Immobilization nitrogen-doped sodium alginate-derived carbon quantum dots on sodium alginate hydrogel for enhanced Pb(II) removal

Heavy metal contamination, particularly from Pb(II), poses severe environmental and health risks due to its toxicity and persistence in ecosystems. This study presents an innovative and sustainable adsorbent composed of nitrogen doped carbon quantum dots (NCDs), derived from sodium alginate and immobilized on a sodium alginate hydrogel (HL-NCDs), for the efficient extraction of Pb(II) from water. The experimental results indicate that PbN and PbC interactions, particularly involving the NH moieties within the carbon quantum dots, are the predominant mechanisms facilitating Pb(II) removal, as confirmed by density functional theory (DFT) calculations. These interactions are substantiated by thermodynamic analyses and charge distribution studies, which highlight the enhanced affinity of HL-NCDs towards Pb(II) ions. The novel HL-NCDs composite material not only demonstrates excellent Pb(II) adsorption efficiency but also suggests broad applicability in water treatment technologies, marking a significant advancement in the use of biomass-derived materials for environmental remediation.