Selective removal of cesium by ammonium molybdophosphate-magnetic Fe3O4-chitosan composites

A new Cs+ adsorbent, Fe3O4-chitosan particles combined with ammonium molybdophosphate (Fe3O4-CTS-AMP composite) were synthesized using a facile method through coordination between CTS and AMP. The surface morphology and chemical composition characterization indicated that Fe3O4-CTS particles and AMP particles were bonded tightly and the composite behaved superparamagnetically. Cs+ adsorption properties of Fe3O4-CTS-AMP composites were studied. The adsorption data fitted well with pseudo-second-order kinetic model and Langmuir-Freundlich adsorption isotherms model. The adsorption equilibrium can be reached fast at 5 min. The maximum adsorption capacity was calculated as 177.8 mg g(-1). The composite also showed high selectivity for Cs+ in coexistence with high concentration of competing cations. The adsorption mechanism of Cs+ for the composite may mainly be the exchange of Cs+ with NH4+. Therefore, the newly developed adsorbent is a kind of potential efficient composite for Cs+ removal from wastewater.