Highly efficient absorption of cationic dyes by nano composite hydrogels based on κ-carrageenan and nano silver chloride

Novel nanocomposite hydrogel was synthesized based on κ-carrageenan and nano-silver chloride by a simple method and applied for the removal of cationic dyes in aqueous solution. Inclusion of nano-silver chloride into the superabsorbent hydrogel was utilized for producing the effective dye absorbent. The dye absorption was more than 98% after 5 min in a 10 ppm aqueous solution at pH = 6. The nanocomposite hydrogel was characterized by FT-IR spectroscopy, SEM, TEM, TGA/DTG, and BET analysis. The absorption of crystal violet was investigated by changing the absorbent dosage, contact time, dye concentration, pH, and temperature. Several kinetic models were used to predict the kinetic behavior of the dye absorption. The best result was obtained with the pseudo-second order model. The results demonstrated that the Temkin model has been fitted better than the other models. The reusability experiments showed that the superabsorbent retained more than 60% of initial activity after 9 cycles.