Degradation of Oxalic Acid and Bisphenol A by Photocatalytic Ozonation with g-C3N4 Nanosheet under Simulated Solar Irradiation

Photocatalytic ozonation of organics under simulated solar irradiation with a g-C₃N₄ nanosheet was investigated. g-C₃N₄ was prepared by calcinations of urea and characterized by TEM, BET, XRD and UV-Vis. Oxalic acid and bisphenol A were used as model substances to evaluate its catalytic ability. The results showed that g-C₃N₄ possess 2D nanosheet structure. The degradation ratio of oxalic acid and bisphenol A with g-C₃N₄/O₃/Solar was 1.50 and 1.92 times as great as the sum ratio when it was individually degraded by g-C₃N₄/Solar and O₃, separately. The results of recycling experiment indicated that g-C₃N₄ catalyst is very stable under experimental conditions.     

Preparation and photocatalytic activity of BiOI/MnxZn1-xFe2O4 magnetic photocatalyst

BiOI/Mn_xZn_1-xFe₂O₄ magnetic photocatalysts were successfully prepared for the first time. With the degradation of simulated RhB wastewater as a pointer to the photocatalytic reaction and combined with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and vibrating sample magnetometer (VSM), the reasons influencing the photocatalytic performance of the magnetic photocatalysts were further explored. The excessive or insufficient Mn-Zn ferrite both leads to a relatively low photocatalytic activity. When the calcination temperature reaches to 200 and 400?°C, the photocatalytic activity is enhanced significantly, but the main active component in the photocatalysts has changed from BiOI to Bi₅O₇I at 400?°C. The nanocomposites prepared under alcohol water environment with hollow microspheres morphology possess a highly photocatalytic efficiency, and the RhB degradation rate within 4?h in the ethanol water environment is significantly higher than that in pure water (98% vs. 59%).     

Influence of calcination temperature on the photocatalytic performance of the hierarchical TiO2 pinecone-like structure decorated with CdS nanoparticles

Herein, a novel hierarchical TiO₂ pinecone-like structure (TPS) has been successfully fabricated for the first time by self-assembling anodic oxidation methods on the Ti plate. Then it was constructed that a series of CdS-TPS nanocomposites with different cycles CdS modifying by a successive ionic layer adsorption and reaction (SILAR) after different temperature annealing in air. The structures and properties of the CdS-TPS were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Current-voltage (I-V), ultraviolet-visible (UV–vis/DRS). The results shown that the optical properties of the CdS-TPS could be rationally tailored by adjusting the CdS-modified cycles and annealing temperature, which significantly enhanced photocatalytic activity. To be used in photocatalytic organic pollutant removal after optimizing both the CdS modification cycles and annealing temperature. The 15-CdS-TPS-500?°C exhibited significantly improved photocatalytic activities of methyl orange (MO) degradation under simulated sunlight irradiation. With 180?min, 85% of the MO (0.05?mM/L, 5?mL) was photodegraded and its kinetic constant reached to 0.0104?min^?1, which is the 3.0 times and 3.6 times quicker than that of 5-CdS-TPS-500?°C and 15-CdS-TPS-0?°C, respectively. This could be ascribed to the result of the synergy effects of the suitable quantity of CdS nanoparticles modifier, the special surface structure, excellent crystallinity, higher electrical conductivity, and band structure matching. The possible photocatalytic mechanism of the CdS-TPS sample is investigated as well.     

Mortality response of folate receptor-activated,PEG–functionalized TiO2 nanoparticles for doxorubicin loading with and without ultraviolet irradiation

TiO₂ nanoparticles (NPs) were synthesized by hydrothermal assisted sol–gel technique. In the next step, as-synthesized NPs were modified by poly ethylene glycol (PEG). Then, folic acid (FA) was conjugated to TiO₂–PEG. Finally, Doxorubicin (Dox) as an anticancer drug was loaded on as-prepared TiO₂–PEG–FA nanocarrier. The optimization of TiO₂ and FA concentration and the influence of ultraviolet (UV) irradiation on photocatalytic activity of nanocarrier and Dox loaded carrier were assessed by utilizing the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT)-assay method.     

