Preparation of amidogen-rich monolithic corn bract via surface graft modification for efficient separation of acid red from wastewater

A novel monolithic amidogen-rich biomass adsorbent was successfully prepared. Corn bract (CB) was employed as adsorbent matrix, and arginine (Arg) was selected as a bonding bridge between the hydroxyls on cellulose that came from CB and modifier molecules to enrich reactive sites and improve reaction activity. Polyethyleneimine (PEI) was then grafted to the surface of CB in a heterogeneous reaction. The resultant CB-g-PEI (CB-grafted-PEI) held a grafting ratio of 60.6%. And the maximum adsorption for (acid red 18) AR18 was reached 506.7 mg/g. As a necessary content of adsorption behavior research, models about isotherm adsorption, adsorption kinetics and adsorption thermodynamics were all inspected. According to the research conclusions obtained, the pseudo-second-order model provides the best explanation for the kinetics of adsorption. The adsorption isotherm of AR18 is in better agreement with the Langmuir isotherm model. The adsorption and desorption experiments were conducted over 6 times. The samples were characterized using FT-IR, SEM and EDS. The study suggests that the CB-g-PEI is an available adsorbent. Graphical abstract