JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2007 | Volume:1 | Issue:1|Papers Count:6

In this research, decolorization and mineralization of Basic Blue 41 (BB 41) were investigated by nanophotocatalytic process using immobilized titania nanoparticles in a batch photoreactor. Photocatalytic decolorization and mineralization processes of dye solutions were performed at pilot scale (10 L). To obtain the details of the photocatalytic degradation of BB 41, UV-Vis and Ion Chromatography (IC) analyses were employed. The effects of major variables governing the efficiency of the process such as H2O2 dosage, dye concentration and anions (NO3-, Cl-, SO42-, HCO3- and CO32-) were investigated. Kinetic analysis indicates that the photocatalytic decolorization rates can usually be approximated first-order model. The nitrate and sulfate anions were measured as photocatalytic mineralization products of BB 41. The results show that the employment of desired operational parameters may lead to complete decolorization and mineralization of BB 41 at pilot scale.

Bitumen is a very important component of anti-corrosion coatings and water proofing membranes which has found many applications. Depending on the application, bitumens have different compositions and physico-chemical properties. Softer bitumen is usually air-blown to adjust the physical properties of the final bitumen. Here, preparation of 60/70, 85/25 and 90/15 bitumens was achieved via physical mixing of air-blown 110/10 bitumen with 85/100 penetration grade and heavy-vacuum slops (HVS) cut. The softening point of the resulting bitumen changes with the asphaltenes’ content, whereas its penetration varies exponentially. This difference in behavior was attributed to the shear forces applied during the tests and was account for via the bitumen viscosity and cohesive energy acting between asphaltenes. Finally, some formulations for the target bitumens were reported via mixing of the above-mentioned raw-materials.

In this work, the behavior of leuco solutions of vat dye was studied by using their spectrophotometeric data. Initially, the leuco solutions of C.I.Vat Green 1 were prepared with different concentration of sodium hydrosulfite and soda. Then, the absorbance spectral of leuco solutions were measured by spectrophotometer. The relationship between color and absorbance of leuco solution and concentration of soda and sodium hydrosulfite was studied. The obtained result shows, that the color and absorbance of leuco solution depend on the amount of soda and sodium hydrosulfite. Beside, the reduction properties of sodium hydrosulfite depend on the concentration of soda. Subsequently, the leuco solution was simulated by using subtractive color mixing low.

The paper reports on the synthesis of water-based alkyd resins and preparation of corresponding water-based paints. Several routes were adapted in the synthesis of alkyd resins. In the first route, non-modified alkyd resins were synthesized at first and then a mixture of the vinyl monomers was grafted on the fatty acid moiety of the alkyd resin via peroxide initiated polyaddition polymerization. In the second route, the vinyl monomers were grafted on fatty acid via peroxide initiated polyaddition polymerization and in the next step the grafted fatty acid was incorporated in the alkyd resin structure through polycondensation polymerization. In the third route, two different methods were adapted. In the first method, the grafted alkyd resins obtained from the first and second routes were reacted with a polyethylene glycol resin (PEG). In the second method, a non-grafted alkyd resin was reacted with PEG and then a mixture of monomers was grafted on fatty acid moiety of the prepared alkyd. Drying time of the films of the prepared resins and paints is similar to that of the solvent-based alkyd resins. The aqueous dispersions of these resins suspend high enough finely-divided titanium dioxide pigment. The gloss of the dried paint film is also high enough. Use of maleic anhydride as dispersing agent is the novelty of this work which is reported for the first time.

Er doped ZnO layers have many applications in optical communications. Transparent Er-doped ZnO thin films were deposited on soda-lime glass substrates by sol-gel method. To optimize the properties, different amounts of Er dopant and temperatures were used. The prepared nano-layers were characterized by XRD and spectrophotometery. All coatings showed ZnO hexagonal wurtzite crystal structure with 14-19nm particle size and very good transmittance (>80%) in the range of 750-1750 nm. The maximum optical transmission was achieved by ZnO film doped with 3.0 wt.% Er and post-heat-treated in air at 550oC.

In the present work, ratio spectra derivative method (p-p) was used in order to determine the dye contents in different bicomponent dye mixtures prepared with three dyes of yellow, scarlet and red colors. The difference between neighboring extremmum values at derivative ratio spectra of bicomponent mixtures of the dyes were used for determination of dye content. The obtained recovery factor, absolute error and relative error by using the proposed derivative technique and normal methods were 99.287, 0.000033, 1.118 and 112.82, 0.00622, 22.693 respectively. The analysis of obtained results via the proposed derivative and normal methods show higher accuracy of the developed method in determination of bicomponent dye solutions.