Biochar from waste green coffee extracted bioactive compounds as materials for ammonium adsorption

Abstract

This study investigates the adsorption potential of AC-GCB biochar, obtained by pyrolyzing green coffee extracted bioactive compounds at 400 ºC, for ammonium removal from groundwater. The biochar's microstructure was characterized using scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectrometry (EDS) Mapping. Optimal adsorption conditions were observed at an initial pH range of 4 to 8, an initial NH4+ concentration of ≤ 25 mg.L-1, and a biochar dose of 10 g.L-1. The ammonium adsorption of AC-GCB was consistent with both Langmuir and Freundlich's adsorption theories (R2 > 0.92). The AC-GCB biochar obtained the maximum adsorption capacity Qm was 14,48 mg.g-1, higher than the control BC-GCB biochar that pyrolysised without bioactive compound extracted with Qm was only 5.41 mg.g-1.