Synthesis of novel adsorbent by incorporation of plant extracts in amino-functionalized silica-coated magnetic nanomaterial for the removal of Zn2+and Cu2+from aqueous solution.

Magnetic nanoparticles owing to their superparamagnetic behaviour and specific reactive sites are facilitated to regenerate and reuse. Our present study determines the cointegration of the plant extracts of Cynodon dactylon and Muraya koenigii with the magnetic nanoparticle coated with silica layer and surface engineered with a specific amine group. The cointegrated magnetic nano adsorbent is characterized for its analytical feature and batch studies are performed to remove zinc (Zn2+) copper (Cu2+) metal ions. Fourier transform infrared spectroscopy reveals the presence of functional entities such as NH2, Si-O-Si, C=C. The size of the cointegrated nano adsorbent (12-30 nm) was confirmed by field emission scanning electron microscopy whereas, a high-resolution transmission electron microscope affirms the nanosize of the particle constituted around 20 nm. Energy dispersive x-ray analysis confirms the presence of elements like Fe, N, Si and was confirmed by X-ray diffraction analysis and vibrating sample magnetometer affirms the superparamagnetic nature with the high magnetic saturation value (Ms - 30 emug-1). The cointegrated nano adsorbent reveals the maximum adsorption capacity of Zn2+ as 78.24 mg.g-1 and Cu2+ as 81.76 mg.g-1 of the adsorbent under the optimized conditions of contact time 45 min, pH 6.0 and temperature 35 °C. Kinetics such as pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion and isotherm studies like Langmuir, Freundlich, Dubinin-Radushkevich and Temkin were performed to understand the mechanism of interaction between the nanoadsorbent and metal ions. The reaction system follows the pseudo-second-order kinetics and Langmuir isotherm model for both the Cu2+ and Zn2+ metal ions. To determine the reusing capacity of the cointegrated nanoadsorbent, the adsorption efficiency was studied for continuous twelve cycles with 80% recovery after subsequent acid treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00696-9. © Springer Nature Switzerland AG 2021.