Coral-inspired “nanotentaclization” porous composite gel for efficient removal of Lead(II) from aqueous solution

Specific surface area and active groups are major concerns in the design and synthesis of metal ion adsorbent. Inspired by coral's high efficiency in preying on tiny plankton in the ocean, we pioneered a simple method for the in situ construction of “nano-tentacles” based on the original porous material skeleton. The introduction of “nano-tentacles” can further redesign and remolding of the existing interconnected pores to increase the specific surface areas and specific chelating sites for target metal ions. Herein, a proof-of-concept design is illustrated by in situ growing (3-aminopropyl)trimethoxysilane (APS) on the inner wall of the porous structure of chitosan/graphene oxide composite gel (CGG). The resulting material (NT-CGG) has a distribution coefficient (Kd) of 1.25 × 108 mL g−1, which exhibits ultrahigh affinity for lead ions, and the uptake capacity can reach 470 mg g−1. More significantly, the NT-CGG can effectively remove lead from 10 ppm to undetectable levels (≤0.02 ppb) with remove efficiency ≥99.9998% in the breakthrough experiment. The method proposed in this paper may be widely applicable to the redesign and remolding of most existing porous materials.