Prussian blue (PB) granules for cesium (Cs) removal from drinking water

•PB granules were used to remove cesium from tap water.•Adsorption isotherms of Cs on PB granules were determined at room temperature.•Cs-PB affinity tolerates challenge from competing ions and hypochlorite.•Column tests and simulated rapid sand filter tests were conducted.•Scenarios of using PB granules as a Cs barrier in waterworks were discussed. Cesium (Cs) removal from tap water has become an emerging issue after the disaster at the Fukushima Daiichi Nuclear Power Plant. Prussian blue (PB), a pigment crystal with a cage size similar to the hydration radius of Cs+, is used in this study for the first time to remove Cs from drinking water. Adsorption isotherms of Cs on PB granules, which were determined at room temperature, fit Langmuir equations. The Cs-PB affinity was high, tolerating the challenge from competing ions and hypochlorite. Column tests and simulated rapid sand filter tests indicate that PB granules are highly efficient Cs adsorbents with low water head loss during applications. Possible scenarios for using PB granules as a Cs barrier in waterworks were discussed.