玉米秸秆全组分气凝胶的制备及其表征

以玉米秸秆为原料, 经溴化锂溶液溶解、叔丁醇溶液置换制备得到玉米秸秆全组分气凝胶, 利用单因素试验对制备条件进行优化, 并通过SEM、FT-IR、N₂吸附-脱附试验和光学接触角等手段表征气凝胶相关性能。研究结果表明: 不同工况下, 溴化锂溶解玉米秸秆形成凝胶的时间均不超过10 min, 在较优条件(溴化锂质量分数66%、反应温度130 ℃、固液比1∶45(g∶g)、反应时间50 min)下制备的玉米秸秆全组分气凝胶密度可低至0.027 4 g/cm³, 比表面积为98.43 m²/g, 并具有超亲水性和超亲油性, 对去离子水和大豆油的最大吸附倍率分别为15.04和18.78 g/g。SEM分析表明制备的全组分气凝胶具有二维片状和三维网络结构; FT-IR分析表明全组分气凝胶中含有纤维素、半纤维素和木质素成分, 纤维素中的氢键网络被破坏。

Preparation and Characterization of Whole Component Aerogel of Corn Straw

Corn straw was used as raw material to prepare the whole component aerogels of corn straw by dissolving in lithium bromide solution and tert-butanol solution replacement. The experimental conditions were optimized by single factor test, and the properties of aerogels were characterized by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FT-IR), N₂ adsorption-desorption test, and optical contact angle test. The results showed that the gelation time of the whole components of corn stalk dissolved in lithium bromide was less than 10 min under different conditions. The density of whole components aerogel of corn stalk was as low as 0.027 4 g/cm³, and the specific surface area was 98.434 8 m²/g under the optimal conditions, i.e., the mass fraction of lithium bromide was 66%, the reaction temperature was 130 ℃, the solid-liquid ratio was 1∶45(g∶g), and the reaction time was 50 min. Furthermore, the aerogel had super hydrophilic and super lipophilic properties, and the maximum adsorption rates of deionized water and soybean oil were 15.04 and 18.78 g/g, respectively. The SEM result showed that the prepared aerogel had two dimensional sheet and three dimensional network structure, and the FT-IR result indicated that the aerogels contained cellulose, hemicellulose and lignin, and the hydrogen bond network in cellulose was destroyed.