Method for easily and fast preparing rice hull-based porous carbon/silicon dioxide composite material

A technology of silicon dioxide and composite materials, applied in the field of porous materials, can solve the problems of complex process operation and high raw material requirements, and achieve the effects of simple process, high product yield and rich raw material sources.

Active Publication Date: 2014-12-17
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The present invention overcomes the disadvantages of complex operation and high requirements on raw materials in the past, uses rice husks as a cheap and renewable resource, and prepares porous carbon / silicon dioxide composite materials through a simple and fast one-step method, making full use of rice husks and obtaining high additional Value materials, which can be used in the fields of polymer addition, adsorption separation, and capacitors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Mix 20 g of 80-mesh rice husk with 40% (mass fraction) H 3 PO 4 Mix according to the impregnation ratio (mass ratio of phosphoric acid and rice husk) 4:1, treat at 600°C for 30 minutes, cool down, wash with water at 90°C until neutral, and transfer the water for each washing while hot, and the obtained product is stored at 120°C The rice husk-based porous carbon / silica composite material with a yield of 43.9% can be obtained by drying under high temperature, in which the silica content is 17.8%, and its specific surface area reaches 1510 m 2 / g, its specific capacitance value measured by electrochemical workstation is 171 F / g, 300 mL of initial washing water is collected for static cooling, and the supernatant is used for reclaiming phosphoric acid, and the phosphoric acid recovery rate is 61.1%.

Embodiment 2

[0028] Mix 20 g of 60-mesh rice husk with 50% H 3 PO 4 Mix according to the impregnation ratio of 5:1, treat at 500 °C for 20 minutes, cool down, wash with water at 60 °C until neutral, pour out the water for each washing while it is hot, and dry the obtained product at 120 °C. Rice husk-based porous carbon / silica composite material with a content of 45.9 %, in which the silica content is 14.8 %, and its specific surface area reaches 1640 m 2 / g, the specific capacitance value is 153 F / g, 300 mL of the initial washing water is collected for static cooling, and the supernatant is used to reclaim phosphoric acid, and the phosphoric acid recovery rate is 76.0%.

Embodiment 3

[0030] Mix 20 g of 20-mesh rice husk with 60% H 3 PO 4 Mix according to the impregnation ratio of 4:1, treat at 400 °C for 90 minutes, cool, wash with water at 40 °C until neutral, pour out the water for each washing while hot, and dry the obtained product at 120 °C to obtain Rice husk-based porous carbon / silica composite material with a content of 48.3 %, in which the silica content is 28.0 %, and its specific surface area is 985 m 2 / g, the specific capacitance value is 187 F / g. 300 mL of the initial washing water was collected for static cooling, and the supernatant was used to recover phosphoric acid, and the recovery rate of phosphoric acid was 62.8%.

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Abstract

The invention relates to a method for easily and fast preparing a rice hull-based porous carbon / silicon dioxide composite material. The method particularly comprises the following steps of: (1) cleaning rice hulls, then crushing into power with a particle size of 20-80 meshes and preparing a phosphoric acid solution; (2) mixing the crushed rice hulls with the phosphoric acid solution; (3) treating the mixture at 400-600 DEG C for 20-90 minutes, and then cooling to obtain a crude product; (4) washing the crude product to neutral by using 40-100 DEG C water, wherein hot water used for washing every time needs to be poured out in time after the hot water is mixed with the crude product; and drying obtained filter residues to obtain the rice hull-based porous carbon / silicon dioxide composite material. The method disclosed by the invention overcomes the defects that the traditional technological operation is complex, has high requirement on raw materials and the like, and is capable of preparing the rice hull-based porous carbon / silicon dioxide composite material through a simple and fast one-step method by utilizing rice hull which is a low-cost renewable resource, thereby sufficiently utilizing the rice hulls and obtaining the material with high additional value; and the material with high additional value can be used in the fields of high-molecular addition, adsorption and separation, capacitors and the like.

Description

technical field [0001] The invention relates to the technical field of porous materials, in particular to a method for obtaining rice husk-based porous carbon / silicon dioxide composite materials by simply crushing rice husks and reacting with phosphoric acid at a certain temperature for a short time without complex pretreatment . Background technique [0002] Because porous materials can be widely used in the fields of adsorption, catalysis, chromatography, separation, photoelectricity, etc., more and more researchers have paid more and more attention to them. Applications such as high-efficiency adsorption and separation, heterogeneous catalysts, and energy storage devices have brought new challenges to porous materials. Higher requirements, in addition to the need for a well-developed pore structure, most of them also need to have a hydrophobic surface and coexistence with active substances. obtained from materials such as clay. [0003] There are many previous patents r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/02C01B33/12
Inventor 李赢石刚石贵阳倪才华王子忱
Owner JIANGNAN UNIV
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