Copper-iron bimetal modified PAN fiber complexes as novel heterogeneous Fenton catalysts for degradation of organic dye under visible light irradiation

A series of Cu-Fe bimetal amidoximated polyacrylonitrile (PAN) fiber complexes with different molar ratios of Cu(2+) to Fe(3+) ions was prepared using a simple exhaustion method, and characterized using FTIR, DRS and XPS, respectively. Then they were tested as the heterogeneous Fenton catalysts for Rhodamine B degradation with H(2)O(2) in the dark and under visible light irradiation. The results indicated that Cu-Fe bimetal amidoximated PAN fiber complexes could more effectively catalyze the dye degradation in water than Fe amidoximated PAN fiber complex, especially in the dark. And introduction of Cu(2+) ions significantly increased their catalytic performance. 0.56 was the optimum molar ratio of Cu(2+) to Fe(3+) ions to achieve the best catalytic activity and stability. This was mainly due to the synergetic effect in the bimetal complexes. Visible light irradiation improved the catalytic activity of the complexes, especially with a low molar ratio of Cu(2+) to Fe(3+) ions.     

Photocatalytic degradation of organic dyes by mesoporous nanocrystalline anatase

Mesoporous nanocrystalline anatase was prepared via EISA employing P123 and CTAB as structure directing agents. The resultant mesoporous crystalline phases exhibited specific surface areas as high as ∼150 m² g⁻¹, average unimodal pore sizes of ∼3 nm and ∼6 nm, and average crystallite size of ∼10 nm; and were used as photocatalysts for the UV degradation of methylene blue, methyl orange, methyl red and rhodamine 6G. The mesoporous anatase phases photodegraded MB, MO and MR ∼2–3 times faster than conventional nanocrystalline anatase and showed limited photocatalytic activity for rhodamine 6G.     

Photocatalytic degradation of organic dyes with manganese-doped ZnO nanoparticles

Manganese-doped and undoped ZnO photocatalysts were synthesized via wet-chemical techniques. Doping of ZnO with manganese (Mn(2+)) was intended to create tail states within the band gap of ZnO. These can subsequently be used as efficient photocatalysts which can effectively degrade organic contaminants only with visible light irradiation. Photocatalysts prepared with these techniques, which were characterized with transmission electron microscopy (TEM), infrared spectroscopy (FTIR), photo-co-relation spectroscopy (PCS) and UV-vis-spectroscopy showed significant difference in the optical absorption of Mn-doped ZnO. Enhancement in optical absorption of Mn-doped ZnO indicates that it can be used as an efficient photocatalyst under visible light irradiation. The photo-reduction activities of photocatalysts were evaluated using a basic aniline dye, methylene blue (MB) as organic contaminant irradiated only with visible light from tungsten bulb. It was found that manganese-doped ZnO (ZnO:Mn(2+)) bleaches MB much faster than undoped ZnO upon its exposure to the visible light. The experiment demonstrated that the photo-degradation efficiency of ZnO:Mn(2+) was significantly higher than that of undoped ZnO and might also be better than the conventional metal oxide semiconductor such as TiO(2) using MB as a contaminant.     

A novel AgMoOS bimetallic oxysulfide catalyst for highly efficiency catalytic reduction of organic dyes and Chromium (VI)

To detoxify chemical pollutants discharge from industries, the researchers pursue always to get new, cost-effective, environmentally friendly and efficient technologies. Herein, novel silver molybdenum oxysulfide (AgMoOS) catalyst which is monoclinic structure with spherical shape nanoparticle and uniform distribution of its elemental composition was successfully synthesized by a facile method. The catalytic performance of AgMoOS was employed for the reduction of methylene blue (MB), methyl orange (MO), 4-Nitrophenol (4-NP), Rhodamine B (RhB) and Chromium (VI) in presence of NaBH₄ under dark condition and a fastest reduction activity was obtained with 2-AgMoOS. A 10 mg of 2-AgMoOS completely reduced 100 mL of 20 ppm of MB, MO, 4-NP, RhB and Cr⁶⁺ within 6, 6, 15, 24 and 24 min, respectively and the reduction kinetic data indicated that the catalytic activity of all AgMoOS catalysts toward these chemical pollutants followed the order: MB > MO > 4-NP > RhB > Cr⁶⁺ ions. The re-usability data toward the reduction of MB, cyclic voltammogram, XPS and XRD spectrum of 2-AgMoOS after the reaction were confirmed a good stability and durability of AgMoOS catalyst. Hence, AgMoOS is an efficient catalyst and provides a practical application for toxic organic dyes degradation and toxic inorganic pollutants containing waste water treatment and other environmental issues.     

