Recyclable structured toxic industrial nickel-containing sludge for efficient anionic contaminant adsorption.

Abstract

Safe, efficient, and simultaneous treatment of toxic industrial sludge and anionic contaminant crisis in one route still remains a persistent global challenge. Herein, we proposed a facile waste-control-waste conceptual design strategy to develop low-cost and high-performance sludge-based adsorbent for not only recycling of toxic waste nickel-containing sludge (NCS) but for the efficient removal of anionic contaminants in wastewater. The as-designed Ni-Allayered double oxides/calcined NCS (Ni-Al LDOs/CNCS) (216.96 m2/g, 0.44 cm3/g) with hierarchical porous structure possessed a larger specific surface area and well-developed porosity compared with raw NCS (60.52 m2/g, 0.26 cm3/g). It was proved that a higher hydrothermal temperature (180°C) and a longer hydrothermal time (24h) both promote the in situ assembly of LDHs nanosheets on CNCS surface. Significantly, the sludge-based adsorbent displayed high adsorption capacity towards five representative anions including F- (~ 31.1mg/g), SO42- (~ 37.7mg/g), NO3- (~ 21.8mg/g), Cl- (~ 28.0mg/g), and H2PO4- (~ 35.8mg/g). Furthermore, the adsorbent maintained desirable adsorption capacity even after 6 adsorption/desorption cycles. Therefore, this study could be potentially extended toward design of other industrial waste sludge-derived high value-added advanced materials and for wastewater treatment applications.