Comparative study for adsorption of congo red and methylene blue dye on chitosan modified hybrid nanocomposite

The present paper reports the synthesis of an eco-friendly and low-cost chitosan modified hybrid Azadirachta indica leaves powder-Kaolinite clay (Chit/AILP-Kao) nanocomposite and further explored as a potential adsorbent to remove hazardous congo red (CR) and methylene blue (MB) dyes from aqueous solution. The optimum pH for the sequestration of CR and MB dye were found to be 6 and 7 respectively. Among the evaluated isotherms, equilibrium data was found to be the best fitted by Langmuir model on the basis of higher value of coefficient R-2 (0.998). The maximum monolayer adsorption capacity (q(m)) for CR and MB dyes were found to be 104.6, 99.01 mgg(-1) respectively at optimum pH and temperature 30 degrees C. To determine the adsorption process kinetic model was best obeyed by pseudo second order on the basis of higher value of coefficient R-2 (0.998). In the thermodynamic parameters, negative values of Delta G degrees and positive values Delta H degrees confirms the spontaneous and endothermic nature of adsorption process. The values of maximum specific surface area for CR dye was found to be 210.7 m(2) g(-1) while for MB dye it was 223.7 m(2) g(-1). The regeneration study confirmed that the present nanocomposite can be regenerated upto fifth cycle successfully.

Automated summary

This paper synthesized an eco-friendly and low-cost chitosan modified hybrid Azadirachta indica leaves powder-Kaolinite clay nanocomposite and investigated its potential as an adsorbent for removing hazardous dyes from aqueous solution. The results showed that the nanocomposite had good adsorption capacity for Congo red and Methylene blue dyes, with the ability to be successfully regenerated multiple times. The study also found that the adsorption process followed pseudo second order kinetics and had thermodynamic parameters indicating spontaneous and endothermic nature.