Valorization of Date Palm By-Products from some Cultivars: Environmental Application Valorization des sous-produits de certaines variétés de palmier dattier: Application environnementale

Abstract

This study investigates the use of agricultural date palm by-products (leafy fronds and empty fruit bunchs of three cultivars Ghars, Degla and Takermost) as sustainable, low-cost biosorbents for the removal of methylene blue dye from aqueous solutions. The research encompasses chemical modifications—using KOH and H₂SO₄ treatments—of the adsorbent materials, their physicochemical characterization, and systematic adsorption experiments to elucidate the key factors influencing adsorption efficiency and mechanisms. Among the modifications, KOH treatment notably enhanced the adsorption capacities, with maximum capacity reaching approximately 4.48 mg/g and dye removal efficiency exceeding 99%. This was linked to the increased surface functional groups and porosity, as confirmed by FTIR, XRD, and SEM analyses. Adsorption was affected by pH, temperature, contact time, and initial concentration, adapting to the Freundlich and Temkin isotherm models, indicative of heterogeneous and cooperative adsorptive interactions. Kinetic analyses consistently aligned with a pseudo-second-order model. Thermodynamic studies revealed spontaneous and exothermic adsorption under ambient conditions. The multistep adsorption mechanism encompasses surface adsorption, external film diffusion, and intraparticle diffusion, which are influenced by the adsorbent type, chemical modification, and dye concentration. It was observed that there are differences among the palm cultivars Degla, Ghars, and Takermost, highlighting the impact of cultivar variation on adsorption performance Bioadsorptives membranes were prepared from KOH-modified empty fruit bunch biomass (Ghars cultivar) combined with sodium alginate for use in treating drainage water in the region between Said Otba and Ain El Beida in the Wilaya of Ouargla. These membranes effectively reduced the biochemical oxygen demand by 50%, the chemical oxygen demand by 23.3%, and the total suspended solids by 36%