Recycling Of Silver Research Articles

Recycling of silver from silicon solar cells by laser debonding

A laser-debonding approach to silver electrode recovery from solar cells is presented to address the critical need for efficient and eco-friendly recycling methods. The study explores the use of UV nanosecond and IR continuous-wave lasers to precisely debond silver electrodes from silicon wafers. By optimizing parameters like laser power, scan speed, and the number of passes, intact silver electrical contact lines were recovered from solar cells. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis confirmed the successful separation of silver from silicon wafers. Furthermore, an increase in the number of laser passes led to the production of silver microparticles, as validated by morphology and compositional studies using EDS. The estimated silver is approximately 90 mg for the Si solar cells of 15.4 * 15.4 cm2 used in the study. To achieve a large area recovery of silver, a MATLAB code incorporating detection algorithms and specific criteria to automate laser scanning by accurately identifying the location of silver electrodes was developed. This presented laser debonding method is not confined to silicon solar cells but can be extended to other solar cell types featuring metal electrodes, offering a versatile solution. By minimizing the use of hazardous chemicals and reducing operational costs, the developed process aligns with the imperative of environmentally responsible photovoltaic waste management.

A Reusable Fluorescent Molecular Self-Assembly Cage for Simultaneous Detection and Recycling of Silver(I) Ion.

Although molecular self-assembled porous materials capable of ratiometric fluorescence probing and recycling of metal ions are both economically and environmentally attractive, very few current efforts have been devoted. Herein, we demonstrated a three-dimensional pure organic cage, namely 4-cage, which can serve as a fluorescent probe for simultaneous ratiometric detection and recycling of Ag+ ion. Taking advantage of the promising emission behavior of its rigidified tetraphenylethylene scaffolds and the chelating ability of its dynamically reversible imine moieties, on one hand, upon the addition of Ag+ , 4-cage undergoes coordination to form a stable but poorly soluble fluorescent complex, Ag+ @4-cage, accompanied by a fluorescence color change from bluish-green to yellowish-green. This allows us to differentiate Ag+ from other cations with high selectivity. On the other hand, upon the addition of Cl- anion, Ag+ @4-cage can be effectively converted into free 4-cage due to the competitive coordination of Cl- with Ag+ . Through this process, secondary usage of 4-cage and the recycling of Ag+ ion can be achieved.

Crisis? What crisis? Recycling of silver for Roman Republican coinage

Dated measurements of lead pollution in deep Greenland ice have become a useful proxy to monitor historical events because interruptions in lead-silver production result in fluctuations in lead emissions. However, the application of the lead emission record has not perhaps received the attention it deserves because of the difficulty in connecting macroscale events, such as wars and plagues, to their economic repercussions. For instance, although debasement of silver coinage with copper has been proposed as a reasonable response to interruptions in silver production, reductions in fineness of the silver denarius, the backbone of Roman coinage from the late third century BC, are not always coincident with decreases in lead deposited in Greenland. We propose that extensive recycling of silver that is evident in the numismatic record can better explain drops in lead emissions and, thereby, the responses to major historical events, such as warfare in the silver-producing areas of the Iberian Peninsula and southern France during the middle and late Roman Republic.

Silver Recycling From Defective GdBCO/Ag High-Temperature Superconducting Bulks

The silver used as a mechanical reinforcement in REBCO bulks accounts for approximately half of the total material costs. Despite this, no viable recycling techniques have yet been published. Thus, we have developed a simple method for silver recycling from end-of-life and failed REBCO bulks based on their dissolution in azeotropic nitric acid and subsequent selective precipitation. The phase compositions of the REBCOwaste, intermediates andfinal product were studied by XRD, which confirmed the preparation of pure metallic silver. The recycled silver was then used to manufacture 28 mm EuBCOsingle-domainbulks, whosesuperconductingproperties showed no significant differences from reference bulks containing commercial Ag <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O. SEM confirmed that the microstructure of the cut bulks was also typical of REBCO bulks. Thus, it appears that the implementation of silver recycling within the REBCO production chain can increase the cost-competitiveness and adoption of REBCO/Ag products while maintaining their properties and microstructure.

The need for design-for-recycling of paper-based printed electronics – a prospective comparison with printed circuit boards

The present study compares conventional printed circuit boards (having glass-fibre and epoxy substrates and etched copper circuits) with paper-based printed electronics (offering flexible, bio-based, and biodegradable substrates with circuit design printed using silver-based inks) and assesses the relevance of e-waste recycling to the latter's sustainability. Therefore, a comparative life cycle assessment between these two options has been undertaken and the global warming impacts were calculated.The impact assessment results underscore that printed electronics offer a consistent sustainability advantage over printed circuit boards only through recycling of silver in the former at the end-of-life. Hence, design-for-recycling and recycling as e-waste are crucial to the sustainability of the current generation of printed electronics. Other foreseen waste treatment options for paper-based printed electronics, such as composting, and paper recycling, are likely to limit the sustainability advantage of printed electronics to circuits with small conductive areas.

