Preparation of Fe3O4 Attached Sepiolite/Poly(vinyl alcohol) Nanocomposite as a Magnetically Separable Dye Adsorbent

In this study, magnetic sepiolite (mSep) was incorporated into the poly(vinyl alcohol) (PVA) biopolymer to develop a cost-effective and ecofriendly nanocomposite adsorbent. The prepared nanocomposites were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Considering the easy separation of adsorbents from solution using a magnetic field, PVA-mSep nanocomposite was used as an adsorbent for removal of the methylene blue (MB) dye from wastewater. The effects of various parameters such as the magnetization of sepiolite, solution pH, adsorbent content, contact time, and initial dye concentration were investigated and optimized for the adsorption of MB onto the nanocomposite adsorbents. The adsorption results revealed that the developed nanocomposite can be considered as an efficient sorbent material for dye removal application. As the dye removal efficiency of PVA/mSep nanocomposite reached up to 99.5%. The experimental data of dye adsorption were better fitted using pseudo-second-order kinetics model. Moreover, the adsorption isotherm studies exhibited that the Freundlich isotherm is favorable. The adsorption of MB onto the adsorbents was thermodynamically evaluated and it was found that the dye adsorption process is spontaneous and endothermic.