Preparation of NaOH Modified Spent Grain Adsorbent and Adsorptive Properties for Dyes

The spent grain which is the by-product of beer production contains cellulose, lignin and other substances. It can be used as an adsorbent material not only for waste utilization, but also to reduce environmental contamination. The structure and morphology of spent grain (SG) were discussed. The NaOH modified spent grain (ASG (alkaline spent grain)) was prepared. And the effects of the parameters such as NaOH concentration, temperature and time on the absorption performance of Methylene blue wastewater were analyzed. The results showed that, when the modifier concentration reached 5 g/L, the temperature and time was 60 degrees C and 120 min respectively, the maximum decolorization could reach 95.87%. The decolorization rate of 55.82% of the original grain increased significantly. The adsorption process of themodified materials was chemical adsorption, and the adsorption behavior could be described by Freundlich and pseudo-second-order kinetics equation.