Tag Archives: PLASTICS

Spheres Trick, Trap and Terminate Water Contaminant

Rice University scientists have developed something akin to the Venus’ flytrap of particles for water remediationMicron-sized spheres created in the lab of Rice environmental engineer Pedro Alvarez are built to catch and destroy bisphenol A (BPA), a synthetic chemical used to make plasticsBPA is commonly used to coat the insides of food cans, bottle tops and water supply lines, and was once a component of baby bottles. While BPA that seeps into food and drink is considered safe in low doses, prolonged exposure is suspected of affecting the health of children and contributing to high blood pressure. The good news is that reactive oxygen species (ROS) – in this case, hydroxyl radicals – are bad news for BPA. Inexpensive titanium dioxide releases ROS when triggered by ultraviolet light. But because oxidating molecules fade quickly, BPA has to be close enough to attack. That’s where the trap comes in.

Close up, the spheres reveal themselves as flower-like collections of titanium dioxide petals. The supple petals provide plenty of surface area for the Rice researchers to anchor cyclodextrin molecules. Cyclodextrin is a benign sugar-based molecule often used in food and drugs. It has a two-faced structure, with a hydrophobic (water-avoiding) cavity and a hydrophilic (water-attracting) outer surface. BPA is also hydrophobic and naturally attracted to the cavity. Once trapped, ROS produced by the spheres degrades BPA into harmless chemicals.

In the lab, the researchers determined that 200 milligrams of the spheres per liter of contaminated water degraded 90 percent of BPA in an hour, a process that would take more than twice as long with unenhanced titanium dioxide. The work fits into technologies developed by the Rice-based and National Science Foundation-supported Center for Nanotechnology-Enabled Water Treatment because the spheres self-assemble from titanium dioxide nanosheets.

Petals” of a titanium dioxide sphere enhanced with cyclodextrin as seen under a scanning electron microscope. When triggered by ultraviolet light, the spheres created at Rice University are effective at removing bisphenol A contaminants from water.

Most of the processes reported in the literature involve nanoparticles,” said Rice graduate student and lead author Danning Zhang. “The size of the particles is less than 100 nanometers. Because of their very small size, they’re very difficult to recover from suspension in water.

The research is detailed in the American Chemical Society journal Environmental Science & Technology.

Source: http://news.rice.edu/

‘WasteShark’, The Aquadrone That Cleans The Ocean Waste

A swarm of autonomous robots that can swim across bodies of water to collect garbage might be the key to saving the oceans. A few years ago, RanMarine Technology, a company from the Netherlands, has introduced WasteShark, an aquadrone that works like a smart vacuum cleaner (essentially, a Roomba for the seas) to gather wastes that end up in waterways before they accumulate into a great big patch in the middle of the Pacific Ocean.

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The operational cost of the vehicle… will be almost nothing. You are basically using compressed air. You are not paying for fuel and also you do not need cooling,” said Mahmoud Yasser, a student who helped design it. The team is now looking to raise funding to expand the project and mass produce the vehicles. They believe they can eventually get the vehicles to top 100 kilometers an hour and run for 100 kilometers before needing to come up for air.

Every year, about 1.4 billion pounds of trash end up in the ocean. Plastics, styrofoam, and other nonbiodegradable materials get dumped into the waters, eaten by fishes and birds or collect into what has become the Great Pacific Garbage Patch — a gyre of debris between California and Hawaii bigger than AlaskaTrash in seas and oceans have become a huge problem, but the WasteShark might be able to help.

RanMarine said that its aquadrones are inspired by whale sharks, “nature’s most efficient harvesters of marine biomass.” The company claims that the vessels can collect up to 200 liters of waste before it needs to be emptied and swim across the water for 16 hours. The WasteShark are autonomous as it can intelligently wade through water and collect trash using sensors. It is equipped with a GPS to track its movements.

Source: https://www.techtimes.com/

Plastic-Eating Enzyme

Scientists have engineered an enzyme which can digest some of our most commonly polluting plastics, providing a potential solution to one of the world’s biggest environmental problems. The discovery could result in a recycling solution for millions of tonnes of plastic bottles, made of polyethylene terephthalate, or PET, which currently persists for hundreds of years in the environment. The research was led by teams at the University of Portsmouth and the US Department of Energy’s National Renewable Energy Laboratory (NREL) and is published in Proceedings of the National Academy of Sciences (PNAS).

 Professor John McGeehan at the University of Portsmouth and Dr Gregg Beckham at NREL solved the crystal structure of PETase—a recently discovered enzyme that digests PET— and used this 3D information to understand how it works. During this study, they inadvertently engineered an enzyme that is even better at degrading the plastic than the one that evolved in nature. The researchers are now working on improving the enzyme further to allow it to be used industrially to break down plastics in a fraction of the time.

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Few could have predicted that since plastics became popular in the 1960s huge plastic waste patches would be found floating in oceans, or washed up on once pristine beaches all over the world. “We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these ‘wonder-materials’, must now use all the technology at their disposal to develop real solutions,” said Professor McGeehan, Director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth,

Source: http://uopnews.port.ac.uk/