A study on physicochemical properties and adsorption performance of modified porous maize starch

Maize starch was carried out enzymatic hydrolysis by mixed enzymes of alpha amylase and glucoamylase at the ratio of 3:1 (w/w) to produce porous starch; the porous starch was then oxidized by sodium hypochlorite to prepare oxidized porous starch; and citric acid cross-linking was followed to prepare cross-linked oxidized porous starch. The modified starch was characterized by SEM, FTIR, DSC and XRD. With the progress of several modifications, the starch structure was seriously damaged, but its adsorption performance is gradually enhanced. The adsorption properties of the modified starch as an ammonium ion adsorbent was also investigated, which showed that adsorption process was a physical adsorption process, and it was in accordance with Freundlich isotherm equations, followed the pseudo-second-order model. (paper)