Optimizing enzymatic dyeing of wool and leather

This work reports on the environmental friendly enzymatic dyeing of wool and leather performed at low temperature and mild pH conditions without any dyeing auxiliaries. The substrates have been dyed with “in situ” generated pigment by means of laccase-catalyzed oxidative coupling of dye modifier 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and dye precursor 1,3-benzenediol in a batchwise process. The process reaction variables (laccase, precursor and modifier concentrations, temperature and dyeing time) were optimized by response surface methodology using an appropriate experimental design. The temperature, precursor concentration, interaction between precursor and modifier and time are the most important factors in the dyeing process. The best-optimized wool dyeing conditions (2 h reaction time, 50 μl laccase (0.1 U), 500 mM precursor, 10 mM modifier at 40 °C) were then successfully applied onto leather material. The enzymatic-dyeing optimized process can be successfully performed on wool and leather at low temperature and mild pH obtaining different hues and depths of shades by varying the modifier concentration and time. The colouring enzymatic system has a good reusability (which has a huge advantage in terms of cost reduction) and washing durability and is comparable in terms of fastness properties to the traditional dyeing process for both wool and leather.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for funding the project UID/CTM/00264/2019 and A. Zille contract IF/00071/2015

Durable Antibacterial Finishing on Organic Cotton by Inclusion of Thymol into Cyclodextrin Derivative

Antibacterial finish was done on organic cotton by incorporation of thymol into monochlorotriazinyl-β-cyclodextrin. Fabric was modified with cyclodextrin derivative in alkaline condition. UV-Visible and FT-IR studies confirmed the presence of cyclodextrin derivative and thymol on modified fabric. The level of thymol entrapped into the fabric was determined quantitatively by HPLC analysis. Agar diffusion test was carried for unwashed and washed fabric against gram positive (S. aureus) and gram negative (E. coli) bacteria. The investigation revealed that modification of fabric with monochlorotriazinyl-β-cyclodextrin retained the antibacterial property even after 10 washing process

Decolorisation of exhausted reactive dye bath using ozonator for reuse

Exhausted Reactive dye bath samples of Turquoise Blue, Olive Green and Navy Blue shades were collected from cotton knit wear dyeing units in Tirupur. Ozonation was conducted in a column reactor system fed with ozone at the rate of 0.16 g/min to assess its efficiency in reducing the color, chemical oxygen demand and total organic carbon. Complete decolorization of the effluent was achieved in 10 min contact time and ozone consumption of 153 mg/ L for Turquoise Blue, 128 for Olive Green and 143 for Navy Blue shades effluents respectively. The corresponding COD removal was 43 %, 44 % and 43 % for the three shades while TOC removal efficiency was 45 %, 45 % and 40% respectively. The results from the reusability studies indicate that the dyeing quality was not affected by the reuse of decolorized dye bath for two successive cycles. It is concluded that ozonation is efficient in decolorization of exhausted dye bath effluents containing conventional reactive dyes. However, the corresponding removal of COD from the textile effluent was not significant

Influence of Ethanolic Plant Extracts on Morphology and Size Distribution of Sol‐Gel Prepared TiO 2

The influence of ethanolic extracts of three common plants (Equisetum arvense, Syzygium aromaticum and Camellia sinensis) on the morphology and size distribution of TiO2 nanoparticles prepared using the sol-gel method is presented. The phytochemicals extracted from the plants acted as surfactants, modifying the growth mechanism and stabilizing high-quality small, quasi-spherical, non-aggregated TiO2 nanoparticles with sizes in the range from 20–50 nm. The most satisfactory result was achieved using extracts of E. arvense. The structural, morphological, and optical properties of TiO2 nanoparticles prepared using E. arvense ethanolic extracts are discussed. After thermal treatment at 550 °C, the TiO2 nanoparticles were present only in the anatase crystalline phase, with a bandgap of 3.27 eV, as confirmed by X-ray diffraction and UV-vis analyses, respectively. These small morphologically homogeneous TiO2 nanoparticles stabilized by low-cost, abundant and eco-friendly capping agents may be useful as components in photovoltaic cells, pharmaceutical and cosmetic products, as well as for photocatalytic uses.Fil: Rodríguez Jiménez, Rafael Aurelio. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Panecatl Bernal, Yesmin. Universidad Interserrana del Estado de Puebla-Ahuacatlán; MéxicoFil: Carrillo López, Jesús. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Méndez Rojas, Miguel Ángel. Universidad de las Américas Puebla; MéxicoFil: Romero López, Anabel. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Pacio Castillo, Mauricio. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Vivaldo, Israel. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Morales Sánchez, Alfredo. Instituto Nacional de Astrofísica; MéxicoFil: Arce, Roberto Delio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Caram, Jorge Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Villanueva-Cab, Julio. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Alvarado, Joaquín. Benemérita Universidad Autónoma de Puebla; Méxic