Controlling Mechanism of Specific Surface Area of Silica Nanoparticles in Carbonation Process
GU Ming-yuan， LIN Rong-yi, GUO Zhan-cheng,
(1. Academic of Metallurgical and Ecological Engineering，University of Science and Technology Beijing (1. Academic of Metallurgical and Ecological Engineering，University of Science and Technology Beijing (1. Academic of Metallurgical and Ecological Engineering，University of Science and Technology Beijing
Abstract：Using sodium silicate as precursor, the controlling mechanism of specific surface area (SBET) of silica nanoparticles synthesized by carbonation process was investigated. The results of orthogonal experiments demonstrated that the order of factors affecting SBET was: sodium silicate concentration>added mass of PEG6000>reactive temperature>flow rate of CO2/N2 mixed gas. Under the optimal conditions of concentration of sodium silicate at 40 g/L, added mass of PEG6000 4 g/L, reactive temperature 80℃, and flow rate of CO2/N2 mixed gas 1.2 L/min, silica nanoparticles synthesized exhibited a high SBET of 318.9 m2/g. With the increase of concentration of sodium silicate, the size of primary particles increased, but SBET of silica particles decreased due to extension of Ostwald ripening process of SiO2 sol in the carbonation solution where pH>7. Due to the effect of temperature on the solubility and Brownian motion of SiO2 sol, the decrease of reaction temperature could accelerate the nucleation of silica and restrain the agglomeration of Si(OH)4 and ≡SiOSi(OH)3, therefore the SBET increased. The increase of SBET was facilitated by PEG6000 due to its steric hinderance effect. However, when PEG6000 in solution exceeded to 7 g/L, the precursor molecules entered into the PEG with tangled long chain, the SBET of synthesized silica nanoparticles would be decreased.
古明远 林荣毅 郭占成. 碳化合成纳米SiO2颗粒比表面积的控制机理[J]. , 2010, 10(4): 795-801.
GU Ming-yuan; LIN Rong-yi; GUO Zhan-cheng;. Controlling Mechanism of Specific Surface Area of Silica Nanoparticles in Carbonation Process. , 2010, 10(4): 795-801.
2010, Vol. 10 
