Reduction in time required for synthesis of high specific surface area silica from pyrolyzed rice husk by precipitation at low pH.
Reduction in time required for synthesis of high specific surface area silica from pyrolyzed rice husk by precipitation at low pH.
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DOI：
10.1016/j.biortech.2011.04.020
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发表时间：
2011-07
影响因子：
11.4
通讯作者：
Dawei Li;Dengyu Chen;Xifeng Zhu
中科院分区：
文献类型：
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作者：
Dawei Li;Dengyu Chen;Xifeng Zhu
以稻壳为原料，在硅酸钠溶液(SSS)中加入H3PO4，使其pH值分别为5.7、5.0、4.1和3.2，制得具有高比表面积(SSA)的多孔二氧化硅。制备过程包括：以聚对苯二甲酸丁二醇酯(PRH)为原料制备SSS，以SSS、H3PO4和聚乙二醇(PEG)为原料制备二氧化硅-聚乙二醇(PEG)复合材料，并对其进行焙烧。所需的制备时间在10小时以下，在pH 3.2下制备的样品的比表面积达到1018×m2/g。降低pH显著增加了聚乙二醇在二氧化硅-聚乙二醇复合材料中的掺入量，因此在500℃焙烧破坏聚乙二醇时，较低pH的样品会产生更多的气孔。本研究开发的工艺可以更有效地将稻壳转化为可用于吸附气体和重金属离子的高附加值多孔材料。
Porous silica with a high specific surface area (SSA) was prepared from pyrolyzed rice husk (PRH) by adding H3PO4to sodium silicate solution (SSS) until the pH values of 5.7, 5.0, 4.1 and 3.2 were achieved. The preparation process involved producing SSS from PRH, forming silica-polyethylene glycol (PEG) composites using SSS, H3PO4and PEG, and calcinating the composites. The required preparation time was below 10 h, and the SSA of the sample prepared at pH 3.2 reached 1018 m2/g. Decreasing pH significantly increased the amount of PEG incorporated into the silica-PEG composites, and hence more pores were generated in the lower pH sample when the PEG was destroyed by calcination at 500 °C. The process developed in this study could lead to more efficient conversion of rice husk into high value-added porous materials that might be used for the adsorption of gas and heavy metal ions.