Synthesis and Characterization of CMC for Potential Application as Adsorbent in Water Treatment

Chitosan is a polymer from natural source with a wide range of applications, such as in the adsorption of heavy metals. However, it presents limitation in relation to pH, because it is insoluble in neutral and alkaline. Thus, a good alternative has been the use of derivatives of chitosan, as carboxymethyl chitosan (CMC). This chemical modification of chitosan may favor the adsorption process, because it broadens the pH range of solubility and the quantity of chemical groups available for the uptake of ions. This work was carried out the synthesis and characterization of carboxymethyl chitosan. The properties of derivatives synthesized were assessed through the study of solubility at different pHs and using the techniques of potentiometric titration, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-vis) spectroscopy and thermal analysis. The results have demonstrated the effective incorporation of carboxylic groups in the structure of chitosan, as well as the dependence of degree of substitution with the concentration of hydroxide during the synthesis. Hence, the chemical functionalization of chitosan for producing carboxymethyl chitosan offers the possibility of applying this new adsorbent for water treatment.