Abstract

Saideh Bagheri^*

DOI : http://dx.doi.org/10.13005/ojc/320163

The focus of this research is on the rapid ultrasound-assisted removal of Bismarck Brown (BB) and Thymol Blue(TB) dyes from aqueous solutions using Mn-Fe₂O₄ nanoparticles loaded on activated carbon (Mn-Fe₂O₄- NPs-AC) as a low cost and environmental friendly adsorbent. The adsorbent was characterized by SEM, FTIR and XRD. The effect of variables such as initial concentration of BB, initial concentration of TB, pH of the solution, adsorbent dosage and sonication time on the removal percentages of BB and TB dyes were simultaneously investigated by central composite design(CCD) under response surface methodology(RSM). It was shown that the adsorption of BB and TB follows the pseudo-second-order rate equation, while the Langmuir model explains equilibrium data. Isotherms had also been used to obtain the thermodynamic parameters such as free energy (ΔG⁰), enthalpy (ΔH⁰) and entropy (ΔS⁰) of adsorption. The negative value of ΔG⁰ indicates the feasibility and spontaneity of the adsorption process. The positive ΔH⁰ suggests the endothermal nature of the adsorption. The positive values of ΔS⁰ reflects the affinity of Mn-Fe₂O₄- NPs-AC towards BB and TB dyes. A small amount of the adsorbent was able to remove more than 99.0% of both dyes rapidly with high adsorption capacity in binary-component system( 70.3 mg/g for BB, and 48.48 mg/g for TB).

Nanoparticle-loaded activated carbon; Response surface methodology; Ultrasound-assisted dye removal; Thymol Blue; Bismarck Brown

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