Low-Cost and High-Capacity Dye Remover: a Study of Methylene Blue Adsorption by a Thermoplastic-Elastomer Blend System

Abstract

A thermoplastic elastomer blend of sulfonated polystyrene-block-poly-(ethylene-ran-butylene)-block-polystyrene (SEBS) copolymer with polypropylene (PP) has been studied for its promising application as an adsorbent. Batch adsorption experiments were performed for the removal of cationic methylene blue from aqueous solution. A detailed characterization on the adsorbent blend was carried out by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry (TGA) in order to determine the microstructural identity and thermal stability. Thermodynamic parameters and kinetic model of the adsorption process were evaluated. High adsorption values were obtained depending on the initial dye concentration and temperature from 303 to 400 mg/g. Gibbs free energy values of the adsorption were found to be 8.6, 5.5, and 5.3 kJ/mol at temperatures 275, 298, and 313 K, respectively, suggesting that the process is not spontaneous. The enthalpy of the adsorption was − 34.2 kJ/mol which indicates that the process is slightly out of physisorption range but at the beginning of chemisorption rage and exothermic in nature. Adsorption process caused a small increase in the disorder with a value of 93.9 J/K mol. Dye adsorption process were found to comply with pseudo-second-order kinetics. Adsorption data were well fitted by Langmuir isotherm model. The study showed that thermoplastic elastomer adsorbent film introduced here has a potential to be an economical alternative to available adsorbents for cationic dye removal of waste waters.

from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2w7maJk