Cellulose carbonization

DeNiro MJ, Epstein S (1979) Relationship between the oxygen isotope ratios of terrestrial plant cellulose, carbon dioxide and water. Science 204 51-53 DeNiro MJ, Epstein S (1981) Isotopic composition of cellulose from aquatic organisms. Geochim Cosmochim Acta 45 1885-1894... 

The changes in cellulose that occur on heating to various temperatures are shown in Fig. 86. The upper curves of cellulose carbonized at a high temperature (above 500°C) resemble closely those of anthracite or even graphite. 

Both the quantity and properties of cellulases produced by microorganisms depend on the culture conditions. Commonly, cellulases are produced by culture of the organism either (a) in a liquid medium, which may be stationary, shaken, or submerged with aeration, or (b) by a Koji process on a solid substrate such as wheat bran (7). The complexity of the crude cellulosic carbon source usually leads to the production of a mixture of hydrolytic enzymes which may include amylases, proteases, chitinases, etc., in addition to the cellulases. Separation of proteins from culture filtrates by high resolution techniques such as chromatography, electrophoresis, or electrofocusing often reveals a number of enzyme species which may differ in specificity toward cellulosic substrates. These forms may represent ... 

Brunner P.H.. Roberts P.V (1980) The significance of heating rate on char yield and char properties in the pyrolysis of cellulose. Carbon, 18,217. 

Figure 1. Cellulose carbon conversion efficiency rjC as a function of gas-phase residence time for various gas-phase temperatures...

The various functional groups were also identified by independent, chemical methods used in organic chemistry [38, 42]. Infrared spectroscopy has also been used for the identification of surface groups. In the beginning, the method suffered from the strong absorption of carbon materials, and poor spectra were obtained. Zawadzki used thin films of cellulose carbonized at 600° C to get acceptable transmission spectra [50], but it is debatable whether such chars are really representative for carbons. It was not possible to heat the cellulose chars... 

Ionic Liquids-Assisted Fabrication of Cellulose/Carbon Nanotube Composites... 

This chapter details the technical procedures used to prepare and analyze lake sediment samples for cellulose carbon and oxygen isotope composition, considers important factors in the interpretation of cellulose isotope data, briefly highlights key results from recent applications, and outlines future research needs and directions. 

Methods for lake sediment sample preparation for cellulose carbon and oxygen isotope analyses have been developed at the University ofWaterloo - Environmental Isotope Laboratory (UW-EIL), (Heemskerk Diebolt, 1994 Edwards et al, 1997 Elgood et al., 1997). 

Figure 3. Flow diagram illustrating steps involved in preparing lake sediment for cellulose carbon and oxygen...

Parallel time-series trends between bulk organic carbon isotope (5 Corg) and cellulose carbon isotope (5 Cceii) profiles may indicate carbon uptake from the same source (i.e. DIC) and can provide further indirect support for an aquatic origin of cellulose. Conversely, stratigraphic variation in the isotopic difference between 5 Corg and 5 Cceii may be due to variable terrestrial contribution (Wolfe et al, 1996). However, these empirical relationships can be complicated by the lower sensitivity of bulk organic matter to fluctuations in... 

Fij>ure 6. Stratigraphic profiles of cellulose carbon isotope composition (i5 ), cellulose-inferred lake water... 

Yapp, C. J. S. Epstein, 1982. A reexamination of cellulose carbon-bound hydrogen 3D measurements and some factors affecting plant-water D/H relationships. Geoch. Cosmoch. Acta. 46 955-965. 

Dissolution of cellulose carbonate in diluted caustic soda... 

Cellulose nitrate is probably the oldest cellulose ester of commercial importance. Cellulose carbonate, cellulose sulphate, cellulose nitrite and cellulose phosphate have all been synthesized and characterized but only cellulose phos jiate shows commercial promise. 

Losty HHW, Blakelock HD, The stmcture and properties of partially pyrolysed cellulose carbon, Proc Conf Ind Carbon and Graphite, 29-35, London, Apr 1965. 

Fig. 10. Variation of the 3-amylasic activity units of the samples obtained from (1) trans-2,3-cellulose carbonate (2)...

Fig, 11. Variation of the g-amylasic activity units of the samples obtained from (1) acid chloride of BIOZAN R (2) CMC acid chloride (DS 2.02) (3) trans-2,3-cellulose carbonate (4) diazotized N-(4-aminophenyl) CMC amide as a function of time. Temperature= 5°C,... 

By comparing the resistance to the severe pH values of the 3-amylase coupled on N-(4-aminophenyl) CMC amide and on trans-2,3--cellulose carbonate, the latter derivative is seen to confer a greater resistance. Within the 1.1-8.9 pH range, the enz3nnatic activity decreases by 30% (Figure 13, curve 2) in comparison with 75% for the former derivative (Figure 13, curve 3) and 95% for the free enzyme (Figure 13, curve 1). 

The Lineweaver - Burk plot of the amyloglucosidase immobilized on cellulose carbonate is practically linear, while for the enzyme coupled on CICMC at different pH values (Figure 14, curves 2 and 3) the linearity is maintained only for increased concentrations of the substrate with increased value. In the former case the plot linearity attests that the amyloglucosidase molecules are located mainly... 

Fig. 14. Lineweaver - Burk plots for a-amylase at pH=5.8 (1) amylo-glucosidase immobilized on ClCMC, at pH=8 (2) and at pH = 9 (3) amyloglucosidase immobilized on cellulose carbonate at pH= 8 (4),...

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