Mesoporous Organic–Inorganic Core–Shell Necklace Cages for Potentially Capturing Cd2+ Ions from Water Sources

Abstract

We report the one-pot synthesis of ball-like nanosphere structures composed of an α-Fe core and an organic shell of ethylenediaminetetraacetic acid that connected together to form a nanochain necklace-like morphology. The hierarchical zigzag nanochain sphere structures have branches growing in clumps, a large surface area, and spherical pore-like cages and entrances for capture/trapping Cd2+ ions from water sources. The pH solution (i.e., at pH 5) plays a key role in the generation of actively negative surfaces along the entire nanochain sphere adsorbent, thereby creating surfaces with strong binding affinity to Cd2+ ions. The thermodynamic and kinetic characteristics indicated that the nanochain sphere adsorbent with macro- and meso-cage caves and organically decorated surfaces show promise for the spontaneous and endothermic capturing of Cd2+ ion containments from water solutions. The zigzag nanochain mesoporous necklace-like structure trapper (MNT) exhibited long-term stability, indicating that it can be used several times (reduced waste volume). The adsorption efficiency and uptake of the deleterious Cd2+ ions retained even after multi-particulate processing of reuse cycles. The pH-dependent Cd2+ ion selectivity indicated high adsorption capacity (526.3 mg⋅g−1) and Cd2+ ion-to-MNT binding affinity, despite the addition of interfering cations or anions. The zigzag nanochain sphere necklace allows the development of a simple and effective adsorbent model for water purification and management of toxins.