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[Display omitted] • A novel MOF derived Co-Al-LDH@Fe 2 O 3 /3DPCNF adsorbents was synthesized. • The hybrid nanocomposites showed excellent adsorption capacities on Cr(VI) and Pb(II). • The adsorption isotherm, kinetics, thermodynamics, and mechanism were discussed in detail. • The composite can be easily recovered by magnet after adsorption process. Metal organic framework (MOF) derived layered double hydroxide (LDHs) are not properly probed in the field of the heavy metal ions adsorption from its aqueous solution, although they demonstrated a high possibility in adsorption. In this report, a Co-Al layered double hydroxide loaded with hematite (α-Fe 2 O 3)@3D porous carbon nanofiber (Co-Al-LDH@Fe 2 O 3 /3DPCNF) was synthesized by a sequential hydrothermal process. The Co-Al LDH was derived from a Co-metal organic framework. FE-SEM, TEM, FTIR, XPS, and BET characterizations and Cr(VI) and Pb(II) adsorption capacities of the composites were investigated in detail. The super hydrophilic Co-Al-LDH@Fe 2 O 3 /3DPCNF exhibited superfast removal efficiencies for Cr(VI) and Pb(II) with maximum adsorption capacities of 400.40 mg g−1 and 426.76 mg g−1, respectively. Precipitation, surface complexation, isomorphic substitution, and electron transfer were considered to be the main adsorption mechanisms. Adsorption isotherms were well fitted using the Sips model, and the adsorption thermodynamics demonstrated that the adsorption process is endothermic and spontaneous. The Co-Al-LDH@Fe 2 O 3 /3DPCNF maintained excellent adsorption capacity after ten cycles. The present study provides a new pathway to significantly improve the adsorption performance and stability of LDHs with easy separation from water body. [ABSTRACT FROM AUTHOR]

Environmental remedies, including adsorption-based water purification, are now being asked to meet the requirement for a low-carbon circular economy requiring low energy and low material consumption. In this regard, we tested the possibility of regenerating adsorbents via cold plasma (CP) treatment for less use of adsorbents and no washing solution. In the adsorption of methylene blue (MB) using carbonized rice husk (CRH) and five successive regeneration cycles by CP treatment, the removal efficiencies were maintained at a moderate level (∼70% of the initial performance), unlike five consecutive adsorption without CP treatment (∼9–13% of the initial performance). The regeneration of CRH by CP treatment was also double-checked by the FESEM, EDS, BET, FTIR, XPS, and surface zeta potential measurements. The successfully recovered adsorption capability is related to the remediation of adsorption sites. It is also worth noting that the required power consumption for recycling by CP treatment was about 6.4 times lower than carbonizing new rice husks. This work provides insights into recovering adsorbents using CP without rigorous, costly, and energy-intensive processes. [Display omitted] • Carbonized rice husk (CRH) was used for adsorption-based removal of dye molecules. • The adsorption kinetics was governed by the pseudo-second-order model. • Cold plasma (CP) treatment successfully regenerated the dye-adsorbed CRH. • CP treatment was workable for the five consecutive adsorption tests of the used CRH. • The regeneration mechanism was discussed in detail based on thorough analyses. [ABSTRACT FROM AUTHOR]