Zirconium phosphate Dispersed on a Cellulose Fiber Surface : Preparation, Charcterization, and Selective Adsorption of Li~+, Na~+,and K~+ from Aqueous Solution

摘要

Highly dispersed zirconium phsophate was prepared by reactiing Cel/ZrO_2(ZrO_2=6.7 wt%; 0.56 mmol g~(-1) of zirconium atom per gram of the material ) with phosphoric acid. High power decoupling angle spinning (HPDEC-MAS)~(31)P NMR and X-ray photoelectron spectroscopy. The X-ray photoelectron spectroscoy data indicated HPO_+4~(2-) is the species present on the fiber surface. The X-ray diffraction patterns showed that zirconium hydrogen phosphate particles were amorphous and had an ion-exchange capacity, determined by ammonia gas adsorption , of 0.30 mmol g~(-1) . The ion-exchange capacities for Li~+, Na~+, and K~+ ions weere determined from ion were determined from ion-exchange isotherms at 298 K and showed the followign values (in mmol g~(-1) ): Li~+ =0.01, Na~+=0.23 , and K~+=0.30. The higher affinity of the surface hydrogen phosphate particles for Na~+ and K~+ is due to its lamelar structure which permits easier diffusion of these two ions whose hydrated radii are smaller that that of Li~+