Adsorption of Basic Dyes from Aqueous Solutions by Depolymerization Products of Post-Consumer PET Bottles

Abstract

The purpose of this work is the removal of basic dyes (Safranine T and Brilliant Green) from aqueous media by depolymerization products (DP) obtained from aminoglycolysis of waste poly(ethylene terephthalate) (PET). The surface morphology and physical properties of depolymerization product were also determined. Adsorption behaviors (adsorption capacities, adsorption kinetics and adsorption isotherms) of these samples were realized at room temperature. Then, the amounts of residual dye concentrations were measured using Visible Spectrophotometer at 530 and 618?nm for Safranine T (ST) and Brilliant Green (BG), respectively. All adsorption experiments were carried out for different depolymerization products (DP1, DP2, DP3, and DP4). Adsorption capacities of depolymerization products for both of dyes decrease with following order: DP2?>?DP4?>?DP1?>?DP3. The maximum adsorption capacities for ST and BG onto DP2 sample were found to be 29 and 33?mg?g-1, respectively. In addition, the adsorption kinetic results show that the pseudo-second-order kinetic model is more suitable than pseudo-first-order model for the adsorption of basic dyes onto DP samples. Adsorption data were evaluated using Langmuir and Freundlich adsorption isotherm models. The results revealed that the adsorption of basic dyes onto DP sample fit very well Langmuir isotherm model. In conclusion, the depolymerization products of post-consumer PET bottles can be used as low cost adsorbent for the removal of basic dyes from wastewaters.