Highly selective and easily regenerated novel porous polyacrylonitrile-ammonium phosphomolybdate beads for cesium removal from geothermal water

A novel porogen-added ammonium phosphomolybdate-polyacrylonitrile (AMP-PAN-N20) was prepared to remove Cs+ from geothermal water. Compared with traditional AMP-PAN, porous AMP-PAN-N20 beads have a smaller particle size, larger adsorption capacity and faster adsorption rate. The adsorption batch experiments were carried out with the research objects' adsorbent contact time, dosage, pH value, initial Cs+ concentration, temperature and competing ions. The results showed that AMP-PAN-N20 could effectively adsorb Cs+ in a wide pH range and high concentration of competing ions. Remarkably, the adsorption performance hardly decreased after ten cycles of adsorption. In addition, the column adsorption tests were obtained using Cs-containing geothermal water. The results showed that the adsorption breakthrough time could be as long as 60 h (flow rate Q = 2 mL·min−1, bed height H = 8 cm), and the maximum dynamic adsorption capacity was 25.62 mg·g−1 under the Thomas model. In addition, the AMP-PAN-N20 maintained good stability after a long time of adsorption.