Nanocomposites and nanomaterials

Nanoporous carbons obtained from food products and wastes of beverage industry
Yu.S. Dzyazko, A.V. Palchik, V.M. Ogenko, T.V. Maltseva, M.O. Chaban
V.I. Vernadskii Institute of General and Inorganic Chemistry of the NAS of Ukraine, 32/34 Palladin ave., 03142, Kyiv, Ukraine
E-mail: Mary.chaban@gmail.com

Food industry produces a large amount of solid wastes, which need utilization. The attractive way is to obtain commercial products, for instance, low-cost sorbents, such as carbons.  They can be manufactured from natural raw materials containing saccharides (carbohydrates). These substances involve OH groups, which can be removed rather easy. Dehydration occurs at lower temperatures (up to 500oC) comparing with other organic polymers. However, the conditions of thermal treatment are rather rigid. Moreover, inert  media are required to obviate burning out of carbon. 
In this work, the carbonization method, which allows us to avoid high temperatures, has been developed. As raw materials, dextrin and lactose were used. The technique provides carbonization in aggressive media under the temperature, which is lower than 150oC. The obtained carbons were washed with deionized water up to neutral pH of the effluent and dried under room temperature under constant mass. The obtained materials were investigated with methods of IR spectroscopy, scanning and transmission electron microscopy. Pore size distributions were obtained by means of the method of nitrogen adsorption-desorption. It has been shown that the material obtained from disaccharide (lactose) is characterized by larger volume of ,micropores and lower volume of nanosized mesopores comparing with carbon originated from polysaccharide (dextrin). Probably it can be caused by lower content of OH groups attributed to dextrin. Nanodimensional particles were found for all types of carbon. The nanoparticles form aggregates and agglomerates, the last formations are of micron size. Functional groups of carbons were recognized by means of IR spectroscopy together with thermogravimetry. Isoelectric point was determined by means of potentiomentric titration, this point is shifted to acidic media, 
The obtained materials coulf be recommended for removal of toxic matters from water, for instance, dyes and pesticides. The possibility of  multiple usage of carbons is also considered. The materials can be applied to modification of inorganic sorbents and membranes in order to realize purposeful control of their hydrophilicity and hydrophobicity.