Applications of carbonaceous adsorbents in the remediation of polycyclic aromatic hydrocarbon-contaminated sediments: A review

Polycyclic aromatic hydrocarbons (PAHs) are widely accumulated in sediments and thus impose great risks to the ecosystem and public health. There is increasing effort on the development of technologies for remediation of PAH-contaminated sediments. Adsorption is one of the most promising remediation technologies is to PAH-contaminated sediments. Carbonaceous adsorbents (CAs) have been considered desirable for adsorbing PAHs due to their cost-effective and eco-friendly nature. The effectiveness of CAs in removal of PAHs, however, can be greatly affected by adsorbent properties, sediment characteristics, and environmental conditions. An accumulating evidence largely from laboratory experiments has shown that CAs can be used for immobilization and decontamination of PAHs in sediments, however, their full potential has not been demonstrated, particularly with respect to field applications. The present review aims to summarize the current progress on CA physical and chemical properties, and mechanisms of the stabilization of PAHs in sediments as well as key factors controlling field applications. In addition, potential environmental effects associated with CA-mediated PAH stabilization is also discussed. Among various CAs, activated carbon and biochar are the most commonly used adsorbents for sediment remediation and thus are the focuses of this review.