| Cigarettes with nano-carbonic filter
Chinese scientists tested the carbonic nanotubes as a filter for cigarettes. The results turned to be very impressive.
Everybody knows about the hazardous effect of the smoking. However, it’s not easy for the humanity to get rid of this habit. So, the scientists have no choice but to look for more and more perfect filters for cigarettes. Carbon nanotubes have already proved their effectiveness in the experiments, during which fluorine, lead and cadmium was removed from the solutions. It was logically to suppose that such materials would successfully manage both to extract different kinds of contamination from the gas phase, for example from cigarette’s smoke.
In their research Chinese scientists used oxidized carbon nanotubes. For the comparison they took standard sorbents – rather industrially widespread synthetic zeolite and activated charcoal.
All the sorbents were put into the filtered cigarette-holder. The smoking process was carried out automatically in standard conditions, which are necessary in the tobacco industry for the determination of smoke composition. The smoke was transmitted through the sorbents, then the filters were weighted and according to the odds of the initial and the final weight the scientists determined (with the method of chromatography) the quantity and the composition of the accumulated components.
Carbonic nanotubes turned to be the most effective sorbents of nicotine (under 0.56 mg/a cigarette) and tar (under 13mg/a cigarette). The effectiveness of nicotine and tar removal with this sorbent is 81,3%, the removal of activated charcoal – 60,6% and zeolite – 41,3%. And it’s despite of the fact that their specific surface is rather smaller (151 m2/g), than the zeolite’s one (766 m2/g) or activated charcoal (904 m2/g).
The images of filters with carbonic nanotubes, which were taken with the help of the tunnel microscope before and after adsorption, explained the cause of such effectiveness of carbonic nanotubes. Curved carbonic nanotubes (with the length 100 nm-microns) form aggregative pores, the length of which is 3-40 nm, i.e. they fit for the adsorption of all the tobacco smoke’s molecules.
The part of harmful substances is adsorbed on the internal surface of the carbonic nanotubes’ wall. Many compounds (most of all, polycyclic aromatic hydrocarbons) are adsorbed or condensed on the outer surface.
According to the authors of the research, the main role in the increase of the nano-carbonic filter’s effectiveness may belong to the capillary condensation of some carbonic nanotubes’ components.
The scientists estimated the optimal carbonic nanotubes amount in the cigarette filter for the most effective removal of both nicotine and tar. It makes 20-30 mg. Even if the price of the cigarette with such filter will increase, the benefit for your health is worthy of such costs.
|