جستجوی مقالات مرتبط با کلیدواژه "dye" در نشریات گروه "مواد و متالورژی"

In this study, zeolite was synthesized and modified using 3-aminopropyl trimethoxy silane. The synthesized materials were identified by FT-IR, SEM, and XRD analyzes and used to separate direct red 80 (DR80) as an organic contaminant from water. The effect of various important factors such as the amount of adsorbent, initial concentration of contaminants and pH was investigated. The results showed that the modified adsorbent had a higher adsorption capacity than the row adsorbent. The amount of dye adsorption is high at lower pH values. The percentage of DR80 dye removal was complete under optimal conditions. Increasing the amount of adsorbent and decreasing the pH increases the percentage of dye removal and increasing the concentration of contaminant reduces the dye removal in the process. The Langmuir, Freundlich and Tempkin isotherm models were used. Isotherm data showed that the adsorption process followed the Langmuir isotherm model. Also, pseodu-first-order, pseodu-second-order and intraparticle diffusion kinetics models were used to investigate the adsorption kinetics. Dye adsorption followed pseodu-second-order kinetics. The results showed that the modified adsorbent could be used as a suitable adsorbent with high adsorption capacity for dye removal from aqueous media.

In the present study, the role of morphology of nanoparticles (NP) of titanium and zinc oxide and nanorods (NR) of zinc oxide with graphene was investigated on the properties of the Dye-Sensitized Solar Cell, In this regard, TiO2 nanoparticles are deposited on ZnO nanorods and nanoparticles, covered on graphene (G) and reduced graphene oxide (RGO) on doped tin oxide glass with fluorine (FTO) using the Dip coating device respectively. Then, the thin-layer nanoparticles made into the N719 pigment solution for 24 hours were sensitized, and subsequently the thin-film nanocomposites (photo-anodes) were bonded with a platinum electrode, and the electrolyte was injected into the cell through the cavities contained in the platinum electrode. EIS, XRD, IV and FESEM techniques were employed for identification of phase analysis, microstructural, electrical properties and optical properties. The results showed that not only the morphology of the ZnO layer but also the type of TiO2 coating process affects the properties of the (G / RGO) -ZnO-TiO2 nanocomposites. According to the results, nanocomposite RGO-ZnO (NP) -TiO2 (NP), in which TiO2 was coated on ZnO nanoparticles, had higher yields than RGO-ZnO (NR) -TiO2 (NP) samples with the presence of ZnO nanorods. Also, the presence of functional groups on the photo-anode surface due to the presence of RGO in these specimens has lower electrical conductivity and efficiency, the results of the G-ZnO-TiO2 nanocomposite confirm the above result.

Two organic dyes based on indoline were prepared as photosensitizer contain phenothiazine as the electron donor group and acrylic acid (Dye 1) and cyanoacrylic acid (Dye 2) as the electron acceptor anchoring. Spectrophotometric measurements of the synthesized dyes in solution and on a ZnO substrate were carried out in order to assess changes in the status of the dyes. The wavelength of maximum absorption of dye 1 and dye 2 in solution are 412 nm and 424 nm and on ZnO films are 429 nm and 438 nm¡ respectively. Maximum dye adsorption time around 10h could be utilized with minimum aggregation or precipitation of the dye on photoelectrode substrate. The effect of Li ions and composition of the iodide/triiodide based electrolyte on the performance of DSSCs were investigated. A high concentration of Li ions in electrolyte was found to be shift the ZnO conduction band edge to more negative potentials that have a direct effect on recombination phenomena. The Maximum conversion efficiency was achieved for dye 2 in the presence of 1mM Li ions around 5.17%.

Conventionally, a film of TiO2 particles of ~300 nm size is employed in DSCs as the back reflector film to enhance the light harvesting. In this study, two electrolytes with different transparencies, iodide-based and cobalt-based electrolytes, were used to investigate the transparency effect of electrolytes on light back-scattering from back scattering layer and also to study its effect on the performance of DSCs. The use of cobalt-based electrolyte is recommended from the view point of optical properties as due to the light absorption in electrolytes, the current density losses are 2.9mA/cm2 and 4.2 mA/cm2 in cobalt- and iodide-based electrolytes, respectively, and the transmission of 100% is observed for cobalt-based electrolyte in 500-600 nm in spite of iodide-based electrolyte. Use of light back-scattering layer, unlike iodide-based cell, causes external quantum efficiency in cobalt-base cell to increase for the wavelengths lower than 350 nm since cobalt-base electrolyte has transparency in this region. In addition, optical calculations demonstrate that in the range 400-500 nm, in which dye has a noticeable absorption, absorption loss is 40% and 30% for iodide- and cobalt-based electrolytes, respectively.

