The alarming rise of carbon dioxide in the atmosphere has led a numerous proposals on how to capture and store carbon dioxide in order to mitigate the damaging emissions from fossil fuels. Popular proposals, some already being tested on a large scale, involve carbon sequestration and subsequent storage in geological formations (geo-sequestration). Other ideas revolve around recycling captured carbon dioxide, for instance by converting it into hydrocarbons that can be re-used to make fuel or plastics. While these solutions would result in removing some carbon dioxide from the atmosphere, their disadvantages are that most of them are expensive, technologically challenging, or energy-intensive. Researchers have now presented the first experimental evidence of a new solar conversion process, combining electronic and chemical pathways, for carbon dioxide capture in what could become a revolutionary approach to remove and recycle CO2 from the atmosphere on a large scale. Rather than trying to sequester or hide away excess carbon dioxide, this new method allows it to be stored as solid carbon or converted in useful products.
Developing chemicals, molecular precursors, and industrial products from petroleum resources is a conventional practice. Plastics, detergents, even pharmaceuticals are derived from petrochemicals. With an increasing focus on the economic and environmental issues associated with the processing of petroleum-based chemicals, scientists are seeking for alternative routes to develop molecules from naturally available plant or crop-based raw materials. Particularly interesting for the fields of nanotechnology is the design and development of soft nanomaterials from renewable sources. Generating these materials from renewable resources could have a significant impact on production technologies and economies.
Metal nanomaterials are often synthesized using the toxic reagent formaldehyde at concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment - however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.
'Smart' windows, or smart glass, refers to glass technology that includes electrochromic devices, suspended particle devices, micro-blinds and liquid crystal devices. Their major feature is that they can control the amount of light passing through the glass and increase energy efficiency of the room by reducing costs for heating or air-conditioning. In the case of self-powered smart windows the glass even generates the energy needed to electrically switch its transparency. A new type of smart window proposed by researchers in The Netherlands makes use of a luminescent dye-doped liquid-crystal solution sandwiched in between electrically conductive plates as an energy-generating window.
Bioethanol, unlike petroleum, is a form of renewable energy that can be produced from common agricultural feedstocks such as sugar cane or corn. Ethanol is already widely used in siome countries, mainly as biofuel additive for gasoline. The tremendous hype about bioethanol in the past few years has now been followed by a debate about how useful bioethanol actually can replace gasoline. Concerns about its production and use relate to the large amount of arable land required for crops, as well as the energy and pollution balance of the whole cycle of ethanol production. Recent developments with cellulosic ethanol production and commercialization may allay some of these concerns. It offers the promise that any plant material, from grass to wood, and not just edible crops, could be used in the production of ethanol fuels. Consequently, cellulosic ethanol could allow ethanol fuels to play a much bigger role in the future than previously thought. With regard to cellulosic production and commercialization, bioethanol production from woody biomass by enzymatic hydrolysis of cellulosic components and fermentation has attracted much attention.
Freshwater could become the oil of the 21st century - scarce, expensive and fought over. While over 70 per cent of the Earth's surface is covered by water, most of it is unusable for human consumption. Technological advances have made desalination and demineralization feasible - albeit expensive - solutions for increasing the world's supply of freshwater. However, nanotechnology- based water purification devices have the potential to transform the field of desalination. Researchers have now demonstrated a new, efficient and fouling-free desalination process based on the ion concentration polarization (ICP) phenomenon - a fundamental electrochemical transport phenomenon that occurs when an ion current is passed through ion-selective membranes - for direct desalination of sea water.
Among various nanomaterial candidates for water treatment, metal oxides have been widely used as removal agents for various heavy metal ions and their removal capacity was found to be relatively reliable. The removal mechanism for heavy metal ions is thought to be the formation of a strong bond between metal ions and metal oxide surfaces. This strong complexation is advantageous for complete removal of heavy metal ions but it presents a drawback if one wants to design a reusable agent by reviving the reaction site for heavy metal ions. Precisely because the removal mechanism is based on the strong complex formation between metal ions and oxide surfaces, recycling of these removal agents has proved to be difficult. Offering a potential solution, researchers have demonstrated a recyclable removal agent for heavy metal ions by fabricating a core-in-shell structure based on a core of carbon nanotubes and an iron oxide microcapsule structure.
Currently, potential and actual applications of nanotechnology in environmental technologies are receiving considerable attention worldwide. Relevant applications include environmental remediation (air, water and soil), monitoring, and resource saving (energy and materials). These technologies are not only intended for markets in wealthy countries, including in Europe, the USA and Japan, but may also be particularly useful for protecting consumers and the environment in emerging economies and developing countries. Furthermore, research groups and companies in emerging economies and developing countries are increasingly active in R+D and manufacturing environmental nanotechnologies, as part of a national knowledge economy. As an example, the ICPC-NanoNet project supports international research cooperation in environmental nanotechnology between the European Union and International Cooperation Partner Countries to the EU. This article focuses on the case of nanotechnology for water purification.