LAUSR

Rice husk is a kind of biomass feedstock with high ash content. The effect of acid washing (HCl, HF and H3PO4) on the inorganic contents in rice husk was analyzed in this study. The optimal pretreatment conditions for pyrolysis product distribution, including acid concentration, washing temperature and washing time, were investigated via pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). Compared with HF and H3PO4, HCl showed the best removal efficiency of alkali and alkaline earth metals (AAEMs) with removal efficiency up to 98% for K, 93% for Ca, 100% for Na and 91% for Mg. Acid washing could increase the yield of specific products, especially sugars. Considering economic costs and the wide range of applications, HCl is the most suitable acid for washing. In order to get the highest yield of all kinds of products, the optimal pretreatment condition of HCl washing is the concentration for 2 mol/L, washing temperature for 60 °C and washing time for 1 h.