Biocomposites based on chitosan and orange peel as a green material alternative for the removal of nitrate in water

The presence of nitrates in drinking water and their negative health effects have prompted research into new materials capable of removing this pollutant. This approach focuses on sustainability, from component sourcing to an environmentally friendly synthesis process. No toxic chemical by-products are generated, no excess water is used to remove the crosslinker, and no additional energy consumption is required. This study presents the results derived from the biocomposites synthesized with chitosan as a biopolymeric matrix (3% w/v) and orange peel as a mechanical support (1:3) using the ionic crosslinking method to remove nitrates. The chitosan and orange peel biocomposites were characterized using scanning electron microscopy, nitrogen physisorption, infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, surface charge distribution, and the point of zero charge. The effect of pH on the maximum nitrate adsorption capacity was evaluated at pH values of 4, 5, 6, and 7 at 25 °C. The maximum adsorption capacity of 8.9 mg g⁻¹ was obtained at pH 4. The proposed adsorption mechanism is based on electrostatic attractions.