In a new study, researchers at Northwestern University showed that brewing tea naturally absorbs heavy metals such as lead and cadmium from water and effectively removes dangerous pollutants from this drink. Heavy metal ions stick to the surface of the tea leaves or are attracted to it, where they remain trapped until the used tea is destroyed.
According to RCO News Agency, “We do not recommend that everyone start using tea leaf as filters,” says Vinayak Dravid. For this study, our goal was to measure the ability of tea to absorb heavy metals.
According to Science Dili, Benjamin Shindel, the first author of the study, says: There may be no specific property in the tea leaves. Any other substance can be crushed to gain similar capability and poured into the water, but the point is that tea is the most consumed drink in the world, so we don’t have to put extra work in the water and they naturally have metals. Remove from water.
Check different variables
To do this study, the researchers examined how different types of tea, tea bags and tea brewing methods affect the absorption of heavy metals. Various tested types included real tea such as black, green, oolong and white tea as well as chamomile and roybus tea. They also examined the difference between tail tea and commercial tea bag.
The researchers made water solutions with known quantities of lead and other metals (chromium, copper, zinc and cadmium) and then heated the solutions at lower temperatures than weld. They then added tea leaves, which stayed from a few seconds to 4 hours at different intervals.
After brewing tea, the researchers examined how much metal content remains in the water. By comparing metal surfaces before and after the addition of tea leaves, they were able to calculate how effectively the metals were removed.
Cellulose bags did the best and did not release microplastic.
After numerous experiments, the researchers identified several trends. It may not be surprising to say that the tea bag is important. After testing different types of tea -free bags, the researchers found that cotton and nylon bags only absorb small amounts of pollutants. However, cellulose bags worked extremely well.
Cellulose, a natural biodegradable substance made of wood paste, provides higher levels of metal absorption than synthetic materials.
“Cotton and nylon bags actually do not remove any heavy metal from the water,” Shindel said. Nylon bags are now problematic because they release microplasts, but most bags used today are made of natural materials such as cellulose. Although they may release micro -cellulose particles, it is a fiber that our body has no problem with.
Time -immersed time, less metals
When comparing different types of tea, the researchers found that the type of tea and its grinding had a small role in absorbing pollutants. Millennium tea leaves, especially black tea leaves, absorb metal ions slightly more than the full leaves.
Shindel explained: When tea leaves become black tea, they wrinkles and their pores open. These wrinkles and pores provide more levels to absorb metals. Milling of the leaves also increases the surface and provides more capacity to connect.
Of all the experiments, one factor was most notable. Tailing played the most important role in the ability of tea leaf to absorb metal ions. The longer the immersion is, the more contaminants are absorbed.
“An any tea that brews or has more levels for a longer time, effectively absorbs more heavy metals,” Schindel said. Some people brew their tea for a few seconds and many metals are not absorbed.
Although these results depend on several factors, tea preparation eliminates some lead from water, which must be significant from the perspective of public health.
According to experiments, the researchers estimate that tea preparation can eliminate about 2 percent of the potential lead. This estimate applies only to a cup of “ordinary” tea, which includes a glass of water and a tea bag that brews for three to five minutes. Changing parameters changes different lead levels. For example, tailoring for more than five minutes excuses more lead.
In high quality areas, lead concentrations are unlikely to reach such high levels and if the conditions are critical, tea brewing will not solve the problem. But the results of this study provide new useful information that can be used in public health research.
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