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1.
ZnO–SnO2 nanoparticles were prepared by coprecipitation method; then Mg, with different molar ratios and calcination temperatures, was loaded on the coupled nanoparticles by impregnation method. The synthesized nanoparticles were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) techniques. Based on XRD results, the ZnO–SnO2 and Mg/ZnO–SnO2 nanoparticles were made of ZnO and SnO2 nanocrystallites. According to DRS spectra, the band gap energy value of 3.13 and 3.18 eV were obtained for ZnO–SnO2 and Mg/ZnO–SnO2 nanoparticles, respectively. BET analysis revealed a Type III isotherm with a microporous structure and surface area of 32.051 and 49.065 m2 g?1 for ZnO–SnO2 and Mg/ZnO–SnO2, respectively. Also, the spherical shape of nanocrystallites was deduced from TEM and FESEM images. The photocatalytic performance of pure ZnO–SnO2 and Mg/ZnO–SnO2 was analyzed in the photocatalytic removal of methyl orange (MO). The results indicated that Mg/ZnO–SnO2 exhibited superior photocatalytic activity to bare ZnO–SnO2 photocatalyst due to high surface area, increased MO adsorption and larger band gap energy. Maximum photocatalytic activity of Mg/ZnO–SnO2 nanoparticles was obtained with 0.8 mol% Mg and calcination temperature of 350°C. 相似文献
2.
In this report, TiO(2) -SiO(2) composite nanoparticles were prepared by the thermal hydrolysis method using titanium tetrachloride and tetraethylorthosilicate as TiO(2) and SiO(2) precursors, respectively. The prepared nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), nitrogen adsorption/desorption and UV-Vis diffuse reflectance spectroscopy (DRS). The results indicated that, in comparison with pure TiO(2), TiO(2)-SiO(2) composite nanoparticles had a higher thermal stability, which prevents phase transformation from anatase to rutile. In addition, the TiO(2)-SiO(2) nanoparticles had a higher specific surface area, larger pore volume, greater band gap energy and smaller crystallite size. Thus, the surface area of TiO(2)-40% SiO(2) composite nanoparticles was about 17 times higher than that of pure TiO(2) nanoparticles. The photocatalytic activity of TiO(2)-SiO(2) composite nanoparticles in the photodegradation of C.I. Basic Violet 2 was investigated. The photodegradation rate of Basic Violet 2 using TiO(2)-40% SiO(2) nanoparticles calcined at 600°C was much faster than that using pure TiO(2) and Degussa P25 TiO(2) by 10.9 and 4.3 times, respectively. The higher photoactivity of the TiO(2)-SiO(2) composite nanoparticles was attributed to their higher surface area, larger pore volume, greater band-gap energy and smaller crystallite size compared with pure TiO(2). 相似文献
3.
Effect of operational parameters on degradation of Malachite Green by ultrasonic irradiation 总被引:1,自引:0,他引:1
The aim of the present study was to apply ultrasonic technique to remove Malachite Oxalate Green (MG) from aqueous solution. An ultrasonic bath with frequency of 35 kHz was used to investigate the effect of different operational parameters such as MG concentration, power density, temperature, mechanical agitation and addition of EtOH, 2-PrOH and iso-BuOH. Decolorization of MG follows a first order kinetics and hydroxyl radicals have an important role in degradation of MG. The apparent reaction rate constant (k(ap)) was influenced by variation of operational parameters. The activation energy was 30.95 kJ/mol in temperature range of 21-34 degrees C, suggesting a diffusion-controlled reaction. Alcohols act as hydroxyl radicals scavengers having undesirable contribution. UV-vis spectral change of MG showed hypsochromic shift occurred with increasing sonication time, proposing N-demethylation process of MG. 相似文献
4.
Soudabeh Saeid Mohammad A. Behnajady Pasi Tolvanen Tapio Salmi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(5):876-883
The photooxidative removal of analgesic pharmaceutical compound phenazopyridine (PhP) from aqueous solutions by UV/H2O2 system with a re-circulated photoreactor was investigated. Response surface methodology (RSM) was employed to optimize the effect of operational parameters on the photooxidative removal efficiency. The investigated variables were: the initial PhP and H2O2 concentrations, irradiation time, volume of solution and pH. The analysis of variance (ANOVA) of quadratic model demonstrated that the described model was highly significant. The predicted values of the photooxidative removal efficiency were found to be in a fair agreement with experimental values (R2 = 0.9832, adjusted R2 = 0.9716). The model predicted that the optimal reaction conditions for a maximum removal of PhP (>98%) were: initial PhP concentration less than 23 mg L–1, initial concentration of H2O2 higher than 470 mg L–1, solution volume less than 500 mL, pH close to 2 and irradiation time longer than 6 min. 相似文献
5.
