A green route for preparation of low surface area SiO sub(2) microspheres from wheat straw ash with activated carbon and NPK compound fertilizer as by-products

In order to make full use of wheat straw ash which is abundant and causes some serious environmental problems in the north of China, an environmentally friendly route is proposed to convert the wheat straw ash to useful materials in this paper. In this route, low surface area SiO sub(2) microspheres...

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Bibliographic Details
Published in:RSC advances 2015-09, Vol.5 (98), p.80238-80244
Main Authors: Cui, Jinlong, Cui, Liying, Cheng, Fupeng, Liu, Lingjuan, Sun, Hongliang, Li, Song, Wen, Zhongsheng, Sun, Juncai
Format: Article
Language:English
Subjects:
Activated carbon
Ashes
Byproducts
Fertilizing
Microspheres
Silicon dioxide
Straw
Triticum aestivum
Wheat
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Summary:In order to make full use of wheat straw ash which is abundant and causes some serious environmental problems in the north of China, an environmentally friendly route is proposed to convert the wheat straw ash to useful materials in this paper. In this route, low surface area SiO sub(2) microspheres are obtained from wheat straw ash, with the activated carbon and Nitrogen-Phosphorus-Potassium (NPK) compound fertilizer as by-products. KOH is used as the silica extraction reagent and H sub(3)PO sub(4) is the precipitator. The resulting SiO sub(2) microspheres with narrow size distribution have an amorphous structure with diameters of approximately 480 nm and a specific surface area of 47.79 m super(2) g super(-1) under the optimized synthesis conditions with a volume ratio of 1 : 1.5 : 1 for extract/water/ethanol, a pH value of 8 and H sub(3)PO sub(4) solution dripping rate of 3 mL min super(-1). In this optimized route, the yields of SiO sub(2) and activated carbon reach 96.77% and 71.89%, respectively. The waste water produced in this process is used to produce NPK compound fertilizer. The whole route is an environmentally friendly process without any emission of pollution.
ISSN:2046-2069
DOI:10.1039/c5ra14622d