LAUSR

Abstract The preparation of novel iron oxide-flax seeds-based hybrid nanocomposite, referred to as magnetic flax-seeds, and its application for water treatment has been reported herein. A simple co-precipitation method was followed and the detailed mechanism of the preparation has been discussed. The prepared magnetic flax-seeds powder was characterized by employing several spectroscopic and microscopic techniques. The characterization results showed that the magnetic nanocomposite possessed massive functional groups of flax seeds and hydroxyl groups of iron oxide. The nanocomposite has a porous structure with particles size distributions in the range 1–14.32 nm. The magnetic composite was investigated for adsorption utility, in water treatment technology, by picking malachite green dye, under the effect of various process parameters, such as pH, contact time, temperature, concentration, and amount of adsorbent. The equilibrium adsorption capacity of the magnetic nanocomposite (dosage = 1.0 g L−1) for malachite green (concentration = 10 mg L−1) was found to be approximately 10 mg g−1 at 30 °C, 7 pH, and 60 min contact time with maximum adsorption capacity Qmax = 52.910 mg g−1. The sorption process was proved feasible and endothermic at all the tested temperatures (30–50 °C) and concentrations (10–60 mg L−1). The adsorption data followed Freundlich isotherm (Kf value 20.893 mg g−1) which suggested the multilayer physisorption process. The kinetic investigation suggested a pseudo-second-order sorption process (K2 = 0.050 g mg−1 min−1) and governed through particle diffusion. The ease in preparation, low cost, magnetic characteristic, and high adsorption capacity will make the water treatment technique more efficient with the magnetic flax-seeds.