Integration of Cynodon dactylon and Muraya koenigii plant extracts in amino‐functionalised silica‐coated magnetic nanoparticle as an effective sorbent for the removal of chromium(VI) metal pollutants

Immobilised magnetic nanoparticles are extensively used owing to their superparamagnetic nature, surface interaction, and binding specificity with the appropriate portentous substances. The present research focuses on the development of a portentous, robust carrier, which integrates the silica‐coated amino‐functionalised magnetic nanoparticle (AF‐MnP) with the plant extracts of Cynodon dactylon (L1) and Muraya koenigii (L2) for the stable and enhanced removal of hazardous hexavalent chromium pollutant in the wastewater. Vibrating sample magnetometer (M _s – 45 emu/g) determines the superparamagnetic properties; Fourier‐transform infrared spectroscopy determines the presence of functional groups such as NH₂, Si–O–Si, C=C; high‐resolution transmission electron microscopy, field emission scanning electron microscope and energy‐dispersive X‐ray spectroscopy determine the size of the green adsorbents in the range of 20 nm and the presence of elements such as Fe, N, and Si determines the efficacy of the synthesised silica‐coated AF‐MnP. The AF‐MnP‐L1 shows the maximum adsorption capacity of 34.7 mg/g of sorbent calculated from the Langmuir isotherm model and the process follows pseudo‐second‐order kinetics. After treatment, the adsorbents can be easily separated from the solution in the presence of an external magnetic field and are reused for nine cycles after acid treatment with the minimal loss of adsorption efficiency.