| dc.description.abstract | This work evaluated lignocellulosic biomass demineralization processes (sugarcane
bagasse, sugarcane straw, energy cane, pine, and eucalyptus residues) using
ultrasonic energy, mechanical stirring, or only mild conditions of heat for
demineralization (silent condition). For scaling up the proposed protocol (12.5 and 25
g), the own bath of US was used as a reactor. After the step of demineralization, the
solution was separated from the solid phase, centrifuged and the inorganics
constituents (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Sr e Zn) were determined for
inductively coupled plasma optical emission spectrometry (ICP OES). Initially, the
demineralization with the US was used as a condition cited in the literature. The
proposed method was optimized with sugarcane bagasse sample. In the best
operational condition (250 mg of sample, 20 mL de H2SO4 1 mol L-¹
, US bath at 25
kHz frequency, 30 min, 70% amplitude, and 50 °C) up 91% demineralization was
obtained for the pool of elements (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Sr, Zn). This
condition was compared with mechanical stirring and in a condition in the absence of
mechanical energy (silent condition), which presented demineralization efficiency of
95% and 83.7%, respectively. In the experiments with scale up (2 L of extractor solvent
and 25 g of sample) the US, mechanical stirring and the silence condition presented
the following demineralization efficiencies: 103.7%; 101.3% and 90.4%, respectively.
These results were obtained considering the pool of all inorganic constituents of the
evaluated biomasses. Additionally, a kinetic study of demineralization was carried out
where it was evaluated the efficiency of demineralization at defined time intervals. This
development of the lignocellulosic biomass demineralization process proved to be
efficient with the use of all the proposed systems. However, with the use of the US, it
was possible to promote the demineralization in shorter time intervals, less than 5 min
(approximately 90%), which was not observed by other systems at the same time (less
than 70%). | |
