Microwave Synthesis of MCM-41 and Its Application in CO<sub>2</sub> Absorption by Nanofluids
Shangyuan Cheng, Youzhi Liu, Guisheng Qi
Abstract
Microwave synthesis method is a green chemical process with mild reaction conditions, fast reaction, and low energy consumption. In this work, an order mesoporous silica material MCM-41 was synthesized by microwave technology. Functionalized MCM-41 was prepared by wet impregnation with polyethyleneimine (PEI). XRD, SEM, TEM, DLS, N 2 adsorption-desorption, FTIR, and TG were used to characterize the physicochemical properties of samples. Furthermore, CO 2 absorption performance in water in the presence of uncalcined MCM-41 and PEI-MCM-41 nanoparticles was evaluated. In addition, the mechanisms of enhanced absorption were also elaborated. The experimental results indicated that the optimum conditions for preparation of MCM-41 were the microwave time of 15 min, microwave temperature of 100°C, and microwave power of 200 W. Under this condition, MCM-41 with narrow particle size distribution, average diameter of 50 nm, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:msub><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mtext>BET</mml:mtext></mml:mrow></mml:msub></mml:math> of 1210.3 m 2 g -1 was obtained. The enhancement effect of PEI-MCM-41 nanoparticles was more obvious than that of uncalcined MCM-41. PEI-MCM-41 as a promoter not only increased the CO 2 diffusion rate but also enhanced the adsorption capacity due to the fact that it owns more active sites that may react with CO 2 . The CO 2 absorption improvement of PEI-MCM-41 (0.1 wt%)/H 2 O was 25.35% higher than that of water.