Preparation of porous starch and its use as a structure-directing agent for production of porous zinc oxide

In this communication, a facile and green method is introduced for the preparation of porous starch (PS), citric acid-modified PS (CAPS) and porous ZnO. PS was created by replacing ice crystals in frozen starch gel with selected solvent using a solvent exchange technique. The porosity of PS was greatly affected by the ethanol/water volume ratios. PS was further modified with citric acid (CA) in order to preserve or maintain its porous state, especially upon contact with aqueous solution. CAPS was subsequently used as a structure-directing agent to prepare ZnO with a porous network structure. The thus obtained PS, CAPS and porous ZnO may find their niche in applications such as adsorbent, structure-directing agents for porous metal oxides or as sensors.