The circular economy, which attempts to decrease agricultural waste while also improving sustainable development through the production of sustainable products from waste and by-products, is currently one of the main objectives of environmental research. Taking this view, this study used a green approach to synthesize two forms of silver nanoparticles: coated silver nanoparticles with olive leaf extract (Ag-olive) and uncoated pure silver nanoparticles (Ag-pure), which were produced by the calcination of Ag-olive at 550 °C. The extract and the fabricated nanoparticles were characterized by a variety of physicochemical techniques, including high-performance liquid chromatography (HPLC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Adult ticks (Hyalomma dromedarii) (Acari: Ixodidae) were used in this study to evaluate the antiparasitic activity of synthesized nanoparticles and extract. Furthermore, the antifungal activity was evaluated against Aspergillus aculeatus strain N (MW958085), Fuserium oxysporum (MT550034), and Alternaria tenuissiuma (MT550036). In both antiparasitic and antifungal tests, the as-synthesized Ag-olive showed higher inhibition activity than Ag-pure and olive leaf extract. The findings of this research suggest that Ag-olive may be a powerful and eco-friendly antiparasitic and antifungal agent. Ag-pure was also evaluated as a photocatalyst under sunlight for the detoxification of Eri-chrome-black T (EBT), methylene blue (MB), methyl orange (MO), and rhodamine B (RhB).

Herein, novel MgAl₂O₄-based quadruple nanocomposites containing different contents of Co/Ni bimetallic doping were synthesized employing gelatin as a green capping agent. Typically, MgAl₂O₄ (MgAl₂O₄-1), 5% NiO-5% CoO@MgAl₂O₄ (MgAl₂O₄-2), 2.5% CoO-5% NiO@MgAl₂O₄ (MgAl₂O₄-3), and 5% CoO-2.5% NiO@MgAl₂O₄ (MgAl₂O₄-4) were synthesized via a one-pot method. The prepared quadruple nanocomposites were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), surface analysis, and Fourier transform infrared spectroscopy (FTIR) spectroscopy. MgAl₂O₄-1, MgAl₂O₄-2, MgAl₂O₄-3, and MgAl₂O₄-4 exhibited surface areas of 75.4, 118.4, 141.1, and 123.0 m² g^-1, respectively, and possessed q_t values of 46.8, 60.9, 72.4, and 60.2 mg g^-1, respectively, toward the indigo carmine (INCR) dye. The INCR sorption onto MgAl₂O₄-1, MgAl₂O₄-2, MgAl₂O₄-3, and MgAl₂O₄-4 followed the pseudo-second-order model, and the liquid film diffusion model controlled the INCR sorption onto MgAl₂O₄-1, MgAl₂O₄-2, MgAl₂O₄-3, and MgAl₂O₄-4 nanocomposites. MgAl₂O₄-3 was selected as the best sorbent for eliminating INCR, and it exhibited enhanced performance at pH 6.0. The MgAl₂O₄ q_t value increased proportionally with the INCR concentration (20 to 100 mg L^-1), and increasing the temperature affected the sorption positively, indicating endothermic sorption. The Langmuir model best fitted among the tested isotherm models, and it predicted a maximum adsorption capacity of 181.0 mg g^-1. MgAl₂O₄-3 was tested for removing INCR from tap water, groundwater, and seawater at 313 K, and it showed an average efficiency of 97.1%, with a standard deviation of 2.4%.

A novel chemosensor has been developed for the accurate and sensitive detection of Hg²⁺ ions in industrial wastewater. This sensor uses a stick-like nanocellulose architecture synthesized via a green method. The unique morphology and surface area of nanocellulose make it an ideal mesoporous substrate for immobilizing the chromophore 1-(benzothiophenyl)-3-(benzooxazolyl)-2-((4-bromophenyl)diazenyl)propane-1,3-dione (azo-dione ligand, ADOL). Comprehensive characterization of the fabricated chemosensor and its nanocellulose base was carried out using FTIR, SEM, TEM, BET surface area, and XRD to evaluate their structural and morphological properties. Spectrophotometric parameters, including pH, response time, selectivity, and sensitivity, were extensively optimized to ensure optimal sensing performance, enabling detection of Hg²⁺ at very low concentrations. Method validation was performed in accordance with ICH (International Council for Harmonisation) guidelines, confirming the reliability of the sensor in terms of limit of detection (LOD), limit of quantification (LOQ), linearity, and precision. The spectrophotometric method achieved a highly sensitive LOD of 9.07 µg L⁻¹. Moreover, the ADOL chemosensor demonstrated excellent reusability, maintaining performance over five cycles following regeneration with 0.1 M thiourea, underscoring its sustainability. Finally, the sensor exhibited outstanding performance in detecting Hg²⁺ across various industrial wastewater samples, highlighting its practical applicability, exceptional selectivity, and high sensitivity for real-world environmental monitoring.

