'Super sand' for better purification of drinking water

'Super sand' for better purification of drinking water

  8:57:00 PM    Science Lover

---

Scientists have developed a way to transform ordinary sand — a mainstay filter material used to purify drinking water throughout the world — into a "super sand" with five times the filtering capacity of regular sand. The new material could be a low-cost boon for developing countries, where more than a billion people lack clean drinking water, according to the report in the ACS journal Applied Materials & Interfaces.

Mainak Majumder and colleagues note that sand has been used to purify water for more than 6,000 years, and sand or gravel water filtration is endorsed by the World Health Organization. Their studies of a nanomaterial called graphite oxide (GO) suggest that it could be used to improve sand filtration in a cost-effective way, they write.

The researchers used a simple method to coat sand grains with graphite oxide, creating a super sand that successfully removed mercury and a dye molecule from water. In the mercury test, ordinary sand was saturated within 10 minutes of filtration, while the super sand absorbed the heavy metal for more than 50 minutes, the scientists discovered. Its filtration "performance is comparable to some commercially available activated carbon," the scientists said. "We are currently investigating strategies that will enable us to assemble functionalized GO particles on the sand grains to further enhance contaminant removal efficiencies," they write.

Read More

Drink Water to Curb Weight Gain? Clinical Trial Confirms Effectiveness of Simple Appetite Control Method

Drink Water to Curb Weight Gain? Clinical Trial Confirms Effectiveness of Simple Appetite Control Method

  7:38:00 AM    Science Lover

---

Has the long-sought magic potion in society's "battle with the bulge" finally arrived? An appetite-control agent that requires no prescription, has no common side effects, and costs almost nothing? Scientists report results of a new clinical trial confirming that just two 8-ounce glasses of the stuff, taken before meals, enables people to shed pounds. The weight-loss elixir, they told the 240th National Meeting of the American Chemical Society (ACS), is ordinary water.

Drinking more water before meals can help promote weight loss, new research suggests. (Credit: iStockphoto/Lise Gagne)

"We are presenting results of the first randomized controlled intervention trial demonstrating that increased water consumption is an effective weight loss strategy," said Brenda Davy, Ph.D., senior author on the study. "We found in earlier studies that middle aged and older people who drank two cups of water right before eating a meal ate between 75 and 90 fewer calories during that meal. In this recent study, we found that over the course of 12 weeks, dieters who drank water before meals, three times per day, lost about 5 pounds more than dieters who did not increase their water intake."

"People should drink more water and less sugary, high-calorie drinks. It's a simple way to facilitate weight management."

Davy pointed out that folklore and everyday experience long have suggested that water can help promote weight loss. But there has been surprisingly little scientific information on the topic. Previous studies hinted that drinking water before meals reduces intake of calories. Lacking until now, however, has been the "gold-standard" evidence from a randomized, controlled clinical trial that compares weight loss among dieters who drink water before meals with those who do not.

The study included 48 adults aged 55-75 years, divided into two groups. One group drank 2 cups of water prior to their meals and the other did not. All of the subjects ate a low-calorie diet during the study. Over the course of 12 weeks, water drinkers lost about 15.5 pounds, while the non-water drinkers lost about 11 pounds.

Davy said water may be so effective simply because it fills up the stomach with a substance that has zero calories. People feel fuller as a result, and eat less calorie-containing food during the meal. Increased water consumption may also help people lose weight if they drink it in place of sweetened calorie-containing beverages, said Davy, who is with Virginia Tech in Blacksburg, Va.

Diet soda pop and other beverages with artificial sweeteners may also help people reduce their calorie intake and lose weight, Davy said. However, she advised against using beverages sweetened with sugar and high-fructose corn syrup because they are high in calories. A 12-ounce can of regular soda pop, for instance, contains about 10 teaspoons of sugar.

Davy noted that that nobody knows exactly how much water people should drink daily. The Institute of Medicine, an agency of The National Academies, which advises the Federal Government on science, says that most healthy people can simply let thirst be their guide. It does not specify exact requirements for water, but set general recommendations for women at about 9 cups of fluids -- from all beverages including water -- each day, and men at about 13 cups of fluids.

And it is possible to drink too much water, a situation that can lead to a rare, but serious, condition known as water intoxication, Davy pointed out.

Read More

New Visible Light Photocatalyst Kills Bacteria, Even After Light Turned Off

New Visible Light Photocatalyst Kills Bacteria, Even After Light Turned Off

  12:34:00 AM    Science Lover

---

In the battle against bacteria, researchers at the University of Illinois have developed a powerful new weapon -- an enhanced photocatalytic disinfection process that uses visible light to destroy harmful bacteria and viruses, even in the dark.

Jian Ku Shang, a professor of materials science and engineering, holds a sample of a new photocatalytic material that uses visible light to destroy harmful bacteria and viruses, even in the dark.

Based upon a new catalyst, the disinfection process can be used to purify drinking water, sanitize surgical instruments and remove unwanted fingerprints from delicate electrical and optical components.

"The new catalyst also has a unique catalytic memory effect that continues to kill deadly pathogens for up to 24 hours after the light is turned off," said Jian Ku Shang, a professor of materials science and engineering at the U. of I.

Read More