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Fabrication and photocatalytic performance evaluation of hydrodynamic erosion–resistant nano-TiO2–silicone resin composite films
摘要： Herein, we present the preparation of nano-TiO2–silicone resin composite films by double liquid phase spray deposition. The films exhibit better adhesion stability and photocatalytic activity under a hydrodynamic erosion condition than conventional nano-TiO2 composite films. The TiO2 layer morphology and effective TiO2 coverage ratio (CR) were affected by the initial curing time (ICT) of the silicone resin, e.g., the increase in an ICT from 10 to 40 min resulted in a CR change from 79.1 to 98.7%. The surface morphology evolution of composite films was studied under a hydrodynamic erosion period of 4 weeks. Obtained results allowed the 4-week evolution to be divided into four stages (pitting, crack pregnant, banded stripping, and surface stripping periods), additionally revealed that the CR of all samples was remained above 65%. The photocatalytic activity of composite films before and after 4-week hydrodynamic erosion was evaluated by rhodamine B degradation experiments. The 4-week erosion only led to the decrease of the photodegradation efficiencies by less than 40% in all cases. Thus, the fabricated TiO2–silicone composite films demonstrated excellent durability and photocatalytic activity under the conditions of long-term hydrodynamic erosion, allowing one to conclude that this work paves the way to the fabrication of next-generation photocatalytic materials for industrial applications.
关键词： Photocatalysis,Film formation mechanism,Silicone resin,Photodegradation,Hydrodynamic erosion resistance,Nano-TiO2
更新于2025-09-23 15:23:52
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Manganese dioxide nanoparticles/activated carbon composite as efficient UV and visible-light photocatalyst
摘要： Manganese dioxide nanoparticles/activated carbon (MnO2/AC) composites and manganese dioxide nanoparticles (MnO2 NPs) are prepared through chemical reduction method. Morphological study shows that MnO2 NPs had cylindrical and spherical shape. The morphological study also revealed that MnO2 NPs were well dispersed on AC while neat Mn NPs present both in dispersed and in agglomerated form. The FT-IR study confirms the synthesis of MnO2 NPs. Zetasizer study presented that the Mn NPs had uniform size and below 100 nm in size and had zeta potential of ? 20 mV, which represent its stability in the suspension form. The synthesized Mn/AC composite and Mn NPs were utilized as photocatalysts for the photodegradation of Congo red (CR) dye. The degradation study shows that MnO2/AC composite degraded CR dye more efficiently than MnO2 NPs under UV and normal light irradiation. The efficient degradation of dye by Mn/AC composite is due to the synergistic effect between dye adsorption on AC and rapid photodegradation by supported MnO2 NPs. The results revealed that Mn/AC composite degraded about 98.53% of CR dye within 5 min while MnO2 NPs degraded 66.57% of dye within the same irradiation time. The recycled catalyst also significantly degraded dye which verifies its sustainability. The effect of catalyst dosage and initial dye concentration was conducted. The degradation rate of dye was found drastically faster in tap water (in presence of catalyst), which might be due to the presence of various mineral ions in the tap water.
关键词： Manganese dioxide,nanoparticles,Activated carbon,Photodegradation,Photocatalyst,Congo red
更新于2025-09-23 15:23:52
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Photocatalytic oxidation of gaseous benzene, toluene and xylene under UV and visible irradiation over Mn-doped TiO2 nanoparticles
摘要： The photocatalytic oxidation of gaseous benzene, toluene and xylene (BTX) over un-doped, 0.1 and 1 wt% Mn-TiO2 nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert gas. The photocatalytic decomposition efficiency and the oxidation products were determined using a Static Photochemical Reactor coupled with FTIR spectroscopy. BTX underwent efficient decomposition over Mn-TiO2 photocatalysts under UV irradiation, more with oxygen presence and less without oxygen. More important toluene and xylene went substantial decomposition over 0.1 mol% Mn-TiO2 under visible irradiation with oxygen presence. The main final oxidation products in the UV photocatalysis of BTX were CO2, CO and H2O, with CO2 and CO yields 4 and 2 respectively. The conversion percentage of benzene, toluene, and xylene to CO2 were 63.6%, 56.4%, 51.8%, and to CO 29%, 26.5%, 23.2%, respectively. In the visible photocatalysis of toluene and xylene the yields of CO were insignificant. Formation of carbon containing deposits on TiO2 surfaces was observed after extensive UV photocatalysis of toluene and xylene, and such by-products surface coverage may reduce the photocatalytic activity of TiO2 samples. Some aspects of the photocatalytic mechanism were examined.
