Nanostructured surfaces

Nanostructure of mixed polymer-surfactant adsorption layers formed at the activated carbon/aqueous solution interface
Wiśniewska M.1, Nowicki P.2, Chibowski S.1, Nosal-Wiercińska A.1
1Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland.
E-mail: wisniewska@hektor.umcs.lublin.pl
2Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.

Due to continuous technological progress various dangerous substances are introduced into waters. There are, among others, inorganic nitrogen and phosphorus compounds, a wide range of organic substances (such as dyes, pesticides, aromatic and aliphatic hydrocarbons, phenols, surfactants, polymers) and heavy metals. Thus, intensive studies of more effective methods of wastewater treatment are still carried out. They include mainly coagulation and flocculation, flotation, ion exchange, membrane processes, redox reactions and adsorption phenomenon. The last process requires the use of various types of solids, e.g. silica gels, zeolites, metal oxides, polymer substances, active carbons as well as different bio-sorbents prepared from waste materials such as nut shells, maize cobs, algae, snail and chitinous shells or even feathers of birds. Porous carbon materials are very common, which results mainly from their strongly developed surface area, large total pore volume, easy regeneration and ability to control the textural parameters by choosing the appropriate conditions of their synthesis. There is a large amount of waste materials (nut shells, fruit stones as well as peels, wood, peat, hay and residues after supercritical extraction of raw plants) that can be used as precursors in the pyrolysis process. In such a way, the considerable reduction of synthesis cost and also elimination of the problem of large amounts of such kind of wastes collection were obtained.
The aim of this study was the synthesis of two biocarbons obtained from corncobs and peanut shells precursors and their usage for removal of undesirable poly(acrylic acid) – PAA macromolecules from mixed solution containing surfactant. The influence of the following surfactants: anionic SDS, cationic CTAB and nonionic Triton X-100 were examined in the pH range 3-10. It was proved that used surface active substances changes adsorption affinity of PAA to the surface of applied biocarbons. The competition of surfactant molecules and polymeric chains, as well as formation of surfactant-polymer complexes are responsible for the specific structure of mixed adsorption layer at the solid-liquid interface.