JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2017 | Volume:11 | Issue:3 |Papers Count:7

In this study, a novel colorimetric chemosensor based on quinazolinone was designed and synthesized for the detection of Cu2+ ions. The structure of synthesized chemosensor (C) was confirmed by Fourrier Transform Infrared (FT-IR), Proton Nuclear Magnetic Resonance (1H NMR) and Carbon Nuclear Magnetic Resonance (13C NMR) spectroscopies. The chemosensor C showed a high selectivity and sensitivity for the detection of Cu2+ ion over the other tested anions and cations in acetonitrile-water solution. Interaction of C with Cu2+ provides remarkable colorimetric change from colorless to yellow, enabling naked-eye detection without any spectroscopic instrumentation. Also, the sensing details were evaluated using UV-Vis spectroscopy. Furthermore, Job’s plot based on spectroscopic data showed one-to-one stoichiometry for the interaction of chemosensor of Cu2+ cation with chemosensor C. Furthermore, the detection limit of chemosensor C towards Cu2+ ions was found to be 67.5 mM.

The first report of Graphene Quantum Dots (GQDs) as novel and highly efficient nano materials for degradation of Arsenazo (III) dye under visible light, is presented here. Preparation of GQDs was carried out by pyrolyzing method. The transition electron microscopy (TEM) and UV–Vis spectroscopy were used for characterizing the GQDs. Effect of the experimental parameters such as pH of dye solution, contact time, concentration of Arsenazo (III) dye and amount of GQDs on the degradation efficiency of dye were studied. The removal efficiency in optimum conditions including pH=4 contact time=120 minutes, the concentration of dye= 45 mg.L-1 and in presence 600 mL GQDs, was observed More than 90%. In general, GQDs had a good performance in dye removal. Finally, the kinetic model for degradation of Arsenazo (III) in the presence of GQDs was discussed. The possible mechanism of visible light photocatalytic degradation is also proposed.

In this study, poly (amidoamine) G-2 dendrimer (PAMAM-G2) were applied as adsorbents for the removal of the dye from the effluent containing dye basic violet 16 (BV16). With increasing pH, contact time and initial dye concentration, increased absorption capacity qe., While the amount of adsorbent, the adsorption capacity was inversely. Which can be attributed to reduced competition among dye molecules to bind to the sorbent. The optimum conditions for dye absorption was determined at pH 11.8, the amount of absorbent 0.6 gr.L-1, dye concentration 40 mg.l-1 and contact time 100 min. Among the factors studied, pH has provided the greatest impact on the absorption capacity and the percentage of dye removal. So that by changing the pH from 8 to 11.8, increased the percentage of dye removal from 68 mg.gr-1 to 102 mg.gr-1. Isotherm equilibrium was consistent with Langmuir isotherm models, Freundlich and Temkin. The results show good agreement with Langmuir isotherm model with a correlation coefficient 0.994 and the maximum absorption capacity was evaluated at optimal conditions mg.g-1 114.38. For adsorption kinetics data, was used three models Pseudo-first-order, pseudo-second-order and influence between the particles. The sorption kinetics in the absorption process followed the pseudo-second-order and intraparticle diffusion models. That is very close to the experimental value, and represents the ability to control the absorption process by chemical agent concentration and intraparticle diffusion. The results indicate the proper efficiency and absorption capacity in removal of BV16 by the PAMAM-G2 dendrimer.

In this research, graphene oxide (GO) was deposited on the surface of graphite electrodes by the electrodeposition (ED) method which was synthesized by the modified Hummer’s method. FESEM images, FTIR analysis and XRD pattern were employed to confirm the structure of GO. TiO2 nanoparticles were further immobilized on the surface of the graphene oxide fabricated graphite electrodes (TiO2-GO-GE) using solvent evaporation and then photocatalytic activity of the prepared TiO2-GO-CE was studied for the discoloration of solutions containing Methylene Blue (MB) cationic dye. The effect of parameters such as initial dye concentration, pH of solution and TiO2 content on the decolorization efficiency of the photocatalytic process was investigated. The obtained results indicated that the prepared TiO2-GO-GE can decolorize MB with high efficiency (90%) after 120 min of photocatalytic process. Stability test was carried out in order to show important role of GO. Then, response surface methodology (RSM) method was employed to optimize photocatalytic process and examine simultaneous effect of parameters. The validity of the model for optimization and prediction of the process with low number of experiments was stablished by experimental results (low difference between predicted value (80.56%) and experimental value (76.47%)) and also by high value of correlation coefficient (96.87%).

6, 8-dichloro-4-hydroxyquinolin-2 (1H)-one (2) was prepared by thermal cyclocondensation reaction of N, Nʹ-bis (2, 4-dichlorophenyl) malonamide (1) at 140-150oC in polyphosphoric acid in a satisfactory yield. This compound as an enol type coupling component was then coupled with diazonium salts of some aromatic amines to synthesis of azo dyes (3)-(9). The structures of the compounds were elucidated using spectral methods FT-IR, 1H NMR and UV-vis. The effects of six organic solvents (acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide and dimethyl sulfoxide), pH and substituents of the diazotizing components on the maximum absorption wavelength of the colorants were discussed and evaluated.

In this research chromium doped malayaite (CaSn(1-x)CrxSiO5) was synthesized as a ceramic red pigment by ceramic method at 1250oC. Four samples of malayaite were synthesized having 0.005, 0.0075, 0.01 and 0.02 molar ratio of chromium and were dispersed in 2-ethyl hexyl stearate by a satellite milling system. The dispersed pigments were printed on the ceramic by silk screen printing method in the industrial situation. The samples were analyzed by XRD, SEM, DRS (Diffuse Reflectance Spectroscopy) and CIE L*a*b* colorimetric system. It was found that change of the amount of chromium concentration from 0.005 to 0.02 in the structure, changes not only the color of the pigment, but also the average particle size and the shape of particles. The shape of the particles changed to rod like particles and the mean diameter of rods was reduced from 500 nm to 150 nm after increasing the concentration of chromium dopant. The printed ceramic were analyzed by SEM and CIE L*a*b* colorimetric system. The mean particle size of the pigments on the printed ceramic was measured less than 100nm.

The ZnCoAl layered double hydroxide (LDH) was synthesized by coprecipitation method. The as-prepared sample were characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). Response surface methodology (RSM) was used to optimize, model and investigate the effect of operational parameters, namely LDH dosage, initial dye concentration, pH and time. Optimal experimental conditions for highest removal efficiency were found as [LDH] = 0.4 g/L, [Dye] = 112 mg/L, pH = 4.8 and Time = 66 min. The predicted degradation efficiency under the optimal conditions was 195 mg g-1. The proposed model was in accordance with the experimental results with R2 of 98.9% and adj-R2 of 97.9%. Equilibrium data were well-represented by the Freundlich isotherm model with Kf = 14.74 which confirms multi-layer adsorption. Kinetic studies showed that pseudo second order model describes the adsorption kinetic behavior well.