Direct dissolution of cellulose in NaOH/thiourea/urea aqueous solution

Jin, Huajin; Zha, Chunxi; Gu, Liwei

doi:10.1016/j.carres.2006.12.023

Cited by 199 publications

(123 citation statements)

References 32 publications

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“…Urea has been discussed as a positive co-solvent for cold alkali (Cai and Zhang 2005;Jin et al 2007;Wernersson et al 2015;Zhang et al 2010), and the addition is reported to promote the dissolution process. In Fig.…”

Section: Effect Of Ureamentioning

confidence: 99%

On the dissolution state of cellulose in cold alkali solutions

et al. 2017

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We have characterized the dissolved state of microcrystalline cellulose (MCC) in cold alkali [2.0 M NaOH(aq)] solutions using a combination of small angle X-ray (SAXS) and static light scattering (SLS), 1 H NMR, NMR self-diffusion, and rheology experiments. NMR and SAXS data demonstrate that the cellulose is fully molecularly dissolved. SLS, however, shows the presence of large concentration fluctuations in the solution, consistent with significant attractive cellulose-cellulose interactions. The scattering data are consistent with fractal cellulose aggregates of micrometre size having a mass fractal dimension D $ 1:5. At 25 C the solution structure remains unchanged on the time scale of weeks. However, upon heating the solutions above 35 C additional aggregation occurs on the time scale of minutes. Decreasing or increasing the NaOH concentration away from the ''optimum'' 2 M also leads to additional aggregation. This is seen as an increase of the SAXS intensity at lower q values. Addition of urea (1.8 and 3.6 M, respectively) does not significantly influence the solution structure. With these examples, we will discuss how scattering methods can be used to assess the quality of solvents for cellulose.

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Section: Effect Of Ureamentioning

confidence: 99%

On the dissolution state of cellulose in cold alkali solutions

et al. 2017

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“…Alkali treatment of cellulose is an irreversible process that leads to a change in supramolecular structure and its morphology, facilitating their solubilization as well as removing components such as lignin and hemicellulose (Zhang et al 2002;Jin et al 2007). This process permits the formation of different types of cellulose that can contain more hydroxyl groups available to react with the metal ions.…”

Section: Adsorbent Treatmentmentioning

confidence: 99%

Coconut Bagasse Treated by Thiourea/Amonium Solution for Cadmium Removal: Kinetic and Adsorption Equilibrium

Neto¹,

Carvalho²,

Honorato³

et al. 2012

BioResources

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Coconut bagasse, an agricultural solid waste was used as biosorbent for the removal of cadmium after modification with thiourea. The adsorption of Cd 2+ was studied at pH 5.5. Langmuir, Freundlich, and Temkin isotherms were used to model the adsorption equilibrium data, and it was found that the system followed the Langmuir and Temkin isotherms. The adsorption capacity of the biosorbent was found to be 35.97 mg g -1 , which is higher or comparable to the adsorption capacity of various adsorbents reported in literature. Kinetic studies showed that the adsorption followed a pseudo-second-order rate model.

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“…The presence of these bonds, as well as the presence of crystalline areas in cellulose, makes this polymer insoluble in water and in most organic solvents [2,4,5]. Therefore, many systems capable of dissolving this polymer have been developed, including NaOH/CS 2 , DMSO/TBAF, LiCl/DMAc, and N 2 O 4 /DMF [6,7], which have disadvantages such as volatility, toxicity, or flammability.…”

Section: Introductionmentioning

confidence: 99%

Properties and Structure of Cellulosic Membranes Obtained from Solutions in Ionic Liquids Coagulated in Primary Alcohols

Fryczkowska

Kowalska

Biniaś

et al. 2018

Autex Research Journal

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This paper presents the results of studies on the preparation of cellulosic membranes, from a solution in 1-ethyl-3- methylimidazolium acetate (EMIMAc), using the phase inversion method. Initially, the membranes were obtained by coagulation of the polymer film in water and primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol), 1-hexanol, 1-octanol) resulting in membranes with significantly differing morphologies. Subsequently, composite membranes were produced, with the support layer being a membrane with the largest pores, and the skin layer a membrane with smaller pores. The resulting membranes were tested for physicochemical and transport properties. The morphology of the membrane surfaces and their cross-sections were investigated by using a scanning electron microscope (SEM). The structure of the membranes, on the other hand, was investigated by FTIR spectroscopy and WAXS structural analysis.

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Direct dissolution of cellulose in NaOH/thiourea/urea aqueous solution

Cited by 199 publications

References 32 publications

On the dissolution state of cellulose in cold alkali solutions

On the dissolution state of cellulose in cold alkali solutions

Coconut Bagasse Treated by Thiourea/Amonium Solution for Cadmium Removal: Kinetic and Adsorption Equilibrium

Properties and Structure of Cellulosic Membranes Obtained from Solutions in Ionic Liquids Coagulated in Primary Alcohols

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