Facile Synthesis and Characterization of Wurtzite/Halloysite Composite for Efficiently Selective Adsorption of Al(Iii) from Acidic Rare Earth Ions Solution

Removal of aluminum ion from rare earth ions solution by selective adsorption was one of the promising methods for green enrichment of the acidic rare earth solution containing aluminum ions. Herein, a series of zinc sulfide/halloysite composites with different phases and content of wurtzite were prepared by facile one-step hydrothermal method using halloysite as the substance. The phase composition, microstructure and specific surface area of the Wurtzite/Halloysite (WZ@Hal) composite were characterized and the selective adsorption behavior of the WZ@Hal composite for aluminum and rare earth ions under different conditions was studied. The results showed that the composite was synthesized through strong electron interaction between sulfur atoms of wurtzite with oxygen atoms on the surface of halloysite. WZ@Hal composite loaded with hexagonal wurtzite showed good adsorption selectivity for Al(III) with a spontaneous exothermic process, while SP@Hal composite loaded with cubic sphalerite displayed no obvious adsorption capacity for both Al(III) and Er(III) with an endothermic process. The adsorption affinity of WZ@Hal for Al(III) was significantly stronger than that of rare earth ions. WZ@Hal showed excellent regeneration and maintained high selective adsorption performance in adsorption-desorption process. The adsorption mechanism was that aluminum ions were adsorbed by electron interaction with sulfur atoms on wurtzite and oxygen atoms of halloysite substrate at the interface of the wurtzite and halloysite. WZ@Hal composite showed excellent selective adsorption performance in the adsorption and separation process of acidic mixed solution of aluminum ion and rare earth ions