A novel catalyst of Fe-octacarboxylic acid phthalocyanine supported by attapulgite for degradation of Rhodamine B

A novel nano-composite catalyst was prepared from immobilization of Fe-octacarboxylic acid phthalocyanine onto the supporting material attapulgite. The morphology and structure of the catalyst were analyzed by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and ultraviolet-visible spectroscopy. The catalyst activity was examined through comparative experiments, and results showed that it exhibited high activity for degradation of Rhodamine B in the presence of hydrogen peroxide. The recycling test was also carried out to prove its reusability in catalytic application.     

A strategy for biomimetic hybridization of electrospun fiber mat cross-sections

Concentrated synthetic body fluid (c-SBF) recipes have been used in biomimetic deposition of calcium phosphate (CaP) phases on electrospun polycaprolactone (PCL) fiber mats. However, cross-sections of mats could not be coated entirely when simple soaking methods had been used. In this study, calcium and phosphate sources that are used in typical c-SBF recipes were placed in two compartments which were separated by PCL fiber mats. By varying the concentrations of calcium and phosphate sources in either compartment according to a thermodynamic model, the difference between pH levels of compartments was adjusted. A gradual and homogeneous increase in supersaturation levels was achieved on both sides of the membrane with the onset of diffusion of species through the membrane. The strategy of separation of c-SBF constituents permitted coatings that extended through the cross-section of mats. In addition, types of CaP phases that can be precipitated on opposite sides of the membrane under different conditions were predicted by the same thermodynamic model. It was possible to coat the cross-sections of mats with the targeted phase mixtures by using the developed modeling approach.     

An efficient biomimetic process for fabrication of artificial nacre with ordered-nanostructure

The authors developed an efficient biomimetic process to fabricate inorganic/organic nanocomposites with clay nano-platelets being the mineral and polyimide being the organic constituency. Samples with thickness of 10–200 μm were produced in a very short time using a centrifugal deposition process. This process resulted in an ordered nanostructure with alternating organic and inorganic layers. The mechanical properties were comparable to that of lamella bones, with a tensile strength of 70–80 MPa, Young's modulus of 8–9 GPa and hardness of about 1–2 GPa. The composite films could be lifted from the substrate and stacked to form bulk material for biomedical applications such as bioactive dental materials or bone replacements. This approach represents a milestone in the development of bulk-form layered inorganic/organic nanocomposites.     

Covalent organic frameworks (COFs) quantum dots as supramolecular cages modified with biochar as nanobio photocatalyst for degradation of organic dyes

In this study, we used co-precipitation assisted solvothermal route to produce self-assembled covalent organic frameworks (COFs) quantum dots modified with biochar structures. In addition, photocatalytic degradation of organic dyes such as methyl red, methyl orange and methyl blue were measured without the need to artificial UV visible light in vitro condition, and degradation rate was estimated at alternate times. The biochar as precursor agent with hydrothermal method as an eco-friendly synthesis route used to provides COFs quantum dot nanostructures with appropriate diameter and size about 3.68 nm. This research presents a new and novel nanocomposite structures with the contribution of biochar as biological material for decolorization of methylene red, orange and blue were calculated using UV–vis spectroscopy. Novel covalent organic frameworks quantum dot membranes with high purity were synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), Atomic force microscopy (AFM), Fourier transformed infrared spectrum (FT-IR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and Brunauer–Emmett–Teller (BET) surface area analysis. Results clearly indicate which self-assembled COFs quantum dots as supramolecular cages modified with biochar synthesized with the cost-effective method act as a high performance photocatalyst for degradation of methylene red, orange and blue organic dyes.

     

TiO2/Si nanowires hybrid system for efficient photocatalytic degradation of organic dye

