Poly(O‐Toluidine)‐polyvinylpyrrolidone copolymer submerged MgFe₂O₄/CS‐OXSWCNTs nanocomposite for removal of acid red dye from aqueous solutions

Abstract

In this study, a new hybrid material was created that exhibits excellent adsorption performance and high stability. POT‐PVP/MgF/CS‐OXSWCNTs NCs were synthesized using a three‐step approach. The process involved the chemical polymerization of poly(o‐toluidine)‐polyvinylpyrrolidone (POT‐PVP) with MgFe2O4 nanoparticles (MgF NPs) and chitosan‐oxidized single‐wall carbon nanotubes (CS‐OXSWCNTs). The synthesis process involved the use of an egg white method to synthesize MgF NPs and cross‐linking chitosan with OXSWCNTs using glutaraldehyde (GA) to obtain CS‐OXSWCNTs. The POT‐PVP copolymer was then used to coat MgF NPs and CS‐OXSWCNTs NCs. The successful synthesis of the NCs with strong component interaction was confirmed by several characterization techniques, including X‐ray diffraction spectroscopy (XRD), Fourier‐transform infrared spectroscopy (FTIR), and Raman spectroscopy. Microscopy analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) verified that the POT‐PVP copolymer had properly coated the MgF NPs and CS‐OXSWCNTs NCs. The N2 adsorption–desorption isotherm verified that the specific surface area of NCs had increased with the addition of MgF NPs and CS‐OXSWCNTs NCs. Furthermore, the composite structure greatly improved the thermal stability of POT‐PVP/MgF/CS‐OXSWCNTs NCs. To evaluate how well the nanocomposites (NCs) eliminated pollutants, an artificially produced toxic effluent that contained acid red dye (A.R) was applied. To investigate their impact on dye removal, several parameters were changed, including pH, adsorbent dosage, time, temperature, and ionic strength. The POT‐PVP/MgF/CS‐OXSWCNTs NCs showed a higher removal rate based on a greater surface area, stability, and conducting power than MgF NPs and POT‐PVP. It was found that 25 mg L−1 and 7.5 mg were the optimal dye concentration and adsorbent dosage, respectively. The POT‐PVP/MgF/CS‐OXSWCNTs NCs achieved 99.46% removal efficiency at an acidic pH of 2. The NCs were found to have a maximum dye adsorption capacity of 107.4 mg g−1, and the adsorption process followed the pseudo‐second‐order kinetics. Thermodynamic analyses revealed that the dye adsorption onto POT‐PVP/MgF/CS‐OXSWCNTs NCs was endothermic, implying a spontaneous and physical adsorption mechanism. It can be inferred from these results that POT‐PVP/MgF/CS‐OXSWCNTs NCs are useful for eliminating dye pollutants from water.