Stability, Stimuli‐Responsiveness, and Versatile Sorption Properties of a Dynamic Covalent Acylhydrazone Gel

Gel adsorbents are promising for pollutant removal from the wastewater. Herein, an acylhydrazone gel is developed from acylhydrazide‐terminated pentaerythritol (PAT) and 2,4,6‐triformylphloroglucinol (TFP) based on dynamic covalent acylhydrazone chemistry. PAT‐TFP gel is stable under various conditions, while it shows reversible Cu(2+) adsorption and desorption. PAT‐TFP gel is studied as a versatile adsorbent for the capture of a range of (bulky) organic contaminants and heavy metal ions from aqueous solutions. Fast and good adsorption capacities are achieved for various dyes (rhodamine B and methyl orange), amines (aniline, p‐chloroaniline, 4‐methylaniline, and p‐aminobenzoic acid), phenols (phenol, 1‐naphthol, p‐methylphenol, and bisphenol A), and metal ions (Cu(2+), Cr(3+), and Hg(2+)). The maximum adsorption capacity is 107.5 mg g(−1) for Cu(2+) and the equilibrium adsorption time is 30 min. PAT‐TFP gel can be regenerated efficiently and used repeatedly.