Efficient removal of Pb(II) from aqueous solutions using chitosan-based hydrogels: PCG and PCC, adsorption performance and mechanism studies

Lead (Pb) is a highly toxic and persistent pollutant that poses a significant threat to human health, making the remediation of lead-contaminated water bodies an urgent priority. In this study, chitosan and acrylic acid were employed as base materials, with graphene oxide (GO) and carboxylated graphene (GC) acting as crosslinking agents to synthesize two novel chitosan-based hydrogels (PCG and PCC). Both PCG and PCC were characterized and subjected to systematic static adsorption experiments. Further investigations focused on PCC, examining the effects of coexisting ions and organic substances (humic acid and fulvic acid), adsorption-desorption cycles, and dynamic column experiments to assess its applicability in complex water environments. The results indicated that under the conditions of pH 4.72, temperature of 25°C, dosage of 0.2 g/L, and an initial concentration of 500 mg/L, PCG and PCC achieved maximum adsorption capacities of 323.83 mg/g and 446.09 mg/g, respectively. PCC exhibited excellent resistance to ion interference and demonstrated good reusability. Additionally, in dynamic column experiments with an influent flow rate of 2 ml/min and a hydrogel dosage of 200 mg, PCC effectively treated simulated wastewater with concentration of 50 mg/L for over 900 minutes. These findings indicate that the developed hydrogels exhibit great potential for large-scale application in the market.