Effect of fulvic acid on neodymium uptake by goethite

► Binary Nd-goethite systems feature a classic cation sorption edge. ► Binary FA-goethite systems: FA is strongly sorbed to goethite below the PZC. ► Ternary systems: FA significantly enhances Nd uptake below the goethite PZC. ► Ternary systems: elevated [FA] suppresses Nd uptake above the goethite PZC. ► Ternary systems: goethite dissolution dramatically increases with elevated [FA].