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    Novel sustainable alternatives for the fashion industry: A method of chemically recycling waste textiles via acid hydrolysis. Sanchis-Sebastiá Miguel,Ruuth Edvin,Stigsson Lars,Galbe Mats,Wallberg Ola Waste management (New York, N.Y.) The fashion industry has a considerable environmental impact, especially due to the increased generation of waste textiles as a result of fast fashion business models. Although fiber-to-fiber recycling processes are being developed, such a process is in reality a downcycling process, in which the mechanical properties of the textile fibers are impoverished with each cycle. Thus, new alternatives are required to completely close the fashion loop through chemically recycling textile fibers unfit for other types of recycling or resale due to their poor quality. We have evaluated the possibility of using acid hydrolysis to directly depolymerize the cotton fibers in waste textiles to produce a glucose solution, which could subsequently be used for the production of chemicals or fuels. Although a one-step procedure with sulfuric acid was unable to deliver high glucose production, it was possible to achieve a glucose yield over 90% through a two-step procedure, in which concentrated and dilute sulfuric acid were combined to exploit the benefits of both concentrations. Glucose concentrations around 40 g/L were achieved by increasing the solids loading in the two-step process, which might be sufficiently high for the fermentation of the solution into high-value products. Thus, this study demonstrates that it would be possible to chemically recycle (cellulose-based) waste textiles via acid hydrolysis, which, if correctly designed, could avoid the need to use enzymes to achieve high conversion efficiencies. 10.1016/j.wasman.2020.12.024
    Two-Step Thermochemical Cellulose Hydrolysis With Partial Neutralization for Glucose Production. Kong-Win Chang James,Duret Xavier,Berberi Véronique,Zahedi-Niaki Hassan,Lavoie Jean-Michel Frontiers in chemistry Cellulose hydrolysis processes using concentrated acid usually involve two steps in order to obtain high glucose yields. The first step (pre-treatment) decrystallizes cellulose while the second step (post-hydrolysis) converts the amorphous cellulose to glucose. The two-step process developed by the Industrial Research Chair on Cellulosic Ethanol and Biocommodities and its industrial partner CRB Innovations Inc., includes an intermediate partial neutralization step, whose purpose is to decrease the amount of dilution water to be added for post-hydrolysis thus minimizing handling costs. In this work, the effect of several operating parameters on the glucose yield of this process was investigated using triticale cellulose and the best conditions yielding fermentable glucose (close to 100%) were determined. These conditions involve pre-treating cellulose at 30°C using 72 wt% HSO with a HSO/dry cellulose mass ratio of 36 over 2 h, followed by a partial neutralization using 20 wt% NaOH at an H/OH molar ratio of 2.3-2.5 and a post-hydrolysis at 121°C for 10 min. Influence of operating parameters on the glucose yield have been investigated.Conditions for producing cellulosic glucose with yields close to 100% have been identified. 10.3389/fchem.2018.00117
    Experimental and theoretical studies on glucose conversion in ethanol solution to 5-ethoxymethylfurfural and ethyl levulinate catalyzed by a Brønsted acid. Wang Shijie,Chen Yihang,Jia Yu,Xu Guizhuan,Chang Chun,Guo Qianhui,Tao Hongge,Zou Caihong,Li Kai Physical chemistry chemical physics : PCCP The fundamental understanding of glucose conversion to 5-ethoxymethylfurfural (EMF) and ethyl levulinate (EL) (value-added chemicals from biomass) in ethanol solution catalyzed by a Brønsted acid is limited at present. Consequently, here, the reaction pathways and mechanism of glucose conversion to EMF and EL catalyzed by a Brønsted acid were studied, using an experimental method and quantum chemical calculations at the B3LYP/6-31G(D) and B2PLYPD3/Def2TZVP level under a polarized continuum model (PCM-SMD). By further verification through GC/MS tests, the mechanism and reaction pathways of glucose conversion in ethanol solution catalyzed by a Brønsted acid were revealed, showing that glucose is catalyzed by proton and ethanol, and ethanol plays a bridging role in the process of proton transfer. There are three main reaction pathways: through glucose and ethyl glucoside (G/EG), through fructose, 5-hydroxymethylfurfural (HMF), levulinic acid (LA), and EL (G/F/H/L/EL), and through fructose, HMF, EMF, and EL (G/F/H/E/EL). The G/F/H/E/EL pathway with an energy barrier of 20.8 kcal mol is considered as the thermodynamic and kinetics primary way, in which the reaction rate of this is highly related to the proton transfer in the isomerization of glucose to fructose. The intermediate HMF was formed from O5 a ring-opening reaction and by the dehydration of fructose, and was further converted to the main product of EMF by etherification or by LA through hydrolysis. EMF and LA are both unstable, and can partially be transformed to EL. This study is beneficial for the insights aiding the understanding of the process and products controlling biomass conversion in ethanol solution. 10.1039/d1cp02986j