关键词： Mn-doped TiO2,Visible - light photocatalysis,Photodegradation of Benzene,Indoors air pollution,Xylene,Toluene
更新于2025-09-23 15:23:52
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CuInS2 sensitized TiO2 for enhanced photodegradation and hydrogen production
摘要： A novel CuInS2/TiO2 (CIS-TO) heterojunction which displayed two different transfer pathways of photo-generated carries under UV–vis and Vis light irradiation was fabricated through a facile in-situ growth method. Under vis-light (λ ≥ 420 nm) excitation, 97.37% RhB (10 mg/L) was photodegraded with 20 mg of 1% CIS-TO photocatalyst within 90 min, and the degradation constant could up to 0.0415 min?1, which was about 8.28 times to pure TiO2 (0.00501 min?1) and the typical heterojunction was formed between CuInS2 and TiO2 to provide the photo-electrons transfer channel. Under UV–vis light irradiation, a Z-scheme heterojunction was formed to provide another highly effective electron transfer channel for hydrogen production and the hydrogen production rate could reach 785.4 μmol g?1 h?1 with 1% CIS-TO photocatalyst, which showed nearly 1.68 times than that of pure TiO2. The enhanced photocatalytic activity could be attributed to the synergistic effect of the sensitization and narrow band gap of CuInS2 which could effectively broaden the spectral response range, enhance the photon utilization and inhibit the recombination of photogenerated electrons and holes. Additionally, the high stability of the material was illustrated by the cycle experiments of photodegradation and hydrogen production.
关键词： Typical heterojunction,Sensitization,Z-scheme heterojunction,Photodegradation,CuInS2/TiO2
更新于2025-09-23 15:23:52
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Synthesis and characterization of composites ZnZr for the photocatalytic degradation of phenolic molecules. Addition effect of ZrO <sub/>2</sub> over hydrozincite Zn <sub/>5</sub> (OH) <sub/>6</sub> (CO <sub/>3</sub> ) <sub/>2</sub>
摘要： BACKGROUND: Composite materials ZrO2/Zn5(OH)6(CO3)2 were prepared in only one step by chemical coprecipitation and thermal hydrolysis of urea. ZrO2 was added at 5, 8 and 10 mol%. The samples were dried at 80°C and characterized by adsorption-desorption of N2 isotherms, XRD, SEM, techniques and DRS, UV-Vis, FTIR and XPS spectroscopies. The materials were assessed in the photodegradation of phenol and polychlorinated phenolic molecules under UV-light irradiation. The possible mechanism was discussed from studies that corroborated o discarded the formation of the species ?OH, ?O2- and h+. RESULTS: The addition of ZrO2 to Zn5(OH)6(CO3)2 resulted in a composite material with high photoactivity. Being the most efficient the sample with 8 mol% of ZrO2. The photodegradation enhancement was partly achieved by an increment in the specific surface area and principally due to localized states originated in the composite interphase which improve the charges transfer. It was found by XPS study that the ZrO2 addition increment the oxygen vacancies which enhance the organic molecule photodegradation via direct holes attack. CONCLUSION: The composite system ZnZr can be an excellent alternative for the persistent organic pollutants photodegradation due to the low cost, high stability and null toxicity of the support Zn5(OH)6(CO3)2.
关键词： ZrO2,hydrozincite,phenol-chlorophenols photodegradation,composites
更新于2025-09-23 15:23:52
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Artificial neural network modeling of a pilot plant jet-mixing UV/hydrogen peroxide wastewater treatment system
摘要： This study deals with the modeling and simulation of an efficient pilot plant photo-chemical wastewater treatment reactor. Treatment of an azo dye (i.e. direct red 23) was performed using a UV/H2O2 process in a jet mixing photo-reactor with 10-L volume. To model the reactor and simulate the treatment process, six important, influential physical and chemical factors such as nozzle angle (hN), nozzle diameter (dN), flow-rate (Q), irradiation time (t), H2O2 initial concentration ([H2O2]0), and pH, were taken into account. In this regard, artificial neural networks (ANNs) were employed as a powerful modeling methodology. Six different ANN architectures were constructed and most appropriate numbers for hidden neuron and learning iteration were determined based on minimization of the mean square error (MSE) function related to the testing data sets. Furthermore, simulation of the reactor efficiency, as well as sensitivity analysis, was performed via the cross-validation outputs. It was found that a three-layered feed-forward ANN composes ten hidden neurons, calibrated at 100th iteration using “trainlm” as learning algorithm and “tansig” and “purelin” as transfer functions in the hidden and output layers can model the process as the best case. The order of importance for variation of the key factors were indicated as [H2O2]0 > t > pH > Q > hN > dN.
关键词： dyes,simulation,wastewater treatment,Advance oxidation process,neural networks,photodegradation,batch reactor
更新于2025-09-23 15:23:52
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Novel design of photocatalyst coaxial ferromagnetic core and semiconducting shell microwire architecture
摘要： We report a novel design of coaxial core-shell magnetic-semiconductor microwire, as a catalyst under sunlight irradiation. The nano/micro hierarchical architecture-like device is comprised of a coaxial core-shell microwire where the core is the ferromagnetic Fe metal and the shell is formed by a semiconducting hematite layer. The fabrication process of our substrate-free device is simply based on controlled thermal oxidation process revealing a simple and low-cost method. The hematite outer microlayer has a mesoporous structure decorated with nanowires. The ferromagnetic and metallic core assume fundamental importance as to mechanical stability, collect the generated photoelectrons, and to be removed back from the dye solution by a magnetic field gradient or simply a magnet. This nano/micro device has exhibited photocatalytic activity to degrade the methylene blue dye under simulated sunlight irradiation. Additionally, the coaxial magnetic/semiconducting can also be designed as a photoanode to drive water oxidation reaction. The coaxial magnetic/semiconducting photoanode response has shown good chemical stability and long activity under simulated sunlight radiation. In fact, this designed architecture gives novel perspective in the development of substrate free photocatalyst.