Adsorption Studies on Ag(I) Using Poly(N-phenylglycine) Membrane and Application in Practical Silver Recycling

Adsorption Studies on Ag(I) Using Poly(<i>N</i>-phenylglycine) Membrane and Application in Practical Silver Recycling

Peroxymonosulfate enhanced photoelectrocatalytic oxidation of organic contaminants and simultaneously cathodic recycling of silver

Degradation of organic contaminants with simultaneous recycling of Ag+ from silver-containing organic wastewater such as photographic effluents is desired. Although photoelectrocatalysis (PEC) technology is a good candidate for this type of wastewater, its reaction kinetics still needs to be improved. Herein, peroxymonosulfate (PMS) was employed to enhance the PEC kinetics for oxidation of phenol (PhOH) at the anode and reduction of Ag+ at the cathode. The degradation efficiency of phenol (PhOH, 0.1 mmol/L) was increased from 42.8% to 96.9% by adding 5 mmol/L PMS at a potential of 0.25 V. Meanwhile, the Ag (by wt%) deposited on the cathode was 28.1% (Ag2O) in PEC process, while that of Ag (by wt%) was 69.7% (Ag0) by adding PMS. According to the electrochemistry analysis, PMS, as photoelectrons acceptor, enhances the separation efficiency of charges and the direct h+ oxidation of PhOH at the photoanode. Meantime, the increasing cathode potential avoided H2 evolution and strongly alkaline at the surface of cathode, thus enabling the deposition of Ag+ in the form of metallic silver with the help of PMS. In addition, PMS combined with PEC process was effective in treating photographic effluents.

АНАЛІЗ СУЧАСНОГО СИРОВИННОГО РИНКУ ЮВЕЛІРНОЇ ПРОМИСЛОВОСТІ

This article is dedicated to analyze of modern tendency of wold commodity market of jewelry industry. At the article the determine of jewelry. At the article was analyzed modern value of raw material of jewelry industry: gold and silver. The main gold and silver mining countries were determined, were analyzed the value of mining and consumption of gold and silver. The market of gold can be viewed from both side as finance market and as raw market. Gold mining is global business with deals on all continents, accepts Antarctica. For many countries, mining of gold is factor of economic development, foreign investment. Mining of gold gets currencies and tax, transport. Market of gold, as raw market has such tendency: large field of gold is at some countries: China (average specific gravity 12,4%), USA (average specific gravity 7,14%), Russia (average specific gravity 7, 42%), Australia (average specific gravity 8,66%). At these countries are watched noticeable and constant growth in production of gold. The main of golden custom is jewelry - average specific gravity 45,60%. The main customer of golden is jewelry industry of India (746 t), Turkey (153t), Saudi Arabia (109t), Russia (109t) and USA (179t). These countries are the main producer of golden jewelries. Another raw market jewelry is silvery market. The world silver market is very monopolized. The main region of mining is countries of Latin America. The main silver mining countries are Mexico (average specific gravity 22,60%), Peru (average specific gravity 17,32%), China (average specific gravity 10,88%). The main field of consumer of silver in electronic industries, photos, and only at third point is jewelry. Consumption of silver of jewelry is not large. Last year such tendency are observed: falling of silver mining rates. It means rather falling of silver reserves, but improve recycling of silver. Also rather rates of silver custom, The most falling is at manufacture of jewelries and silver plate. Investment to silver is very actual. As source of statistic information are using of international organization report: World Gold Council, World Silver Institute.

Alternative Materials for Printed Circuit Board Production: An Environmental Perspective

This article investigates the potential environmental impacts of four-layer printed circuit board (PCB) production from cradle to grave. The study starts with a lifecycle assessment of conventional PCB production. Then, the alternative materials of polyethylene terephthalate (PET), polylactic acid (PLA)/glass fiber composite and paper are investigated for the substrate. A conventional PCB adopts copper as the conductive material and requires an etching process. The environmental impacts of changing the conductive deposition method to an additive method by printing silver nanoparticles is studied. In a conventional PCB, electricity generation contributes 41% of the global warming potential (GWP) and 38% of the abiotic resource depletion (ADP), in the fossil category. By applying an additive manufacturing method, the GWP of PCB manufacturing can be reduced to 14% of that of the conventional method. A sensitivity analysis of silver recycling illustrates that a 40% higher silver recycling rate would decrease the GWP of silver material by about 48–60%. Uncertainty in the energy consumption of PCB production would alter the environmental impacts; however, even with the most conservative energy consumption in a conventional PCB production method, the environmental impacts of the additive method are about five times lower than those of conventional PCB production.

