Nanostructured surfaces

Simultaneous removal of Pb(II), poly(acrylic acid) and Triton X-100 from their mixed solution using nanostructured activated biocarbons
Wiśniewska M.1, Nowicki P.2, Gęca M.1
1Department of Radiochemistry and Environmental Chemistry, Institute 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;
2Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
The residue after extraction of horsetail herb was used as the precursor in this study. The starting material was subjected to direct physical activation with steam at 800 °C, for 1h. Such prepared biochar was next subjected to two variants of post-activation treatment. The first modification involved two-steps washing procedure, firstly with a hot 5 % solution of HCl and later with demineralized water, whereas the second method included washing only with demineralized water.
The biochars prepared are characterised by medium developed surface area and mesoporous structure with considerable contribution of micropores, which varies from 34 to 44 % depending on the procedure of post-activation treatment. Its turned out that the washing procedure applied has also an huge impact on the chemical nature of the adsorbent surface. Sample treated with hydrochloric acid and next with demineralised water shows strong acidic character of the surface (pH below 5) whereas analogous material washed only with water contain three-fold more groups of basic character than acidic one, and its pH is over 10.
The obtained biochars were used as adsorbents for simultaneous removal of hazardous lead(II) ions, poly(acrylic acid) – PAA polymer and Triton X-100 nonionic surfactant from their mixed solution. Such a complicated systems of adsorbates are not practically studied and there is no data on the mechanism of interactions in the heavy metal-polymer-surfactant mixed adsorption layer. Moreover, for each component of the system the adsorbed amount was determined. It was shown that prepared biochars can be successfully used as sorbents of toxic heavy metal ions as well as undesirable macromolecular and surface active compounds from wastewaters. Moreover, their effective regeneration is also possible (desorption with the usage of 0.1M HCl and NaOH).