▎ 摘　　要

NOVELTY - A carbonaceous composite complex is formed by dispersing magnetic particles of metal oxide in the carbon matrix containing graphene sheet. The ratio number of metal atom to the number of carbon atoms in carbonaceous composite complex is 0.0005-0.5. The carbonaceous composite complex has a saturated magnetization of 5 e mu /g or more and a BET specific surface area of 300 m2/g or more. USE - Carbonaceous composite complex is used in adsorbent for removing to-be-adsorbed substance (all claimed) such as cesium ion, stolon lithium ion and methylene blue in underground water and industrial wastewaters. ADVANTAGE - The carbonaceous composite complex has large specific surface area and excellent magnetic properties. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) manufacture of carbonaceous composite complex, which involves mixing the metal salt chosen from at least one of iron salt, cobalt salt and nickel salt, and water-soluble polysaccharide in presence of water to form mixture, carbonizing the obtained mixture to form carbonized material and activating the obtained carbonized material; and (2) removal of to-be-adsorbed substance, which involves contacting the adsorbent containing the carbonaceous composite material with a liquid containing to-be-adsorbed substance to adsorb the substance and recovering the adsorbent by magnetic force.