Highly efficient Cd(Ⅱ) removal using 3D N-doped carbon derived from MOFs: Performance and mechanisms

作者：Xu Conglei; Wang Hao; Shang Yaxin; Li Beibei; Yu Danning; Wang Yifei

来源：Journal of Hazardous Materials, 2022, 436: 129149.

DOI：10.1016/J.JHAZMAT.2022.129149

• N
• -doped carbon
• Cd(Ⅱ)
• Physical adsorption
• Electrostatic interaction
• Cd
• 2+
• -π interaction

Cadmium (Cd) removal is imperative to ensure the safety of aquatic-ecosystem, yet its effective removal technology has remained elusive by far. To address this concern, three-dimensional N-doped carbon (NC) polyhedrons affording ample porosity is fabricated based upon the thermal carbonization and KOH activation of zeolitic imidazolate framework-8 (ZIF-8) precursor. Thus-derived activated NC (a-NC) adsorbent not only overcomes the inherent instability of ZIF-8 but also harvests a maximum Cd(Ⅱ) adsorption capacity of 370.2?mg?g?1, which evidently surpasses those of bare NC counterpart as well as previously reported adsorbents. Impressively, a-NC achieves ca. 100% removal of aqueous Cd(Ⅱ) in a broad working pH range (5?9), and particularly attains stable performances (81?92%) in various realistic water. Theoretical calculations in combination with experimental characterizations further offer mechanistic insight into the enhanced removal exerted by a-NC. Notably, owing to the increased specific surface area (3041 vs. 389?m2 g?1) and enhanced sp2 carbon content (91.7 vs. 68.8%) of a-NC as compared to NC, advanced Cd(Ⅱ) adsorption via a-NC can be exhibited. Our designed a-NC material harnessing favorable recycling capability would be in particular attractive in the realm of practical Cd(Ⅱ) remediation.