Développement d'un système de filtration des eaux usées destinées à l'irrigation agricole utilisant des nanoparticules issues des noyaux de dattes.

Abstract

Water scarcity in arid regions is one of the major environmental challenges, making the reuse of treated wastewater for agricultural irrigation a necessity. This study aims to develop a low-cost filtration system based on activated carbon and nanoparticles derived from date pits (Phoenix dactylifera) as environmentally friendly materials for wastewater treatment. The materials were prepared and characterized through physicochemical analyses, and their pollutant removal efficiency was evaluated. The nanoparticles were tested for the removal of organic dyes, while activated carbon was assessed for its ability to remove heavy metals. Subsequently, a prototype filtration unit combining both materials was designed and applied to real wastewater samples intended for agricultural reuse. Characterization analyses confirmed the formation of zinc oxide (ZnO) nanoparticles with a hexagonal wurtzite crystal structure and an average crystallite size of (12 ± 0.1) nm. UV– Visible spectroscopy revealed a characteristic absorption peak at 373.2 nm, confirming the successful synthesis of ZnO nanoparticles and their optical properties. The results demonstrated high removal efficiencies for organic dyes, reaching approximately 80% for Methylene Blue, 93% for Congo Red, 100% for Rhodamine B, and 90% for Methyl Orange, with a significant contribution from the photocatalytic process. In addition, the antioxidant activity (using vitamin C as a reference standard) ranged from 55.22% to 88.09%. Activated carbon also exhibited a high adsorption capacity for heavy metals, achieving removal efficiencies of 69.62% for copper (Cu²⁺), 87.84% for zinc (Zn), and 96.01% for ferric chloride (FeCl₃). Regarding emerging contaminants, moderate removal efficiencies were obtained for glucose (20%) and paracetamol (16%). These findings highlight the effectiveness of date pit-derived materials as sustainable alternatives to conventional treatment systems. This biotechnological approach contributes to the valorization of agricultural waste and offers promising prospects for water purification and the promotion of sustainable irrigation practices in arid regions.