Highly Efficient Magnetic Nitrogen-Doped Porous Carbon Prepared by One-Step Carbonization Strategy for Hg²⁺ Removal from Water

Abstract

Hydrophilic magnetic N-doped porous carbon composites (MNPCs) with high special surface areas and rich nitrogen content was prepared via simple one-step carbonization of zinc oxide nanoparticles (ZnO NPs), 2-methylimidazole (HmIm), and FeO@SiO magnetic nanoparticles (MNPs) mixture directly. During the carbonization process, ZnO NPs directly reacts with HmIm to yield porous ZIF-8 while the MNPs are incorporated into the frameworks to generate magnetic metal-organic frameworks (MFCs), and the MFCs acts as a self-sacrificing template to prepare MNPC. The obtained MNPCs via simple one-step carbonization strategy display higher adsorption capacity (429 mg g) for Hg ions than MNPC-T700-M3-T (382 mg g) which was obtained by two-step synthesis strategy for comparison. It also exhibits very fast adsorption dynamics (adsorption rate constant (K) = 2.45 g mg min) for Hg and could efficiently remove 95% Hg in 2 min for 20 mg L Hg solution. Furthermore, the prepared MNPC exhibits good chemical stability and the adsorption capacity is still more than 95% even after 10 adsorption-elution cycles. The proposed method is easy-processing and economic, which not only provides highly efficient MNPCs for metal ions capture but also paves the ways toward various MFCs with different ligands through solvent/additive-free synthesis approaches.

Facile Fabrication of N-Doped Magnetic Porous Carbon for Highly Efficient Mercury Removal

“…The calculated maximum adsorption capacity (495 mg g –1 ) from Langmuir isotherm model is very close to the experimental value. Compared with MNPC-T700-M3 that was reported in our previous work, the N-MPCs prepared here via one-pot pyrolysis exhibit better dispersion (e.g., without aggregation), lower cost, as well as easier preparation process (MNPs were required to be prepared first for MNPC-T700-M3). What’s more, N-MPC-700-7/3 with lower surface area (406 versus 653 m 2 g –1 ) and similar N content (12.8 versus 12.9 wt %) exhibited improved adsorption performance for Hg 2+ , which is probably due to the fact that their chemical forms of N are different.…”

“…N-MPCs were prepared via the modified pyrolysis method . In a typical synthesis process, a mixture of HmIm (11.0 mmol), Co­(OH) 2 (2.5 mmol), and ZnO NPs (2.5 mmol) were sealed in a quartz tube after uniform grinding.…”

“…Recently, MOFs with paramagnetic metallic notes (i.e., Fe, Co, or Ni) have served as self-template for preparing MPC materials by taking advantage of their various components as well as flexible structure. − Utilizing porous materials (MOFs, − COFs, or LDHs , ) as direct sacrificial template to prepare MPC simplifies the preparation greatly (i.e., only a single calcination step involved without any additional paramagnetic metal source) , and provides an effective solution to meet the above issues. In our recent research work, a facial strategy was proposed for the synthesis of N-doped magnetic porous carbons (N-MPCs) by using the mixture of Fe 3 O 4 @SiO 2 MNPs, ZnO, and HmIm as precursor. However, MNPs should be prepared in advance, and the serious aggregation of MNPs during pyrolysis would deteriorate the homogeneity of the obtained N-MPCs.…”

Magnetic graphene oxide grafted with different hydrophobic chain lengths low‐generation polyamidoamine dendrimers for adsorption of Pb(II) and Hg(II) in aqueous solution

“…Additional weight loss of HMGO‐PAMAM‐G1.0 could be due to the degradation of low‐generation PAMAM dendrimers grafted onto the HMGO‐NH 2 . The third stage starts around 650°C and ends at 800°C, the obvious weight loss of HMGO‐NH 2 attributes to the removal of carbon oxidation of GO . The corresponding DTA curve (Fig.…”

Porous BMTTPA–CS–GO nanocomposite for the efficient removal of heavy metal ions from aqueous solutions

“…surfaces for environmental contaminant removal from polluted water. 25,26 For example, polypyrrole-rGO, chitosan-rGO and SH-GO/Fe 3 O 4 nanocomposite have been used as new heavy metal ion adsorbents. [27][28][29][30] In particular, graing a target polymer onto the surface of GO is an effective way to improve the performance of graphene.…”