The remediation potential and kinetics of Pb2+ by the organic frameworks of Cladophora rupestris

Abstract Cladophora rupestris is ubiquitous in many kinds of waterbodies, and C. rupestris biomass can serve as a carrier for adsorbing and transferring heavy metals. In this paper, the organic frameworks of C. rupestris (CROF) was produced by treating C. rupestris biomass with CH3COOH. Batch experiments and characterization were performed. Results showed CROF had a specific surface area of 2.58 m2/g and an external surface area of 2.06 m2/g. Many mesopores were present in CROF, mainly distributed in 2.5–7.5 nm. The zeta potentials were within the range of − 4.46–−13.98 mV in the tested pH of 2.0–9.0. The maximum adsorption capacity (\({q}_{max}\)) of Pb2+ on CROF was 15.02 mg/g, and 97% of Pb2+ was adsorbed onto CROF after 25 min. Unexpectedly, CROF could effectively adsorb Pb2+ in large pH range. The protein secondary structures and carbon skeletons of CROF all worked in adsorption. The main Pb2+ adsorption mechanisms were pore filling, electrostatic attraction, Pb–π interaction, and surface complexation. Therefore, it is valuable as a biosorbent for the removal of Pb2+ from waterbodies.