Facile Preparation of Ammonium Molybdophosphate/Al-MCM-41 Composite Material from Natural Clay and Its Use in Cesium Ion Adsorption

Graphical A composite ammonium molybdophosphate/Al-MCM-41 material is synthesized by a one-pot method with natural clay as the silica and aluminum source. A modified “liquid-phase transport” step allows the use of impure natural clay as the starting material to produce pure product without sedimentation pretreatment. The composite material is effective for the adsorption of cesium ions from brine. Ordered hexagonal mesoporous aluminosilicate matrix (Al-MCM-41) with incorporated ammonium molybdophosphate (AMP) was successfully synthesized by a one-pot synthesis method with natural clay from low-grade potash ores of Qinghai salt lake as the silica and aluminum source. We introduced a modified “liquid-phase transport” step, which allowed the use of impure natural clay as a starting material to directly produce pure product without sedimentation pretreatment. The resultant product was characterized by X-ray fluorescence (XRF) spectroscopy, FTIR spectroscopy, XRD, TEM, 27 Al and 31 P magic-angle spinning (MAS) NMR spectroscopy, and N 2 adsorption/desorption, which indicated that the AMP was immobilized in the mesoporous structure of Al-MCM-41. The adsorption capacity of the final product for the removal of cesium ions in solution was also investigated. The results suggested that salt lake clay is a promising low-cost precursor for the production of mesoporous aluminosilicate supports through one-pot syntheses, and the final composite material is effective for the adsorption of cesium ions from solutions containing other alkali metal ions.