3D MXene hybrid architectures for the cold-resistant, rapid and selective capture of precious metals from electronic waste and mineral

2022 ◽  
Vol 428 ◽  
pp. 132493
Author(s):  
Zhen Qin ◽  
Hongxia Deng ◽  
Ruihua Huang ◽  
Shanshan Tong
Recycling ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 8
Author(s):  
Tetiana Shevchenko ◽  
Michael Saidani ◽  
Yuriy Danko ◽  
Ievgeniia Golysheva ◽  
Jana Chovancová ◽  
...  

Efficient electronic waste (e-waste) management is one of the vital strategies to save materials, including critical minerals and precious metals with limited global reserves. The e-waste collection issue has gained increasing attention in recent years, especially in developing countries, due to low collection rates. This study aims to search for progressive solutions in the e-waste collection sphere with close-to-zero transport and infrastructure costs and the minimization of consumers’ efforts towards an enhanced e-waste management efficiency and collection rate. Along these lines, the present paper develops a smart reverse system of e-waste from end-of-life electronics holders to local recycling infrastructures based on intelligent information technology (IT) tools involving local delivery services to collect e-waste and connecting with interactive online maps of users’ requests. This system considers the vehicles of local delivery services as potential mobile collection points that collect and deliver e-waste to a local recycling enterprise with a minimum deviation from the planned routes. Besides e-waste transport and infrastructure costs minimization, the proposed smart e-waste reverse system supports the reduction of CO2 through the optimal deployment of e-waste collection vehicles. The present study also advances a solid rationale for involving local e-waste operators as key stakeholders of the smart e-waste reverse system. Deploying the business model canvas (BMC) toolkit, a business model of the developed system has been built for the case of Sumy city, Ukraine, and discussed in light of recent studies.


Author(s):  
Christian Galasso ◽  
Xabier Lekube ◽  
Ibon Cancio ◽  
Antonio Dell’Anno ◽  
Christophe Brunet ◽  
...  

Author(s):  
Sanjay Kumar Koli ◽  
Athar Hussain

Electronics waste is becoming a major global issue. Huge accumulation of e-waste and its recycling through primitive means for extraction of precious metals are a real concern in the developing countries due to the presence of hazardous materials in e-waste. The major portion of e-waste generated domestically as well as illegally imported is recycled in a crude manner leading to pollution of the environment. Current practices of e-waste management in India encounters many challenges like the difficulty in inventorization, ineffective regulations, pathetic and unsafe conditions of informal recycling, poor awareness of consumers, and reluctance on part of stakeholders to address the issues. As a result, toxic materials enter waste stream with no special precautions to avoid the known adverse impacts on the environment and human health. Resources are wasted when economically valuable materials are dumped. This chapter highlights the hazards caused due to improper handling of e-wastes and also describes some appropriate measures to be adopted for its management and safe disposal.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3456
Author(s):  
Maria Beatriz Q. L. F. Torrinha ◽  
Hugo A. M. Bacelo ◽  
Sílvia C. R. Santos ◽  
Rui A. R. Boaventura ◽  
Cidália M. S. Botelho

The recovery of critical and precious metals from waste electrical and electronic equipment (WEEE) is an environmental and economic imperative. Biosorption has been considered a key technology for the selective extraction of gold from hydrometallurgical liquors obtained in the chemical leaching of e-waste. In this work, the potential of tannin resins prepared from Pinus pinaster bark to sequester and recover gold(III) from hydrochloric acid and aqua regia solutions was assessed. Equilibrium isotherms were experimentally determined and maximum adsorption capacities of 343 ± 38 and 270 ± 19 mg g−1 were found for Au uptake from HCl and HCl/HNO3 (3:1 v/v) solutions containing 1.0 mol L−1 H+. Higher levels of acidity (and chloride ligands) significantly impaired the adsorption of gold from both kinds of leaching solutions, especially in the aqua regia system, in which the adsorbent underperformed. Pseudo-first and pseudo-second order models successfully described the kinetic data. The adsorbent presented high selectivity towards gold. Actually, in simulated aqua regia WEEE liquors, Au(III) was extensively adsorbed, compared to Cu(II), Fe(III), Ni(II), Pd(II), and Zn(II). In three adsorption–desorption cycles, the adsorption capacity of the regenerated adsorbent moderately decreased (19%), although the gold elution in acidic thiourea solution had been quite limited. Future research is needed to examine more closely the elution of gold from the exhausted adsorbents. The results obtained in this work show good perspectives as regards the application of pine bark tannin resins for the selective extraction of Au from electronic waste leach liquors.


