Money does not grow on trees but gold is possible. An international team of scientists has found a way to develop and harvest gold from crops.
The gold mining technique called phytomining uses plants to extract precious metal particles from the soil. Some plants are endowed with the ability to absorb roots and concentrate metals such as nickel, cadmium and zinc in leaves and roots. For years, scientists have discovered how to use these superaccumulator plants to remove pollutants.
However, in the past, researchers had never known any natural gold-absorbing plants. The reason is that, gold is not easily soluble in water, so plants do not have any natural way to absorb these precious metal particles through their roots.
"Under certain chemical conditions, we can create solubility for gold," said Chris Anderson, an environmental geochemical expert at Massey University in New Zealand.
15 years ago, Mr. Anderson demonstrated for the first time the ability to capture yellow mustard plants from soil that used to process chemicals and contain gold particles.
The mechanism of operation of the technique is basically as follows: Find a fast growing tree with a lot of leaves on the ground, such as mustard, sunflower or tobacco plants. It is also good to grow those plants on soil containing gold, even on waste piles or landfills around old gold mines.
Exploiting gold in the current popular way cannot extract 100% gold from the surrounding minerals, so certain gold can be wasted. Once the plants grow to their maximum height, the team will treat the soil with a chemical that makes the gold soluble. When the tree evaporates, pulls up the water and escapes through small holes in its leaves, this process absorbs both the gold-containing water from the soil and accumulates in the biomass of the plant. After that, the team just harvested gold.
The gold collected in plants is just nanoparticles. So this could be a great potential for the chemical industry, which uses gold nanoparticles as catalysts for chemical reactions.
"Phytomining technology will not replace traditional gold mining practices. Its value lies in helping to handle and remedy the consequences of contaminated gold mines," Anderson said .
Chemicals used to dissolve gold also stimulate plants to absorb soil pollutants such as mercury, arsenic and copper - common pollutants in gold mine waste, which can cause Potential danger to humans and the environment.
Mr. Anderson is currently working with Indonesian researchers to develop a small-scale support system for manual gold miners to use new techniques to reduce mercury pollution from operations. their.
However, some scientists warn, the risks to the environment associated with gold development can be huge. Cyanide and thiocyanate, toxic chemicals commonly used by companies to expose gold out of rock seams, must be used to dissolve gold particles into water in the soil."The process itself has been able to create environmental problems," said J. Scott Angle, an agronomist from the University of Georgia (USA).