Herein, titanium dioxide (TiO₂)-coated vertically aligned silicon nanowires (SiNWs/TiO₂) were fabricated and evaluated for photocatalytic degradation of organic dyes. Aligned SiNWs arrays were prepared by facile metal-assisted chemical-etching process with varying the etching time that was followed by TiO₂ nanoparticles coating using sputtering technique. The TiO₂ film crystallized in pure anatase phase with an average crystalline size of 50 nm, as was elucidated with X-ray diffraction studies. SEM analysis showed nanowires with varying lengths from 2.5 to 13.5 µm and confirmed the homogenous surface decoration with TiO₂. The homogeneous distribution of TiO₂ nanoparticles on nanowires was co-evidenced with Energy-Dispersive X-ray spectroscopy (EDX) and Raman spectra analysis. The developed SiNWs/TiO₂ was exploited for photocatalytic degradation of methylene blue; the role of hydrogen peroxide was also elucidated. The highest photocatalytic efficiency of 96% was achieved for SiNWs/TiO₂ with optimum nanowire length of 3.5 μm. The developed photocatalyst was found to be almost stable even after 190 days (~?5 months) and could be used as reusable and easily removable photocatalysts. The current study highlighted the SiNWs/TiO₂/H₂O₂ system as excellent candidate for water remediation applications.

     

Synthesis,structural and optical properties of Ag doped ZnO nanoparticles with enhanced photocatalytic properties by photo degradation of organic dyes

In present paper chemical route based synthesis of Ag doped ZnO nanoparticles (NPs) by co-precipitation method is reported to develop ZnO NPs for photo catalytic application. XRD confirms the structural purity of ZnO NPs. FESEM and TEM study reveals the surface and ultra structure morphology of NPs. EDAX study confirms the purity and homogeneity of NPs. The Ag/ZnO NPs with different weight percentage of Ag relative to ZnO were applied under visible light irradiation for evaluating heterogeneous photo catalytic degradation of methylene blue (MB) and Brilliant blue (BB) respectively. The presence of Ag in ZnO enhance MB and BB dye degradation effectiveness from 96.78 to 98.66 and 82.15 to 97.36% for pure ZnO and maximum Ag doped ZnO (x?=?0.1) respectively. In comparison of MB and BB final degradation ability, MB dyes have more effective photo catalytic efficiency towards different oxidizing species to degradation process.     

微/纳米ZnO绒球的制备及光催化降解有机染料

以谷氨酸-氟硼酸(GluBF4)离子液体水溶液为反应介质,以物质的量比为1∶6的二水合醋酸锌[Zn(Ac)2·2H2O]和NaOH为原料,室温下制备前驱体,再微波辅助加热制备了微/纳米ZnO粉体,获得了单一形貌较高比表面积微/纳米ZnO绒球。利用扫描电镜(SEM)、X射线衍射(XRD)、比表面(BET)、能谱(EDS)等对产物进行了结构与性能表征。所得产物为六方晶系纤锌矿结构,绒球直径在1.6~3.0μm之间,粒径平均尺寸20.4nm,绒球比表面积为28.3m2/g,产物纯度高,收率95.6%。该纳米材料在自然光下表现出较高的光催化活性和形态稳定性。分别配制浓度为10mg/L的100mL甲基橙(methylorange,MO)、溴甲酚绿(bromocresolgreen,BG)水溶液,30mg纳米ZnO为光降解催化剂,太阳光激发下5h脱色率分别达74.3%和86.4%,重复利用5次,催化剂形貌不变、重量未发生变化。     

Photocatalytic degradation of selected dyes by titania thin films with various nanostructures

Titania thin films with various nanostructures of quasi-aligned nanorods, well-aligned nanotubes and nanoparticle aggregates were fabricated and utilized to assist photodegradation of three typical dye derivatives in water, i. e., rhodamine B (RB), methylene blue (MB) and methyl orange (MO). The thin films were characterized by X-ray diffraction, scanning electron microscope and UV-Vis diffuse reflectance spectra. It is found that the bandgap of most lab-fabricated thin films can be estimated more appropriately assuming a direct transition between the valance band and the conduction band of titania. The so-called natural ageing phenomenon was evidence for all the films to assist photodegradation of RB and MB in water; but not discernible for MO, which was much reluctant to photodegradation. MB decomposed much quickly than RB when assisted by titania with predominantly anatase; on the other hand, rutile favored the photodegradation of RB than that of MB. Titania thin films with top morphologies of quasi-aligned nanorods or nanotubes were found to possess advantageous turnover frequency and photonic efficiency over commercial P25 titania and sol-gel derived titania to assist photodegradation of RB and MB in water.     

One-pot hydrothermal synthesis of hierarchical porous manganese silicate microspheres as excellent Fenton-like catalysts for organic dyes degradation

Towards bottlenecks demonstrated by typical Fenton-like catalysts in advanced oxidation processes(AOPs)for wastewater treatment,novel hierarchical porous Mn2+Mn...     