Economic assessment model of the silver recycling industry

Silver Element (SE) is exploited in making coins, jewelry, silverware, electronics devices, medical and decorative stuff, confectionery products, mirrors and glass making, and making up photography films, etc. Because of its antibacterial properties, the SE is utilized in the pharmaceutical industry. One of its important characteristics is high resistance to chemical solvents. The SE has historically had a special position and value among the people because of its precious status and its widespread use, especially in the field of medicine. The Silver Metal (SM) has been used as a trading agent rather than money. The present research investigated the silver recycling industry from photography films and their belongings to deploy an economic assessment model empirically. By the current research, an economic assessment model was developed that can be assigned to assess any engineering &amp; industrial project in the screening step of project identification via the Environmental Impact Assessment (EIA) plan. Also, the developed model can be employed to estimate the economic indices of breakeven point, economic value-added, and time of return on investment. The configuration of the model is highly emphasized in electronic software's.

Silver recycling in the Viking Age: Theoretical and analytical approaches.

The recycling (remelting) of precious metals is commonly seen as a major impediment in provenancing studies. Yet in cases where known silver sources are both limited and geochemically well‐characterized, there are opportunities to evaluate silver flows at different temporal and geographical scales. Here, we provide a theoretical and analytical framework for assessing the impact of precious metal recycling in a historical context in which silver remelting was the norm: Viking Age Scandinavia (c.800–1050 ce). Harnessing new, large‐scale, Pb isotope and trace element datasets, we demonstrate the potential for revealing the contribution of Western European and Islamic silver sources to discrete archaeological assemblages and defined coin and artefact groups. We then use chemical markers of change in imported silver to assess the longevity of circulating silver stocks. Rather than acting as a barrier to understanding, recycling provides a lens through which to evaluate long‐distance trade networks, the movement of silver and the frequency of recycling events.

Silver Nanoparticle-Anchored Human Hair Kerateine/PEO/PVA Nanofibers for Antibacterial Application and Cell Proliferation.

The main core of wound treatment is cell growth and anti-infection. To accelerate the proliferation of fibroblasts in the wound and prevent wound infections, various strategies have been tried. It remains a challenge to obtain good cell proliferation and antibacterial effects. Here, human hair kerateine (HHK)/poly(ethylene oxide) (PEO)/poly(vinyl alcohol) (PVA) nanofibers were prepared using cysteine-rich HHK, and then, silver nanoparticles (AgNPs) were in situ anchored in the sulfur-containing amino acid residues of HHK. After the ultrasonic degradation test, HHK/PEO/PVA nanofibrous mats treated with 0.005-M silver nitrate were selected due to their relatively complete structures. It was observed by TEM-EDS that the sulfur-containing amino acids in HHK were the main anchor points of AgNPs. The results of FTIR, XRD and the thermal analysis suggested that the hydrogen bonds between PEO and PVA were broken by HHK and, further, by AgNPs. AgNPs could act as a catalyst to promote the thermal degradation reaction of PVA, PEO and HHK, which was beneficial for silver recycling and medical waste treatment. The antibacterial properties of AgNP-HHK/PEO/PVA nanofibers were examined by the disk diffusion method, and it was observed that they had potential antibacterial capability against Gram-positive bacteria, Gram-negative bacteria and fungi. In addition, HHK in the nanofibrous mats significantly improved the cell proliferation of NIH3T3 cells. These results illustrated that the AgNP-HHK/PEO/PVA nanofibrous mats exhibited excellent antibacterial activity and the ability to promote the proliferation of fibroblasts, reaching our target applications.

Efficient Recycling of Silver and Copper from Sintering Dust by Chlorination Roasting Process

In this study, the Ag and Cu evolution in the sintering dust was extracted by chlorination roasting process, and the mechanism of the process was analyzed by atomic absorption spectroscopy, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectrometry. In addition, in order to better understand the chlorination roasting process, the mechanism and thermodynamics of roasting reaction were analyzed. The recovery of Ag and Cu reached 99.05% and 59.32%, respectively, under the conditions of roasting temperature of 1423 K, holding time of 60 min, and the air flow rate of 400 L/h. Thermodynamic analysis showed that MgO and SiO2 could promote the production of Cl2 and HCl and that CuO could be chlorinated by Cl2 at 1421 K, but it was not amenable for HCl. Compared with CuO, Ag was more easily chlorinated at high temperatures. Experimental results indicate that silver and copper can be efficiently extracted, indicating that the chlorination roasting is a promising pyrometallurgical treatment for the recycling of sintering dust.

