Russian scientists develop effective sorbing agents on the basis of fungal chitin.

Ability of various fungi to absorb heavy metals is a widely known fact – that is why even edible mushrooms, which grow in non-healthy ecological areas, can damage human health. This property has a simple explanation – all mushrooms contain chemical compounds, which include chitin, a polysaccharide with effective sorbing properties. Scientists suggested using said compounds for “catching” heavy metals, thus purifying water and water solutions. Mushroom bodies can also be used as sorbents; however, extracted compounds are much more effective.

Russian biologists have done an enormous piece of work - they found fungi with needed components, extracted said components, identified them and found out, which fungi contain more substances of interest. Biologists started with collecting various types of mushrooms – higher fungi Basidiomycetes (fungi with many-celled mycelium, like honey agarics, paxils, champignons and fly agarics) and Ascomycetes (cup fungi, like morels), drying and mincing them. Then fungal powder underwent successive extraction with sodium hydroxide, hydrochloric acid and hydrogen peroxide solutions. Scientists extracted chitin complexes with other polymers: chitin-glucan complexes and chitin-glucan-melanin complexes. After that mentioned compounds were identified, and their sorbing properties were studied on cadmium and nickel ions.

However, some fungi showed weak sorbing properties, despite they were rich in chitin. Worst sorbents for cadmium were extracted from Ramaria flava (an edible mushroom, which looks like coral), and bad absorption solution for nickel came from sharp agarics (Lactarius torminosus). Mentioned fungi aren’t suitable for purification water from heavy metals. Anyway, extracting process takes a long time, since chitin-containing compounds should spend in solution about an hour for most full extraction.

Scientists currently search for a sorbing agent for another serious toxin – water-soluble lead compounds, and at the same time study effects of dye sorption on said compounds. Of course, they do not forget about making affordable product out of fundamental research.

Scientists from other Russian regions also rack their brains over new sorbents – in the end of 2008 researchers will present an experimental industrial unit, which contains carbon sorbents and makes purification of industrial gases and liquids possible. These units will prevent emissions of finest particles from enterprises of ferrous and non-ferrous metallurgy to the atmosphere.

Brand new carbon sorbent is developed in Saint-Petersburg, moreover, a new pack for this sorbent is created – this pack provides perfect sterile conditions. New sorbent is covered with fluorine, shows high sorption capacity and doesn't damage blood corpuscles. This very useful substance in packed into a sterile column, preventing dust generation while storing and transporting.

Source:
    Science & Technologies

Kizilova Anna