Photothermal Switchable Cellulose Nanocrystals-Graphene Oxide Ionic Imprinted Aerogel for Selective Adsorption and Controlled Desorption of Dysprosium Ions

The regeneration of high-performance adsorbents has become an important bottleneck limiting the industrial application of adsorbent materials. In this paper, we use cellulose nanocrystals as the motif and graphene oxide as the functional monomer to prepare ion-imprinted aerogels (P-ICA), which effectively improves the adsorption kinetics and adsorption selection. Moreover, the photothermal conversion croconaine and the temperature-sensitive monomer N-isopropylacrylamide (NIPAM) were introduced. Under the irradiation of 808 nm near-infrared light, croconaine converts light energy into heat energy and transfers it to the PNIPAM chain to shrink the PNIPAM chain, thus changing the spatial size of the imprinting site and realizing the controlled green desorption of Dy(III). The experimental data showed that the maximum adsorption capacity of P-ICA was able to reach 72.08 mg g–1. Moreover, P-ICA had a good selective adsorption capacity for Dy(III). Most importantly, the effective adsorption performance of P-ICA could be maintained at up to 90.43% after five adsorption–desorption cycles by the reversible photothermal conversion system. This confirms that smart photothermally responsive aerogels with novel green regeneration means are efficient and green materials for Dy(III) recycling.