Ultrasound-assisted extraction of natural dye from Swietenia mahagoni and its application on silk fabric

The current study deals with the extraction of natural dyes from the flower of the Sweitenia mahagoni plant by ultrasound-assisted extraction method using ethanol as solvent. Box-Behnken design has been employed to optimize and investigate the effect of three independent variables (sample-solvent ratio, sonication time and extraction temperature) on the natural dye yield. The results reveal that the experimental data are fitted to a second-order polynomial equation using multiple regression analysis with high coefficient of determination value (R2> 0.98, Adj. R² >0.96 & Pred. R² >0.81). Optimal extraction conditions for the dyes yield are: sample-solvent ratio 1/20 g/mL, sonication time 30 min and extraction temperature 50°C. Under these conditions, the highest dyes yield is predicted to be 0.855%. FTIR spectroscopy has been used to identify the major chemical group in the extracted dye. Further, dyeing of silk fabric has been carried out by an exhausted dyeing method and the dyeing property and fastness properties of the dyed samples are also assessed

Ultrasound-assisted extraction of natural dye from Swietenia mahagoni and its application on silk fabric

69-77The current study deals with the extraction of natural dyes from the flower of the Sweitenia mahagoni plant by ultrasound-assisted extraction method using ethanol as solvent. Box-Behnken design has been employed to optimize and investigate the effect of three independent variables (sample-solvent ratio, sonication time and extraction temperature) on the natural dye yield. The results reveal that the experimental data are fitted to a second-order polynomial equation using multiple regression analysis with high coefficient of determination value (R2> 0.98, Adj. R² >0.96 & Pred. R² >0.81). Optimal extraction conditions for the dyes yield are: sample-solvent ratio 1/20 g/mL, sonication time 30 min and extraction temperature 50°C. Under these conditions, the highest dyes yield is predicted to be 0.855%. FTIR spectroscopy has been used to identify the major chemical group in the extracted dye. Further, dyeing of silk fabric has been carried out by an exhausted dyeing method and the dyeing property and fastness properties of the dyed samples are also assessed

Hydrothermal synthesis of cobalt substitute zinc-ferrite (Co1-xZnxFe2O4) nanodot, functionalised by polyaniline with enhanced photocatalytic activity under visible light irradiation

Fabrication and development of effective visible-light-responsive photocatalysts are required to tackle critical environmental issues. The aim of this study was to develop a nanocomposite material with improved photocatalytic activity for the degradation of industrial dyes such as Reactive Orange-16 (RO-16), Reactive Blue (RB-222), Reactive Yellow-145 (RY-145), and Disperse Red-1 (DR-1) without the need for a post-separation process after use. Here we report the hydrothermal synthesis of nanodots of Co1-xZnxFe2O4 (x = 0.3, 0.5 and 0.7), coated with polyaniline, by in situ polymerization. The Co1-xZnxFe2O4 nanodots, coated with polyaniline (PANI) nanograins, facilitated optical properties by easily capturing visible light. X-ray Diffraction (XRD) patterns and Scanning Electron Microscopy (SEM) images have confirmed the single-phase spinel structure of Co1-xZnxFe2O4 nanodot and nano-pore size of the Co1-xZnxFe2O4/PANI nanophotocatalyst. The specific surface area of the Brunauer–Emmett–Teller (BET) of the Co1-xZnxFe2O4/PANI photocatalyst was determined to be 24.50 m2/g by multipoint analysis. The final Co1-xZnxFe2O4/PANI (x = 0.5) nanophotocatalyst showed high efficiency in the catalytic degradation of toxic dyes (∼98% within 5 min), with good mechanical stability and recyclability under visible light irradiation. The nanophotocatalyst was re-used and its efficiency was largely maintained, even after seven cycles (∼82%) of degradation. The effects of various parameters, such as initial dye concentration, nanophotocatalyst concentration, initial pH of dye solution, and reaction kinetics were studied. According to the Pseudo-first-order kinetic model, photodegradation data followed the first-order reaction rate (R2 > 0.95) of degradation of dyes. In conclusion, a simple and low-cost synthesis process, speedy degradation and excellent stability of polyaniline-coated Co1-xZnxFe2O4 nanophotocatalyst could be used as a promising photocatalyst for dye-wastewater treatment

Facile extraction and characterization of calcium hydroxide from paper mill waste sludge of Bangladesh

Herein, paper mill waste sludge (PMS) from two different sources has been investigated to extract calcium hydroxide, Ca(OH)2 by a facile and inexpensive extraction process. PMS samples, collected from local paper mill plants of Bangladesh, were the main precursors wherein HCl and NaOH were used for chemical treatment. The as-synthesized products were analysed by a variety of characterization tools including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) elemental analyses. Our studies confirm that the extracted product contains Ca(OH)2 as a major content, albeit it also includes CaCO3 phase owing to the inescapable carbonation process from the surrounding environment. The particle size of the synthesized products is in the range of 450–500 nm estimated from SEM micrographs. The crystallite domain size of the same estimated from XRD analyses and was found to be approximately 47 and 31 nm respectively for product-A and product-B considering major (101) Bragg peak of Ca(OH)2. The yield percentage of the isolated products is about 65% for samples collected from both sources