RESUMO
Chitosan nanorod with minimum particle size of <100 nm was prepared by crosslinking low molecular weight chitosan with polyanion sodium tripolyphosphate and physicochemically characterized (FT-IR, XRD, SEM, AFM, TGA and DSC) for waste water treatment. Its sorption capacity and sorption isotherms for chromium (Cr) were studied. The effect of initial concentration of Cr ions, sorbent amount, agitation period and pH of solution that influence sorption capacity were also investigated. It was found that nanochitosan in the solid state was rod shaped which could sorb Cr (VI) to Cr (III) ions effectively. Based on the Langmuir, the Freundlich and the Temkin sorption isotherms, the sorption capacity of chitosan nanoparticles is very high and the adsorbent favors multilayer adsorption. The kinetics studies show that the adsorption follows the pseudo-second-order kinetics, which infers the transformation of Cr (VI) to Cr (III). From the results it was concluded that nanochitosan is an excellent material as a biosorbent for Cr removal from water.