Kinetics and isotherm studies on acid dye adsorption using thermal and chemical activated Jatropha husk carbons

Abstract

Activated carbon was prepared from Jatropha husk, as a biodiesel byproduct waste, by physical (JHC) and chemical (ZnCl2) activation (ZAJHC), as an adsorbent for the removal of acid dye Acid blue 83 (AB83). Batch adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, initial dye concentration, adsorbent dose, and initial solution pH. The AB83 loaded and unloaded adsorbent materials were characterized by SEM, EDX, XRD, and FTIR. Lagergren first-order, Pseudo second-order, Intraparticle diffusion and Bangham's models were used to evaluate the kinetics and mechanism of the adsorption. The Langmuir, Freundlich, and D–R isotherm models were tested to represent the equilibrium data and the constants of the isotherms were determined by using the experimental data. Normalized deviation (Δq) is used to quantify the correlation of experimental results with the models. The maximum adsorption capacity (Qo) obtained was 7.59 and 27.93 mg g−1 at a temperature of 35°C for JHC and ZAJHC, respectively. The favorable pH for maximum AB83 adsorption was pH 2.0 for both JHC and ZAJHC. The desorption studies discovered that the regeneration and reusability of the adsorbent can be easily achieved. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 719–732, 2018.