Graphene Oxide-based Adsorbents for Pb(II) Removing in Water: Progresses on Synthesis, Performance and Mechanism

Pb(II) pollution in water constitutes a serious form of heavy metal pollution that endangers both ecological environment and human health. As an effective sewage treatment technology, adsorption has been considered an economic and common method because of its low cost, environmental friendliness and easy operation. Graphene oxide (GO), an innovative material with superior properties, has garnered extensive research as an ideal adsorbent. Nonetheless, GO still faces many challenges in practical applications due to its limited surface functional groups, suboptimal adsorption selectivity and poor regenerative properties. Current main research focuses on developing various modification strategies to enhance the adsorption performance of GO. In this paper, modification methods of GO and their adsorption mechanisms are reviewed. Firstly, three strategies for improving Pb(II) adsorption properties of GO-based materials are introduced, including N/S functionalization, morphological alteration and magnetization. Their adsorption properties covering adsorption capacity, adsorption selectivity, regeneration, and other performance metrics of GO-based adsorbents are evaluated. Subsequently, the adsorption mechanisms of Pb(II) by GO-based adsorbents such as physical adsorption, electrostatic attraction, ion exchange, and surface complexation are summarized to develop highly efficient GO-modified materials. Finally, the future development of GO-based materials for Pb(II) adsorption is prospected. This review provides novel insights for rational design of emerging GO-based adsorbents and serves as a reference foundation for research and application of GO-modified materials in Pb(II) treatment.