Carbon nanodot-induced Eu3+-based fluorescent polymeric hydrogel for excellent phase-separation absorption of VOC

Abstract

Hydrogels with environment remediation function have attracted increasing interest in the past decades. Herein, we report the in situ preparation of heat-set fluorescent Eu³⁺ hydrogels derived from terpyridine-modified PEI polymers (PEI-LysTPY) via sol–gel transition. We demonstrate that carbon dots with abundant amine groups, which are formed by pyrolysis of PEI derivatives, behave as efficient linkers to trigger the hydrogelation process of the Eu³⁺/PEI-LysTPY assembly. The aggregation-induced emission enhancement (AIE) phenomena of Eu³⁺ is observed in the hydrogelation process. As applications for environment remediation, the hydrogel exhibits an excellent absorption (acetone: 2.58 g g⁻¹ and methanol: 2.04 g g⁻¹) for acetone gas or methanol gas (kinds of volatile organic compounds). Interestingly, the hybrid carbon dot-based hydrogel could selectively absorb acetone or methanol gas to form two phases, including the acetone-lean phase as the gel state and the acetone-rich phase as the solution state. The two phases could be easily separated. Additionally, the hydrogel could be reused by the reabsorption of solution and solute. This work supplies a unique method for the phase-separation absorption of VOCs using carbon dot-accelerated hydrogels with high absorption capacity, good stability and reusability ability.