag2O NPs) using Paeonia emodi (P. emodi) fresh leaves extract as reducing agent. The average crystallite size was found to be 38.29 nm, calculated from the FWHM of the diffraction bands of X-rays diffractometer (XRD). The morphological study was made by performing transmission electron microscopy (TEM) and scanning electron microscope (SEM) and the particles size estimated from the micrographs of both techniques are 38.29 and 86.4 nm respectively. The energy dispersive X-ray (EDX) was used to study the purity and percent composition of the Ag2O NPs. The band gap energy (4.02 eV) and surface functional groups was studied by diffuse reflectance spectroscopy (DRS) and fourier transform infrared spectroscopy (FTIR) respectively. The 97.78% methylene blue (MB) was degraded in the presence of Ag2O NPs and UV-Visible light source in 180 min. The antibacterial activity of the Ag2O NPs were tested against Gram-positive (Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus)) and Gram-negative (Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) bacteria. It was found that the Ag2O NPs have strong growth inhibiting activity against Gram-negative bacteria than Gram-positive bacteria.
关键词： Photocatalytic degradation,Methylene blue,Eco-friendly,Antibacterial Activity,Silver oxide,Leaves extract
更新于2025-09-23 15:23:52
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Removal of pharmaceutically active compounds (PhACs) from real membrane bioreactor (MBR) effluents by photocatalytic degradation using composite Ag2O /P-25 photocatalyst
摘要： Pharmaceutically active compounds (PhACs) are emerging pollutants causing serious challenges to wastewater treatment plants due to poor biodegradability. In this study, the enhanced removal of highly recalcitrant and commonly monitored PhACs, carbamazepine (CBZ) and diclofenac (DCF) by heterogeneous photocatalysis was investigated using 5% Ag2O /P-25 photocatalyst. The photocatalyst was characterized by scanning electron microscope (SEM-EDX), Brunauer-Emmett-Teller (BET), and UV-vis diffuse reflectance spectra (UV-DRS). The effects of catalyst dose, initial pollutants concentration, and mineralization during the photocatalytic degradation of PhACs were investigated. The matrix effect was assessed in deionized water (DW) and real membrane bioreactor effluent (RME). Optimal CBZ and DCF removals of 89.10 % and 93.5 %, respectively for 180 min of UV irradiation were achieved at catalyst dosage of 0.4 g L-1 in DW matrix. However, the optimal catalyst dosages for CBZ and DCF in RME matrix were increased by factor 2 and 1.5, respectively, to achieve the same degree of removal. Declining trends of removal rate were observed when initial concentrations of both the PhACs were increased under optimal catalyst dosages, and kinetics seem to fit the Langmuir-Hinshelwood model. Photo-induced holes and ?OH were the dominant oxidation species involved in the photocatalytic degradation of the PhACs. A plausible reusability of 5% Ag2O /P-25 photocatalyst was observed for both the PhACs. Moreover, various aromatic/aliphatic intermediates generated during the photodegradation CBZ were identified using fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry, and a possible multi-step degradation pathway was proposed. Overall, the removal of PhACs using 5% Ag2O /P-25 photocatalyst showed promising results in real wastewater.
关键词： PhACs,transformation products,Ag2O/P-25 photocatalysts,matrix effect,photocatalytic degradation
更新于2025-09-23 15:23:52
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Photocatalytic degradation of pharmaceutical micro-pollutants using ZnO
摘要： This research paper presents the results of an experimental investigation of the degradation of three different contaminants including progesterone (PGS), ibuprofen (IBU), and naproxen (NAP) using ZnO as the photocatalyst and ultraviolet (UV) light as a source for catalysts activation. Two operating parameters, namely, catalyst loading and initial concentration of contaminants, were tested in a batch photocatalytic reactor. To demonstrate the large-scale applications, experiments were also conducted in a submerged membrane photocatalytic reactor. It has proven that ZnO photocatalyst degraded the three contaminants very efficiently under almost all the studied experimental conditions, with efficiency rates of 92.3, 94.5, and 98.7 % for PSG, IBU, and NAP, respectively. The photodegradation kinetics study was performed to calculate the reaction rate constant, which is found to follow pseudo-first order kinetics. The membrane photocatalytic reactor was efficient to remove pollutants and it is observed that the degradation rate increases with increasing the membrane oscillation frequency approaching that of the stirred reactor.
关键词： Photocatalytic degradation,Progesterone,Ibuprofen,Photocatalytic batch reactor,Naproxen,Oscillatory membrane reactor,ZnO
更新于2025-09-23 15:22:29
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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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A unique (4,4,5)-connected 3D zinc (II) metal-organic framework for highly efficient photodegradation of Rhodamine B under UV light
摘要： A new zinc (II) metal-organic framework, [Zn3(L)2(nbta)2]n (1) (L = 1,4-bis(benzimidazol-1-yl)-2-butene, H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid) was hydrothermally synthesized and structural characterized. 1 possesses a unique 3D (4,4,5)-connected network with a Schl?fla symbol of {42.63.8}2{44.62}{47.63}2. Furthermore, the photocatalytic property of 1 for degradation of the Rhodamine B (RhB) was examined under UV irradiation.
