Adsorption of Congo Red by Poly(Dimethyl Diallyl Ammonium Chloride)/Polyacrylamide Hydrogels with Excellent Acid and Alkali Resistance

Abstract

Cationic hydrogels, poly(dimethyl diallyl ammonium chloride)/polyacrylamide (PDMDAAC/PAM), were prepared for the removal of congo red (CR) from aqueous solution. Process parameters affecting the adsorption efficiency were systematically investigated. The results showed that the calculated monolayer adsorption capacity of the cationic hydrogels was found to be 200 to 465 mg/g. The hydrogels showed appreciable adsorption capacities within pH range investigated. The adsorption process well obeyed pseudo-second-order kinetics and the Langmuir isotherm. The ion exchange dominated the whole adsorption mechanism. All the information suggests that the as-prepared cationic hydrogels show potential applications in the fields of wastewater treatment for the removal of anionic dyes such as CR.

Keywords:

• adsorption isotherm
• adsorption kinetics
• cationic hydrogels
• congo red
• PDMDAAC/PAM

ACKNOWLEDGEMENTS

The authors thank the joint support by the National Natural Science Foundation of China (No. 20877077) and the Science and Technology Support Project of Gansu Provincial Science and Technology Department (No. 0804GKCA03A).