Synthesis and characterization of a new activated carbon supportedammonium molybdophosphate composite and its cesium-selectiveadsorption properties

摘要

A new Cs+ adsorbent, activated carbon loadedammonium molybdophosphate (AMP-AC) was prepared by repeating batch reaction of H_3PO_4 and (NH_4)_6Mo_7PO-(24).Thesurface of the activated carbon particles was coated with AMPmicrocrystals through a controlled crystallization process. TheX-ray diffraction (XRD) analysis identified the AMP loadedon AC with the formula of (NH_4)_3PO_4(MoO_3)_(12).4H_2O.Scan-ning electron microscope images demonstrated that the fineAMP crystals was successfully immobilized and uniformlydistributed on the porous carbon substrate. The effects ofmedium acidity, contact time, temperature and competing ionson Cs+ uptake by the composite were investigated. The resultsshow that the as-prepared adsorbent keeps high selectivity andadsorption capacity (' 0.75 mmol/g) for Cs+ in acidic feedsolution (0.1 M HNO3), even in the presence of plentifulcompeting cations, Na~+,Zn~(2+), Sr~(Cr~(3+)and La~(3+), whileactivated carbon itself has no specific affinity for Cs+. Theadsorption process could be described by Langmuir adsorp-tion equations. There is no significant difference (9.4%) onCs+ adsorption by the composite during system temperaturechanging from 298 to 348 K.