A Trinuclear Zinc Coordination Cluster Exhibiting Fluorescence, Colorimetric Sensitivity, and Recycling of Silver Ion and Detection of Cupric Ion.

The detection and reusage of transition-metal ions play a crucial role in human health and environmental protection. Recently, various analytical methods and substances have been successfully applied to probe or sense silver ions; however, rare representative examples have been presented regarding the simultaneous detection of silver and silver recycling with the elemental silver powder form. Herein, an unparalleled sensing mechanism for silver ions and recycling silver in its elemental form is exemplified by a fluorescent trinuclear zinc coordination cluster possessing the dual function of colorimetric sensing of silver and responding cupric ions. A Schiff-base-based trinuclear zinc coordination cluster, 1, with formula Zn3(L1)2(CH3COO)2(H2O)2, has been successfully synthesized by the initial exploration of multidentate ligand H2L1-((E)-2,4-di-tert-butyl-6-((2-hydroxy-3-methoxybenzy-lidene)amino)phenol) with various metal ions under self-assembly reactions. Complex 1 is highly fluorescent in solution and as a solid, in addition to acting as a fluorescence sensor toward AgI in ethanol media. Compound 1 displays distinctive sensing of AgI through the fluorescence quenching effect at 576 nm and signal augment at 446 nm over 11 kinds of cations in the absence of interference. The proposed sensing mechanism is attributed to the ligands in 1 which interact with AgI; the ligands undergo oxidation cyclization reaction, leading to the formation of 2 with the formula Zn3(L2)4(CH3COO)2·2CH3CH2OH·H2O, and AgI reduction to elemental Ag powder. Compound 1 presents specific selectivity and sensitivity for AgI in ethanolic solution with a detection limit of 0.1722 μM. The orange color of 1 changes to colorless during the mixing of a small amount of AgI, revealing its potential practical application in naked-eye detection of AgI. Furthermore, 2 exhibits obvious fluorescence emission at 448 nm (λex = 380 nm) and selectively responds to CuII over 11 kinds of metal ions with the fluorescence "turn-off" owing to the formation of 3 in ethanolic solution; it also has a detection limit of 0.0226 μM.

Determining the amount, type and management of dental wastes in general and specialized dentistry offices of Northern Iran

Dental wastes need comprehensive identification, planning and management due to the presence of hazardous chemicals. The aim of the present study was to investigate the quantity, quality and management of wastes in general and specialized dental offices in Babol, Mazandaran Province. This research was conducted in 40 general dentistry offices with 52 dental units and 240 patients per day and in 13 specialized dentistry offices with 21 units and 78 patients per day through random sampling. Samples were analyzed at the end of the work hour after transferring to a suitable place. The total amount of wastes generated was 333.8 and 340.9 g/unit/day as well as was 72.3 and 91.7 g/patient/day in general and specialized dentistry offices, respectively. In general and specialized dentistry offices, the amount of infectious wastes was 95 and 83.2 g/unit/day as well as 20.6 and 22.4 g/patient/day; Domestic-type wastes was 113.4 and 124.7 g/unit/day as well as 24.6 and 33.5 g/patient/day; chemical toxic waste was 47.3 and 47.04 g/unit/day as well as 10.2 and 12.6 g/patient/day; sharps was 66.1 and 69.6 g/unit/day as well as 14.3 and 18.7 g/patient/day; and amalgams was 11.9 and 16.4 g/unit/day as well as 2.6 and 4.43 g/patient/day. The recycling of silver and mercury was carried out in 7.5% of specialized dentistry offices. Training the dentists is required to perform the activities related to the reduction, separation and recycling of wastes as well as to implement the plan of collection, transportation and disposal of infectious, sharp, chemical-toxic and amalgam wastes according to the relevant criteria.

Recycling of Silver and Zinc from Silver Oxide Battery Waste

AbstractA remarkable number of batteries are used for powering various types of devices; however, after use, batteries are randomly thrown away, causing potential environmental damage to the bio‐habitats and a loss of resources. Battery recycling processes should be comprehensively studied to address the aforementioned issues.

