Effective removal of carcinogenic dye from aqueous solution by using alginate-based nanocomposites

Significant efforts are applied to prepare novel nanomaterials in which functionalized multi-walled carbon nanotubes (COOH-MWCNTs) are dispersed in alginate-chitosan network under ultrasonic waves. Instrumental techniques like scanning electron microscopy, thermal analysis (thermogravimetric analysis/differential scanning calorimetry), Fourier transform infrared spectroscopy, X-ray diffractometry, and Brunauer-Emmett-Teller are used for characterization of materials. Nanocomposite films are also evaluated based on swelling behavior. These techniques and measurements indicated the interacted and more stable nature of nanocomposites compared to the starting materials. The prepared films are used as sorbents to remove the Congo red dye from the aqueous solution. Various experimental parameters like contact time, temperature, pH, and dosage are varied to explore their effect on adsorption capacity. Nanocomposites films are analyzed for % desorption and recycled in the adsorption process successfully for 12 times. The adsorption mechanism involved is a pseudo-first-order mechanism. While isothermally, the Freundlich model appears to fit better than the Langmuir adsorption model. The high adsorption efficiency with more strength and regeneration suggests nanocomposite films as the best alternative for already existing petroleum-based membranes.