Fabrication of surface-engineered superparamagnetic nanocomposites (Co/Fe/Mn) with biochar from groundnut waste residues for the elimination of copper and lead metal ions

Industrial wastewater is highly toxic and needs to be treated before being let into large water bodies. They have been treated using various biological and chemical processes. In this study, integrated magnetic nanoparticles (cobalt, ferrous and manganese) are fabricated with the specific amino group on the silica-coated surface layer with the size of 50 nm. The integrated magnetic nanocomposites are combined with the biochar obtained from groundnut shell are used to eradicate copper and lead pollutants in wastewater. Analytical techniques like Fourier transform infrared spectroscopy provides specific entities alike amino, hydroxyl and silica vibrational stretches; scanning electron microscopy gives over nanoadsorbent size around 30–50 nm and the presence of elemental constituents such as cobalt, manganese, ferrous, nitro, and silica was examined by energy dispersive X-ray analysis. High-resolution transmission electron microscopy figures nanoparticle size around 50 nm. Vibrating sample magnetometer determines the superparamagnetic nature of the particle to be around (magnetic saturation)—50 emu/g. Above nanoadsorbent evaluates an enhanced adsorption capacity pursued upon 436.8 mg/g for copper and 318.9 mg/g—lead ions in an optimal conditions (pH 5, temperature 30 °C, associated contact—1 h). Further exploration of zeta potential, kinetics model, two-parameter and three-parameter isotherm pattern evaluates a reaction pattern on nanoadsorbent with metallic interactions. The metal interactive study showed an excellent fit for pseudo-second order, double exponential kinetics and Langmuir–Freundlich isothermal pattern. The thermodynamic system exhibits a spontaneous and exothermic reaction process. Adsorbent possesses an excellent reusable capacity, where it could be reused for 10 continuous cycles upon the consecutive acid washes. Graphic abstract