A novel zirconium phosphonate adsorbent for highly efficient radioactive cesium removal

Abstract

A novel layered functionalized zirconium phosphonate adsorbent (DB-ZrP) was prepared by intercalating of 3, 4-dibenzo-21-crown-7 into the interlamination of α-ZrP. DB-ZrP not only efficiently combined the advantages of α-ZrP and 3, 4-dibenzo-21-crown-7 including the good stability and strong adsorption ability, but also overcame their disadvantages such as the loss of crown ether in aqueous solution and the collapsing of the layered structure of α-ZrP under rigid condition. Remarkably, DB-ZrP exhibited preferential Cs+ adsorption from HNO3 media even in the presence of competing ions, and the maximum Cs+ adsorption capacity obtained from a Langmuir isotherm model was 177.98 mg g−1, which was attributed to the wider layer distance and abundant adsorption sites after intercalating of 3,4-dibenzo-21-crown-7. The kinetics dates indicated the adsorption process was slow and the intra-particle diffusion was the main rate-controlling step. The thermodynamic coefficients suggested the passage of Cs+ ions through the liquid solid boundary was endothermic and spontaneous. The adsorbent could be reused in several cycles without no significant loss. Moreover, this excellent adsorption performance of DB-ZrP had also been observed in radioactive experiment for 137Cs removal from HNO3 media, which further specified that as-prepared DB-ZrP was a sustainable as well as efficient adsorbent for practical decontamination of radioactive liquid waste.