This has been attributed to an increase in the content and toxicity of the extractives from the inner to outer heartwood (Sherrard and Kurth [1933]).
Despite the minor dissolution of hemicellulosic sugars, extraction with mild alkali removed most of the extractives from the bark and improved the raw material mass closure to 95% in comparison to the 88% value obtained after water-ethanol extraction.
However, method revision and optimisation was required, particularly for the effective removal of extractives from the raw material to ensure that representative and reproducible values for the major lignin and carbohydrate components could be derived.
Therefore, prediction of extractives from the NIR spectra can be expected to be more difficult (Poke and Raymond 2006).
This higher yield might be explained by the removal of the extractives from the bark prior steam pretreatment.
NIR-spectra for C, N, P, lignin and extractives were obtained from the finely ground and dry samples for the wave number range from 4000 to 11,000 cm− 1 using a Tensor 37 spectrometer (Bruker Optics GmbH, Ettlingen, Germany).
As the extractive values were determined from a separate analysis, the "double counting" of extractives from both the "overestimated lignin" values and extractive values themselves likely resulted in the observed, slightly higher summative mass closure.
The values for glucan, xylan, arabinan, acetyl groups, acid insoluble lignin, ash and extractives ranged from 37.4 to 39.6%, 19.5 to 23.3%, 1.3 to 2%, 2.2 to 3%, 1.3 to 1.9% and 4.3 to 5%, respectively.
Roughly, the percentages of glucan, hemicellulose, lignin and extractive content of the samples ranged from 38%to4343%, 25%to3232%, 17% to 24%, and 2% to 7%, respectively.
Complex, hypersaline brines originating from the mining and extractive metallurgical industries have the potential to be treated using Eutectic Freeze Crystallization (EFC).