In this paper we synthesized two new organic days (dye 1 and dye 2) based on thioindigo with phenothiazine as the electron donor group. We used acrylic acid and cyanoacrylic acid as the electron acceptor anchoring group in dye 1 and dye 2 respectively. The proposed dyes were synthesized from phenothiazine as the starting material by standard reactions and characterized by different techniques such as melting point، FTIR، 1HNMR، elemental analysis and UV-Visible spectroscopy after purification. Spectrophotometric measurements of the synthesized dyes in solution and on a TiO2 substrate were carried out in order to assess changes in the status of the dyes. The wavelength of maximum absorption for dye1 and dye 2 in solution are 499 nm and 505 nm and on TiO2 films are 523 nm and 527 nm، respectively. Finally، the proposed dyes used as sensitizer in a dye solar cell structure and their photovoltaic properties investigated. The Conversion efficiency for dye 1 and dye 2 are 2. 34% and 3. 07%، respectively.

Dye-sensitized solar cells based on ordered mesoporous TiO2 films were fabricated by sol-gel technique. X-ray diffraction (XRD) analysis revealed that anatase phase was crystallized at 300 °C with initially crystallite size 3.2 nm and the crystallization was improved to 700 °C. Surface area analysis showed that the specific surface area of the films decreased from 163.43 to 87.15 m2/g and the pore size increased from 5.05 to 8.75 nm as the annealing temperature increased from 400 to 600 °C. The transmittance spectra that measured by UV/Vis spectrophotometer revealed that the transmittance maxima of the films decreased in the visible region and the absorption edges shifted to longer wavelengths. Photovoltaic measurements showed that the power conversion efficiency of the films initially enhanced to the maximum value of 3.61% with the increasing film thickness to 1.7 μm and then declined when the film thickness increased further.

Two new organic dyes based on indoline were prepared and phenothiazine was utilized as the electron donor and cyanoacrylic acid as the electron acceptor anchoring groups. All synthesized dyes prepared by standard reactions from phenothiazine as the starting material. To this end, phenothiazine as the starting material was alkylated, further aminated with POCl3 and subsequently nitrated with nitric acid. The obtained compounds were reacted with cyano acetic acid to prepare synthesis dyes. These dyes together with their corresponding intermediates were purified and characterized by FTIR, 1HNMR, 13CNMR, elemental analysis and UV-Visible analytical techniques. Spectrophotometric evaluations of the prepared dyes in solution and on a TiO2 substrate were carried out in order to assess changes in the status of the dyes. The wavelength of maximum absorption for each dyes in solution are 405 nm and 417 nm and on TiO2 films are 422nm and 436 nm, respectively. Finally, dye sensitized solar cells were fabricated in order to determine the current density/photovoltage curves and conversion efficiencies of each dye. The conversion efficiency for each dyes were 3.21% and 3.87%, respectively.

In this study, SiO2/ TiO2/ zeolite tertiary composites with (STZ) high adsorption capability and high photocatalytic activity were synthesized by immobilizing mixed silica and titanium dioxide nanoparticles on modified zeolite via sol-gel method. The characteristics of chemistry and morphology of composites were investigated by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Addition of silica particles enhanced the uniform dispersion of titanium dioxide nanoparticles on modified zeolite by changing in surface charge of zeolite.Furthermore, FTIR spectra showed successful immobilizingof SiO2 and TiO2nanoparticlesinto the zeolite with AL (IV) and Si-O-Ti bonds. Surface area of the composites increased significantly after immobilizing of silica and titanium dioxide nanoparticles, and thus greatly improved the photodegradation efficiency. The optimal condition for complete decolorization with STZ0.2-0.4 and STZ 0.4-0.2 composites was found in 30 min.

In this research, a novel dye based on N-allylnaphthalimide containing thiourea was synthesized and its properties as fluorescent sensor and colorimetry for fluoride ion were studied in DMF solution. Results reveal that the fluorescence emissions of the dye were only ‘switched off ‘in the presence of fluoride ion. The dye also showed remarkable spectral shifts in visible region by adding the fluoride ions, also, green-yellow to purple color changes occurs. Thus it could serve as a colorimetric and fluorescent sensor for fluoride ion.