Chitosan based Schiff bases have received much attention now-a-days in various fields. Thus the present study deals with the synthesis and the application of carboxymethyl chitosan Schiff base derivatives for the wastewater treatment. Carboxymethyl Chitosan (CMC)/2, 3-Dimethoxy Benzaldehyde Schiff base derivative was synthesized and characterized Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies. FTIR analysis indicated that Schiff base reaction take place in between CMC and 2, 3-Dimethoxy Benzaldehyde. The XRD results demonstrated the appearance of a new crystallization peak of Carboxymethyl chitosan Schiff base (CMCSB). The prepared adsorbent was used to adsorb lead (II) ions in aqueous solution. Various parameters such as adsorbent dose, initial pH, agitation period and different initial concentration of lead (II) ions which influenced the adsorption capacity were investigated. The equilibrium adsorption data were fitted to Langmuir and Freundlich isotherm models. Kinetic data correlated well with the pseudo second-order kinetic model.