Gold Extraction through Vesicles Self-Assembled by Cationic Gemini Surfactant and Sodium Deoxycholate

Chitosan functionalized with N,N-(2-aminoethyl)pyridinedicarboxamide for selective adsorption of gold ions from wastewater

The recovery of gold from wastewater has always been a research hotspot. Here, a novel chitosan-based adsorbent (CS-DPDM) was successfully synthesized by functionalizing chitosan with (N, N-(2-aminoethyl))-2,6-pyridinedicarboxamide. The adsorbent was analyzed by fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H NMR), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and zeta potential method (Zeta). To investigate the adsorption performance of CS-DPDM for Au(III), the effects of pH, temperature, adsorption time and initial concentration were discussed. The maximum adsorption capacity of CS-DPDM for Au(III) at pH 5.0 is 659.02 mg/g at 318 K. The adsorption is a spontaneous endothermic behavior, and the adsorption process follows the quasi-second-order kinetic and Langmuir isotherm models, indicating that a single layer of chemical adsorption may have occurred on the surface of the adsorbent. The competitive adsorption and repetitive experiments show that CS-DPDM has considerable selectivity and reusability for Au(III). X-ray photoelectron spectroscopy (XPS) results show that N and O functional groups adsorb Au(III) on the surface of CS-DPDM through electrostatic, chelation and reduction. These results indicate that CS-DPDM has broad application prospects in recovering gold ions from aqueous solutions.

Engineering of UiO-66-NH2 as selective and reusable adsorbent to enhance the removal of Au(III) from water: Kinetics, isotherm and thermodynamics

Efficient removal of gold ions from wastewater has become a hot research topic. A new metal-organic framework material (PAR-UiO-66) was prepared by post-modification of UiO-66-NH₂. A series of characterizations proved the successful preparation of PAR-UiO-66. The batch adsorption experiment was carried out. Under the room temperature (298 K) of and pH 4.0, the optimal adsorption capacity of PAR-UiO-66 for gold ions was 683.45 mg/g, which was an increase of 426.8 mg/g compared with that of UiO-66-NH₂. The adsorption of gold ions on PAR-UiO-66 accords with pseudo-second-order kinetics and Langmuir isotherm modles. The adsorption process was endothermic and spontaneous. PAR-UiO-66 has good selectivity and still has 92.5% adsorption efficiency after five repeated adsorptions. The adsorption mechanism is electrostatic attraction, reduction and chelation.

Behavior and mechanism investigation of separating Pt and Ir by liquid–liquid extraction using a mixed [C6bet]Br/[C6mim][NTF2] system

Separation of Pt(iv) and Ir(iv) was realized by selectively reducing Ir(iv) to Ir(iii) using NH₂OH·HCl.

Highly selective detection of nitrotoluene based on novel lanthanide-containing ionic liquids

Two novel rare-earth ionic liquids demonstrate high selectivity toward nitrotoluene in the presence of other aromatic compounds.