Trends in the Use and Recovery of Electronic Waste As Aggregates in Eco-friendly Concrete

The management of electronic waste (e-waste) mainly from televisions and computers, has turned into an environmental issue due to the increased demand in the electronics sector and the highly toxic contents (mercury, lead, or cadmium) of some of these devices that make them almost unrecoverable. Therefore, these valuable devices become wastes disposed of in landfills. Worldwide, some scholars have proposed recycling methods that re-introduce these wastes streams in the manufacturing process of heavy concrete, pavement, concrete blocks, and clay bricks among other unconventional products. The replacement rates of virgin materials with recycled e-waste fluctuate according to the type of waste. Nevertheless, the use of e-waste generates a positive environmental impact due to the less demand for virgin materials such as river sand and gravel. This study aimed to review the current e-waste recycling state-of-the-art such as circuit boards (PCB), high-impact polystyrene (HIPS), cathode ray tube (CRT), and LCD screens. A systematic review of scientific literature published in the last 10 years (2010–2019) was done through the SCOPUS database. The results showed a maximum potential replacement rate of 40% for this type of waste, given the effect on the physical and thermomechanical properties of the concrete.

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Recovery of base and precious metals from PCBs (Printed Circuit Boards) in waste electrical and electronic equipment (WEEE)

World Journal of Advanced Research and Reviews ◽

10.30574/wjarr.2022.13.1.0734 ◽

2022 ◽

Vol 13 (1) ◽

pp. 001-011

Author(s):

Yete Pélagie ◽

Togbe FC Alexis ◽

Yovo Franck ◽

Suanon Fidèle ◽

Sidohounde Assou ◽

...

Keyword(s):

Printed Circuit Boards ◽

Electronic Waste ◽

Precious Metals ◽

Developed Countries ◽

Waste Recycling ◽

Electronic Equipment ◽

Circuit Boards ◽

African Countries ◽

Printed Circuit ◽

Advantages And Disadvantages

Natural minerals are a powerful tool in politics when some have a major role in production. Its depletion is now a hot topic worldwide. Thus, the safety of the environment, natural surface water, groundwater and the protection of soils from chronic contamination by metallic and inorganic elements is a global concern. Indeed, industrialization and development have led to the generation of huge and varied amounts of waste, including electronic waste (e-waste), which is released into the environment. Although e-waste is classified as hazardous, most of it is not recycled and developed countries with strict environmental protection legislation send most of their e-waste to developing countries where regulations are lax. These electronic devices and components after being used are simply dumped into the environment due to lack of treatment and recycling strategy. As a result, they become a threat to the environment, ecosystems and humans. African countries are among the most vulnerable nations. But they are unfortunately ignored and underestimated. To date, there is no e-waste recycling unit (factory) in most African countries and mainly in the Republic of Benin. In response to this challenge, this study explored the different techniques used for the recycling of waste electrical/electronic equipment in order to develop a new environmentally friendly approach in future work, for the extraction and recycling of the usual and valuable metallic elements contained in electronic waste (printed circuit boards) released into the environment. For this purpose, a bibliographic research was carried out from 20 April to 16 October 2021. The results obtained allowed us to identify the advantages and disadvantages of existing recycling methods.

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Leaching and Selective Recovery of Cu from Printed Circuit Boards

Metals ◽

10.3390/met9101034 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1034 ◽

Cited By ~ 7

Author(s):

Manivannan Sethurajan ◽

Eric D. van Hullebusch

Keyword(s):

