油页岩灰渣提取硅酸钠制备纳米二氧化硅

Preparation of Silica Nanoparticles Using Sodium Silicate Extracted from Oil Shale Ash as Precursor

以油页岩灰渣提取的硅酸钠为原料,采用溶胶-凝胶法并结合多种纳米粉体分散技术,制备了分散性好、粒径均一的纳米SiO2,其平均粒径约为10 nm。制备过程中聚乙二醇(PEG)的加入能够有效的降低纳米SiO2的表面能,减少粒子的团聚,PEG的最佳浓度为3.0%;超声振荡的空化作用所释放出的巨大冲击波和微射流,能有效地击散纳米SiO2团聚体,其最佳超声时间为0.5 h;硅酸湿凝胶与正丁醇共沸蒸馏能有效脱除凝胶中的水,防止干燥过程中颗粒间硬团聚。

Spherical silica nanoparticles with average particle size of 10 nm were synthesized using sodium silicate extracted from oil shale ash as silica source.The results showed that the addition of poly（ethylene glycol）（PEG） could effectively prevent the aggregation of silica nanoparticles and tune the particle size,the optimal PEG concentration was found to be 3.0%.Ultrasonication is a key factor to the formation of small,uniform nanoparticles and an optimized hydrolysis-condensation period for ultrasonication is 0.5 h.The azeotropic distillation evidently suppresses agglomeration and a possible mechanism of azeotropic distillation was also proposed.