Construction of smart photo-responsive imprinted composite aerogel and its selective adsorption for recovery of rare earth dysprosium ions

The adsorption of dysprosium ions from rare earth waste by hydrometallurgy is of great significance for both sustainable resource development and environmental protection. However, poor adsorption kinetics, low selectivity and difficult desorption regeneration cycle of adsorption limit the separation and recovery of rare earth ions. Herein, a photo-responsive imprinted cellulose nanocrystal composite aerogel (P-IAM) was prepared by introducing azobenzene-silane for selective adsorption of dysprosium ions. Highly ordered pore structure templated by cellulose nanocrystal effectively improve the adsorption rate; coupled with ion imprinting technology for highly selective adsorption separation of Dy3+; more importantly, inspired by nature's light response, light response modulation mechanism of aerogel can achieve green desorption. It was shown that the adsorption-desorption of P-IAM was possible under the variation of Vis-UV light. When Dy3+ solution concentration was 250 mg L-1, the maximum adsorption capacity of P-IAM achieved 68.65 mg g-1. In the presence of competing ions, P-IAM still has good recognition and memory ability for Dy(Ⅲ). In addition, P-IAM was still able to reach 87.19% of its initial adsorption capacity after five cycles, maintaining a good adsorption capacity and green regeneration capability. These studies provide a green technology basis for the recovery of Dy(III).