SORPTIVE REMOVAL OF PHARMACEUTICALS FROM AQUEOUS SOLUTIONS USING Ni(II),Fe(III)- LAYERED DOUBLE HYDROXIDES AND THEIR FERROMAGNETIC OXIDES

The features of obtaining and structure formation of homogeneous phases of nitrate forms of layered double hydroxides of Ni(II) and Fe(III) (NiFe-LDHs) with different ratios of components in the reaction mixture, as well as their oxide derivatives, were studied. The synthesis was carried out by hydrothermal precipitation from aqueous solutions, allowing the controlled production of homogeneous NiFe-LDHs phases and their subsequent conversion into magnetically separable oxide derivatives. According to the data of X-ray diffraction analysis, the conditions for obtaining the samples provide the required level of crystallinity and characteristic structural features of synthetic layered double hydroxides of the type of natural hydrotalcite and nickel ferrite. A comparative assessment of their adsorption performance with respect to the organic toxi­cant was carried out. The adsorption capacity of the synthesized materials was evaluated using diclofenac sodium as a model anionic organic pollutant. The influence of various parameters, such as pH, initial diclofenac concentration, and contact time, on the adsorption capacity was systematically investigated. The results demonstrated that the synthesis conditions significantly influenced the adsorption performance. Kinetic studies revealed a mixed diffusion mechanism for diclofenac sorption onto the layered double hydroxides. Furthermore, the adsorption isotherms were successfully fitted to the Langmuir model, indicating a homogeneous distribution of adsorption sites. Although the presence of competing anions somewhat reduced the adsorption capacity for diclofenac, the adsorbent demonstrated good reusability, allowing for multiple adsorption-desorption cycles. These findings highlight the potential of hydrothermally synthesized NiFe-LDHs effective adsorbents for the removal of anionic pollutants from aqueous solution.