Study on Exhaustion Behaviour of Red Chili on Cotton Fabric

Dying is a popular practice in textile industry which is prevalent at all parts of the world from the period of ancient civilization. Initially, natural dyes i.e. dye derived from natural resources like vegetables, flowers, minerals, plants etc. were used. Now-a-days, due to technological and scientific innovations synthetic dyes are processed at large scale in the laboratories as it is still one of the most profitable industry globally. However, the rapid utilization of chemicals in textile industry for production of synthetic dyes causes degradation of environment like soil pollution, water pollution etc. Hence, it is necessary to promote the utilization of natural dyes globally. In this paper, the exhaustion of dye extracted from red chillies, one of the most used vegetables same has been studied on cotton fabrics at different temperatures using UV-Visible light spectrophotometer. The colour strength of the fabric before and after application of soap therein are also studied experimentally. Keywords: Natural dye, red chillies, cotton fabrics, exhaustion of dye, absorption.

Enhancement of Charge Transport of a Dye-Sensitized Solar Cell Utilizing TiO2 Quantum Dot Photoelectrode Film

A dye-sensitized solar cell (DSC) is the third generation of solar technology, utilizing TiO2 nanoparticles with sizes of 20–30 nm as the photoelectrode material. The integration of smaller nanoparticles has the advantage of providing a larger surface area, yet the presence of grain boundaries is inevitable, resulting in a higher probability of electron trapping. This study reports on the improvement of charge transport through the integration of quantum dot (QD) TiO2 with a size of less than 10 nm as the dye absorption photoelectrode layer. The QD TiO2 samples were synthesized through sol–gel and reflux methods in a controlled pH solution without surfactants. The synthesized samples were analyzed using microscopic, diffraction, absorption, as well as spectroscopic analyses. A current–voltage and impedance analysis was used to evaluate the performance of a DSC integrated with synthesized TiO2 as the photoelectrode material. The sample with smaller crystallite structures led to a large surface area and exhibited a higher dye absorption capability. Interestingly, a DSC integrated with QD TiO2 showed a higher steady-state electron density and a lower electron recombination rate. The shallow distribution of the trap state led to an improvement of the electron trapping/de-trapping process between the Fermi level and the conduction band of oxide photoelectrode material, hence improving the lifetime of generated electrons and the overall performance of the DSC.

Synthesis and Characterization of Solid-state Fe-exchanged Nano-bentonite and Evaluation of Methyl Orange Adsorption

A new adsorbent was synthesized using ion-exchange between iron salts and bentonite modified with acetyl trimethylammonium bromide (CTAB) in the solid phase. Ion exchange was performed in the solid-state at a temperature of 100 ° C for 2 min. Various analyzes such as X-ray diffraction (XRD), scanning electron microscopy (SEM), porosity measurement (BET), infrared Fourier transform (FT-IR), transmission electron microscopy (TEM), X-ray energy diffraction (EDX), and thermal weighing (TGA) were used to characterize the synthesized nano-adsorbents. Under optimal conditions (pH = 7, time 60 min, concentration of dye solution 150 ppm, and amount of nano-adsorbent 0.75 g / l), the modified nano-adsorbent absorbed 73% of the methyl orange (MO) dye. Adsorption isotherm studies and kinetic model showed that the pseudo-second-order model and Langmuir equation agree with the obtained results. After three reductions of the modified nano-adsorbent in the photo-Fenton process, the dye absorption percentage was 69.50%.

Study of the Effect of Solvent Polarity on Transitions of Absorption and Fluorescence Spectrum of a Erythrosine Dye

In this paper, the absorption and fluorescence spectra of Erythrosine dye laser liquid solution dissolved with acetone and ethanol solution were studied in different concentrations (10-3, 10-4, 10-4 M). The results showed an increase in absorption and fluorescence intensity by increasing polarity of the solvent. Some of the linear optical properties of the prepared models were also studied. The results showed an increase in the absorbance, linear refractive index, and linear absorption coefficient with an increase in solvent polarity and the molar concentration against a decrease in the permeability value, as well as the quantitative production efficiency was calculated based on the results of the absorption spectra and fluoridation. The Purpose of the search Study the effect of solvent polarity on both absorption and fluorescence spectra, and on linear and electrical optical properties. Keywords: Erythrosine Laser dye, absorption, fluorescence spectra and Polar solvents (acetone and ethanol).

