Rapid industrialization has resulted in serious heavy metal pollution. The removal of heavy metal ions from solutions is very important for environmental safety and human health. Poly (amidoamine) (PAMAM) dendrimers are artificial macromolecular materials with unique physical and chemical properties. Abundant amide bonds and amino functional groups provide them with a high affinity for heavy metal ions. Herein, PAMAM-functionalized adsorbents are reviewed in terms of different nanomaterial substrates. Approaches in which PAMAM is grafted onto the surfaces of substrates are described in detail. The adsorption isotherms and kinetics of these adsorbents are also discussed. The effects of PAMAM generation, pH, adsorbent dosage, adsorption time, thermodynamics, and ionic strength on adsorption performance are summarized. Adsorption mechanisms and the further functionalization of PAMAM-grafted adsorbents are reviewed. In addition to the positive results, existing problems are also put forward in order to provide a reference for the optimization of PAMAM-grafted adsorbents of heavy metal ions.

In this work, polyamidoamine (PAMAM)-functionalized water-stable Al-based metal–organic frameworks (MIL-53(Al)-NH₂) were proposed with enhanced fluorescence intensity, and used for the sensitive detection of heavy metal ions in aqueous solution. The size and morphology of MIL-53(Al)-NH₂ were effectively optimized by regulating the component of the reaction solvents. PAMAM dendrimers were subsequently grafted onto the surface with glutaraldehyde as a cross-linking agent. It was found that the size and morphology of MIL-53(Al)-NH₂ have great influence on their fluorescence properties, and PAMAM grafting could distinctly further improve their fluorescence intensity. With higher fluorescence intensity, the PAMAM-grafted MIL-53(Al)-NH₂ showed good linearity (R² = 0.9925–0.9990) and satisfactory sensitivity (LOD = 1.1–8.6 μmol) in heavy metal ions determination. Fluorescence enhancement and heavy metal ions detection mechanisms were discussed following the experimental results. Furthermore, analogous water-stable Materials of Institute Lavoisier (MIL) metal–organic frameworks such as MIL-53(Fe)-NH₂ were also proved to have similar fluorescence enhancement performance after PAMAM modification, which demonstrates the universality of the method and the great application prospects in the design of PAMAM-functionalized high-sensitivity fluorescence sensors.