Tang Baokun, Bi Wentao, Row Kyung Ho
Department of Chemistry and Chemical Engineering, Inha University, Incheon, 402-751, Korea.
Bioprocess Biosyst Eng. 2014 Jul;37(7):1417-25. doi: 10.1007/s00449-013-1114-0. Epub 2013 Dec 25.
Although most of the water in a bio-ethanol fermentation broth can be removed by distillation, a small amount of water remains in the bio-ethanol distillate as the water-ethanol azeotrope. To improve the use of ethanol as a fuel, glucose-modified silica, as an adsorbent, was prepared using a facile method and applied to the dehydration of bio-ethanol distillate. The factors affecting the adsorption capacity of the adsorbent, such as the particle size, initial concentration of water in the samples, adsorption temperature and adsorbent dose, were examined by measuring the adsorption kinetics and equilibrium. The Langmuir, Freundlich and Temkin isotherms were used to evaluate the adsorption efficiency. Of these, the Freundlich and Temkin isotherms showed a good correlation with the experimental data. The Langmuir isotherm showed some deviation from the experimental results, and indicated that adsorption in this case was not a simple monolayer adsorption. The property of the adsorbent was attributed to functionalized silica with many hydroxyl groups on its surface. An examination of the separation factors of water/ethanol revealed the modified silica to have preferential selectivity for water. Compared to activated carbon and silica, glucose-modified silica exhibited higher adsorption capacity for water under the same adsorption conditions. In addition, the glucose-modified silica adsorbent exhibited a relatively constant adsorption capacity for five adsorption/desorption cycles.
虽然生物乙醇发酵液中的大部分水可通过蒸馏去除，但由于水 - 乙醇共沸物的存在，生物乙醇馏出物中仍残留少量水。为了提高乙醇作为燃料的利用率，采用简便方法制备了葡萄糖改性二氧化硅作为吸附剂，并将其应用于生物乙醇馏出物的脱水。通过测量吸附动力学和平衡，研究了影响吸附剂吸附容量的因素，如粒径、样品中水的初始浓度、吸附温度和吸附剂用量。采用朗缪尔、弗伦德里希和坦金等温线来评估吸附效率。其中，弗伦德里希和坦金等温线与实验数据显示出良好的相关性。朗缪尔等温线与实验结果存在一定偏差，表明在这种情况下吸附并非简单的单层吸附。吸附剂的性能归因于其表面带有许多羟基的功能化二氧化硅。对水/乙醇分离因子的考察表明，改性二氧化硅对水具有优先选择性。与活性炭和二氧化硅相比，在相同吸附条件下，葡萄糖改性二氧化硅对水表现出更高的吸附容量。此外，葡萄糖改性二氧化硅吸附剂在五个吸附/解吸循环中表现出相对恒定的吸附容量。
