Effect Of Dye Molecules Research Articles

Effect of dye molecules and electrode material on the settling behavior of flocs in an electrocoagulation induced settling tank reactor (EISTR)

A simple electrocoagulation induced settling tank reactor (EISTR) was fabricated to study the dye removal and sedimentation kinetics of Amido Black 10B (AB), Methyl Violet (MV), Eosin Yellow (EY), Malachite Green (MG), Methylene Blue (MB), Rhodamine 6G (R6G), their binary, tertiary mixtures and actual textile effluent. Optimum conditions such as current density, electrolysis time, initial pH and NaCl concentration to achieve high color removal efficiency (CRE) and sludge settling velocity were evaluated for the removal of 100mg/L AB dye. The CRE and chemical oxygen demand (COD) reduction, initial sludge settling velocity, final sludge height and turbidity reduction were measured. These experiments indicate that 81–99% CRE, 54–68% COD reduction and 73–88% turbidity reduction can be achieved for the synthetic as well as textile dye wastewater systems. Around 3.8Ah of charge loading per gram of dye was found to be sufficient for high CRE and satisfactory sedimentation kinetics for most of the dyes. The energy requirement was found to be 24±3Whg−1 of dye molecule. Fe electrodes perform better when compared to Al electrode in similar operating conditions. XRD and SEM studies indicate that relatively large porous low density aluminum hydroxide flocs formed under the induced sedimentation conditions do not settle effectively. Relatively smaller and denser iron hydroxide flocs generated using Fe electrode leads to relatively better performance.

The Effect of Dye Molecules and Surface Plasmons in Photon-Induced Hot Electron Flows Detected on Au/TiO2 Nanodiodes

We report the combined influence of dye molecules and surface plasmons on hot electron flows generated by the absorption of photons. The study was enabled by the deposition of merbromin and rhodamin B on Au/TiO2 Schottky diodes that exhibit connected island-shaped gold thin films. The short-circuit photocurrent and incident photon-to-electron conversion efficiency (IPCE) measured on Au/TiO2 diodes show significant amplification of the photocurrent when the dye molecules are present on the modified Au islands/TiO2, indicating that the combination of dye molecules and surface plasmons increases the energy conversion efficiency. The positions of the IPCE peaks are in good agreement with the absorbance spectrum of the dye molecules and surface plasmons, suggesting that the detection of hot electron flows can be used as a novel sensing mechanism to characterize charge transport through organic–inorganic and metal–oxide interfaces.

Surface anchoring effect on guest–host ferroelectric liquid crystal response time – an electro-optical investigation

The effect is reported of surface anchoring on various electro-optical parameters of a pure ferroelectric liquid crystal (FLC) and five mixtures with different concentrations of dye. The Anthraquinone D5 dye was used as guest entity, whereas Felix 17-000 was used as host in this investigation. The presence of dye molecules in the FLC dramatically affects the electro-optical properties compared with those of the pure system. Electro-optical parameters such as spontaneous polarization and rotational viscosity not only change with the addition of dye but they are also strongly dependent on the concentration of dye in pure FLC. The effect of dye molecules on the anchoring energy of the pure FLC system was also investigated. Due to strong anchoring energy on FLC substrate, its effect on response time was also studied. An improvement in the contrast ratio after dye doping was observed. The value of spontaneous polarization increases due to addition of dye, suggesting that molecular alignment improves, which is very useful from the application point of view.

The effect of dye molecules in titania‐silica hybrid coatings for corrosion protection

PurposeThe purpose of this paper is to develop a corrosion resistant zinc‐free coating for interstitial free steel.Design/methodology/approachThe objective was achieved by developing a titania‐silica hybrid coating through a sol‐gel process by incorporating a dye molecule. The role of dye molecules was particularly important for enhancing the anti‐corrosion properties of the coating. The approach of current research was to develop a low‐temperature coating process that can bring similar performance to that obtained in case of zinc coating. Titania and silica precursors were mixed by stirring under a nitrogen atmosphere at 80°C to formulate a low‐temperature coating. The dye molecules were added before addition of water for subsequent hydrolysis. This complete formulation was applied over steel sheets using a roll coater as the application method.FindingsThe ranking order of improved corrosion resistance was found to be PATMS>EETMS>GPTMS and the addition of trace amount of tartrazine dye (60‐65 mg/l of liquid) in PATMS increased the corrosion service life in saline environments from 168 to 216 h, thus showing a promising improvement. Scanning Kelvin Probe results indicated that the corrosion reaction is controlled cathodically in presence of dye and, electrochemical impedance spectroscopy results exhibited a charge transfer resistance (Ct) of coating with dye of 419Ω cm2, which was higher than that of a similar coating without dye (360Ω cm2), indicating increased corrosion protection.Research limitations/implicationsThis coating had improved barrier protection but lacked cut edge protection. Future work will focus on adding sacrificial protection by introducing compatible corrosion inhibitors, especially dye molecules, which are photosensitive.Practical implicationsThis coating has huge potential for use in the automotive sector, especially for certain automotive parts (i.e. helm flanges), which suffer from poor durability in salty and high‐humidity atmospheres.Social implicationsSince this coating formulation utilises a partially aqueous base, some environmental impact cannot be avoided, but it will have less impact than a complete solvent base formulation.Originality/valueThe novelty of the work was the introduction of dye molecules as the corrosion inhibitor and their compatibility in the hybrid coating system.

Coupling Between Plasmonic Resonances in Nanoparticles and Porphyrins Molecules

A driving force for the growing interest in nanoassemblies is the use of nanoparticles linked to organic molecules. The goal of our research is to investigate the coupling of gold and silver nanoparticles (GNP and AgNP) with porphyrins molecules. We prepared water-soluble GNP and AgNP by reducing the noble metal complex salt with sodium citrate. The exchange of the initial ligand (citrate ions) with porphyrins formed hybrid nanostructures and change the electronic properties of GNP and AgNP. We highlighted the importance of the pH value to obtain the coupling of nanoparticles and porphyrins. We have shown that the absorption spectra of AgNP have a strong overlap with that of porphyrins. The effect of dye molecules on the plasmon properties of nanoparticles was demonstrated by UV-Vis, fluorescence and electrochemical spectroscopy (OTTLE cell). These new hybrid materials will be helpful for the design of light harvesting cells and sensors.

Effect of dye molecules on black film stability and property of aqueous core phase

The black soap films of cationic surfactant cetyltrimethylammonium bromide with three kinds of dye molecules have been investigated using UV-Vis spectroscopy. The film stability is greatly improved with the addition of anionic dye and is relevant to the number of negative charges of the dye molecule and the distance between the negatively charged groups in the molecular system. The neutral and anionic dye molecules increase the monolayer cohesion to promote film stability. The aqueous core phases in the black soap films show a specific microenvironment different from that on the corresponding micellar surfaces.