Abstract: In order to understand the difference between domestic activated carbon (ACP) and foreign activated carbon (ACD) in the decolorization efficiency of zein, the decolorization efficiency and microstructure of ACP and ACD were compared. The results showed that there was no significant difference between the decolorization efficiencies of zein solution and extract, but the pigment adsorption rate of ACP (77.31%) was higher than that of ACD (67.27%). Furthermore, scanning electron microscopic analysis showed that the structure of ACP was extended inwards while the structure of ACD was less porous. Then, specific surface analysis and pore size analysis showed that the specific surface area and total pore volume of ACP (1 438.082 m2/g, 1.310 cm3/g) were bigger than those of ACD (779.809 m2/g, 0.626 cm3/g) because there were more micropores and mesopores in the structure of ACP. Meanwhile, the surface of ACD showed more carboxylic acid and lactone functional groups, which could enhance the chemical adsorption of activated carbons effectively when bound to the hydroxyl groups in the pigment molecules. Simultaneously, ACD was more homogeneous in particle size, which was beneficial to the solid-liquid separation after decolorization. Taken together, ACD is more suitable for zein decolorization.

Key words: zein, activited carbon, decolorization, microstructure characterization