Green Valorization of Pomegranate Peel Waste into an MgO Nanocomposite for Sustainable and High-efficiency Turbidity Removal in Water and Wastewater Treatment

Abstract

Pomegranate peel waste (PPW) was successfully utilized as a renewable biomass precursor to develop an MgO-based nanocomposite through a simple and environmentally sustainable synthesis process for water purification. The prepared PPW–MgO nanocomposites were systematically examined using XRD, FTIR and TGA to investigate surface functional groups, crystal structure, and thermal behavior. Among the synthesized formulations, PPW–MgO (0.50) displayed the most desirable physicochemical characteristics, with uniformly distributed MgO nanoparticles and an optimized surface charge, resulting in turbidity elimination efficiency of 81.9% under optimum coagulant dosage of 2.0 g L-1, conditions of pH 4.6, and settling time of 40 min. The superior clarification efficiency was attributed to the cooperative effect of hydroxyl-rich pomegranate peel matrix and MgO NPs, which enhanced particle destabilization through interparticle bridging, sweep flocculation and charge neutralization. Relative to conventional coagulants like alum and polyaluminum chloride, PPW–MgO (0.50) achieved comparable or higher treatment performance while exhibiting excellent biodegradability, a residual Mg concentration below 0.05 mg L-1, and an estimated cost of approximately ₹20 per kg. Overall, the developed MgO nanocomposite derived from pomegranate peel waste represents an economical, scalable, and environmentally sustainable material for water and wastewater treatment, while simultaneously promoting agricultural waste valorization within a circular economy framework.