Simultaneous scavenging of Cd(II) and Pb(II) from water by sulfide-modified magnetic pinecone-derived hydrochar

Abstract

Sulfide-modified magnetic hydrochar described as MHC-S4 was synthesized by simultaneously supporting Fe3O4 nanoparticles and grafting sulfide-containing groups onto pinecone-derived hydrochar. The MHC-S4 could effectively adsorb Cd(II)/Pb(II) over a wide pH range, and could achieve fast uptake equilibrium within 25 min. Moreover, the MHC-S4 possessed excellent adsorption properties in single system with maximum monolayer uptake of 62.49 and 149.33 mg/g for Cd(II) and Pb(II). While the binding rate and uptake of metal ions by MHC-S4 in binary system were inferior to that of single system, and Pb(II) exhibited conspicuous inhibition to Cd(II) adsorption onto MHC-S4. Furthermore, the MHC-S4 was demonstrated to achieve excellent Cd(II)/Pb(II) binding primarily through electrostatic interaction, ion exchange and complexation. These results suggested the sulfide-modified magnetic hydrochar as a high-performance adsorbent for heavy metals removal.