Porous silica synthesis out of coal fly ash with no residue generation and complete silicon separation  

作　　者：Tongyao Ju Siyu Han Fanzhi Meng Li Lin Jinglin Li Kailun Chen Jianguo Jiang 

机构地区：[1]School of Environment,Tsinghua University,Beijing 100084,China

出　　处：《Frontiers of Environmental Science & Engineering》2023年第9期197-208,共12页环境科学与工程前沿（英文）

基　　金：support by the National Natural Science Foundation of China(No.22176108).

摘　　要：Ordered mesoporous silica materials exhibit enormous potential in industrial production.Since coal fly ash(CFA)is abundant in Si,it has become a green and promising way to utilize CFA by synthesizing porous silica materials.However,the stable crystalline structure of CFA limits the extraction of Si,and the residue is generated during the process of extracting Si.In this work,we proposed a no-residue method to synthesize ordered mesoporous silica out of CFA.Sodium carbonate(Na_(2)CO_(3))was used to reconstruct the crystals of the CFA,and the calcined mixture then directly reacted with the precipitators.This method combined the process of Si extraction and porous material synthesis.In this method,no residue was generated and the silicon in both amorphous and crystalline phases of CFA was fully utilized.By this method,the extraction efficiency of Si was increased from 31.75%to nearly 100%.The as-synthesized mesoporous silica had a highly-ordered pore structure with a space group of la-3d,a surface area of 663.87 m^(2)/g,a pore volume of 0.41 cm^(3)/g,and an average pore diameter of 2.73 nm.The mechanism of crystalline transformation and material structure formation were systematically studied.This method provides a new idea to dispose of CFA and synthesize porous silica materials.

关 键 词：Coal fly ash Alkali fusion Micro-/meso-porous Si Zeolite MCM-48 Crystalline transformation 

分 类 号：O61[理学—无机化学]