Halloysite and Laponite Hybrid Pigments Synthesis with Copper Chlorophyll

Sustainable and green materials have been studied in dye and pigment productions to reduce their environment impacts from being produced and applied. Although natural dyes are an excellent choice to move from agrowaste, some improvements must be made before they are applied given their poor fastness. One way of improving natural dye properties is their adsorption into nanoclay structures to give hybrid pigments. This work used tubular halloysite and laminar laponite to adsorb and stabilize natural copper chlorophyll. With a statistical design of experiments, we observed interactions between synthesis factors, such as pH, ionic strength, and surfactant or silane modification. Cool hybrid pigments with high TSR (%) values and a wide color range were obtained by using dispersions with only distilled water at room temperature. Successful chlorophyll adsorption on both nanoclay surfaces took place by XRD and DTA analyses. The maximum natural dye absorption for both nanoclay types took place under acid conditions, pH 3–4, and in the presence of mordant. The TSR (%) improved by the silane pH interaction, and halloysite hybrid pigments obtained higher TSR values than the laponite ones. Finally, a wide chromatic green color range was obtained with the surfactant modification in both nanoclays, and the color fastening was also improved in the hybrid pigments application. The samples generated with 10% of hybrid pigments from both nanoclays and an Epoxy bioresin, show higher colorfastness than the sample with the natural chlorophyll, due to the nanoclays–dye interaction and protection.

ENHANCEMENT OF DYE ABSORPTION OF COTTON FABRIC THROUGH OPTIMIZATION OF BIOPOLYMER TREATMENT

"Environmental pressure is pushing towards the ‘green’ alternatives to synthetic or petro-chemically derived products. Biopolymers are replacement materials suitable for different chemical processes. The surface modification of textile fibres using biopolymers is considered as the best route for modern textile treatments, to minimize the generation of wastewater containing salts, unfixed dye and other chemicals, which may affect the environment and human health. To avoid these problems, the pretreatment of cotton with biopolymers is a safe option in eco-friendly dyeing. In the present work, chitosan was selected for application on cotton textile for improving its dyeing efficiency with natural dye (onion skin). Chitosan is a versatile polycationic polysaccharide possessing hydroxyl and amino functional groups, which can easily be fabricated with desired functional properties. The chitosan treatment was standardized on the basis of dyeing properties, such as percent dye absorption, colour strength (K/S) and wash fastness. When the chitosan treatment was applied with optimized parameters, it was found that the chitosan treated onion skin dyed fabric showed higher dye absorption (66.17%), colour strength (16.52) and wash fastness rating than the alum treated dyed fabric. Thus, the chitosan treatment enhanced the dyeing properties of cotton fabric towards the application of natural dye (onion skin), without using any metallic salt. To conclude, the chitosan treatment is a safe and environmentally benign route to improve the natural dye absorption of cotton fabrics."

Novel Graphene Oxide Nanohybrid Doped Methacrylic Acid Hydrogels for Enhanced Swelling Capability and Cationic Adsorbability

Novel versatile hydrogels were designed and composited based on covalent bond and noncovalent bond self-assembly of poly(methacrylic acid) (PMAA) networks and nanohybrids doped with graphene oxide (GO). The structures and properties of the neat PMAA and the prepared PMAA/GO hydrogels were characterized and analyzed in detail, using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, swelling and cationic absorption, etc. The swelling results showed that the water penetration follows the non-Fick transport mechanism based on swelling kinetics and diffusion theory. The swelling capacity of PMAA and composited PMAA/GO hydrogels toward pH, Na+, Ga2+, and Fe3+ was investigated; the swelling ratio was tunable between 4.44 and 36.44. Taking methylene blue as an example, the adsorption capacity of PMAA/GO hydrogels was studied. Nanohybrid doped GO not only self-associated with PMAA via noncovalent bonding interactions and had a tunable swelling ratio, but also interacted with water molecules via electrostatic repulsion, offering a pH response of both the network and dye absorption. Increases in pH caused a rise in equilibrium swelling ratios and reduced the cumulative cationic dye removal.

The Cell Performances of DSSCs with ZnO Nanorod Electrodes

To date, dye-sensitized solar cells (DSSCs) based on TiO2 nanoparticles have been widely investigated due to their high conversion efficiency. However, constructing TiO2 into a structure of nanorods with a high aspect ratio is difficult to be achieved. On the other hand, nanorod/nanowire arrays may provide some advantages, such as an efficient pathway for electron transport and a larger surface area for dye absorption. ZnO is one kind of metal oxides that can be formed into nanorods easily with various methods. Here, we reported our works on the preparation of ZnO nanorods and investigate its DSSC performance. We found that the cell performance was very affected by the diameter of the nanorods, which may then indicate that charge transfer and charge extraction processes are more effective in the cell with a smaller nanorod diameter.