NMR Investigation of the Fractionation of Water–Ethanol Mixtures with Starch and Its Cross-Linked Forms
详细信息 查看全文
- 作者：Leila Dehabadi ; Lee D. Wilson
- 刊名：Energy & Fuels
- 出版年：2016
- 出版时间：July 21, 2016
- 年：2016
- 卷：30
- 期：7
- 页码：5684-5692
- 全文大小：433K
- 年卷期：0
- ISSN：1520-5029
文摘
The development of low-cost materials and efficient methods for the fractionation of water and ethanol in binary mixtures is of great interest for food processing and biofuels production. Herein, we report a systematic study of a series of linear and branched starch-based biopolymers along with their modified forms via cross-linking with epichlorohydrin (EPI) at variable EPI composition. The fractionation properties of these adsorbent materials were studied in binary ethanol–water solutions and compared against those of neat solvents. 1H NMR spectroscopy was used to assess the binary solvent composition for the study of isotherms for the respective solvent components. The monolayer adsorption capacity (Qm) for starch and its cross-linked forms varied from 0.01 to 2.70 g·g–1 for water and ethanol in binary mixtures according to the Sips isotherm model. The fractionation selectivity [Rselectivity; Qm(W)/Qm(E)] of starch-EPI adsorbents for water (W) and ethanol (E) in binary mixtures ranges from 3.8 to 80. At saturative conditions in binary W–E mixtures, the Rselectivity isotherm parameter reveals unique solvent-selective uptake that depends on the amylose versus amylopectin composition and the EPI content of these cross-linked materials. The unique water uptake properties of starch and its cross-linked forms illustrate the role of textural properties and relative hydrophobic character of the polymer network based on the selective adsorption properties. Starch and its modified forms represent a promising class of adsorbent materials and a sustainable technology for the adsorptive-based fractionation of W–E binary mixtures.