Removal of Methylene Blue by Poly(vinyl alcohol)/MMT Nanocomposite Hydrogel from Aqueous Solutions: Kinetic Study

فاقد چكيده فارسي

Nanocomposite Hydrogels having high amount of functional groups, enhanced swelling abilities, and improved mechanical properties are recently used as novel functional adsorbents for removal of dyes from aqueous solutions. Nanoparticles (such as clays) incorporation into the hydrogel structure increased not only the adsorption capacity but also the adsorption rate. In this work, adsorption feasibility of a cationic dye, methylene blue, onto nanocomposite hydrogels on the basis of poly(vinyl alcohol) and montmorillonite was experimentally investigated. Poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels containing 10 wt% of poly(vinyl alcohol) (based on the total mass of hydrogel) and 0, 4, 8 and 12 wt% of montmorillonite (based on the dried mass) were prepared using the freezing-thawing cyclic method. The effects of immersion time and montmorillonite content were investigated with respect to the dye adsorption capacity of nanocomposite hydrogels. The experimental results were fitted to pseudo-first-order and pseudo-second-order diffusion kinetic models. The results showed that the nanocomposite hydrogels have higher adsorption capacity than the montmorillonite-free hydrogel sample and the adsorption capacity was increased with increasing the montmorillonite loading level in samples.