稻壳联产纳米白炭黑与活性炭的研究

A Study on Production of Nano-Silica and Active Carbon from Rice Husk

研究了由稻壳同时制备纳米白炭黑和活性炭的最佳工艺条件,并对提高产品质量的主要因素作了初步探讨。由滤液硅酸钠溶液制备纳米白炭黑可采用氯化铵中和,聚乙二醇-6000作表面活性剂,所得纳米白炭黑质量完全符合国家标准。筛选出了反应的最佳工艺条件:与稻壳灰反应的NaOH的浓度为2.5mol/L,反应时间为4h,反应温度100℃。在此条件下,SiO2的提取率为95%,白炭黑的白度在90%以上,所得活性炭的亚甲蓝吸附值为140ml/g以上。制备的纳米白炭黑制品为白色絮状沉淀,经X射线衍射分析,结果表明制品为无定形非晶态物质。TEM分析可知,粒子呈球形,粒径为40nm左右。红外光谱分析发现,纳米白炭黑中的SiO2为无定形水合二氧化硅。

The optimum technological conditions for synchronous preparation of nano-silica and active carbon from carbon rice husk were researched and the main factors for improvement of product quality were discussed. The nano-silica can be prepared by reaction of sodium silicate solution and ammonium chloride, and by using glycol-6000 as suffactant. The prepared nano-silica is completely consistent with the national standard. The optimal technological parameters for the reaction were NaOH concentration 2.5 mol/L, time 4 hours and reaction temperature 100℃. Under these conditions, 90% silicon oxide can be solved out,the whiteness of silica aerogel is above 90% and the value of active carbon adsorption of methylene blue is over 140 ml/g. The prepared nano-siliea product is a white floecule precipitate. The results shows that nano-silica product is an amorphous substance by analysis of X-ray diffraction and its particle is spherical with average size of about 40 nm under analysis of TEM. Infrared absorption spectrum analysis shows that SiO2 in nanosilica is amorphous hydrated silica.