Photocatalytic degradation of methylene blue and sulfisoxazole from water using biosynthesized zinc ferrite nanoparticles

The extensive occurrence of textile and pharmaceutical contaminants and their metabolites in water systems has posed significant concerns regarding their possible threat to human health and the environmental system. As a result, herein ZnFe₂O₄ nanoparticles were synthesized through the use of Monsonia burkeana plant extract. The synthesized nanoparticles were characterized using XRD, FTIR, UV–vis, SEM, EDS, TGA, BET, PL, EPR and VSM. XRD showed that the crystalline structure of ZnFe₂O₄ nanoparticles with a calculated crystal size of 25.03 nm was formed. FT-IR confirmed the characteristic functional groups contained within the M. burkeana plant were deposited on the formed ferrite nanoparticles. BET analysis confirmed the mesoporous nature of ZnFe₂O₄ with an average pore diameter of 31.6 nm. Morphological studies demonstrated that the formed nanoparticles had spherical as well as rod-like shapes. ZnFe₂O₄ photocatalyst illustrated that it may be effortlessly detached by an external magnetic field. The optimum conditions for the 99.8% removal of Methylene Blue was obtained at pH12, within 45min and at the optimum dosage of 25 mg of the catalyst. The as-prepared ZnFe₂O₄ nanoparticles proved to be easily separated and recycled, and remained efficient even after 5 reuses, proving that the material is highly stable. The ROS studies also demonstrated that electrons are the main factors contributing to the degradation of MB. Upon testing the photocatalytic performance of the sulfonamide antibiotic, sulfisoxazole in water showed a degradation of 67%. This study has shown that these materials can be used in targeting textile and pharmaceutically polluted water.     

Efficient sunlight and UV photocatalytic degradation of Methyl Orange,Methylene Blue and Rhodamine B,using Citrus×paradisi synthesized SnO2 semiconductor nanoparticles

In this work, tin dioxide (SnO2) Nanoparticles (NPs) were synthesized through green synthesis, using Citrus × paradisi extract as a stabilizing (capping). The extract concentrations used were 1, 2 and 4% in relation to the aqueous solution. The resulting SnO2 NPs were used for the degradation of Methyl Orange (MO), Methylene Blue (MB) and Rhodamine B (RhB), under both solar and UV radiation. The NPs were characterized via Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM-SAED), the Brunauer-Emmett-Teller (BET) theory, Ultraviolet to Visible spectroscopy (UV–Vis), and Photoluminescence spectroscopy (PL); while the photocatalytic degradation was evaluated using UV-VIS. The results showed that the Citrus × paradisi extract is a good medium for the formation of SnO2 NPs. These NPs presented quasi-spherical morphology, particle sizes of 4–8 nm, with a rutile phase crystalline structure, and with banned gap of 2.69 at 3.28 eV. The NPs had excellent photocatalytic properties under solar radiation, degrading 100% of the OM in 180 min. Furthermore, under UV radiation, 100% degradation of the three dyes was achieved in a short time; 20 min for MO, and 60 min for MB and RhB. Therefore, green synthesis is a feasible medium for the formation of SnO2 NPs with good photocatalytic properties.     

Adsorption efficiency and photocatalytic activity of fly ash-based geopolymer foam mortar

