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• The innovative green synthesis method of copper oxide nanoparticles was efficient. • The material used as adsorbent obtained a high methylene blue removal of 96.91%. • The adsorbent obtained a maximum adsorption capacity of 166.021 mg g−1 at 318 K. • The thermodynamic parameters indicated a spontaneous and endothermic process. The study proposed a method of obtaining copper oxide nanoparticles through green synthesis using pomegranate leaf for application in the adsorption of methylene blue. The synthesized material was characterized. The kinetic data fitted to pseudo-second-order and the intra-particle diffusion model, which showed three steps: film, intra-particle diffusion and equilibrium. The equilibrium data fitted to the Langmuir model, resulting in the maximum adsorption capacity of 166.021 mg g−1 at 318 K. Also, the thermodynamic parameters indicated a spontaneous, endothermic and reversible process. The results showed a high efficiency of the proposed adsorbent, obtaining up to 96.91% of removal. [ABSTRACT FROM AUTHOR]

This paper explores the feasibility of functionalizing mango stones with iron oxide magnetic nanoparticles (MS-Fe 3 O 4) by coprecipitation in batch adsorption processes. The synthesized material was characterized and applied in chloroquine (CQN) and sertraline hydrochloride (SER) removal from contaminated waters. The biosorbent was subjected to a regenerative study and treatment using a synthetic mixture of contaminants to evaluate its applicability in real effluents. The biosorbent was analyzed by transmission electron microscopy images, scanning electron microscopy, dispersive X-ray spectroscopy, Fourier transform infrared spectra, and zeta potential to characterize its chemical and morphology properties. The techniques applied showed the effectiveness of the proposed modification. In the adsorption experiments, the optimal adsorbent dosage was 0.01 g for both contaminants. The pH strongly influenced the adsorption of the drugs on MS-Fe 3 O 4 , and the best results were obtained in the pH range of 5–6. Kinetic data showed a better fit to the pseudo-second-order model, and the equilibrium time was achieved in 16 h for CQN and 4 h for SER. Isotherm studies revealed maximum adsorptive capacities of 49.42 and 64.79 mg g−1, respectively, for CQN and SER, at 318 K, demonstrating that the increase in temperature is a favorable factor, and the Sips model better describes the process. The thermodynamic parameters indicate an endothermic (ΔH° >0), spontaneous (ΔG° <0), and reversible (ΔS° >0) nature of the adsorption. This process is essentially governed by physical forces, such as hydrogen and π-π bonds. However, it is also valid to consider the presence of electrostatic forces due to the ionizing nature of CQN and SER. The MS-Fe 3 O 4 biosorbent showed good performance when evaluated in a synthetic mixture of four contaminants, with an overall removal efficiency of approximately 86% and the regenerative capacity of three reusing cycles. [Display omitted] • Reutilization of agro-industrial wastes contributes to circular economy perspective. • The evaluated biosorbent is a promising material for wastewater treatment. • MS-Fe 3 O 4 obtained q máx of 49.42 and 64.79 mg g−1 for chloroquine and sertraline hydrochloride adsorption. • The biosorbent demonstrated a global removal efficiency of 86% in synthetic mixture of contaminants. [ABSTRACT FROM AUTHOR]