微波辐射稻壳灰制纳米SiO_2

目的]研究稻壳灰制备纳米SiO2的方法,为稻壳灰综合利用提供参考。方法]在微波辐射条件下,采用稻壳灰为原料制备出硅酸钠。而后,又以这种硅酸钠为原料,用化学沉淀法制备出纳米SiO2。结果]研究了焙烧温度、表面活性剂的用量及溶液pH值对纳米SiO2粒径的影响。硅酸的聚合速度与溶液的pH值有很大关系,而聚合速度直接影响到硅酸的分子量,进而影响SiO2的粒径,溶液pH值在5~6最好;焙烧温度对SiO2的粒径及形貌有较大影响,温度高了,团聚多,形貌不好;表面活性剂的用量需达到一定值才可防止粒子团聚。结果表明：在PEG添加量为≥0.15 g时,经过600℃焙烧后,可制备近似球形的纳米SiO2。结论]利用微波辐射提取稻壳灰中的SiO2,通过化学沉淀法可制备近似球形的纳米SiO2。该方法操作简单,易于工业化,有利于稻谷壳灰的综合利用。

Research on the Preparation of Nano Silica from Rice Husk Ash with Microwave Treatment

Objective] The reference for the comprehensive utilization of rice husk ash was provided through the research on the preparing method of the silica nano from rice husk ash.Method] The sodium silicate was prepared with rice husk ash as raw material under the condition of microwave radiation;and then,the nano silica was prepared with sodium silicate as the raw material by means of the method chemical precipitation.Results] The effect of the calcination temperature,the amount of surfactant and the pH value ...