Chemically modified chitosan­sodium alginate as chemo-sensor adsorbent for the detection of picric acid and removal of biebrich scarlet.

We report here on the green synthesis method of hydrogel nanocomposite (Na-Ala/Chit-cl-polyAAm/CQDs) incorporated with carbon quantum dots for picric acid sensing and biebrich scharlet dye removal from industrial waste water. The nanocomposite precursor was derived from chitosan­sodium alginate hybrid backbone and acrylamide monomer through the formation of semi-IPN matrix (Na-Ala/Chit-cl-polyAAm). The swelling percentage of semi-IPN can be controlled through process parameters such as reaction time, temperature, pH, water volume, acrylamide, N,N'-methylenebisacrylamide and ammonium persulphate concentrations. Hydrogel nanocomposite displayed 99% quenching efficiency for the selective detection of picric acid and 96% dye removal efficiency was found to be observed for the removal of biebrich scarlet dye. The sorption was found to be favorable though Freundlich and Temkin adsorption isotherms along with the 2nd order kinetics. The devices were found to be recyclable and reusable up to six consecutive cycles indicating their applicability in textile industries for the treatment of effluents.