Study On The Preparation Of Nano-cerium Oxide And Its Particle Size Control

Ceria,as a cheap and widely used rare earth oxide,has important applications in the fields of ultraviolet absorption,water pollution treatment,mechanical polishing and so on.In this paper,the dispersion stability conditions of nano cerium in water were discussed.In the W/O microemulsion system,cerium oxide nanoparticles with controllable 10-100nm size were prepared by changing the experimental parameters.（1）The dispersion stability of nano ceria in water was investigated by physical and chemical methods.It is found that the dispersion efficiency of ultrasonic wave is much better than that of mechanical stirring.Adding dispersant can improve the dispersion stability of nano ceria powder in water.The dispersion stability of nano ceria powder is closely related to the structure and concentration of dispersant.The dispersion effect of inorganic electrolyte with small molecule is better;For organic small molecular dispersant,the ionic dispersant with small hydrophilic group has good dispersion effect,and the chain length of oleophilic group has little effect on the dispersion effect.The longer the chain length of lipophilic group in non-ionic tween series dispersants is,the better the dispersion effect is;The steric hindrance effect of organic polymer polyethylene glycol series dispersants is greater,but they are easy to entangle with each other,resulting in particle aggregation and particle size increase.When the concentration of dispersant is about 0.01 mol/L,the dispersing effect of various dispersants on nano ceria powder is better.（2）In the W/O microemulsion system,cerium nitrate was used as raw material,cyclohexane as oil phase and n-butanol as cosurfactant.The effects of surfactant type,calcination temperature,surfactant dosage,cosurfactant dosage,cerium nitrate concentration and oil phase dosage on product size were investigated.It is found that the type of surfactant affects the particle size and agglomeration of nano ceria.The particle size of ceria prepared by cationic surfactant is smaller than that of anionic surfactant and has good dispersion;The agglomeration of nano ceria prepared by nonionic surfactant is serious,which makes the particle size larger and the distribution range wider.The results show that the amount of surfactant has the most obvious effect on the particle size of nano ceria,and nano ceria with particle size distribution of 12-21nm,21-39nm,55-82nm and 61-95nm can be prepared by changing the amount of surfactant;Calcination temperature,cosurfactant dosage,cerium nitrate concentration and oil dosage have less effect on the particle size of nano ceria than surfactant dosage,and nano ceria with particle size distribution of 12-52 nm can be prepared.By adjusting the experimental parameters,Ce O₂nanoparticles with controllable size of 10-100nm can be prepared.