Kinetic Investigation of Silver Recycling by Leaching from Mechanical Pre-Treated Oxygen-Depolarized Cathodes Containing PTFE and Nickel

This paper focuses on the recycling of silver from spent oxygen-depolarized cathodes through an innovative combination of pre-treatment methods and leaching. A silver- and polytetrafluorethylene (PTFE)-rich fraction was produced by cryogenic milling, screening, and magnetic separation. In order to understand the kinetic leaching mechanism, the silver-rich fraction was leached by different concentrations of nitric acid and hydrogen peroxide. Results showed that nickel influences the silver leaching. This leads to complex reaction systems, which cannot be described by the Arrhenius law.

From Iberia to the Southern Levant: The Movement of Silver Across the Mediterranean in the Early Iron Age

The origins of the silver trade across the Mediterranean, and the role of the Phoenicians in this phenomenon, remain contentious. This is partly because of difficulties encountered when trying to assign archaeological silver to its geological sources. Here we present a reanalysis of Iron Age silver hoards in the southern Levant, which demonstrates not only that recycling of silver was widespread in the Early and Late Iron Age, but that the components of this mixed silver originated from the Aegean, Anatolia and the western Mediterranean. An assessment of lead isotope analyses combined with compositional data allows the identification of mixing lines based on gold levels in the silver and the Pb crustal age (or, more loosely, geological age) of the ore from which the silver originated. It is shown that, from as early as the 11th century BC, these mixed silver signatures derive from the Taurus mountains in Anatolia, from Iberia and an unknown source—with Sardinia as an additional possibility—and Laurion in Greece in the Late Iron Age. In contrast to copper, which was deliberately alloyed with silver, gold appears to have been mixed unintentionally, through the melting down of silver objects with gold parts. It is suggested that vertical mixing lines (with constant Pb crustal age but variable Au), may indicate the melting down and mixing of silver in times of unrest, both here and in other contexts. Gold and lead concentrations in the silver indicate that native silver from Iberia was most likely used in the Early Iron Age, suggesting that the first people to convey silver to the southern Levant were not miners but traders who had acquired silver directly from the indigenous Bronze Age inhabitants of Iberia. However, evidence of the exploitation of jarosite also supports that silver ore mining and cupellation was ongoing in Iberia at a similar time, and continued in the Late Iron Age—potentially a result of technological transfer from the East. In essence, the western Mediterranean origin of the silver in these Early Iron Age southern Levantine hoards supports an emerging picture of Mediterranean interactions and trade relations in the increasingly bright Dark Ages (c. 1200–800 BC).

Reliable, environmentally friendly method for the recycling of spent Ag/α-Al2O3 catalysts using (NH4)2Ce(NO3)6

Abstract Traditionally, Ag-containing solid wastes are leached by nitric acid in order to recycle the noble metal. However, the huge amounts of emission of toxic nitrogen oxides demand the development of a new method for silver recycling. Recently, considering the Ce(IV) solution could be regenerated with electrolyzation method, our group invented a novel environmentally friendly process by using Ce(IV) as the oxidant to dissolve silver from the spent Ag/ɑ-Al2O3 catalysts without NOx emission. To find out the optimal parameters, in this work, the leaching reaction was thoroughly investigated with respect to the temperature, oxidant and HNO3 concentrations, stirring speed, and time. The optimized leaching reaction gave the leaching silver rate 99.8% in 1 h. The kinetic plots suggested a shrinking core model with the internal diffusion-controlled process and the activation energy of 38.83 kJ·mol− 1. The order in which the experimental conditions influence the reaction was determined through orthogonal analysis: temperature > oxidant concentration > HNO3 concentration > stirring speed.

Initiating silver recycling efforts: Quantifying Ag from used burn dressings

Abstract Acticoat™ is a silver nanoparticle burn and wound dressing. Following use they are sent to the landfill where silver leaching into the environment can occur. Although the toxic effects of silver are known, no study has calculated the amount of silver remaining in used dressings. Herein we quantify the amount of silver in used relative to unused dressings to establish a need for recycling initiatives. Acticoat™ dressings obtained from British Columbia Children’s Hospital were sampled and an acid digestion to extract silver was optimized and performed. The concentration of silver was measured by atomic absorption spectroscopy. Method validation samples determined the accuracy and precision of our methodology. In an unused sample of Acticoat™, there was (1.2 ± 0.8) mg silver/cm 2 , with a standard deviation of 0.08 mg silver/cm 2 and %RSD of 7% at the 95% confidence interval. In a used sample of Acticoat™, (0.7 ± 0.4) mg silver/cm 2 was found, with a standard deviation of 0.3 mg silver/cm 2 and %RSD of 39% at the 95% confidence interval. There was no statistical loss of silver in the used dressings compared to the unused dressings indicating reason to evaluate silver recycling initiatives to prevent further silver environmental toxicity.