Environmental Technologies and Eco-innovation in the Czech ...

pressure, it complies with the strictest requirements for many liquid filtration
facilities. Nano-fibres may therefore help to resolve the global lack of drinking water,
may help to make sea water desalinisation easier and more efficient.
Furthermore, nano-fibres may be used in producing energy from renewable
resources. Nano-fibres can replace both classical silica cells and the new generation
of cells with nano-composites 10 . They also enable operation in aggravated light
conditions (no sunshine) and the use of mobile power sources (the combination of
solar cells with batteries for nano-fibres).
5.3 | Absorption materials based on natural minerals
Natural materials that may be used as absorbents for water contaminants or waste
gases include minerals such as montmorillonite, bentonite, kaolinite, halloysite,
etc. However, natural minerals are hydrophilic 11 and are unsuitable for absorbing
organic pollutants. They feature layered structures with a layer thickness of ca 1 nm.
The space between individual layers, the interlayer, is filled with inorganic cations
which compensate for the negative charge in inner layers of a mineral. Replacing
inorganic cations in interlayers by organic cations causes changes to the mineral’s
properties and therefore becomes organophilic 12 and enables the absorption of
organic pollutants. The properties of absorbents are given by organic cations used.
For clay minerals, minerals based on smectites are the most frequently used for these
modifications to environmental technologies. For waste water treatment technologies,
organically modified clays may be used separately as absorption materials for treating
waste water contaminated by organic compounds, e.g. crude oil hydrocarbons, or in
combination with active coal. They can form a part of the clay barriers and absorbents
of organic substances in dumps.
Another suitable natural material seems to be vermiculite, whose use is currently
being analysed at the University of Mining – the Technical University of Ostrava. The
research is mainly aimed at preparing and testing organically modified vermiculite for
absorption of organic substances from waste water and gases. Organically modified clay
has been made from vermiculite mined in the Czech deposit of Letovice and efficiently
absorbs organic substances found in waste water.
10 nano-composites – materials consisting of two or more different components where one of them is up to tens of nanometers;
these are mostly nano-particles of active substances
11 hydrophilic – able to absorb water or be diluted in water
12 organophilic – able to bound organic substances or dilute in organic solvents