Hardwood–Based Granular Activated Carbon for Metals Remediation

Abstract

Hardwood waste such as oak chips is an abundant, high‐carbon content by‐product with little value other than for burning as fuel. This study optimizes conditions for the production of granular activated carbon, which has excellent metal ion adsorption properties, using oak chips as a source material. Oak chips were dehydrated with 30% phosphoric acid at 170oC and activated at 400–500oC in the presence of breathing air. Metal ion (Cu2+) adsorption capacities for two representative hardwood‐based carbons were 1.1–1.2 mmol Cu2+ adsorbed/g of carbon. Surface areas of the two carbons were 656 and 730 m2/g, respectively, and surface charges were 3.44 and 4.16 mmol H+ eq/g, respectively. These carbons were compared with several commercial metal‐ion‐adsorbing materials to determine their efficacy relative to the commercial samples. The comparative studies indicated that oak chip carbons had higher metal ion adsorption capacities than all of the commercial samples except for the materials containing carbon/cation exchange resin mixtures.