Nano Sieves

The hybrid membranes are suitable for ‘drying’ solvents and biofuels, an application for which there is a large potential market worldwide. Until renewable energies such as solar and wind power become more feasible, other clean energy options are being explored. Clean coal technology is one such option which enhances efficiency and reduces environmental pollution through a process that can capture and store carbon dioxide emissions.

1. Description

2. Why

3. How

4. Future Trends

5. Related Links

Description

Techniques already exist for capturing carbon dioxide from smokestacks, but they use large amounts of energy - 15 to 20 percent of the total electricity output of a power plant, according to one estimate. Those materials, called amines, only release the carbon dioxide they’ve absorbed if heated. This means that capturing CO2 could add 90 % to the cost of producing electricity from coal.

The main advantage of membrane technology is that it consumes far less energy than common distillation techniques.
The cyclohexane conversion in the γ-MnO₂ nano-sieve membrane reactor is higher than that in the conventional packed bed reactor.

Researchers have developed porous materials that can soak up 80 times their volume of carbon dioxide. This means the greenhouse gas could be cheaply scrubbed from power-plant smokestacks.

Why

It’s fast and highly selective filtering design and does not require an active input of metabolic energy.
It is a very energy efficient alternative to existing techniques like distillation.
The hybrid membranes are suitable for ‘drying’ solvents and bio-fuels, an application for which there is a large potential market worldwide.

The main advantage of this technology is that it consumes far less energy than common distillation techniques with water and steam.Researchers from the Centre are creating nano-sieves, which can be fitted to existing power stations and petrochemical plants. These ‘worlds smallest sieves’ separate carbon dioxide from hydrogen – the hydrogen can then be converted into electricity in fuel cells and the CO2 buried (a process known as geological sequestration).

How

These nano-sieves are created by coating a porous substrate with a thin film of zirconium and titanium oxides. These coatings act like a sieve with tiny nano-holes, one billionth of a metre in diameter, and allow the smaller hydrogen molecules to pass through, while capturing the carbon dioxide, leaving water as the only byproduct of coal power stations.

The previous generations of ‘nano-sieve’ membranes, made of silica, degrade because they react.
By mixing organic molecules with inorganic - to produce new materials is producing great advances.
In the nano membrane, part of the ceramic links is therefore replaced by organic links.

By doing this, water doesn’t have the chance to ‘attack’ the membranes.Manufacturing the new hybrid membranes is simpler than that of ceramic membranes, because the material is flexible and will not show cracks.Such carbon dioxide capture and storage could be essential to reducing greenhouse-gas emissions. Countries such as the United States that depend heavily on coal for electricity will see most benefit. The first stage, capturing the carbon, is particularly important, since it can account for 75 percent of the total costs, according to the Department of Energy.

Future Trends

The carbon dioxide is absorbed by the new materials, then it could be released through pressure changes, compressed, and, finally, pumped underground for long-term storage.It provides a new convenience for probing the vibrational structure and the physical properties of the fullerene or other similar molecules, in particular, the adsorption behaviour, and the interaction of fullerene with gold nano-particles.Further funding for the research, led by Prof Max Lu and Dr Joe da Costa, was announced by the queensland government earlier this year with a contribution of $1.05 million under its Smart State National and International Alliance program. Scientists and engineers from the ARCCFN will be working together with researchers from the German Industrial Research Institute, Forschungszentrum Jülich (FZJ), as the first project to come from a 2004 energy technology agreement signed between Queensland and North Rhine Westphalia (Germany). The research is also being supported by the Centre for Low Emission Technology.

Keywords

Nano-sieve membrane; Suspending particles sintering, SERS; AAO; Nano-sieve; C₆₀/C₇₀; γ-MnO₂ nanometer powders.

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