Hydroxyapatite‐spent cathode carbon block modified asphalt and molecular dynamics simulation study.

The highly toxic substances contained in spent cathode carbon blocks (SCCB) pose a serious threat to human health and the ecological environment, and are difficult to recycle. To address this issue, we utilize H2O2 to oxidize cyanides and grow hydroxyapatite (HAP) on spent cathode carbon blocks to adsorb fluoride ions, achieving controlled removal of cyanides and fluorides. Subsequently, the hydroxyapatite‐spent cathode carbon block composite material (H‐SCCB) is applied to modified asphalt, and simulations of the interaction between hydroxyapatite interfaces and asphalt components are conducted. The results indicate that the total cyanide and fluoride ion concentrations in the experimental wastewater meet the discharge standards for industrial wastewater in China. Hydroxyapatite successfully grows on SCCB, presenting a rich porous structure and significantly increased surface area. Mechanical testing shows that 4% H‐SCCB exhibits optimal performance, with a 23.28% increase in complex modulus (G*) compared to the matrix asphalt. Creep recovery capability (R) increases by 54.32% and 7%, respectively. Additionally, molecular dynamics simulations reveal that the interface adsorption between hydroxyapatite and asphalt binder is primarily influenced by electrostatic forces. Under the influence of hydroxyapatite, the diffusion abilities of asphalt four components are as follows: resin > aromatic > saturate > asphaltene. [ABSTRACT FROM AUTHOR]