Algae have adsorption properties and reducing agents due to their rich content. In this study, palladium nanoparticles (Pd NP), platinum nanoparticles (Pt NP), and iron oxide nanoparticles (Fe₃O₄ NP) were prepared from Codium macroalgae using green synthesis. The structure of the synthesized nanoparticles was elucidated by X‐ray diffractometry, Fourier transforms infrared spectroscopy, Brunauer–Emmett–Teller analysis, transmission electron microscopy, ultraviolet‐visible spectroscopy and scanning electron microscopy‐energy dispersive X‐ray spectrometry and their use as nanoadsorbents for the removal of pollutants from aqueous media was investigated in detail. Naproxen (NPX), an anti‐inflammatory drug, and the dyes methylene blue (MB) and cresol red (CR) were selected as pollutants for this study. Batch adsorption experiments were conducted using both real wastewater obtained from the Organised Industrial Zone of Isparta Province and synthetic water samples prepared with tap water from Burdur Province and pure water. Under optimum adsorption conditions, Pd NP showed significant efficiency in the real wastewater sample, with an adsorption capacity of 37.19 and 50.03 mg g^–1 for CR and NPX, respectively, within 150 min. In comparison, Pt NP showed an adsorption capacity of 40.01 mg g^–1 for MB within the same timeframe. These findings indicate that while Pd NP showed the highest adsorption capacity for both CR and NPX, Pt NP showed the highest adsorption capacity for MB. The Langmuir model and the pseudo‐second‐order equation were more suitable to describe the adsorption behavior of CR, MB, and NPX. In addition, studies on the desorption and reusability of the nanoadsorbents were carried out under the same optimum experimental conditions.

Magnetic iron oxide (Fe₃O₄) nanoparticles, iron oxide chitosan (Fe₃O₄-CS) and iron oxide alginate (Fe₃O₄-AT) nanocomposite beads were synthesised using green synthesis method. They were used as both adsorbents for the adsorption of methyl orange (MO) dye from the wastewater and heterogeneous catalysts for the catalytic wet peroxidation (CWPO) of MO. While the dye removal was successfully performed with Fe₃O₄NPs, Fe₃O₄-CS and Fe₃O₄-AT in both adsorption studies and CWPO, the highest removal efficiency (99%) in the shortest time (8 min for adsorption, 20 min for CPWO) was obtained with Fe₃O₄-CS for MO removal. The adsorption experiments were performed with the batch techniques at different contact time, pH, initial dye concentration, temperature, amount of adsorbent and foreign ion effect parameters by Fe₃O₄-CS adsorbent. The equilibrium was quickly reached after 30 min at pH 3 and 298 K. Fitting equilibrium data to Langmuir, Temkin and Freundlich isotherms showed that Langmuir model was more suitable to describe MO adsorption with a maximum monolayer adsorption capacity of 132 mg/g at 298 K. The Experimental data were analysed using intra particle diffusion, pseudo-first-order and pseudo-second-order kinetic models and it was found that the adsorption kinetics followed a pseudo-second-order equation. Based on thermodynamic studies, adsorption process occurred as spontaneous and exothermic. The effects of the amount of catalyst, pH, temperature and H₂O₂ concentration were investigated to determine their catalytic activities for the decomposition of MO with CWPO technique. The reusability of Fe₃O₄-CS for both adsorption and CWPO techniques for MO removal was performed, and the adsorption and oxidation efficiency was found to be 97%. Moreover, the reaction kinetics was also investigated and the oxidation reaction was in good agreement with the pseudo-first order kinetic model. The activation energy (Ea) of the reaction was found to be 10.72 kJ/mol.

Cu(II) was separated and preconcentrated using solid phase extraction and a slotted quartz tube (SQT) and determined in drinking water and walnuts by flame atomic absorption spectrometry. The procedure is based on the sorption of copper(II) on a column filled with a resin followed by elution with 5 mL of 3 mol L⁻¹ nitric acid in the first preconcentration step. To increase the sensitivity of system, the preconcentration parameters for copper(II) were optimized. The SQT was used as the second preconcentration step to further improve the sensitivity. The enrichment factor and detection limits were 640 and 0.23 µg L⁻¹, respectively. Another advantage of this method is the presence of a wide pH range for copper(II) sorption with high effectiveness in acidic media. The accuracy of method was confirmed by the analysis of a spinach leaves certified reference material (NIST 1570a).