Fast and highly efficient removal of 2,4-D using amino-functionalized poly (glycidyl methacrylate) adsorbent: Optimization, equilibrium, kinetic and thermodynamic studies

Abstract

Experimental design has been applied to consider any possible interaction between process parameters with fewer experiments as well as to create a response model influenced by several factors and to optimize the response. In this study, response surface methodology (RSM), which is cost-effective and less laborious for process optimization has been applied to observe the performance of amino-functionalized poly (glycidyl methacrylate) as adsorbent (AR) in the 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption from aquatic media in terms of adsorbent dose (0.0125-0.05 g), temperature (20-30 degrees C) and stirring speed (100-200 rpm). The greatest adsorption capacity was calculated as 99.4470 mg g(-1) for 100 mg/L solution under the optimal conditions (0.05 g of adsorbent and 100.01 revolution speed per minute at 28.725 degrees C). on the other hand, experimental outcome displayed that 2,4-D adsorption on the adsorbent was notably quick, where >83% of the adsorption occurred within the first 15 min, and reached almost equilibrium at 60 min and the adsorbent had a relatively high adsorption capacity changing between 100 and 450 mu mol/g (20-100 mg g(-1)) according to adsorbent dosage. The rate of adsorption was represented by both pseudo-second-order and Elovich models more efficiently than the pseudo first-order kinetic model. The equilibrium data were found to be compatible with the relevant isotherm models such as Langmuir (1-4), Freundlich and Dubinin-Radushkevich (DRK). The findings of the thermodynamic study indicate that the concerned adsorption system is applicable, endothermic and enthalpy driven. (C) 2018 Published by Elsevier B.V.