Recycling of powder coke to cost effective adsorbent material and its application for tertiary treatment of coking wastewater

Rapid removal of recalcitrant organic contaminants from coking wastewater remains a challenge. Powder coke is a burden to coke plant and environment, has the potential as a cost-effective absorbent material. But its absorption capacity is limited by the dense crystalline carbon structure and low surface activity. This study proposes a facile method to fabricate powder coke-derived adsorbent by tuning the surface functional groups. Results revealed that the obtained powder coke-derived adsorbent presented a relatively smooth surface, worm-like pore structure and discernible graphitization degree. The O1S and N1S functional groups were increased from 27.7% to 52.2%. The adsorption of recalcitrant organic contaminants from coking wastewater was increased by 70%, implying significantly by the reduced UV254. The increased N and O-contained functional groups on the surface could introduce hydrophobic force and pi-pi EDA interactions, which are responsible to the enhanced interactions between powder coke-derived adsorbent and recalcitrant organic contaminants (PAHs and BAD, etc). The engineering aspect of the powder coke-derived adsorbent was discussed in the perspective of recent advances and challenges. This study provides scientific basis for its effective use of powder coke as an adsorbent for tertiary treatment of coke wastewater, so as to achieve the dual purposes of clean production and environmental protection. (C) 2020 Elsevier Ltd. All rights reserved.