Separation of ethanol/water azeotrope using compound starch-based adsorbents

Area of Science:

• Materials Science
• Chemical Engineering
• Green Chemistry

Background:

• Ethanol dehydration is crucial for producing anhydrous ethanol.
• Existing methods often involve high energy consumption and costs.
• Development of efficient, cost-effective, and sustainable adsorbents is needed.

Purpose of the Study:

• To formulate and evaluate a novel starch-based adsorptive agent (ZSG-1) for efficient ethanol dehydration.
• To determine the optimal conditions for water adsorption using ZSG-1.
• To assess the recyclability and environmental impact of ZSG-1.

Main Methods:

• Experimental preparation of five starch-based materials.
• Selective water adsorption experiments in a fixed-bed absorber packed with ZSG-1.
• Adsorption kinetics analysis using the Bohart-Adams equation.
• Calculation of adsorption heat (ΔHabs) via inverse gas chromatography.

Main Results:

• ZSG-1 demonstrated high adsorption capacity and efficiency, yielding 99.7 wt% anhydrous ethanol.
• Adsorption kinetics followed the Bohart-Adams model.
• The adsorption process was identified as exothermic and physisorption (ΔHabs = -3.16 x 10^4 J/mol).
• ZSG-1 proved to be recyclable for multiple uses.

Conclusions:

• ZSG-1 is a highly effective, low-cost adsorbent for producing anhydrous ethanol.
• The physisorption nature and recyclability of ZSG-1 highlight its sustainability.
• ZSG-1 offers a viable alternative to conventional ethanol dehydration methods, with potential for integration into upstream processes and reduced pollution.