Adsorption behavior and mechanism of Lead (Pb2+) by sulfate polysaccharide from Enteromorpha prolifera

Lead (Pb2+) pollution poses severe healthy and ecological risks to humans. In this work, sulfate polysaccharide from Enteromorpha prolifera (SPE) was utilized for Pb2+ adsorption from simulated intestinal fluid. In order to evaluate its adsorption behaviors comprehensively, batch adsorption of Pb2+ was investigated under different conditions. Results showed that SPE presents high adsorption ability for Pb2+ through chemical adsorption process and the maximum adsorption capacity for Pb2+ was 278.5 mg/g. And SPE exhibited higher removal efficiency (≥60%) for trace Pb2+ (<10 mg/L) compared to that of other adsorbents based on polysaccharide. Besides, its adsorption can be described by Langmuir isotherm and pseudo-second-order kinetic models. Further, XRD, FTIR, and XPS were used to characterize the possible interaction of Pb2+ with SPE, and the results showed that carboxyl and hydroxyl groups in SPE play more important role than that of sulfate group. Our work represents the first assessment of Pb2+ adsorption properties of SPE. This investigation highlights the potential application of SPE to protect the body from hazard of food-derived heavy metals.