Structure-performance relationship of graphene aerogels in heavy metal remediation: Advances in preparation, mechanisms, and functionalization

Graphene aerogels have attracted significant attention in the remediation of heavy metal pollution due to their three-dimensional hierarchical porous structure and tunable surface chemistry. However, achieving large-scale application requires a systematic understanding of the relationships among synthesis methods, structural features, and functional performance. This review summarizes recent progress in the preparation strategies, adsorption mechanisms, and functional modifications of graphene aerogels. By comparing gelation techniques such as hydrothermal reduction and sol-gel crosslinking, the synergistic effects of π-π stacking and hydrogen bonding in regulating pore structure are elucidated. Various drying methods including freeze drying, supercritical CO₂ drying, and vacuum drying are evaluated in terms of their advantages and limitations. Regarding adsorption mechanisms, graphene aerogels capture heavy metals through multiple pathways, including physical adsorption, electrostatic adsorption, complexation with oxygen-containing functional groups, cation-π electron donor interactions, ion exchange and precipitation reactions. To overcome challenges related to structural stability and selectivity in practical applications, advanced functionalization strategies have been systematically reviewed. Natural polymers enhance structural robustness, synthetic polymers enable ion-specific recognition, atomic doping optimizes reduction and complexation properties at the electronic level and inorganic hybrids provide magnetic recovery and multifunctional synergy. These functionalization strategies not only elucidate the intrinsic connection between structural modulation and performance enhancement in graphene aerogels but also offer new insights into their optimization under complex environmental conditions. In summary, this review systematically synthesizes advances in the preparation, mechanisms, and functionalization of graphene aerogels, aiming to deepen the overall understanding of their structure-performance relationship. It further provides a theoretical foundation and academic guidance for future research on pollutant selectivity, structural stability enhancement, and the regulation of environmental adaptability.