Effects of washing pretreatment on properties and pyrolysis biochars of penicillin mycelial residues

In the context of bioenergy with carbon capture and storage, biochars has attracted much attention because of its unique advantages, and ash content is one of the important factors affecting the quality of biochars. Therefore, this paper performed the effects of ash removal on the properties and pyrolysis biochars of PMR with deionized water and 0.1 mol L−1 H2SO4. The results showed that water washing (WW) could remove 52.51% of ash, and ash removal rate of acid washing (AW) was up to 80.56%. AW had the highest removal efficiency of the inorganic: 94.90% of K, 88.41% of Ca, 91.25% of Na, 85.10% of Mg and 71.01% of P. TG results showed that the final residue mass of PMR (17.34 wt%) and W-PMR (12.41 wt%·min−1) were higher than that of WS-PMR (9.19 wt%·min−1) with the order of PMR > W-PMR > WS-PMR. In addition, AW not only changed the surface phase of biochars, but also changed the types of functional group, while WW only changed the surface phase of biochars. More importantly, the washing pretreatment has a positive effect on the pore size and adsorption performance of activated carbons (ACs).