Cellulose nanocrystals by acid vapour: towards more effortless isolation of cellulose nanocrystals

2017 ◽  
Vol 202 ◽  
pp. 315-330 ◽  
Author(s):  
Marcel Lorenz ◽  
Stefan Sattler ◽  
Mehedi Reza ◽  
Alexander Bismarck ◽  
Eero Kontturi
Keyword(s):  
Cellulose Nanocrystals ◽  
Materials Science ◽  
Crystal Surface ◽  
Acid Catalyst ◽  
Strong Acid ◽  
Degree Of Polymerization ◽  
Full Potential ◽  
Cellulose Fibres ◽  
Formidable Challenge ◽  
Pre Treatment

Cellulose nanocrystals (CNCs) are topical in materials science but their full potential is yet to be fulfilled because of bottlenecks in the production: the process consumes huge amounts of water, recycling the strong acid catalyst is difficult, and purification steps are cumbersome, particularly with lengthy dialysis. Production of CNCs with HCl vapour overcomes many of these difficulties but the dispersion of CNCs from the already hydrolysed fibre matrix is a formidable challenge. This study is a fundamental effort to explore very basic means to facilitate CNC dispersion from cotton linter fibres (filter paper), hydrolysed to levelling off degree of polymerization by HCl vapour. The introduction of carboxylic groups on the cellulose crystal surface proved the most efficient method to alleviate dispersion with good yields (ca. 50%) and a provisional possibility to tune the CNC length. By contrast, attempts to directly disperse untreated hydrolysed fibres in various organic solvents and aqueous surfactant solutions were unsuccessful. The results showed that hydrolysis of native cellulose fibres by HCl vapour is indeed a viable method for producing CNCs but it has more potential as a pre-treatment step rather than a full-fledged process on its own.

scholarly journals Controlled Depolymerization of Cellulose Fibres Isolated from Lignocellulosic Biomass Wastes

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Suh Cem Pang ◽  
Lee Ken Voon ◽  
Suk Fun Chin
Keyword(s):  
Lignocellulosic Biomass ◽  
Acid Catalyst ◽  
Degree Of Polymerization ◽  
Second Order ◽  
Water Soluble ◽  
Cellulose Fibres ◽  
Amberlyst 15 ◽  
Pseudo Second Order ◽  
Chain Lengths ◽  
Optimized Conditions

Various types of lignocellulosic biomass wastes (LBW) had been successfully converted into cello-oligomers with different chain lengths via a controlled depolymerization process. Cellulose fibres isolated from LBW samples were dissolved with room temperature ionic liquid (RTIL) in the presence of an acid catalyst, Amberlyst 15 DRY. The effects of reaction time on the degree of polymerization and yields of water-insoluble cello-oligomers formed were studied. Besides, the yields of water-soluble cello-oligomers such as glucose and xylose were also determined. The depolymerization of cellulose fibres isolated from LBW was observed to follow both second-order and pseudo-second order kinetics under specific conditions. As such, cello-oligomers of controllable chain lengths could be obtained by adjusting the duration of depolymerization process under optimized conditions.

Polypyrrole based strong acid catalyst for acetalization

2011 ◽  
Vol 13 (9) ◽  
pp. 1820-1824 ◽  
Author(s):  
Xuezheng Liang ◽  
Yuxiao Cheng ◽  
Chenze Qi
Keyword(s):  
Acid Catalyst ◽  
Strong Acid

Fabrication and Processing of Pineapple Leaf Fiber Reinforced Composites

2016 ◽  
pp. 125-147 ◽  
Author(s):  
S. H. Sheikh Md. Fadzullah ◽  
Zaleha Mustafa
Keyword(s):  
Natural Fiber ◽  
Fiber Reinforced Composites ◽  
Full Potential ◽  
Cellulose Content ◽  
Matrix System ◽  
Reinforced Composites ◽  
Pineapple Leaf Fiber ◽  
Fiber Extraction ◽  
Pre Treatment ◽  
High Cellulose

There is an increasing interest worldwide in the use of Pineapple Leaf Fibers (PALF) as reinforcements in polymer composites, since this type of natural fiber exhibit attractive features such as superior mechanical, physical and thermal properties, thus offer potential uses in a spectrum of applications. PALF contains high cellulose content (between 70-82%) and high crystallinity. However, being hydrophilic, it posed a compatibility issue particularly in a hydrophobic polymeric matrix system. Thus, their shortcoming need to be addressed to ensure good interfacial bonding at the fibers/matrix interphase before their full potential can be harnessed. This chapter summarized some of the important aspects relating to PALF and its reinforced composites, particularly the main characteristics of the fiber, extraction and pre-treatment process of the fibers. Following this, discussions on the available fabrication processes for both short and continuous long PALF reinforced composites are presented.

