Utilization of magnetically responsive cereal by-product for organic dye removal

0466684 - ÚVGZ 2017 RIV US eng J - Journal Article
Baldíková, Eva - Politi, D. - Maděrová, Zdeňka - Pospíšková, K. - Sidiras, D. - Šafaříková, Miroslava - Šafařík, Ivo
Utilization of magnetically responsive cereal by-product for organic dye removal.
Journal of the Science of Food and Agriculture. Roč. 96, č. 6 (2016), s. 2204-2214. ISSN 0022-5142. E-ISSN 1097-0010
R&D Projects: GA ČR GA13-13709S
Grant - others:GA MŠk(CZ) LO1305
Institutional support: RVO:67179843
Keywords : modified rice straw * aqueous-solution * methylene-blue * wheat-straw * activated carbon * cost adsorbents * crystal violet * anionic dyes * adsorption * acid * barley straw * magnetic modification * magnetic adsorbent * microwave-assisted synthesis * organic dyes
Subject RIV: GC - Agronomy
Impact factor: 2.463, year: 2016

BACKGROUND: Barley straw, an agricultural by-product, can also serve as a low-cost and relatively efficient adsorbent of various harmful compounds. In this case, adsorption of four water-soluble dyes belonging to different dye classes (specifically Bismarck brown Y, representing the azo group; methylene blue, quinone-imine group; safranin O, safranin group; and crystal violet, triphenylmethane group) on native and citric acid-NaOH-modified barley straw, both in magnetic and non-magnetic versions, was studied.
RESULTS: The adsorption was characterized using three adsorption models, namely Langmuir, Freundlich and Sips. To compare the maximum adsorption capacities (q(max)), the Langmuir model was employed. The q(max) values reached 86.5-124.3 mg of dye per g of native non-magnetic straw and 410.8-520.3 mg of dye per g of magnetic chemically modified straw. Performed characterization studies suggested that the substantial increase in q(max) values after chemical modification could be caused by rougher surface of adsorbent (observed by scanning electron microscopy) and by the presence of higher amounts of carboxyl groups (detected by Fourier transform infrared spectroscopy). The adsorption processes followed the pseudo-second-order kinetic model and thermodynamic studies indicated spontaneous and endothermic adsorption.
CONCLUSION: The chemical modification of barley straw led to a significant increase in maximum adsorption capacities for all tested dyes, while magnetic modification substantially facilitated the manipulation with adsorbent.
Permanent Link: http://hdl.handle.net/11104/0264933