High efficiency gold extraction through photo-luminenscent vesicles self-aggregated by sodium dodecyl sulfate and carbon quantum dots with a visual fluorescent method for Au(III) detection

Due to the great demand of gold for society innovation, gold recovery technology from second resources are attracting attentions. Herein, we constructed a novel kind of vesicles featuring photo-luminescent for high efficiency gold extraction by combining carbon quantum dots (CQDs) and sodium dodecyl sulfate (SDS), reaching 96.8 % of extraction efficiency (E%). A bilayer-membrane structure (> 300 nm) with negatively charges (-14.8 +/- 1.5 mV) was observed by TEM and characterized by zeta potential measurements. The effect of single factor such as equilibrium time, pH, salinity and vesicles concentration were evaluated. The coordination number 6:1 was determined by Job's method. Then, by the combination of H-1 NMR, zeta potential analysis and size distribution analysis, anion exchange mechanism was proposed. Because of the fluorescence and strong anti jamming properties of carbon quantum dots, a novel fluorescent probes for the Au(III) detection in wasted water solution was designed, whose fluorescence cannot be quenched by general base metals, such as Ag+, Al3+, Cu2+, Fe3+, Ni2+ and soon. Based on the investigation of corresponding gold concentration which could quench the fluorescence of a certain concentration of vesicles, this kind of vesicles could be applied in gold detection. Approximate concentration of gold could be known by watching if the fluorescence quench or not. Or the mixture could be analyzed by PL spectrophotometer, the rough concentration of gold could be known if the fluorescent intensity under 100.