Synthesis, characterization, and application of novel reusable clay-based magnetic nanocomposite for the removal of organic dyes from water

In this study, a new synthesized magnetic nanocomposite was used as an adsorbent for the removal of toxic cationic dye methylene blue (MB). The adsorbent incorporated three components to produce a nanocomposite named Fe3O4/GO/natural clay. The characterization techniques were used to study the physical and chemical properties of nanocomposite and approve the successful synthesis. XRD of the Fe3O4/GO/natural clay nanocomposite indicated the crystalline structure with the appearance of characteristic peaks of each component. Also, the FT-IR of Fe3O4/GO/clay nanocomposite showed a significant change in the peak intensity of natural clay after the addition of GO and magnetic NPs which attributed to the successful interaction between GO and magnetic NPs with the functional groups on the surface of clay. The TEM and SEM images of the nanocomposite showed that the magnetic NPs, clay, and GO excellently interacted in one appropriate structure with the deposition of clay and magnetic NPs on the GO surface which serves as a matrix holding them. The MB adsorption system was optimized by varying several parameters, including pH, adsorbent dosage, contact time, starting concentration, ionic strength, and competing ions. Furthermore, the adsorption isotherm showed that the highest adsorption capacities of 999.34 and 1108.54 mg/g for the Fe3O4/GO/natural clay and Fe3O4/natural clay nanocomposites, respectively, followed the Langmuir isotherm. Additionally, the kinetic analysis showed that a pseudo-second-order model better explained the adsorption on both nanocomposites. The nanocomposite can be reused for multiple cycles with a little drop in its initial performance, according to reusability research conducted up to six times using ethyl alcohol as the eluent. As a result, this reasonably priced adsorbent might be employed as a beneficial and effective dye adsorbent for the removal of MB from water while maintaining the safety of the water quality.