From Trash to Treasure: E-waste is a Literal Gold Mine

SEATTLE (Scrap Monster):  Electronic waste, or e-waste, is a rapidly growing problem. Each year, the world generates approximately 50 million tons of this type of waste.

It’s alarming to note that only 20% of e-waste is recycled, while the rest finds its way to landfills or incineration – both of which contribute to environmental pollution.

However, scientists have found a shining opportunity amid this grim reality, proving that every cloud truly has a silver (or gold) lining.

Transforming e-waste into gold

The idea of extracting gold from electronic waste is not new. It is estimated that a ton of electronic waste contains at least 10 times more gold than a ton of regular ore from which gold is mined.

But the devil is in the detail, or in this case, in the gold extraction process. Traditional techniques involve using harsh toxins like cyanide, which pose major environmental risks.

Yet, scientists at the College of Agriculture and Life Sciences at Cornell have devised an ingenious solution that is eco-friendly and doubly beneficial.

The new method does not just extract gold from e-waste, it also uses the precious metal to convert carbon dioxide (CO2), a key greenhouse gas, into useful chemicals.

Extracting gold with precision

The research, led by postdoc researcher Amin Zadehnazari, is rooted in the creation of vinyl-linked covalent organic frameworks (VCOFs).

These VCOFs are designed to pick out gold ions and nanoparticles from the intricate circuit boards found in discarded electronic devices, and they do so with remarkable precision and efficiency.

One of the VCOFs was found to capture a whopping 99.9% of the gold, leaving behind other metals like nickel and copper.

“We can then use the gold-loaded COFs to convert CO2 into useful chemicals,” noted Zadehnazari. “By transforming  CO2 into value-added materials, we not only reduce waste disposal demands, we also provide both environmental and practical benefits. It’s kind of a win-win for the environment.”

Building a greener future

The unique properties of the VCOFs lie in their building blocks – tetrathiafulvalene (TTF) and tetraphenylethylene (TPE).

Tetrathiafulvalene is rich in sulfur, which makes it a natural magnet for gold. TTF also demonstrated an amazing endurance, withstanding 16 washings and reuses without showing significant loss of adsorption efficiency.

Another fascinating aspect of this method is its ability to convert CO2 into organic matter under ambient CO2 pressure at 50 degrees Celsius (122 degrees Fahrenheit), a result of carboxylation.

This process doubles the benefit of the technique, as it is not just extracting precious metal but also reducing the levels of a potent greenhouse gas.

Selectively capturing gold from e-waste

Study co-author Alireza Abbaspourrad, a professor of food chemistry and ingredient technology, emphasized the importance of this selective recovery.

“Knowing how much gold and other precious metals go into these types of electronics devices, being able to recover them in a way where you can selectively capture the metal you want – in this case, gold – is very important,” said Abbaspourrad.

As we face a future burdened with 80 million metric tons of e-waste by 2030, it has become more crucial than ever to find sustainable ways of dealing with this issue.

The method developed by the Cornell team provides us with a glimmer of hope – a vision of a future where waste becomes wealth, and where our technological habits serve nature rather than harm it.

The growing challenge of e-waste

E-waste is more than just an environmental problem; it’s a global crisis. Rapid technological advances and shorter product lifespans have fueled an unprecedented rise in discarded electronics.

Most of the waste comes from high-income countries, but its disposal disproportionately affects lower-income countries, where lax regulations result in unsafe recycling practices.

E-waste is manually dismantled in informal sectors in many regions, often exposing workers to hazardous substances such as lead, mercury, and brominated flame retardants.

These toxic chemicals not only harm human health but also leach into soil and water, posing long-term ecological risks.

The new VCOF technology developed at Cornell is a critical step forward in addressing the growing challenges of e-waste.

Courtesy: www.earth.com