Boron nitride quantum dots loading red phosphorus for efficient visible-light-driven photocatalytic degradation of organic pollutants

Journal of Materials Science: Materials in Electronics - Constructing new metal-free green materials opens up new research directions for photocatalysis. Red phosphorus (RP) modified by boron...     

A novel Z-type ZnIn2S4 nanosheet-coated TiO2 nanorods heterostructures for efficient photocatalytic degradation of tetracycline

Journal of Materials Science - The construction of heterojunction structures of semiconductor photocatalysts to achieve efficient separation of photogenerated electron–hole pairs is important...     

ZnO/Ag nanocomposite: An efficient catalyst for degradation studies of textile effluents under visible light

Degradation of model organic dye and industry effluent was studied using different weight percentages of Ag into ZnO as a catalyst. In this study, the catalysts were prepared by thermal decomposition method, which was employed for the first time in the preparation of ZnO/Ag nanocomposite catalysts. The physical and chemical properties of the prepared samples were studied using various techniques. The specific surface area, which plays an important role in the photocatalytic degradation, was studied using BET analysis and 10 wt.% Ag into ZnO showed the best degrading efficiency. The optical absorption (UV–vis) and emission (PL) properties of the samples were studied and results suggest better photocatalytic properties for 10 wt.% Ag sample compared to other samples.     

Biosynthesis of tin oxide (SnO2) nanoparticles using jujube fruit for photocatalytic degradation of organic dyes

In this study, tin oxide (SnO₂) nanoparticles were synthesized via a green route using jujube fruit as a non-toxic, renewable reducing agent, and excellent stabilizer. The biosynthesized SnO₂ nanoparticles were characterized by X-ray diffraction analysis (XRD), Fourier-Transform infrared (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Moreover, the photocatalytic activity of the novel SnO₂ nanoparticles was investigated for degradation of two organic dyes which were named methylene blue (MB) and eriochrome black-T (EBT) under direct sunlight. An excellent performance was observed and about 90% and 83% of degradation efficiencies were achieved for MB and EBT, respectively. The high stability of the photocatalyst also makes SnO₂ nanoparticles easily to reuse at least four times without any remarkable loss in activity.     

Hydrothermal Sm-doped tungsten oxide vertically plate-like array photoelectrode and its enhanced photoelectrocatalytic efficiency for degradation of organic dyes

Samarium doped tungsten oxide film was synthesized by a hydrothermal method with sodium tungstate as W precursor and samarium oxide as dopant. After annealing at 450 °C for 0.5 h, the morphology and structural characterization of as-prepared films were determined with scanning electron microscopy, X-ray diffraction and high-resolution transmission electron microscope. For the pure and Sm-doped WO₃ films serving as the photoanodes, photoelectrocatalytic properties were demonstrated by degrading methyl orange and methylene blue solution, showing that Sm-doped WO₃ film has faster degrading rate than pure WO₃ film. Photoelectrochemical properties were investigated using linear sweep voltammetry, electrochemical impedance spectroscopy, Mott–Schottky and incident photon to current conversion efficiency. Sm-doped WO₃ achieves a high photocurrent of 1.50 mA cm^?2 at 1.4 V versus. Ag/AgCl, which is 1.8 times as high as that of pure WO₃ film (0.83 mA cm^?2). Moreover, photogenerated hole injection efficiency was improved by retarding the recombination at the interface of electrode/electrolyte. The results indicate the Sm₂O₃ formed by excess doping led to a better photoelectrocatalytic and photoelectrochemical activities of Sm-doped WO₃ film, suggesting that the doping of Sm is a favorable strategy to improve the performance of WO₃ film photoanode.     

A new efficient catalyst UDCaT-1 for the alkylation of ethylbenzene with ethanol to diethylbenzene

Vapour phase alkylation of ethylbenzene with ethanol to diethylbenzene is industrially relevant. Diethylbenzene is an important raw material for the conversion to divinyl benzene monomer. Conventionally it is prepared from diacetophenone by reduction. It is also prepared by vapour-phase alkylation of ethylbenzene with ethylene using zeolites as the catalyst. The current work dealt with the alkylation of ethylbenzene with ethanol using UDCaT-1 as the catalyst, which is a synergistic combination of hexagonal mesoporous silica (HMS) and sulphate modified zirconia materials. There is no need to use absolute ethanol; dilute ethanol can also be effectively used. UDCaT-1 was found to be more active and selective in comparison with other acid catalysts used. Kinetic interpretation has been made by studying the important process parameters using UDCaT-1 as the catalyst. A complete theoretical and experimental analysis is presented. Electronic Publication