Adsorption of Co(II) and Mn(II) ions from pure terephthalic acid wastewater onto Na-bentonite

Abstract

AbstractRemoval of Co(II) and Mn(II) ions from the pure terephthalic acid (PTA) wastewater onto Na-bentonite has been investigated in this work. Batch experiments were performed to elucidate the effects of various parameters, such as dosage of adsorbent, temperature, and initial pH, on the adsorption process. It has been found that the simulated adsorption process of the pseudo-second-order kinetic model was in better agreement with experimental results than that of the pseudo-first-order and intra-particle diffusion kinetic models. Moreover, the adsorption experiments were conducted at four temperatures, which was 298.15, 308.15, 318.15, and 328.15 K, respectively, with the initial metal concentrations ranging from 30 to 120 mg L−1, so as to study the adsorption thermodynamics. Compared with the Freundlich and Dubinin–Radushkevich models, the Langmuir isotherm model agreed better with experimental data. The Gibb’s free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) of the adsorption pr...