High and selective Ag(I) bulk liquid membrane transport with N,N-diethyl-N′-camphanyl thiourea and structure of the complex

Advanced membrane-based high-value metal recovery from wastewater

Considering the circular economy and environmental protection, sustainable recovery of high-value metals from wastewater has become a prominent concern. Unlike conventional methods featuring extensive chemicals or energy consumption, membrane separation technology plays a crucial role in facilitating the sustainable and efficient recovery of valuable metals from wastewater due to its attractive features. In this review, we first briefly summarize the sustainable supply chain and significance of sustainable recovery of aqueous high-value metals. Then, we review the most recent advances and application potential in promising state-of-the-art membrane-based technologies for recovery of high-value metals (silver, gold, rhenium, platinum, ruthenium, palladium, iridium, osmium, and rhodium) from wastewater effluents. In particular, pressure-based membranes, liquid membranes, membrane distillation, forward osmosis, electrodialysis and membrane-based hybrid technologies and their mechanism of high-value metal recovery is thoroughly discussed. Then, engineering application and economic sustainability are also discussed for membrane-based high-value metal recovery. The review finally concludes with a critical and insightful overview of the techno-economic viability and future research direction of membrane technologies for efficient high-value metal recovery from wastewater.

Synthesis and characterization of N-(Arylcarbamothioyl)-cyclohexanecarboxamide derivatives: the crystal structure of N-(naphthalen-1-ylcarbamothioyl)cyclohexanecarboxamide

A number of N-(arylcarbamothioyl)cyclohexanecarboxamide derivatives (aryl substituents: phenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, o-tolyl, p-tolyl, 3-methoxyphenyl, 4-methoxyphenyl and naphthalen-1yl) have been synthesized. The compounds obtained were characterized by elemental analyses, IR spectroscopy and ¹H-NMR spectroscopy. N-(naphthalen-1-ylcarbamothioyl)cyclohexanecarboxamide, H₂L⁹, was also characterized by a single crystal X-ray diffraction study. This compound, C₁₈H₂₀N₂OS, crystallizes in the triclinic space group Pī, with Z = 2, and unit cell parameters a = 6.9921(14) Å, b = 11.002(2) Å, c = 12.381(3) Å, α = 113.28(3)°, β = 99.38(3)°, and γ = 101.85(3)°. The cyclohexane ring adopts a chair conformation. The molecular conformation of the compound is stabilized by an intramolecular (N2-H2•••O1) hydrogen bond which forms a pseudo-six-membered ring.