A simple and fast ultrasound-assisted treatment for demineralization of sugarcane bagasse

Demineralization using ultrasonic energy was evaluated to remove the inorganic fraction of sugarcane bagasse. To evaluate the efficiency of the proposed ultrasound-assisted approach, the inorganic fraction (alkaline and alkaline earth metals and other elements - Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr, and Zn) was monitored in the biomass. The proposed process was developed by evaluating the extracting medium, feedstock amount, acoustic frequency, acoustic amplitude, process temperature and process time. The most efficient condition for the inorganic fraction removal (45 kHz, 70 % amplitude, 1 mol L⁻¹ of H₂SO₄, 50 °C for 30 min) allowed a demineralization efficiency of approximately 100 % (25 g of feedstock). The main feature of this work is related to the capability of this energy source for speeding up the process, which was 90 % efficient since the first minute of treatment, associated with relatively mild operational conditions of pressure and temperature.