Behnajady MA Eskandarloo H Modirshahla N Shokri M 《Photochemistry and photobiology》2011,87(5):1002-1008
In this work, TiO(2) nanoparticles in anatase phase was prepared by sol-gel low temperature method from titanium tetra-isopropoxide (TTIP) as titanium precursor in the presence of acetic acid (AcOH). The effects of synthesis parameters such as AcOH and water ratios, sol formation time, synthesis and calcination temperature on the photocatalytic activity of TiO(2) nanoparticles were evaluated. The resulting nanoparticles were characterized by X-ray diffraction, UV-Vis reflectance spectroscopy, transmission electron microscopy and Brunauer-Emmett-Teller techniques. Photocatalytic activity of anatase TiO(2) nanoparticles determined in the removal of C. I. Acid Red 27 (AR27) under UV light irradiation. Results indicate that with increasing AcOH/TTIP molar ratio from 1 to 10, sol formation time from 1 to 3 h and synthesis temperature from 0 to 25°C, increases crystallite size of synthesized nanoparticles. It was found that optimal conditions for low temperature preparation of anatase-type TiO(2) nanoparticles with high photocatalytic activity were as follows: TTIP:AcOH:water molar ratio 1:1:200, sol formation time 1 h, synthesis temperature 0°C and calcination temperature 450°C. 相似文献
6.
Photo and Chemical Reduction of Copper onto Anatase‐Type TiO2 Nanoparticles with Enhanced Surface Hydroxyl Groups as Efficient Visible Light Photocatalysts
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Hamed Eskandarloo Alireza Badiei Mohammad A. Behnajady Ghodsi Mohammadi Ziarani 《Photochemistry and photobiology》2015,91(4):797-806
In this study, the photocatalytic efficiency of anatase‐type TiO2 nanoparticles synthesized using the sol–gel low‐temperature method, were enhanced by a combined process of copper reduction and surface hydroxyl groups enhancement. UV–light‐assisted photo and NaBH4‐assisted chemical reduction methods were used for deposition of copper onto TiO2. The surface hydroxyl groups of TiO2 were enhanced with the assistance of NaOH modification. The prepared catalysts were immobilized on glass plates and used as the fixed‐bed systems for the removal of phenazopyridine as a model drug contaminant under visible light irradiation. NaOH‐modified Cu/TiO2 nanoparticles demonstrated higher photocatalytic efficiency than that of pure TiO2 due to the extending of the charge carriers lifetime and enhancement of the adsorption capacity of TiO2 toward phenazopyridine. The relationship of structure and performance of prepared nanoparticles has been established by using various techniques, such as XRD, XPS, TEM, EDX, XRF, TGA, DRS and PL. The effects of preparation variables, including copper content, reducing agents rate (NaBH4 concentration and UV light intensity) and NaOH concentration were investigated on the photocatalytic efficiency of NaOH‐modified Cu/TiO2 nanoparticles. 相似文献
7.
Leila Airemlou Behnajady Mohammad A. Mahanpoor Kazem 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(10):2015-2024
Russian Journal of Physical Chemistry A - In this paper, pure ZnO, Ag, and Mg mono-doped and co-doped ZnO nanoparticles were synthesized via sol-gel method. The synthesized nanoparticles were... 相似文献
8.
In this study, TiO(2)- and Mg-doped TiO(2) nanoparticles with different dopant contents were prepared by sol-gel method. The prepared photocatalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and diffuse reflectance spectroscopy (DRS) techniques. The results of BET analysis indicated a pore diameter of 8 nm and surface area of 48.5 m(2) g(-1). XRD patterns of pure and doped TiO(2) nanoparticles at 450 °C revealed that all phases are anatase. The particle size obtained from TEM was less than 20 nm. The band gap energy of Mg-doped TiO(2) nanoparticles was lower than that of TiO(2) . The photocatalytic activity of the pure and doped nanoparticles has been compared in the removal of C.I. Acid Red 27 (AR27). The photocatalytic activity of Mg-doped (0.2 mol%) TiO(2) for the degradation of AR27 was higher than that of bare TiO(2) nanoparticles. Results of total organic carbon analysis and changes in the AR27 UV-Vis peaks indicated 99% mineralization and extinguishing of all peaks in UV and visible regions is possible with Mg-doped TiO(2) nanoparticles. Removal efficiency of AR27 was sensitive to the parameters such as catalyst dose, pollutant concentration and light intensity. 相似文献
9.
Jila Talat-Mehrabad Morteza Khosravi Nasser Modirshahla Mohammad A. Behnajady 《Research on Chemical Intermediates》2016,42(2):595-609
In this study, we successfully prepared pure, mono-doped, and Ag, Mg co-doped TiO2 nanoparticles using the sol–gel method, with titanium tetraisopropoxide as the Ti source. The prepared samples were characterized by X-ray powder diffraction (XRD), specific surface area and porosity (BET and BJH) measurement, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence, and energy dispersive X-ray spectroscopy techniques. The XRD data showed that the prepared nanoparticles had the same crystals structures as the pure TiO2. Also, DRS results indicated that the band gap of co-doped photocatalyst was smaller than that of the monometallic and undoped TiO2 and that there was a shift in the absorption band towards the visible light region. Furthermore, the photocatalytic activity of the prepared catalysts was evaluated by the degradation of C.I. Acid Red 27 in aqueous solution under visible light irradiation. The results showed that Ag (0.08 mol%), Mg (0.2 mol%) co-doped TiO2 had the highest photoactivity among all samples under visible light. It was concluded that co-doping of the Ag and Mg can significantly improve the photocatalytic activity of the prepared photocatalysts, due to the efficient inhibition of the recombination of photogenerated electron–hole pairs. The optimum calcination temperature and time were 450 °C and 3 h, respectively. 相似文献
10.
Russian Journal of Applied Chemistry - The photocatalytic degradation of phenazopyridine (PhP) as a model contaminant from pharmaceutical compounds was studied using batch-recirculated photoreactor... 相似文献