Researchers are applying various strategies to designing nanoscale propulsion systems by either using or copying biological systems such as the flagellar motors of bacteria or by employing various chemical reactions. Different practical micromotor applications, ranging from drug delivery, to target isolation and environmental remediation, have thus been reported over the past 2-3 years. Yet, there are no reports on a nanomachine-based toxicity assay approach, analogous to the use of live aquatic organisms for testing the quality of our water resources.
Increasingly we are observing glass windows as a key building material in modern construction design. Specially in the urban areas presence of high rise residential and commercial buildings are clearly visible. At the same time, it is important to make this increasing urbanization as green as possible. With an increase in building height, its power consumption rises not only because of the presence of more people but also because lifting water, operating elevators, etc. require extra amounts of power. Therefore, developing a complementary source of power which is clean and otherwise wasted is a key research topic for a sustainable future. Researchers at KAUST explored a novel idea to integrate micro- to nanoscale thermoelectric materials with the window glasses to generate thermoelectricity based on the temperature difference that exists between the hot outside and relatively cold inside.
Buildings and other man-made structures consume as much as 30-40% of the primary energy in the world, mainly for heating, cooling, ventilation, and lighting. 'Smart' windows are expected to play a significant role in reducing the energy consumption of homes in two ways: by generating energy themselves; and by providing better insulation by allowing light in and keeping the heat out (in hot summers) or in (in cold winters). Vanadium dioxide (VO2) has long been recognized as a a material of significant technological interest for optics and electronics and a promising candidate for making 'smart' windows: it can transition from a transparent semiconductive state at low temperatures, allowing infrared radiation through, to an opaque metallic state at high temperatures, while still allowing visible light to get through. In new work, researchers have now offered a simple method for promoting the production of monoclinic VO2 nanoparticles by doping.
Nanotechnology products, processes and applications have the potential to make important contributions to environmental and climate protection by helping save raw materials, energy and water as well as by reducing greenhouse gases and problematic wastes. Great hopes are being placed on nano-technologically optimized products and processes that are currently under development in the energy production and storage sectors. Emphasis is often placed on the sustainable potential of nanotechnology, but this in fact represents a poorly documented expectation. Determining a product's actual effect on the environment - both positive and negative - requires considering the entire life cycle from the production of the base materials to disposal at the end of its useful life. Not every 'nano-product' is a priori environmentally friendly or sustainable, and the production of nanomaterials often requires large amounts of energy, water and environmentally problematic chemicals.
The global cement industry is currently one of the largest single emitter of carbon dioxide, generating on average about 830 kg of this greenhouse gas for each 1000 kg of cement produced. Considering that the worldwide annual production of cement is a whopping 3.8 trillion kg, the cement industry alone accounts for approximately 5-6% of man-made CO2 emissions. Researchers have now presented a solar-powered process to produce cement without any carbon dioxide. In their STEP (Solar Thermal Electrochemical Production) process, cement limestone undergoes low energy electrolysis to produce lime, O2 and reduced carbonate without carbon dioxide emission. In this new technique, the kiln limestone-to-lime process is replaced by an electrolysis process which changes the product of the reaction of the limestone as it is converted to lime.
Polyurethane (PU) foam is an extremely versatile material that commonly is used in bedding, upholstery and building insulation. However, PU foam is very flammable, often resulting in dripping of melted material that enhances flame spread through the formation of a pool fire under the burning object. Brominated flame retardant compounds (e.g. pentabromodiphenyl ether) have been used to reduce foam flammability but there is growing evidence that these chemicals are toxic to the environment and living organisms. Replacing brominated flame retardants in polymer formulations with safer and more environmentally-friendly alternatives has also sparked the interest of nanoscientists. One recent effort to create an environmentally-friendly flame retardant system involves the layer-by-layer assembly of thin films using materials obtained from completely renewable sources.
Technological advances have made desalination and demineralization of seawater feasible, albeit expensive, solutions for increasing the world's supply of freshwater. Among various desalination technologies, reverse osmosis membranes have been widely used for water reclamation. However, external energy required and high operational pressure used (above 75 bar for reverse osmosis desalination and 25 bar for reverse osmosis water recovery from wastewater) make reverse osmosis membrane water reclamation processes energy intensive - not exactly an advantage given the rising cost of energy and the negative climate impact of fossil fuels. Researchers have now demonstrate the novel concept of a "desalination battery", which operates by performing cycles in reverse on our previously reported mixing entropy battery.
Many batteries still contain heavy metals such as mercury, lead, cadmium, and nickel, which can contaminate the environment and pose a potential threat to human health when batteries are improperly disposed of. Not only do the billions upon billions of batteries in landfills pose an environmental problem, they also are a complete waste of a potential and cheap raw material. Unfortunately, current recycling methods for many battery types, especially the small consumer type ones, don't make sense from an economical point of view since the recycling costs exceed the recoverable metals value. Researchers in India have carried out research to address the recycling of consumer-type batteries. They report the recovery of pure zinc oxide nanoparticles from spent Zn-Mn dry alkaline batteries.