Molecular Design of a Low-Odor Xanthate Surfactant: Synergistic π–π Stacking and Oriented Adsorption Assembly for Efficient Flotation of Chalcopyrite

The inherent malodor and low selectivity of xanthates limit their applicability in processing complex mineral systems under modern green chemistry principles. Therefore, the current study presents a novel surfactant, O -(2-[bis(phenylmethyl)amino]ethyl) xanthate (PAEX), characterized by a unique “umbrella-like” structure that incorporates a highly electronegative N atom and two π-electron-rich benzyl groups into an ethyl xanthate skeleton. The intermolecular π–π stacking in PAEX promoted molecular association and significantly suppressed volatility, thereby eliminating the malodor associated with traditional xanthates at the molecular level. Sulfide-specific electronic nose sensors indicated a 74.78% decrease in PAEX responses compared with conventional isobutyl xanthate responses. Furthermore, the synergistic combination of tailored electronic properties and the distinctive umbrella-like architecture endowed PAEX with exceptional selective collection capabilities. Its slightly reduced electron-donating ability and enhanced electron-accepting capacity facilitate selective adsorption at Cu(I) sites on chalcopyrite surfaces. The unique umbrella-like structure promoted a homogenized vertical adsorption orientation, while, hydrophobic interactions and π–π stacking drove the association of “canopy” structures, thereby stabilizing adsorption and enhancing hydrophobicity. A recovery difference of 77.25% was achieved between chalcopyrite and pyrite at a dosage of 1 × 10 –5 mol/L. The pronounced malodor and inferior flotation performance of a nonaromatic structural analog underscored the efficacy of this molecular modification strategy. Overall, this study provides a comprehensive approach to the rational molecular design of surfactants by synergistically manipulating electronic and spatial structures, establishing a foundation for the development of high-performance, environmentally benign reagents for industrial applications.