Self-assembling 2D/2D (MXene/LDH) materials achieve ultra-high adsorption of heavy metals Ni2+ through terminal group modification

The application of two-dimensional metal carbides (MXenes) in heavy metal processing has attracted more and more attention. In this experiment, using titanium carbide as a 2D platform, an atomic-scale 2D/2D adsorbent alk-MXene/LDH was constructed by in situ mechanical self-assembly and alkali-level intercalation to remove Ni2+. Due to its unique layered structure, the oxidized functional groups and available active binding sites of MXene nanoplatelets constitute a unique adsorbent for removing heavy metals in water. The adsorption capacity of alk-MXene/LDH adsorbent for Ni2+ was 222.717 mg/g. The efficiency of Ni2+ was 97.35%, and the synthesized material could efficiently remove Ni2+ under a wide range of pH conditions (pH = 5–13). The adsorption behavior was studied using Redlich-Peterson adsorption isotherms, pseudo-second-order kinetics and thermodynamic models. In this study, the adsorbent exhibited excellent reproducibility after 8 adsorption-desorption cycles. According to the experimental results and various characterizations, the mechanism of the adsorbent was revealed. This study indicates that the atomic scale 2D/2D large basal plane has great potential in adsorbents.