Tag Archives: pollution

Metallic NanoParticles 50 Times More Effective As Catalysts

Scientists at Tokyo Institute of Technology produced subnano-sized metallic particles that are very effective as catalysts for the oxidation of hydrocarbons. These catalysts can be as much as 50 times more effective than well-known Au-Pd bimetallic nanocatalysts.
The oxidation of aromatic hydrocarbons is critically important for producing a great variety of useful organic compounds that are used throughout all types of industries. These oxidation processes require the use of catalysts and solvents, which are usually environmentally hazardous. Thus, finding a solvent-free oxidation process using nanosized catalytic particles has attracted considerable attention. Interestingly, sub-nanoscale catalytic particles (subnanocatalysts, or SNCs) composed of noble metals are even better at their job because their increased surface area and unique electronic state results in favorable effects for oxidizing hydrocarbons and also prevents them from getting oxidized themselves. This makes them cost-effective because the amount of metal required for SNCs is lower than for nano-sized catalysts.

A team including Dr. Miftakhul Huda, Keigo Minamisawa, Dr. Takamasa Tsukamoto, and Dr. Makoto Tanabe at Tokyo Institute of Technology (Tokyo Tech), led by Prof. Kimihisa Yamamoto, created multiple types of SNCs by using dendrimers, which are tree-like spherical molecules that can be used as a template to contain the desired catalysts. “Dendrimer is expected to provide internal nanospaces that could be suitable for catalytic conversion in the presence of metal particles,” explains Yamamoto . The scientists created various catalysts of different sizes, depending on the noble metal used and the number of atoms of each catalytic particle.

Each dendrimer molecule hosts a subnano-sized metallic particle that allows for the oxidation of aromatic hydrocarbons, such as toluene (left), to produce useful organic compounds, such as benzoic acid (right). Oxygen molecules are represented in red.

They compared their performance to find the best noble metal for making SNCs and then tried to determine the mechanism behind their high catalytic activity. Smaller SNCs were found to be better, while less oxophilic metals (such as platinum) were superior. The team postulated that the surface of platinum SNCs does not oxidize easily, which makes them reusable and results in the highest catalytic performance of the Pt19 SNC that can be as high as 50 times more effective than the common Au-Pd nanocatalysts. The team will continue working to shed light on these catalytic phenomena. “The development of a more detailed mechanism including theoretical considerations is currently in progress,” says Tanabe. The applications of such catalysts could greatly contribute for reducing pollution and enhancing our effective use of Earth’s metal resources.

Source: https://www.titech.ac.jp/

Plastic Waste In Antarctica

Plastic waste and toxic chemicals found in remote parts of the Antarctic this year add to evidence that pollution is spreading to the ends of the Earth, environmental group Greenpeace said.

Microplasticstiny bits of plastic from the breakdown of everything from shopping bags to car tires – were detected in nine of 17 water samples collected off the Antarctic peninsula by a Greenpeace vessel in early 2018, it said. And seven of nine snow samples taken on land in Antarctica found chemicals known as PFAs (polyfluorinated alkylated substances), which are used in industrial products and can harm wildlife.

 We may think of the Antarctic as a remote and pristine wilderness,” Frida Bengtsson of Greenpeace’s Protect the Antarctic campaign said in a statement about the findings. But from pollution and climate change to industrial krill fishing, humanity’s footprint is clear,” she said. “These results show that even the most remote habitats of the Antarctic are contaminated with microplastic waste and persistent hazardous chemicals.”

The United Nations’ environment agency says plastic pollution has been detected from the Arctic to Antarctica and in remote places including the Mariana Trench, the deepest part of the world’s oceans in the Pacific.

UN agency said that less than a 10th of all the plastic ever made has been recycled, and governments should consider banning or taxing single-use bags or food containers to stem a tide of pollution.

Souce: https://www.reuters.com/

Project To Map Ocean Floor By 2030

Set to map the entirety of the global ocean floor by 2030, the Nippon Foundation-GEBCO Seabed 2030 Project has started operations, based on a seed money pledge of US$2 million-per-year from the Japan-based Nippon Foundation.

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Officially launched during the United Nations Ocean Conference (5-9 June 2017) in New York, the project draws on the experience of international organizations and mapping experts under the coordination of UNESCO’s Intergovernmental Oceanographic Commission (IOC) and the International Hydrographic Organization (IHO).

Having a comprehensive map of the ocean floor could assist global efforts to combat pollution, aid marine conservation, forecast tsunami wave propagation, and help inform the study of tides and wave action. It could also help in search and rescue operations, as in the disappearance of the MH370 Malaysian Airlines flight in March 2014.

Despite its obvious useful applications, detailed bathymetric data – the topography of the ocean floor – is still missing for much of the global ocean. More than 85% of the world ocean floor remains unmapped with modern mapping methods, and by any technological standards we know more about Mars than we do about the depths of the ocean.

Source: http://www.unesco.org/