The indiscriminate application of pesticides in agricultural practices has significantly increased pesticide concentrations in aquatic environments. This study focused on the feasibility of employing chitosan beads incorporating selenium nanoparticles to effectively remove pesticides (permethrin) from aqueous solutions and aquaculture. Selenium nanoparticles were produced using Kytococcus schroeteri, with diameters ranging from 10.1 to 22.4 nanometers. Se-NPs were synthesized utilizing a bacterial cell-free supernatant rich in enzymes and metabolic byproducts that catalyze nanoparticle formation. Therefore, the application of these nanoparticles for pesticide removal does not appear to pose a threat to living organisms. Selenium nanoparticles were immobilized in chitosan to produce a composite material (CS-Se-NPs) to remove pesticides. The CS-Se-NPs composite beads exhibited a remarkable 99% adsorption efficiency for permethrin. Under optimal conditions (room temperature, pH 7), 0.5 grams of beads removed 99% permethrin from a 25 ml pesticide solution (0.1 mg L-1) within 60 minutes. This method effectively eliminates any potential risks to human health. These findings suggest that the biosynthesized CS-Se-NPs composite is a promising, eco-friendly material for water purification