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A critical evaluation of magnetic activated carbon’s potential for the remediation of sediment impacted by polycyclic aromatic hydrocarbons
- Zhantao Han, Badruddeen Sani, Jarkko Akkanen, Sebastian Abel, Inna Nybom, Hrissi K. Karapanagioti, David Werner
- Journal of hazardous materials 2015 v.286 pp. 41-47
- Lumbriculus variegatus, activated carbon, adsorbents, adverse effects, bioavailability, biochar, pollutants, polycyclic aromatic hydrocarbons, remediation, reproduction, sediments
- Addition of activated carbon (AC) or biochar (BC) to sediment to reduce the chemical and biological availability of organic contaminants is a promising in-situ remediation technology. But concerns about leaving the adsorbed pollutants in place motivate research into sorbent recovery methods. This study explores the use of magnetic sorbents. A coal-based magnetic activated carbon (MAC) was identified as the strongest of four AC and BC derived magnetic sorbents for polycyclic aromatic hydrocarbons (PAHs) remediation. An 8.1% MAC amendment (w/w, equal to 5% AC content) was found to be as effective as 5% (w/w) pristine AC in reducing aqueous PAHs within three months by 98%. MAC recovery from sediment after three months was 77%, and incomplete MAC recovery had both, positive and negative effects. A slight rebound of aqueous PAH concentrations was observed following the MAC recovery, but aqueous PAH concentrations then dropped again after six months, likely due to the presence of the 23% unrecovered MAC. On the other hand, the 77% recovery of the 8.1% MAC dose was insufficient to reduce ecotoxic effects of fine grained AC or MAC amendment on the egestion rate, growth and reproduction of the AC sensitive species Lumbriculus variegatus.