Oct. 17, 2013 — A little amount of appropriately prepared powder is poured in water polluted with phenol and cellulose. A bit of the sun and after fifteen minutes harmful compounds disappear, and the powder can be filtered off and reused. Sounds like a fairy tale? Perhaps, but it is not magic, only a masterly use of chemistry and physics by researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw.
Many areas worldwide are affected by the problem of growing water pollution by wastes from wood and paper industries, including cellulose and phenol derivatives. Removal of these agents from water can be easier in future due to low cost and easy-to-produce photocatalysts developed by Dr Juan Carlos Colmenares' group from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw.
Catalysts are substances that participate in the chemical reactions, speed their courses and (almost) fully recover after the reactions are completed. In typical catalytic processes the catalysts must be activated at high temperatures, typically of several hundred degrees centigrade, often at a significantly increased pressure.
The photocatalysts designed and synthesised at the IPC PAS are much less demanding. They are activated by solar or UV light, and the actual chemical reaction can take place at a temperature of about 30°C and under normal pressure. Such conditions naturally occur in many places on Earth.
The crucial component of the new photocatalysts is titanium dioxide doped with small amount of iron or chromium atoms. All these materials are commonly available and cheap. The photocatalysts are deposited on appropriate supports – silica grains or zeolites (aluminosilicates) – using common laboratory equipment: a rotary evaporator and an ultrasonic bath.
“Ultrasonic irradiation of a solution containing precursors of titania and chromium or iron generates microbubbles of high pressure and temperature. We can manage these conditions and prepare nanocomposite materials which are very stable”, explains Dr Colmenares.
Chromium or iron doped catalytic materials so prepared have been studied and characterised in detail at the Institute of Physical Chemistry of the PAS and by the Prof. Krzysztof Kurzyd
Many areas worldwide are affected by the problem of growing water pollution by wastes from wood and paper industries, including cellulose and phenol derivatives. Removal of these agents from water can be easier in future due to low cost and easy-to-produce photocatalysts developed by Dr Juan Carlos Colmenares' group from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw.
Catalysts are substances that participate in the chemical reactions, speed their courses and (almost) fully recover after the reactions are completed. In typical catalytic processes the catalysts must be activated at high temperatures, typically of several hundred degrees centigrade, often at a significantly increased pressure.
The photocatalysts designed and synthesised at the IPC PAS are much less demanding. They are activated by solar or UV light, and the actual chemical reaction can take place at a temperature of about 30°C and under normal pressure. Such conditions naturally occur in many places on Earth.
The crucial component of the new photocatalysts is titanium dioxide doped with small amount of iron or chromium atoms. All these materials are commonly available and cheap. The photocatalysts are deposited on appropriate supports – silica grains or zeolites (aluminosilicates) – using common laboratory equipment: a rotary evaporator and an ultrasonic bath.
“Ultrasonic irradiation of a solution containing precursors of titania and chromium or iron generates microbubbles of high pressure and temperature. We can manage these conditions and prepare nanocomposite materials which are very stable”, explains Dr Colmenares.
Chromium or iron doped catalytic materials so prepared have been studied and characterised in detail at the Institute of Physical Chemistry of the PAS and by the Prof. Krzysztof Kurzyd