Evaluation of the black soybean hulls agro-industrial waste for chloroquine removal from aqueous medium and treatment of multi-components

The COVID-19 pandemic increased the pollution of water resources by some contaminants, e.g., chloroquine (CQN), due to its probable benefit in the treatment of the virus. Thus, is necessary the removal of CQN from water through advanced techniques. Black soybeans have been widely used due to their benefits to human health, and as a result, there was an increase in soybean husk residue, the main by-product of the soybean processing industry. Given the current scenario and the need to develop new uses for this agricultural residue, this study aimed to establish an economical and environmental biotechnology by the CQN adsorption process onto black soybean hulls (BSH) for the first time. BSH was characterized by physicochemical and spectroscopic techniques that demonstrated porosity, organic functional groups and negative surface charges. The pH study did not affect CQN adsorption pronouncedly, indicating that pi-interactions and hydrogen bonds are the main mechanisms of the adsorption process. The maximum adsorption capacity was 75.06 +/- 2.24 mg g(-1) with 240 min of contact time at 288 K. In order to verify the biosorbent applicability, the safranin orange dye and triclosan adsorption were also evaluated onto BSH. The absorption peaks of the contaminants used in the synthetic mixture demonstrated a removal rate of 90.81 +/- 0.80% for safranin orange, 66.79 +/- 1.12% for triclosan and 70.62 +/- 0.67% for CQN. The satisfactory removal of other contaminants indicates that BSH is a promising, affordable and environmentally friendly biosorbent with applicability potential for alternative treatment of contaminated water.