Colored cotton wastes valuation through thermal and catalytic reforming of pyrolysis vapors (Py-GC/MS)

This study aims to analyze the products of the catalytic pyrolysis of naturally colored cotton residues, type BRS (seeds from Brazil), called BRS-Verde, BRS-Rubi, BRS-Topázio and BRS-Jade. The energy characterization of biomass was evaluated through ultimate and proximate analysis, higher heating value, cellulose, hemicellulose and lignin content, thermogravimetric analysis and apparent density. Analytical pyrolysis was performed at 500 °C in an analytical pyrolyzer from CDS Analytical connected to a gas chromatograph coupled to the mass spectrometer (GC/MS). The pyrolysis vapors were reformed at 300 and 500 °C through thermal and catalytic cracking with zeolites (ZSM-5 and HZSM-5). It has been noticed that pyrolysis vapor reforming at 500 °C promoted partial deoxygenation and cracking reactions, while the catalytic reforming showed better results for the product deoxygenation. The catalyst reforming of pyrolysis products, especially using HZSM-5 at 500 °C, promoted the formation of monoaromatics such as benzene, toluene, xylene and styrene, which are important precursors of polymers, solvents and biofuels. The main influence on the yields of these aromatic products is due to the catalytic activity of ZSM-5 favored by increased temperature that promotes cracking reactions due expanded zeolites channels.

Utilization of Old Coconut (Cocos nucifera) Husk Waste as Potential Source of Natural Dye and its Dyeing Properties on Cotton Cloth

Coconut husk is considered waste and its fibers can be used as a source of natural dyes for textiles. The objective of this research is to obtain natural dyes from old coconut (Cocos nucifera) husk waste fibers through the extraction process. Brown color was produced in the liquid-liquid extraction method. The brown color natural dyes were then used to dye cotton cloth. Three different binding agents were used during the fixation process, i.e. tunjung, naphtol salt, and alum. The coloring results of the natural dye on the cotton cloth were as follow: with alum binding agent the resulting color was light brown (cream), whereas tunjung binding agent produced a greenish brown color, and using napthol salt binding agent produced yellow color. The colored cotton cloths were tested for their color fastness properties against rubbing, soap washing, and sunlight exposure. The measurement scale used was grey scales, which was used to evaluate the color change (color fading) and color staining (color transfer) during color fastness testing. In general, based on the results, the colored cotton cloth using alum as binding agent showed better color fastness properties against rubbing, soap washing, and sunlight exposure compared to the ones using tunjung and naphtol salt binding agents.

Phytomass and production components of colored cotton under salt stress in different phenological stages

ABSTRACT Scarcity of good quality water is a limiting factor for irrigated agriculture, especially in semi-arid regions, which induces the use of waters with high salt concentration in crop irrigation. In view of the above, the objective of this study was to evaluate the phytomass accumulation and production components of colored cotton genotypes during the different development stages, under conditions of high salinity, with plants grown in lysimeters under greenhouse conditions, at the Center for Technology and Natural Resources of the Federal University of Campina Grande, Paraíba, Brazil. Three cotton genotypes (‘BRS Rubi’, ‘BRS Topázio’ and ‘BRS Safira’) irrigated with salinized water (9 dS m-1) during the three stages of crop development (vegetative, flowering and fruiting) were evaluated. The experiment was conducted in a randomized block design with three repetitions and three plants per plot, in drainage lysimeters filled with 24.5 kg of an Oxisol, with sandy loam texture. Irrigation with salinized water during the vegetative stage promoted greater phytomass accumulation in the genotypes of naturally colored cotton. In the initial stages of the cotton development, irrigation with saline water can be used with the lowest losses in production components, which are negatively affected when saline water is applied in the fruiting stage. Among the genotypes, ‘BRS Topázio’ is the most tolerant to irrigation water salinity in terms of seed cotton weight and lint cotton weight, regardless of the development stage.

Spectrophotometric color matching for pre-colored fiber blends based on a hybrid of least squares and grid search method

Computer color matching can improve production efficiency and reduce costs in color spun. However, in practice the computer color matching success rate for pre-colored fiber blends has not been good, leading to customers being unsatisfied with the accuracy of the color matching results. Aiming to improve the accuracy, a hybrid of least squares and grid search method has been proposed for spectrophotometric color matching of pre-colored fiber blend based on the improved Kubelka–Munk (K-M) double-constant theory. Two-primary, three-primary, four-primary, and five-primary pre-colored cotton fiber blends were prepared as standard samples to evaluate the color matching accuracy of the proposed method. Compared with the least squares method and the grid search method, the proposed method achieved better color matching effects and greatly shortened the calculation time, respectively. For 42 pre-colored fiber blends, the average color difference between the predicted results obtained by the proposed method, least squares method, and grid search method and the spectrophotometer measurements were respectively 0.29, 0.53, and 0.36 CIE2000 units. The experimental results indicated that the proposed method could predict the formulation of standard samples quickly and effectively, and that it was superior to other methods in providing satisfactory color matching results for the enterprises.