Comparative studies of chitosan and its nanoparticles for the adsorption efficiency of various dyes

Chitosan has been considered as a chelating agent with the potential for the adsorption of dyes, metal ions and proteins. This study was aimed to prepare and characterize different fungal chitosan nanoparticles (FCI-1 to FCI-6 NPs) by ionic gelation method and to evaluate its efficacy on the sorption of various commercial dyes. Morphological observations showed that the FCI-1 is nearly spherical in shape with particle size ranging from 2 to 30 nm, as determined by electron microscopic studies. Electron micrograph revealed that FCI-1 NPs were stable even after eighteen months of storage at 4 degrees C. Adsorption efficiencies of FCI-1 NPs and FCI-1 were estimated against various dyes such as RBB, MO, DR, NBB and CSB using spectrophotometry. Out of the dyes tested, FCI-1 NPs showed better adsorption efficiency for CSB whereas only RBB followed Langmuir isotherm. The adsorption of remaining dyes may probably be through random adsorption. The results indicated that FCI-1 NPs could be used as efficient sorbents in treating industrial dye effluents. (C) 2017 Elsevier B.V. All rights reserved.