Fig. 2

Photographic images and SEM images of DBC and DBC charcoal: (a1) photograph of DBC; (a2 and a3) SEM of DBC; (b1) photograph of 650 °C DBC charcoal; (b2 and c2) SEM of 650 °C DBC charcoal; (c1) photograph of 900 °C DBC charcoal; (c2 and c3) SEM of 900 °C DBC charcoal