Aminated graphitic carbon derived from corn stover biomass as adsorbent against antibiotic tetracycline: Optimizing the physicochemical parameters

There is an urgent demand to abate contamination of the water resources and wastewaters from antibiotics, released predominately from the municipal and healthcare effluents. Herein, we modified an eco-friendly and renewable agro-waste/biomass material in order to obtain an efficient adsorbent against the antibiotic tetracycline hydrochloride (TC). Corn stover biomass was thermally converted to porous reduced graphite oxide (RGO) and then was post functionalized to an aminated graphitic carbonaceous material (ACS-RGO). The materials were characterized by nitrogen adsorption/desorption, scanning electron microscopy (SEM), transmission electron microscope (TEM), as well as Raman and FTIR spectroscopy. The sorption process was statistically modeled, by systematically varying crucial factors, based on Box–Behnken design (BBD). The model analysis illustrated the effect of independent variables and their correlations in order to determine the optimum parameters/conditions. The highest TC removal (100%) was found to occur for initial TC concentration of 48.74 mg/L, 0.98 gL dosage of adsorbent, 51.6 min contact time and at pH = 7.4. The maximum monolayer adsorption capacity estimated to be 132.9 mg of TC per gram of ACS-RGO.