Synthesis of magnetite-maghemite nanocomposite adsorbents coated with leaf extract for removal of lead ions from water

Contaminated groundwater poses threats to human health and the environment. Nanocomposites have attracted attention for their potential to remove heavy metals. This study aimed to develop magnetite-maghemite nano- composite adsorbents coated with leaf extract for removing lead (Pb) ions from water. The nanocomposite was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray powdered diffraction (XRD), scanning electron microscopes (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), dynamic light scattering (DLS), Brunauer-Emmett-Teller (BET), zeta potential, and vibrating-sample magnetometer (VSM) analysis. The XRD analysis showed the nanocomposite's average size was 16 nm. The adsorbent's surface isoelectric point (point of zero charge, pHpzc) was 6.1. The adsorption capacity of the composite was found to be 108.57 mg/g at an adsorbent dosage of 1.5 g/L, a pH of 6.5, a contact time of 15 min, and an initial lead concentration of 10 mg/L. The adsorption was followed by the Langmuir isotherm model and best fitted with the pseudo-2nd-order kinetic model (R2 = 0.998). Regeneration studies showed that the adsorbent could be used for five consecutive cycles. The study showed that magnetite-maghemite nanocomposite adsorbents coated with leaf extract are sustainable for removing Pb(II) from water.