Fly ash-based geopolymer foam mortar (GFM) was used as an adsorbent material to methylene blue (MB) and also the dye removal material using the photocatalytic mechanism. The GFM, containing 50 wt% river sand aggregate, was prepared to have approximately 46% open porosity, pore size distribution between 0.01 and 3.5 mm, and water permeability of 0.2 cm/s. The variation of adsorption efficiency and adsorption capacity with the contact time of the GFM was first evaluated using various GFM dosages (10, 20, 50, 80, and 100 g/L). The adsorption efficiency at equilibrium (AE_e) was found to linearly increase, while adsorption capacity (q_ae) exponentially decayed, with an increase of loading dosages. The photocatalytic removal efficiency of ~100% was obtained with 50, 80, and 100 g/L GFM loading dosages, with a shorter time at higher dosages. The GFM could be reused, without regeneration, for 5 cycles. The AE_e and q_ae for each reused cycle did not noticeably change suggesting the reusability. The photocatalytic removal efficiency, however, was found to decrease with an increase of the reused cycle. After the 5^th cycle, the highest removal efficiency was reduced to ~70%. The attempts to treat the GFMs with hydrochloric (HCl) and phosphoric (H₃PO₄) acid to reduce the excess alkaline did not give satisfactory results as expected. The photocatalytic removal efficiency had subsided after the treatment with both acids.     

Synthesis of novel p-n heterojunction Cu2SnS3/Ti3+-TiO2 for the complete tetracycline degradation in few minutes and photocatalytic activity under simulated solar irradiation

In this research work, p-n heterojunction Cu₂SnS₃/Ti³⁺-TiO₂ photocatalysts were synthesized by using a facile hydrothermal method to degrade tetracycline and produce hydrogen energy. The properties of Cu₂SnS₃/Ti³⁺-TiO₂ was analyzed by using XRD, SEM, TEM, HRTEM, BET, PL and UV–vis characterization. The HPLC-MS and TOC analyzer systems were used to analyze the intermediate products during the photocatalysis deprivation and total organic carbon. The characterizations showed that the addition of self-doped Ti³⁺ and Cu₂SnS₃ into TiO₂ enhanced the material's crystallinity, increased the absorption region from 450 nm to 750 nm, increased the surface area of the material from 234 to 583 m²/g and reduced the recombination of charge carriers. Under visible light irradiation, Cu₂SnS₃/Ti³⁺-TiO₂ exhibited excellent degradation performance and stability. The increase in the efficiency of the material is due to the creation of an internal electric field induced by the p-n heterojunction and reduction in the bandgap of the material, which efficiently reduced the rate of recombination, increased the surface area for light absorption and increased the transfer of charge carriers. The Cu₂SnS₃/Ti³⁺-TiO₂ photocatalyst degraded 100 % tetracycline and produced 510 μmol/hg hydrogen energy. The Cu₂SnS₃/Ti³⁺-TiO₂ composite exhibited good stability even after six cycles Cu₂SnS₃/Ti³⁺-TiO₂ degraded 98–99 % TC under visible light irridiation. The efficiency of Cu₂SnS₃/Ti³⁺-TiO₂ was also analyzed in the outdoor environment, confirming that this material can be effectively used in practical applications.     

Formation of crystalline titanium dioxide on barrier layer-forming metals in aqueous electrolytes by anodic spark deposition—first mechanistic conceptions

A spark deposition process for the generation of crystalline titanium dioxide layers on barrier layer-forming metals such as Al, Ti, Mg, Zr, etc. was investigated. The process was carried out at high voltages and currents in an aqueous electrolyte. The electrolyte composition is provided and it could be shown that the electrolyte system used has great influence on the properties of the oxide layers. From the titanium balance, it was proven that most of the layer originates from the deposition of electrolyte compounds rather than from conversion of substrate material. Mechanistic conceptions of the layer formation are presented and supported by analytical determination of some reaction intermediates. The titanium dioxide layers generated were characterised regarding their physical and chemical properties.     

La／金红石相TiO2的光催化性能

以钛酸丁酯和氧化镧为原料,通过一步法合成金红石相TiO2和La／金红石相TiO2。利用XRD、比表面积、DRS、Zeta电位等表征La／金红石相TiO2的光催化活性性能。结果表明,质量分数1．00％的La／,金红石相TiO2光催化活性最优。以甲基红、甲基橙和亚基甲蓝为降解目标的光催化,其反应动力学参数与表征结果吻合。