纳米氧化铈在醇水混合溶液中的分散行为

Dispersion Behavior of CeO_2 Nano-particles in Ethanol-water Mixed Solution

通过沉降实验结合分光光度计、透射电镜等手段,考察了纳米氧化铈在不同比例醇水混合溶液(包括无水乙醇和纯水)中的超声分散性和悬浮稳定性;同时,测量了其在不同比例醇水混合溶液中的Zeta电位,并初步探讨了其分散机制。研究表明,随着醇水混合溶液中乙醇含量的减小,纳米氧化铈的超声分散性和悬浮稳定性均呈现出先升后降的规律;当乙醇含量为40%(体积分数)时,纳米氧化铈的超声分散性和悬浮稳定性均达到最好,其分散率为52.7%,且静置10天后的沉降率也仅为20.2%;此外,在该体系中纳米氧化铈保持其初始粒径的能力较强。纳米氧化铈在醇水混合溶液中的分散不遵守双电层理论,而与分散介质对颗粒的溶剂化作用有关。

The ultrasonic dispersity and the suspension stability of CeO2nano-particles in different proportional ethanol-water mixed solutions including absolute ethanol and pure water have been investigated through sedimentation experiments with the aid of spectrophotometer,transmission electron microscope（ TEM） and other means. Meanwhile,Zeta electric potentials of CeO2nano-particles in different proportional ethanol-water mixed solutions were measured,and the dispersion mechanism was preliminary explored. Results show that the ultrasonic dispersity and the suspension stability of CeO2nano-particles present the pattern of increase first and then decline with the decrease of the ethanol content in ethanol-water mixed solution. When the ethanol content is 40%,both the ultrasonic dispersity and the suspension stability of CeO2nano-particles reach the best. The dispersion ratio is 52. 7% and the sedimentation ratio of CeO2nano-suspensions after standing for 10days is only 20. 2%. Moreover,CeO2nano-particles dispersed in the solution with 40% ethanol content have the best ability to maintain the original grain diameter. The dispersion of CeO2nano-particles in ethanol-water mixed solution does not follow the DLVO theory but maybe relate to the solvation of dispersion medium towards particles.