XPS and NMR analyze the combined forms of Pb in Cladophora rupestris subcells and its detoxification.

In this study, the combined forms of Pb in Cladophora rupestris (L.) (C. rupestris) were investigated via X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR), different Pb concentrations (0, 0.5, and 5.0 mg/L), and C. rupestris subcells were explored. Results showed that combined forms of Pb mainly account for Pb-polysaccharides (Pb-OH of carbohydrates) in the cell wall, Pb-protein (Pb-N= and (C-N-) 2 Pb) in the organelle, and Pb-organic acid (Pb-sulfates, (CO) 2 -Pb and (COO) 2 -Pb) in the soluble fraction. Pb-S-containing group (Pb-C-S) could formed in subcelluar when C. rupestris was subjected to high Pb stress. Meanwhile, Pb 2+ could penetrate the C. rupestris cells via the formed chelate between GSH/MT and -OH functional groups. Results could help understand the role of subcellular fraction in the algae remediation and detoxification to heavy metal.