The presence of antibiotics in aquatic systems presents significant ecological and health risks. Herein, Fe₃O₄/MgAl₂O₄ (MgFeAl-1), 2.5%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-2), 5%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-3), and 10%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-4) were synthesized, selecting glucose as a capping agent, and 600 °C as calcination temperature. The TEM, EDX, BET, XRD, and FTIR techniques were employed to characterize the preidentified sorbents. The average size of MgFeAl-1, MgFeAl-2, MgFeAl-3, and MgFeAl-4 was about 6.53, 5.0, 7.61, and 10.52 nm, respectively, and they exhibited surface areas of 114.15, 154.02, 153.36, and 128.54 m² g⁻¹, respectively. The sorbents were tested for the removal of ciprofloxacin (CFCN) from aqueous solutions using the batch protocol. The MgFeAl-2 exhibited the highest performance, achieving an adsorption capacity of 99.45 mg g⁻¹, and the sorption equilibrium was reached within 60 min. The pseudo-second-order model best described CFCN sorption onto MgFeAl-2, and liquid-film diffusion influenced CFCN sorption. The CFCN adsorption onto MgFeAl-2 was well represented by the Langmuir isotherm model (R² = 0.93), indicating a monolayer adsorption. The thermodynamic results indicated a spontaneous, endothermic sorption process. A four-cycle MgFeAl-2 reusability study showed an average efficiency of 90%. Notably, MgFeAl-2 was effective in treating natural-water matrices, with a slight reduction in seawater due to ionic interference. The findings highlight the potential of MgFeAl-2 as an affordable and reusable adsorbent for removing antibiotics from contaminated water.

This work focused on synthesizing MgSiO₃ (0%Mo@MgSi), 2.5%MoO3@MgSiO₃ (2.5%Mo@MgSi), 5%MoO₃@MgSiO₃ (5%Mo@MgSi), and 10%MoO₃@MgSiO₃ (10%Mo@MgSi) by a single-step process utilizing butylated hydroxytoluene (BYHT) as a novel capping agent. The X-ray diffraction analysis of the synthesized nanohybrids indicated amorphous nanohybrids, while the energy-dispersive X-ray spectroscopy results illustrated variations in the MoO₃ doping dosages. The 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids exhibited average sizes of 17.6, 12.2, 11.7, and 9.9 nm, respectively, and surface areas of 43.53, 40.95, 42.17, and 44.98 m²·g⁻¹, respectively. The examination of 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids toward the oxytetracycline (OTC) sorption resulted in q_t values of 72.89, 116.89, 98.39, and 78.46 mg·g⁻¹, respectively. The OTC sorption onto the 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi aligned with the nonlinear pseudo-second order model, and both the intraparticle and liquid-film diffusion models co-influenced the OTC sorption onto the four nanohybrids. Increasing the temperature decreased OTC sorption on 2.5%Mo@MgSi, indicating exothermic sorption. The Langmuir isotherm model was more suitable than the Freundlich model for describing OTC adsorption on 2.5%Mo@MgSi. The Dubinin–Radushkevich energy (E_D ≤ 8.0 kJ·mol⁻¹) and the Gibbs free energy (ΔG° ≤ 20 kJ·mol⁻¹) supported each other’s outcomes about the OTC removal onto 2.5%Mo@MgSi being via physisorption. The ΔG° values increased proportionally with temperature, indicating that OTC sorption becomes more spontaneous as temperature decreases. Moreover, the 2.5%Mo@MgSi exhibited excellent stability in OTC elimination up to the third cycle.