关键词： Semi-rigid bis(benzimidazole),Hydrothermal synthesis,Crystal structure,Metal-organic framework,Zinc (II),Photocatalytic degradation
更新于2025-09-23 15:22:29
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Translucent packed bed structures for high throughput photocatalytic reactors
摘要： Translucent photocatalytic reactor structures are investigated as a possible alternative to numbering up as a method for the scale-up of microreactors. The structure and the light source design is elaborated to introduce this concept. The light field was characterized using a ray tracing algorithm. A rectangular reactor made from glass was designed using borosilicate spheres small enough to create an array of interconnected microchannels in the reactor. It was found that ray tracing can be used as a proper tool to easily design multiple-LED light sources and predict respective irradiance patterns. The performance of the reactor was assessed using the apparent rate constant, the space-time yield and the photocatalytic space-time yield, a recently introduced performance parameter which takes into account the lamp power and the reactor productivity. The apparent rate constant of the reactor for an incoming irradiance of 191 W m?2 was found to be 0.82 min?1, which is, to our knowledge, in the range of microreactors and 1–2 orders of magnitude higher than any high throughput immobilized reactor in literature. With a photocatalytic space-time yield of 0.657 m3 day?1 m?3 reactor kW?1 our reactor was amongst the best reported performers in terms of productivity and energy efficiency. This performance is related to the high specific illuminated surface area of 4267 m2 m?3 and high catalyst load of 1.9 g L?1.
关键词： Light distribution,Structured reactors,Photocatalysis,Photocatalytic degradation,LED,Reactor engineering
更新于2025-09-23 15:22:29
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Co2+ Substituted ZnCuFe2O4 (0.0?≤?x?≤?0.5) Ferrites: Synthesis, Magneto-structural and Optical Properties for Their Photocatalytic Performance
摘要： The cobalt (Co2+) has been successively substituted in ZnCuFe2O4 to obtain Zn0.5?xCoxCu0.5Fe2O4 (0.0 ≤ x ≤ 0.5) ferrites by auto-combustion technique. Prior to photocatalytic degradation, all as-synthesized ferrites were characterized to study their structure, composition, morphology, magnetic and optical behavior. The shifting of tetrahedral as well as octahedral stretching peaks towards higher frequencies observed in the Fourier transform infrared spectroscopy indicates that Co2+ ion is substituted in ZnCuFe2O4. X-ray diffraction pattern confirms the formation of single-phase cubic spinel with decrease in average lattice constant from 8.3915 to 8.3224 ? with increase in Co2+ substitution. The photocatalytic performance of obtained ferrite catalyst was determined using methylene blue (MB) as model dye under visible light and direct sunlight. The degradation of MB with as-obtained photocatalyst under sunlight improves (91%) which proves the effective utilization of visible light active magnetic photocatalyst.
关键词： Photocatalytic degradation,Magnetic materials,Methylene blue,Sol-gel method,Spinel ZnCuFe2O4
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Aflatoxin B1 by activated carbon supported TiO2 catalyst
摘要： The photocatalytic efficiency of activated carbon supported TiO2 catalyst (AC/TiO2) for degradation of aflatoxin B1 (AFB1) under UV-Vis light was evaluated in this study. AC/TiO2 was prepared by simple hydrothermal synthesis and characterized by scanning electron micrograph (SEM), X-ray diffraction (XRD) and FT-IR. The various factors including catalyst dosage, pH value and light source affecting the degradation efficiency of AFB1 were also investigated. The higher degradation efficiency of AFB1 by AC/TiO2 composite (98 %) than bare TiO2 (76 %) were attributed to a higher surface area and enhanced visible light intensity by the synergy of AC and TiO2. The degradation process of AFB1 was fitted with the pseudo-first-order kinetic model. In addition, the catalyst can be easily separated from the solution and keep good activity. The hole (h+) and the hydroxyl radicals (?OH) were found to play an important role in the degradation of AFB1. These results demonstrated that AC/TiO2 possess synergy of high absorption capacity and photoactivity, thus supplying a simple, efficient and green approach for the degradation of AFB1.
关键词： AC/TiO2 catalyst,Photocatalytic Degradation,Aflatoxin B1
更新于2025-09-23 15:22:29
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Enhanced photocatalytic activity of hierarchical titanium dioxide microspheres with combining carbon nanotubes as “e-bridge”
摘要： Enhancing photocatalytic activity of titanium dioxide (TiO2) by efficient charge separation is essential but challenging. Herein, the recombination between photo-generated e–-h+ pairs is effectively hindered owing to the “e-bridge” formed between hierarchical TiO2 microspheres and carbon nanotubes (CNTs). The as-prepared three-dimensional TiO2 microspheres covered by intercrossing lamellar crystals are abundant in pores and sharp edges, forming an ideal interface with large surface area and numerous active sites for photocatalysis. Combined with CNTs, the TiO2 microspheres are connected and stabilized. Moreover, the CNTs serve as pathways for electrons, benefiting the effective separation of e–-h+ pairs and accounting for the superior photocatalytic activity. Transient fluorescence spectra shows that the lifetime of electrons on TiO2 prolongs from 5.23 ns to 10.14 ns assisted by CNTs. In aqueous matrix, electrons gathering on the CNTs can react with O2 to produce O2–, and simultaneously, plenty of holes left in TiO2 host generate OH by oxidizing adsorbed H2O, producing abundant active species for photocatalytic degradation of 4-nitrophenol. The highest degradation efficiency in removing organic contaminants is achieved on TiO2@CNTs hybridized with CNTs weight ratio being 5%.
关键词： e-Bridge,Titanium dioxide,Carbon nanotubes,Organic pollutant,Photocatalytic degradation
更新于2025-09-23 15:22:29