Figure 9
Scanning electron microscopic images of dilute acid/Fe2+ cocatalyst-pretreated corn stover. (A) through (C) The top row shows images of dilute acid-pretreated corn stover (CS) controls from 150°C, 0.5 wt% H2SO4, 20-minute pretreatments. (D) through (F) The middle row shows images of CS samples from dilute acid/Fe2+ cocatalyst pretreatment (that is, 0.5 wt% H2SO4 supplemented with 0.5 mM FeSO4) at 150°C for 20 minutes. (G) The bottom row shows a scanning electron microscopic image of dilute acid/Fe2+ cocatalyst-pretreated corn stover at ×100, 000 original magnification. This image is an enlargement of a selected area of panel (F). Arrows indicate lignin droplets.