A new material made from orange peels could remove mercury pollution from the ocean
Since the Industrial Revolution, our exposure to mercury has risen quite sharply. The upper ocean now has 3.4 times as much mercury as it did pre-Industrial Revolution and it easily makes its way into the food chain. Yellowfin tuna stocks have seen a 3.8 percent increase in mercury levels every year since 1998 and they've even discovered that the Grand Canyon is full of mercury, far exceeding wildlife toxicity thresholds.
The burning of coal and the mining industry are the biggest culprits and too much exposure to mercury can lead to serious health problems for humans and wildlife. There have been ideas for ways to remove mercury pollution, but none have been cost-effective or able to scale up to a global solution.
Researchers at Flinders University in Australia believe that they have finally found the solution that meets both of those criteria. They have created a new material that is made from waste from the citrus and petroleum industries and is capable of sucking mercury out of both soil and water.
The dark red polymer material is made using limonene, a compound found in orange peels, and sulphur. It turns yellow when it absorbs mercury, making it suitable for both mercury detection and clean-up. Because the components to make the material come from large waste streams, the university says the material is "dirt-cheap" to produce meaning it could easily be used in widespread applications like lining pipes for domestic and waste water, large-scale environmental clean-up operations and even for reducing mercury levels in large bodies of water like the oceans.
The petroleum industry creates about 70 million tons of sulphur every year and the citrus industry produces 70,000 tons of limonene. By using these components in the material, large waste streams are being remade into something useful while mercury is removed from the environment.
The researchers found that the material can also remove other toxic metals from water and it safely stores the pollutants until it can be removed. The team's findings will be published in the journal Angewandte Chemie International Edition and they are working on making a commercial version of the material.