Ionic imprinted CNTs-chitosan hybrid sponge with 3D network structure for selective and effective adsorption of Gd(III)

Abstract

From economical and environmental standpoint, it is very meaningful for selective recovery of Gd(III) via adsorption from the real waste solution. At present, conventional adsorbents are impeded by poor adsorption capacity, low selectivity, complicated preparation and eco-pollution. To this end, a novel imprinted CNTs-chitosan hybrid sponge (COOH-CNTs/CS-IIS) with 3D network structure was fabricated via easy polymerization-lyophilization method for selective adsorption of Gd(III). The imprinting sites dispersing on the surface of channels in COOH-CNTs/CS-IIS can achieve the selective adsorption to Gd(III) and improve adsorption capacity. The combining of biomass chitosan sponge with oxidized CNTs not only further enhances the adsorption capacity and mechanical strength of COOH-CNTs/CS-IIS but also actualizes its rapid retrieval by the squeeze of elastic sponge. Systematic adsorption tests indicate that COOH-CNTs/CS-IIS has a maximum adsorption capacity of 71.95 mg g−1, and can adsorb 88.9% of the ultimate adsorption within 60 min. The selectivity tests show that COOH-CNTs/CS-IIS exhibits preferential adsorption for Gd(III) with a distribution coefficient of 0.656 L g−1. Furthermore, COOH-CNTs/CS-IIS has excellent regeneration performance. Considering its cost-effectiveness, eco-friendliness, user-friendliness, easy preparation and favorable adsorption performance, COOH-CNTs/CS-IIS holds great promise in selective recovery of Gd(III) from the real waste solution.