Micron-sized nonporous silicon carbide (SiC) powder of the spent heating elements of a graphite furnace were used as the common precursor of two different forms of carbide-derived carbon (CDC) synthesized by chlorination at different temperatures: (1) graphitic and (2) amorphous Si-CDCs. Whereas the former material having high electroconductivity was used as an efficient electrode of a microbial fuel cell (MFC), the latter material having high specific surface area was used as an efficient adsorbent for aqueous hexavalent chromium (Cr(VI)). The MFCs generated a significantly high maximum power density of ∼1570 ± 30 mW/m2 and open circuit potential of ∼460 ± 5 mV. The adsorbents exhibited a significantly large adsorption capacity of ∼95 ± 5 mg/g. This study has developed for the first time two types of Si-CDCs having different physicochemical characteristics, from the common SiC precursor via the facile route of different temperature conditions, for bioelectricity generation and environmental remediation applications.