Growth of a mesoporous Zr-MOF on functionalized graphene oxide as an efficient adsorbent for recovering uranium (VI) from wastewater

In this study, a mesoporous PCN-222/GO-COOH adsorbent, based on the growth of a mesoporous zirconium-metalloporphyrin metal-organic framework (PCN-222) on the carboxylated graphene oxide (GO-COOH) to recover U(VI) from wastewater, was designed and prepared through solvothermal method and ultrasonication assisted stir technique. The U(VI) adsorption performance of the PCN-222/GO-COOH adsorbent was evaluated. The results indicated that the mesoporous PCN-222/GO-COOH adsorbent could effectively recover U(VI) and show an excellent adsorption capacity (426 mg/g), which was superior to those of GO-COOH and PCN-222 probably because the complexation and synergistic effect between GO-COOH and PCN-222 were facilitated by the ultrasonication assisted stir technique. And the PCN-222/GO-COOH adsorbent showed excellent reusability and selectivity for U(VI) adsorption, which also had outstanding adsorption performances in the complex wastewater. Furthermore, the chemical and monolayer adsorption dominated the U(VI) adsorption behavior of PCN-222/GO-COOH adsorbent. The excellent adsorption capacity, selectivity and reusability for U(VI) rendered PCN-222/GO-COOH composites as a promising adsorbent for recovering U(VI) from wastewater.