Enhanced bio-energy recovery in a two-stage hydrogen/methane fermentation process

2009 ◽  
Vol 59 (11) ◽  
pp. 2137-2143 ◽  
Author(s):  
M. J. Lee ◽  
J. H. Song ◽  
S. J. Hwang
Keyword(s):  
Hydrogen Production ◽  
Fermentation Process ◽  
Continuous Production ◽  
Strong Acid ◽  
Treatment Method ◽  
Engineering System ◽  
Production Rates ◽  
Two Stage ◽  
Methane Fermentation ◽  
Pre Treatment

A two-stage hydrogen/methane fermentation process has emerged as a feasible engineering system to recover bio-energy from wastewater. Hydrogen-producing bacteria (HPB) generate hydrogen from readily available carbohydrates, and organic acids produced during the hydrogen fermentation step can be degraded to generate methane in the following step. Three strong acids, HCl, H2SO4, and HNO3, were tested to determine the appropriate pre-treatment method for enhanced hydrogen production. The hydrogen production rates of 230, 290, and 20 L/kg-glucose/day was observed for the sludge treated with HCl, H2SO4, and HNO3, respectively, indicating that the acid pre-treatment using either HCl or H2SO4 resulted in a significant increase in hydrogen production. The fluorescent in situ hybridization method indicated that the acid pre-treatment selectively enriched HPB including Clostridium sp. of cluster I from inoculum sludge. After hydrogen fermentation was terminated, the sludge was introduced to a methane fermentation reactor. This experiment showed methane production rates of 100, 30, and 13 L/kg-glucose/day for the sludge pre-treated with HCl, H2SO4, and HNO3, respectively, implying that both sulfate and nitrate inhibited the activity of methane-producing bacteria. Consequently, the acid pre-treatment might be a feasible option to enhance biogas recovery in the two-stage fermentation process, and HCl was selected as the optimal strong acid for the enrichment of HPB and the continuous production of methane.

Characteristics of Cellulose from Lespedeza stalks Steam Pretreated with Low Severity Steam and Post-Treatment by Alkaline Peroxide for Energy Production

2012 ◽  
Vol 578 ◽  
pp. 30-34
Author(s):  
Yang Xing ◽  
Lv Yang Liu ◽  
Zhao Qin Su ◽  
Li Wei Zhu ◽  
Jian Xin Jiang
Keyword(s):  
Degree Of Polymerization ◽  
Average Degree ◽  
Post Treatment ◽  
Raw Material ◽  
Steam Pretreatment ◽  
Material Synthesis ◽  
Glucose Yield ◽  
Alkaline Peroxide ◽  
Pre Treatment ◽  
Lespedeza Stalks

Lespedeza crytobotrya is a shrub species with properties of substantial biomass and widely distributes in the desert region of China. The cellulose separated from Lespedeza after pre-treatment can be enzymatic hydrolyzed into glucose for ethanol or other chemicals production, which are important renewable fuels or raw material for other material synthesis. Moreover it also can be used for cellulosic material production. So it is necessary to evaluate the cellulose of Lespedeza crytobotrya before its utilization. In this study four cellulosic fractions were isolated by pretreatment with low severity steam and post-treatment with alkaline peroxide. They were comparatively studied by sugar analysis and the average degree of polymerization. After alkaline peroxide post-treatment, the hemicelluloses in the cellulosic fractions were removed markedly. The treatment intensity had a profound effect on the average degree of polymerization, which was increased firstly and then decreased. A combination of low severity steam pretreatment and alkaline peroxide post-treatment is an effective method for Lespedeza stalks to obtain high glucose yield.

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