Figure 2From: Direct production of biodiesel from high-acid value Jatrophaoil with solid acid catalyst derived from ligninScanning electron microscope (SEM) image of Kraft lignin char without chemical activation. Figure 2 shows SEM images of the pyrolyzed Kraft lignin char without phosphoric acid pretreatment. The surface of char in Figure 2 is smooth and has fewer pores.Back to article page