2,4-dichlorophenoxyacetic acid adsorption from contaminated water through activated carbon reclaimed with zero-valent iron and titanium dioxide

Abstract

The sol-gel method was used for the synthesis of zero-valent iron/titanium dioxide supported on activated carbon (Fe0/TiO2/AC) adsorbents, and the adsorbents were comprehensively characterized by XRF, XRD, FT-IR, BET, FE-SEM, and EDX analyses. The batch experiments were performed to evaluate the effect of adsorbent type, pH of solution, pollutant initial concentration, and contact time on the 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption efficiency. The equilibrium experiments revealed that the Langmuir isotherm was in good agreement with the adsorption equilibrium data, whereas the adsorption kinetic experiments indicated that the adsorption procedure was described perfectly through a pseudo-first-order kinetic model. The obtained maximum adsorption capacities from Langmuir isotherms of 86.5, 87.5, 86,57, and 88.76 mg/g were achieved for Activated Carbon (AC), zero-valent iron/activated carbon (Fe0/AC), titanium dioxide/activated carbon (TiO2/AC), and Fe0/TiO2/AC at the 2,4-D initial concentration of 90 mg/L, pH = 4 and 25°C, respectively. © 2018 Sharif University of Technology.All rights reserved.