Sequential removal of phosphate and cesium by using zirconium oxide: A demonstration of designing sustainable adsorbents for green water treatment

- Life cycle extension of adsorbents is desirable for sustainable water treatment.
- The life cycle of ZrO2 is extended to sequentially remove phosphate and cesium.
- Surface adsorbed phosphate can be converted to a zirconium phosphate overlayer.

Adsorption is one of the most cost-effectiveness methods to effectively remove pollutants particularly in the low concentration region. Extending life cycle of adsorbents is hence highly desirable for the perspective of green water treatment as it would ultimately reduce environmental impacts and associated cost in the waste disposal and adsorbent synthesis. In this study, we demonstrate the extension of the life cycle of zirconium oxide (ZrO2) adsorbent for sequentially removing phosphate and cesium. High affinity of ZrO2 to phosphate allows surface adsorbed phosphate to be converted to a zirconium phosphate overlayer in the following thermal treatment. By this manner, waste zirconium oxide adsorbent in the end of phosphate removal can be functionalized as a new cation exchange material for following Cs removal application. Importantly, our demonstrated strategy provides a valuable example in arranging and designing a sustainable adsorbent for green water treatment in the future.

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