The purpose of this study was to synthesise, characterize and evaluate environmental application (degradation of dyes and pesticides) of chitosan nanoparticles. The chitosan nanoparticles were synthesized by ionic gelation process and characterized. The physicochemical properties of the nanoparticles were determined by size and zeta potential analysis, scanning electron microscope (SEM), atomic force microscopy (AFM), FTIR analysis and XRD pattern. The photocatalytic degradation was studied with the help of industrial dyes, and pesticides. Adsorption experiments were carried out to highlight the adsorption efficiency of the organic compound with different parameters like pH, dosage and time. A sharp increase in the percent reduction of dyes and pesticides was observed as the adsorbent dose increased. The kinetic data were modelled with the pseudo first-order and pseudo second-order kinetic equations. © 2018 Technoscience Publications. All Rights Reserved.