Preparation of a distillers’ grains derived lignin-chitosan adsorbent for enhanced the distillery wastewater treatment

The distillers' grains and wastewater produced by alcohol fermentation process pose a threat to the ecological environment. This study has designed a method of treating waste with waste, which uses the lignin from distillers’ grains as the base and combining with chitosan to prepare an efficient adsorbent for distillery wastewater treatment. The prepared lignin-chitosan adsorbent was characterized by various methods, its surface was rough and had abundant functional groups, which facilitated the adsorption of pollutants. The COD, TP, TN and NH ₄ ⁺ -N were selected as the typical wastewater indicators to evaluate the treatment effect of the adsorbent on the distillery wastewater. The results showed that lignin-chitosan adsorbent reached adsorption equilibrium for the four pollutants at 120 mins, and the adsorption rates were all above 85%. The adsorption process was in good accordance with the quasi-second-order kinetics dominated by chemical adsorption, and it indicates that the adsorption rate of the adsorbent to the pollutant mainly depends on the interaction between the adsorbate and the surface active site. In addition, the removal rate can still achieve 75% after 5 adsorption cycles. These findings indicate its potential for large-scale applications and promise as a green alternative to activated carbon or synthetic adsorbents.