关键词： Photoelectrochemical performance,Hematite photoanodes,Photodegradation,Micro/nano architecture,Core-shell microstructures,Thermal oxidation
更新于2025-09-23 15:23:52
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Adsorption and photodegradation efficiency of TiO2/Fe2O3/PAC and TiO2/Fe2O3/zeolite nanophotocatalysts for the removal of cyanide
摘要： The synthesized TiO2/Fe2O3 nanostructures supported on powder activated carbon (PAC) and zeolite at different mole ratios of Fe3+/TiO2 were characterized by XRD, XRF, FESEM, EDX, TEM, FTIR, BET and, PL analyses and their cyanide photodegradation mechanism was thoroughly discussed. The results confirmed not only TiO2/Fe2O3/PAC had higher photocatalytic and adsorption capability but also better structural stability and reusability for cyanide removal than TiO2/Fe2O3/zeolite. The first order kinetics model indicated that the photodegradation rate using TiO2/Fe2O3/PAC was 1.3 times higher than that of TiO2/Fe2O3/zeolite. The response surface methodology (RSM) assessment showed that pH, irradiation time and initial cyanide concentration using UV/H2O2/TiO2/Fe2O3/zeolite system had more effects on the degradation respectively; whereas the effectiveness of UV/H2O2/TiO2/Fe2O3/PAC process was highly influenced by initial cyanide concentration than the other two parameters. High R2 and well-fitted residual plots approved the accuracy of the models in predicting the cyanide degradation efficiency using both the photocatalysts.
关键词： and adsorption comparison,Cyanide,Response surface methodology (RSM),TiO2/Fe2O3/zeolite and TiO2/Fe2O3/PAC photocatalysts,Photodegradation,Kinetic
更新于2025-09-23 15:23:52
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Ag/Tio <sub/>2</sub> /AOF as an Easily Reused and Highly Active Catalyst for Dye Photo-Degradation
摘要： A novel TiO2 loaded with Ag photocatalyst covering on a modified fiber surface was prepared by a coordination-hydrolysis combined with photo-reduction process. The samples were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscope (SEM), X-ray photoelectron spectroscope (XPS) and ultraviolet visible diffuse reflectance spectra (UV-vis DRS). Compared with powder TiO2, the TiO2/amidoxime fiber (TiO2/AOF) and Ag/TiO2/amidoxime fiber (Ag/TiO2/AOF) exhibited a significant absorption edge of red-shift from ultraviolet to visible light region. The samples’ activities were investigated and the results showed that Ag/TiO2/AOFs exhibit excellent photocatalytic activities-about 99% decomposition rate of Rhodamine B with 100 minutes of visible light irradiation. The catalyst exhibits excellent catalytic activity and is easily recovered and reused.
关键词： Rhodamine B,Silver,Amidoxime fibers,Photodegradation,Titanium dioxide
更新于2025-09-23 15:23:52
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Classification of pre-dyed textile fibers exposed to weathering and photodegradation by non-destructive excitation-emission fluorescence spectroscopy paired with discriminant unfolded-partial least squares
摘要： Undyed textile fabrics such as Acrylic 864, Nylon 361 and Cotton 400 were pre-dyed with Basic Green 4 (BG4), Acid Yellow 17 (AY17) and Direct Blue 1 (DB1) dyes, respectively; and then exposed to two extremely diverse weather conditions in the United States: desert and humid environmental settings in Arizona (AZ) and Florida (FL) respectively, for different time intervals of exposure, which included 0, 3, 6, 9 and 12 months. After every interval of a 3 months period, ten fibers were uniformly sampled from each cloth piece, and fluorescence microscopy was employed to collect two-dimensional excitation and fluorescence spectra (2-D spectra) and three-dimensional (3D) excitation-emission matrices (EEMs). A significant loss of fluorescence intensity was observed upon fiber exposure to outdoor weathering conditions. For a comprehensive statistical data analysis and to be able to discriminate between any two single fibers weathered under different conditions, a multiway calibration algorithm known as discriminant unfolded partial least-squares (DU-PLS) method was applied to the exposed fibers. Results indicate that fluorescence spectroscopy combined with DU-PLS has the ability to appropriately classify and differentiate between any two pairs of dyed cotton or nylon fibers (acrylic in some cases) exposed to dry versus humid weather environments under different time intervals of exposure. These results provide the foundation for future studies towards a non-destructive approach capable to provide information on the weathering history of the fiber.
关键词： Discriminant unfolded partial least squares,Fiber analysis,Photodegradation,Excitation emission matrices,Weathering,Fluorescence spectroscopy
更新于2025-09-23 15:23:52