Copper Sulfide ◽

Printed Circuit Boards ◽

Electronic Waste ◽

Waste Recycling ◽

Ferric Sulfate ◽

Molar Ratio ◽

Circuit Boards ◽

Optimum Conditions ◽

Selective Recovery ◽

Printed Circuit

Printed circuit boards (PCBs), a typical end-of-life electronic waste, were collected from an E-waste recycling company located in the Netherlands. Cu and precious metal concentration analyses of the powdered PCBs confirm that the PCBs are multimetallic in nature, rich, but contain high concentrations of Cu, Au, Ag, Pd, and Pt. Ferric sulfate concentration (100 mM), agitation speed (300 rpm), temperature (20 °C), and solid-to-liquid ratio (10 g·L−1) were found to be the optimum conditions for the maximum leaching of Cu from PCBs. The ferric sulfate leachates were further examined for selective recovery of Cu as copper sulfides. The important process variables of sulfide precipitation, such as lixiviant concentration and sulfide dosage were investigated and optimized 100 ppm of ferric sulfate and (copper:sulfide) 1:3 molar ratio, respectively. Over 95% of the dissolved Cu (from the multimetallic leachates) was selectively precipitated as copper sulfide under optimum conditions. The characterization of the copper sulfide precipitates by SEM-EDS analyses showed that the precipitates mainly consist of Cu and S. PCBs can thus be seen as a potential secondary resource for copper.

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Recycling of cathode ray tube panel glasses as aggregates of concrete blocks and clay bricks

Journal of Material Cycles and Waste Management ◽

10.1007/s10163-015-0350-6 ◽

2015 ◽

Vol 18 (3) ◽

pp. 552-562 ◽

Cited By ~ 9

Author(s):

Jang-Soo Lee ◽

Heung-Min Yoo ◽

Se-Won Park ◽

Sung-Jin Cho ◽

Yong-Chil Seo

Keyword(s):

Clay Bricks ◽

Cathode Ray Tube ◽

Concrete Blocks

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Brominated flame retardants (BFRs) in PM2.5 associated with various source sectors in southern China

Environmental Science Processes & Impacts ◽

10.1039/d0em00443j ◽

2021 ◽

Author(s):

qiqi li ◽

Tao Wang ◽

yuan zeng ◽

yun fan ◽

Shejun Chen ◽

...

Keyword(s):

Flame Retardants ◽

Southern China ◽

Electronic Waste ◽

Brominated Flame Retardants ◽

Waste Recycling ◽

Recycling Facilities

The present study investigated legacy and novel brominated flame retardants (BFRs) in atmospheric PM2.5 associated with various urban source sectors in a city and electronic waste (e-waste) recycling facilities in...

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Food Waste-Assisted Metal Extraction from Printed Circuit Boards: The Aspergillus niger Route

Microorganisms ◽

10.3390/microorganisms9050895 ◽

2021 ◽

Vol 9 (5) ◽

pp. 895

Author(s):

Carlotta Alias ◽

Daniela Bulgari ◽

Fabjola Bilo ◽

Laura Borgese ◽

Alessandra Gianoncelli ◽

...

Keyword(s):

Solid State ◽

Aspergillus Niger ◽

Food Waste ◽

Solid State Fermentation ◽

Printed Circuit Boards ◽

Electronic Waste ◽

Metal Extraction ◽

Circuit Boards ◽

Printed Circuit ◽

Waste Printed Circuit Boards

A low-energy paradigm was adopted for sustainable, affordable, and effective urban waste valorization. Here a new, eco-designed, solid-state fermentation process is presented to obtain some useful bio-products by recycling of different wastes. Urban food waste and scraps from trimmings were used as a substrate for the production of citric acid (CA) by solid state fermentation of Aspergillus niger NRRL 334, with a yield of 20.50 mg of CA per gram of substrate. The acid solution was used to extract metals from waste printed circuit boards (WPCBs), one of the most common electronic waste. The leaching activity of the biological solution is comparable to a commercial CA one. Sn and Fe were the most leached metals (404.09 and 67.99 mg/L, respectively), followed by Ni and Zn (4.55 and 1.92 mg/L) without any pre-treatments as usually performed. Commercial CA extracted Fe more efficiently than the organic one (123.46 vs. 67.99 mg/L); vice versa, biological organic CA recovered Ni better than commercial CA (4.55 vs. 1.54 mg/L). This is the first approach that allows the extraction of metals from WPCBs through CA produced by A. niger directly grown on waste material without any sugar supplement. This “green” process could be an alternative for the recovery of valuable metals such as Fe, Pb, and Ni from electronic waste.

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