Browsing by Author "Wang, Yingfeng"

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    Degradation of cellulose polymorphs into glucose by HCl gas with simultaneous suppression of oxidative discoloration
    (Elsevier Science Ltd., 2023-02-15) Wang, Yingfeng; Pääkkönen, Timo; Miikki, Kim; Maina, Ndegwa Henry; Nieminen, Kaarlo; Zitting, Aleksi; Penttilä, Paavo; Tao, Han; Kontturi, Eero; Department of Bioproducts and Biosystems; School common, CHEM; Materials Chemistry of Cellulose; Biopolymer Chemistry and Engineering; Wood Material Science; University of Helsinki
    As cellulose is the main polysaccharide in biomass, its degradation into glucose is a major undertaking in research concerning biofuels and bio-based platform chemicals. Here, we show that pressurized HCl gas is able to efficiently hydrolyze fibers of different crystalline forms (polymorphs) of cellulose when the water content of the fibers is increased to 30–50 wt%. Simultaneously, the harmful formation of strongly chromophoric humins can be suppressed by a simple addition of chlorite into the reaction system. 50–70 % glucose yields were obtained from cellulose I and II polymorphs while >90 % monosaccharide conversion was acquired from cellulose IIIII after a mild post-hydrolysis step. Purification of the products is relatively unproblematic from a gas-solid mixture, and a gaseous catalyst is easier to recycle than the aqueous counterpart. The results lay down a basis for future practical solutions in cellulose hydrolysis where side reactions are controlled, conversion rates are efficient, and the recovery of products and reagents is effortless.
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    Recycling of Vat and Reactive Dyed Textile Waste to New Colored Man-Made Cellulose Fibers
    (ROYAL SOC CHEMISTRY, 2019) Haslinger, Simone; Wang, Yingfeng; Rissanen, Marja; Lossa, Miriam; Tanttu, Marjaana; Ilen, Elina; Määttänen, Marjo; Harlin, Ali; Hummel, Michael; Sixta, Herbert; Department of Bioproducts and Biosystems; Department of Design; Biorefineries; Biopolymer Chemistry and Engineering; Fashion/Textile Futures; Fresenius University of Applied Sciences; VTT Technical Research Centre of Finland
    The successful recycling of colored textile waste and reuse of respective dyes would represent a major milestone of global efforts to reduce the environmental impact of the textile industry. The chemical upcycling of dyed pre- and postconsumer cotton waste is promoted by studying the spinability and color fastness of seven vat and reactive dyes (i.e. Indanthren Blue BC 3%, Indanthren Red FBB coll, Indanthren Brilliant Green FBB coll, Levafix Brilliant Red E-4BA, Levafix Blue E-GRN gran, Remazol Brilliant Blue R spec, and Remazol Black B 133%) during dry-jet wet spinning. Apart from the fabrics dyed with Levafix Brilliant Red E-4BA, all samples dissolved in 1,5-diazabicyclo[4.3.0]non-5-ene actetate, a superbase based ionic liquid, and could be converted to new colored man-made cellulose fibers. It was found that there is a clear discrepancy between the recyclability of dyed pre- and postconsumer cotton waste, resulting in significantly higher fiber properties up to tenacities of 59.8 cN/tex and elongations of 13.1% in case of the latter. All recycled fibers displayed a noticeable color change in the CIELab space (ΔE = 8.8-25.6) throughout the spinning process. Despite these deviations, almost all fibers and demo fabrics produced thereof exhibited bright colors that can be reused in textile industry. Only Remazol Black B 133% did not sufficiently translate to the new textile product. The wash and rubbing fastness of the fabrics knitted from the regenerated fibers was superior to the dyed waste fabrics mainly because of the homogenous distribution of the dyes along the fiber cross-section.
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    Simultaneous recycling of cellulose fibres and dyes from dyed cotton waste in the form of dyed lyocell fibers
    (2018-08-28) Wang, Yingfeng; Haslinger, Simone; Kemian tekniikan korkeakoulu; Sixta, Herbert