ABSTRACT
Background: In order to propose a destination for the bottom ash generated from biomass burning, its morphology, functional groups and mineral phases were studied. Dipyrone has been extensively used as an antipyretic, increased due to cases of COVID-19, and due to excretion by urine, incorrect disposal and industrial effluents has been destined to wastewater, being harmful to human and animal life. The present study proposes using biomass ash for the adsorption of dipyrone. Result(s): The characterization of biomass ash shows a sufficient surface area size for adsorption, and a mainly amorphous structure with some peaks of quartz, calcite and other mineral phases. The results show that the kinetic model which best describes the adsorption is the pseudo-first-order model. The Langmuir model best fits at 25 degreeC, and the Freundlich model best describes the adsorption at 35 and 45 degreeC. The thermodynamic parameters indicated that the process is endothermic with a maximum adsorptive capacity of 65.27 mg g-1. In addition, the adsorption is spontaneous, disordered and chemical. The ionic strength study reveals that the adsorbent is promising for real effluent treatment and there is evidence that electrostatic interaction is not the primary adsorptive mechanism, agreeing with the result obtained from pH testing. The proposed mechanism for dipyrone removal involves hydrogen bonds, pi bonds and electron donor-acceptor complex. Conclusion(s): The results are promising in comparison with recent literature and solve two environmental problems: biomass bottom ash disposal and pharmaceutical removal in aqueous medium. The ash may be regarded as a low-cost and environmentally friendly adsorbent. © 2023 Society of Chemical Industry (SCI).
ABSTRACT
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 π-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. © 2023 Taylor & Francis Group, LLC.