1. EQUILIBRIUM AND THERMODYNAMIC STUDIES ON THE BIOSORPTION OF TOLUENE ONTO SUNFLOWER ANNUUS MODIEFIED PITH.
- Author
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Knapik, Ewa and Stopa, Jerzy
- Subjects
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THERMODYNAMIC equilibrium , *HYDROPHOBIC surfaces , *OIL spills , *RICE hulls , *SUNFLOWERS , *TOLUENE , *MECHANICAL properties of condensed matter , *POLYDIMETHYLSILOXANE - Abstract
Application of sorbents is one of most promising methods for removal oil spills from water surface. Plant fibres (kapok, straw, rice husks, nutshells) are very popular due to their availability and biodegradability. The disadvantage of these materials is their low selectivity towards water. One of the methods of modifying the surface properties of materials is the immobilization of controlled nanoparticles on the surface. In this way, plant fibres are used as a cheap carrier and the introduced nanoparticles improve medium’s sorption properties (make the surface hydrophobic, increase the specific area of the sorbent). The unmodified sunflower parenchyma is a bio-waste from agriculture with interesting structural properties. The material has a highly porous, ordered, spongy, honeycomb-like structure. To date, it has not been studied as potential sorbent for hydrocarbons removal from aquatic environment. SiO2-sunflower pith nanocomposite was prepared via impregnation of hydrophobic SiO2 nanoparticles on pith surface using polydimethylsiloxane (PDMS) as coupling agent and its performance in the removal of toluene from water was investigated. The prepared nanocomposite was characterized using SEM and FTIR analyses confirming the deposition of SiO2 nanoparticles throughout the heterogeneous surface of pith. The maximum sorption capacities of raw and modified parenchyma were 3.54 and 4.18 g/g, respectively. The batch equilibrium data were fitted well by Temkin and Toth equations. This proves the heterogeneity of the sorbent surface and the possibility of forming an adsorbate polylayer. The rate of adsorption increases with temperature rising from 20 to 40°C, but the maximum equilibrium sorption capacity decreases due to an increased solubility of toluene in water. The present findings indicate that the sunflower biomass could be a potential alternative as sorbent precursors for hydrocarbons removal from polluted wastewaters. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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