Efficient Removal of Heavy Metal Ions with An EDTA Functionalized Chitosan/Polyacrylamide Double Network Hydrogel

Abstract

A ethylenediaminetetra-acetic acid (EDTA) cross-linked chitosan and N,N-methylenebis(acrylamide) (MBA) cross-linked polyacrylamide based double network hydrogel was successfully synthesized via a two-step method and then employed for heavy metal ion adsorption. Various adsorption conditions, such as pH, ionic strength, adsorbent dosage, and contact time were investigated. CTS/PAM gel have a theoretical maximum Cd(II), Cu(II), and Pb(II) sorption capacities of 86.00, 99.44, and 138.41 mg/g, respectively, at experimental conditions. The adsorption process of CTS/PAM gel on the heavy metal ion was identified to be endothermic and follows an ion-exchange reaction. The application of this gel adsorbent was demonstrated using practical industrial effluent. We found that it could effectively treat practical wastewater with all kinds of heavy metals. At an adsorbent dosage of 8 g/L, the total metal ions concentration declined from 448.5 to 5.0 mg/L. Simultaneously, the CTS/PAM gel exhibited remarkable mechanical strength and good recyclability. This study shows that CTS/PAM gel offers great potential for practical application in the removal of heavy metal ions from contaminated aquatic systems.