Synthesis and characterization of coral-like hierarchical MgO incorporated fly ash composite for the effective adsorption of azo dye from aqueous solution

摘要

In the present work, coral like hierarchical magnesium oxide (MgO) incorporated fly ash (FA) composite (FAMgO) synthesised by sol-gel method was evaluated for the adsorption of Reactive Black 5 (RB5) azo dye from aqueous solution. Adsorbent characterization using FE-SEM, XRD and FT-IR ascertained the formation of the FAMgO composite. Batch mode sorption studies were carried out for RB5 azo dye removal as a function of pH, FAMgO dose, initial dye concentration and temperature. The compliance of Langmuir isotherm model (R-2 = 0.999) corroborated the homogeneous nature of sorption of RB5 dye onto FAMgO with the sorption capacity (Q(max)) of 48.78 mg g(-1). The regression coefficient value revealed the best fit of pseudo-second-order model with the Q(e) value of 29 mg g(-1). The thermodynamic parameters such as Delta G degrees, Delta H degrees and Delta S degrees suggested the spontaneous and endothermic nature of RB5 dye sorption onto FAMgO and suitable mechanism has been proposed. (C) 2018 Elsevier B.V. All rights reserved.