Author(s):  
Moonisa A. Dervash ◽  
Syed Maqbool Geelani ◽  
Rouf Ahmad Bhat ◽  
Dig Vijay Singh ◽  
Akhlaq Amin Wani

Electronic waste (e-waste) is one of the swift waste streams and comprises of end of life electronic products. The Western countries as alternative destinations for disposal ship the wastes to underdeveloped and developing countries where labor cost is reasonably meager and environmental laws are feebly implemented. When not recycled, the e-waste is either incinerated or landfilled. These methods involve not only wasting valuable metals but also creating potential risk for the environment. These substances are detrimental to nervous system, kidneys, bones, reproductive system, and endocrine system, and some of them are even carcinogenic and neurotoxic. Thus, extensive research is needed to evolve sophisticated technology which may help to curb environmental pollution and contribute towards sustainable development in terms of recycling of precious metals.


2020 ◽  
pp. 0734242X2095284
Author(s):  
Amit Kumar ◽  
Maria E Holuszko ◽  
Travis Janke

Waste Printed circuit boards (PCBs) are one of the most valuable and recycled components of electronic waste due to the presence of precious metals such as copper, silver, gold and palladium. The rejects of the PCB recycling process, named non-metal fraction (NMF) have continuously been sent to landfills. Several researchers have proposed alternative use of NMF as secondary materials such as fillers in composites or as adsorbent. This study is focused on the potential application of the PCB recycling rejects as waste-derived fuel or alternative fuel in the cement industry. Approximately 2 million metric tonnes (Mt) of this waste was produced in 2014 globally and estimated to reach 6.5 million Mt in 2050. The presence of high organic matter in the NMF renders it useful as an alternative fuel. The organic content of the NMF could also potentially be increased using gravity separation and thus increasing its net calorific value. The study showed that the NMF could provide up to 21 MJ kg-1 of heating value with low heavy metal and ash concentration. A comparison with other waste-derived fuel sources is also presented in the paper.


2014 ◽  
Vol 955-959 ◽  
pp. 2743-2746 ◽  
Author(s):  
Jian Feng Yin ◽  
Si Hui Zhan ◽  
He Xu

Waste mobile phone has become the largest number of electronic waste, and recycling of metals from mobile phone would ensure resource recycling and reduce environmental degradation. Based on the contents of metals analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), containing copper and precious metals such as gold, the paper compared the extraction processes of gold, copper from waste mobile phone printed circuit board (PCB). In this study, two processes, nitric acid and thiourea (NT), sulfuric acid-hydrogen peroxide and iodine (SAHPI) were used to leach copper and gold, respectively. The recovery rate of copper was found to be 96.42%, and 94.3% of the gold was leached in the former process. Similar trends were obtained for the leaching of copper and gold in the latter process, but it was lower that about 95.27% of copper was recycled, while 93.4% of gold were leached. Both the two processes were nontoxic and non-cyanide system. However, thiourea is not stable and easy to decompose in alkaline solution, and the technology has disadvantage of instability. Iodine leaching on the other hand is comparatively a environmental process. Therefore, the optimal choice is the combined process of SAHPI method, while further research is required to develop cost effective and environmentally friendly processes.


Author(s):  
R. Alani ◽  
A. Ogunbanmwo ◽  
D. Nwude ◽  
M. Ogbaje

The main aim of this research was to assess the extent of the problems associated with inappropriate e-waste management and recycling practices. Electronic wastes (E-wastes) are generated from products that are designed for use with a maximum voltage of 1000 volts for alternating current and 1500 volts for direct current. These wastes contain hazardous materials such as lead, mercury, cadmium, brominated flame-retardants, valuable metals such as aluminium, nickel, copper, and certain precious metals such as gold, silver and platinum group metals (PGMs) which pose both human and environmental health threats. They have negative impacts on the health of workers and nearby residents; hence, residents of buildings located around and beside e-wastes dumpsites were randomly selected for this study. Well, run-off and borehole water samples as well as soil samples from different sites in Alaba international market, and Ikeja computer village in Lagos, Nigeria were analyzed for zinc, lead, iron, copper, nickel and chromium. Using additional information from questionnaires and interviews, impacts of e-waste dumps on the health of workers and residents near the study areas were investigated. The results were analysed using descriptive frequency count and tables which confirmed the presence of heavy metals in soils and water samples of the case study areas and hence appropriate recommendations were outlined to address the menace of e-waste disposal and as well as the need for improvement in e-waste management and recycling for economic opportunities and improved health standard within the Lagos Metropolis.


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