Environmentally Benign, Rapid, and Selective Extraction of Gold from Ores and Waste Electronic Materials

Yue, Chunlin; Sun, Huaming; Liu, Wenjing; Guan, Binbin; Deng, Xudong; Zhang, Xu; Yang, Peng

doi:10.1002/ange.201703412

“…[1,2] They are,t herefore,p recious and their demand is continuously growing.T he possibility to recycle the elements from multi-metal materials such as printed circuit boards (PCBs) is crucial when sustainability and the circular economy are considered. [3][4][5][6][7] In general, recovery of Au in the mining industry is mostly based on the hydrometallurgical cyanidation process,which relies on the use of stoichiometric amounts of cyanide salts and produces large amounts of hazardous waste. [8,9] Consequently,an ew and fairly unexploited concept known as dissolution of noble metals in organic solvents is highly attractive as it offers the possibility to develop benign and selective dissolution methods.…”

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confidence: 99%

“…Thes tudy was initiated by conducting Au dissolution experiments using our previously published procedure: [18] A small amount of fine Au powder was added to a16mm EtOH solution of 4-PSH, and the mixture was stirred for 23 hunder 10 bar of O 2 at 22 8 8C. This resulted in only 14 %o fd issolved Au ( [3][4][5][6], showing that the dissolution efficiency correlates directly with the 4-PSH concentration. Importantly,q uantitative dissolution of the Au sample was achieved either with an extended reaction time and al ow 4-PSH concentration or within 25 min using a4 -PSH concentration of 203 mm (Table 1, entries 2a nd 7).…”

mentioning

confidence: 99%

Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions

Räisänen

¹

,

Heliövaara

²

,

Al-Qaisi

³

et al. 2018

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Dissolution of elemental gold in organic solutions is ac ontemporary approach to lower the environmental burden associated with gold recycling.Herein, we describe fundamental studies on ah ighly efficient method for the dissolution of elemental Au that is based on DMF solutions containing pyridine-4-thiol (4-PSH) as ar eactive ligand and hydrogen peroxidea sa no xidant. Dissolution of Au proceeds through several elementary steps:i somerization of 4-PSH to pyridine-4-thione (4-PS), coordination with Au 0 ,and then oxidation of the Au 0 thione species to Au I simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is aA u I complex bearing two 4-PS ligands and SO 4 2À as ac ounterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.

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“…41 Thus, 5 might be useful to detect and recover Au(III) ions from electronic waste, which is of great economic benefit, considering that the Au content of discarded PCs and mobile phones (280 g/ton) is much higher than that from gold ore (5 g/ton). [42][43][44][45][46] The THF/water mixture of 5 with 90 vol% water fraction was selected to detect Au 3+ owing to its highest PL intensity. Meanwhile, a large variety of metal ions including Hg 2+ , Cu 2+ , Cr 3+ , Pb 2+ , Ag + , Cd 2+ , Ni 2+ , Fe 3+ , Mn 2+ , Zn 2+ , Al 3+ , Na + , and K + were also tested with the same aqueous mixture of 5.…”

Section: Results and Discussion Reactionmentioning

confidence: 99%

Visualized Degradation of Poly(alkynoate)s Toward Diols and Structure Controlled Multifunctional N-Heterocyclic Compounds

Song¹,

Bai²,

Liu³

et al. 2020

Preprint

0

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Degradable polymers are highly desirable due to the tremendous growth of polymer wastes. Some polymers could be degraded under strong acidic or basic conditions toward unknown or unvalued products (i.e. downcycling). New methods to degrade polymers into monomers or high-value-added materials (i.e. upcycling) are more preferred for sustainable developments. In this work, linear and cross-linked poly(alkynoate)s were successfully degraded by benzamidine with 100% conversion into not only diols, a kind of monomers, but also high-value-added N-heterocyclic compounds of pyrimidone and imidazolone derivatives in high yields through controlling the reaction conditions. Notably, thanks to the AIE feature of the degraded products, the degradation process could be visualized under UV light via gradually increased luminescent intensity of the reaction mixtures, which facilitates the monitoring of the polymer degradation. Using this highly efficient degradation reaction, fluorescence patterns could be generated through microcontact printing (μCP) of the stamp on the thin films of poly(alkynoate)s. Moreover, the pyrimidone derivatives could be applied in bioimaging and inhibiting bacteria, and the imidazolone derivatives could be used for the detection and recovery of gold (III) ions from electronic waste and serve as the ﬂuorescent sensor to detect in situ generated amines from food spoilage. Thus, this work presents a visualized and high value product-selective degradation to solve the end-of-life issue of polymers.

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“…This gold extraction approach was hence applied to extract Au 3+ directly from discarded computer processing units (CPUs), whose metal scrap chippings were soaked in an aqueous solution of N-bromosuccinimide and pyridine, 44 to obtain a blue solution with 436.72 mg/L of Cu 2+ , 115.06 mg/L of Ni 2+ , and 10.40 mg/L of Au 3+ . After the solution (8 mL) was treated with the solid powder of 5 (1 mg), The [Au 3+ ] decreased significantly with the enrichment efficiency of 89.42% ( Figure 8D, Table S4).…”

Section: Results and Discussion Reactionmentioning

confidence: 99%

Visualized Degradation of Poly(alkynoate)s Toward Diols and Structure Controlled Multifunctional N-Heterocyclic Compounds

Song¹,

Bai²,

Liu³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Degradable polymers are highly desirable due to the tremendous growth of polymer wastes. Some polymers could be degraded under strong acidic or basic conditions toward unknown or unvalued products (i.e. downcycling). New methods to degrade polymers into monomers or high-value-added materials (i.e. upcycling) are more preferred for sustainable developments. In this work, linear and cross-linked poly(alkynoate)s were successfully degraded by benzamidine with 100% conversion into not only diols, a kind of monomers, but also high-value-added N-heterocyclic compounds of pyrimidone and imidazolone derivatives in high yields through controlling the reaction conditions. Notably, thanks to the AIE feature of the degraded products, the degradation process could be visualized under UV light via gradually increased luminescent intensity of the reaction mixtures, which facilitates the monitoring of the polymer degradation. Using this highly efficient degradation reaction, fluorescence patterns could be generated through microcontact printing (μCP) of the stamp on the thin films of poly(alkynoate)s. Moreover, the pyrimidone derivatives could be applied in bioimaging and inhibiting bacteria, and the imidazolone derivatives could be used for the detection and recovery of gold (III) ions from electronic waste and serve as the ﬂuorescent sensor to detect in situ generated amines from food spoilage. Thus, this work presents a visualized and high value product-selective degradation to solve the end-of-life issue of polymers.

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Environmentally Benign, Rapid, and Selective Extraction of Gold from Ores and Waste Electronic Materials

Cited by 51 publications

References 35 publications

Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions

Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions

Visualized Degradation of Poly(alkynoate)s Toward Diols and Structure Controlled Multifunctional N-Heterocyclic Compounds

Visualized Degradation of Poly(alkynoate)s Toward Diols and Structure Controlled Multifunctional N-Heterocyclic Compounds

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