Synthesis and characterization of a new activated carbon supported ammonium molybdophosphate composite and its cesium-selective adsorption properties

Abstract

A new Cs + adsorbent, activated carbon loaded ammonium molybdophosphate (AMP-AC) was prepared by repeating batch reaction of H 3 PO 4 and (NH 4 ) 6 Mo 7 O 24 . The surface of the activated carbon particles was coated with AMP microcrystals through a controlled crystallization process. The X-ray diffraction (XRD) analysis identified the AMP loaded on AC with the formula of (NH 4 ) 3 PO 4 (MoO 3 ) 12 ·4H 2 O. Scanning electron microscope images demonstrated that the fine AMP crystals was successfully immobilized and uniformly distributed on the porous carbon substrate. The effects of medium acidity, contact time, temperature and competing ions on Cs + uptake by the composite were investigated. The results show that the as-prepared adsorbent keeps high selectivity and adsorption capacity (∼0.75 mmol/g) for Cs + in acidic feed solution (0.1 M HN0 3 ), even in the presence of plentiful competing cations, Na + , Zn 2+ , Sr 2+ , Cr 3+ and La 3+ , while activated carbon itself has no specific affinity for Cs + . The adsorption process could be described by Langmuir adsorption equations. There is no significant difference (9.4%) on Cs + adsorption by the composite during system temperature changing from 298 to 348 K.