Kinetics, isotherms and thermodynamic modeling of liquid phase adsorption of Rhodamine B dye onto Raphia hookerie fruit epicarp

Abstract

Highly efficient low cost adsorbent was prepared from Raphia hookerie fruit epicarp. Characteristics of the prepared low cost adsorbent (RH) was established using scanning electron microscope (SEM), Fourier Transform Infra Red (FTIR) and Brunauer–Emmett–Teller (BET) surface area. RH was applied for Rhodamine B (RhB) uptake from aqueous solution. Equilibrium adsorption data were fitted using four isotherms and kinetic data tested with five kinetic models. The BET surface area obtained was 0.00351 m2/g; SEM reveals large pores that could enhance the uptake of large molecules. Freundlich isotherm best described the uptake of RhB onto RH, the maximum monolayer adsorption capacity (qmax) was 666.67 mg/g. Pseudo second order model best described the kinetics of adsorption process. Energy of adsorption (E) obtained from D-R isotherm suggests physical adsorption. Desorption efficiency follows the order H2O>HCl>CH3COOH. Cost analysis shows that RH is about 1143 times more economical when compared with commercial activated carbon.

Keywords

• Raphia hookerie
• Biomass
• Rhodamine B
• Adsorption
• Thermodynamics
• Kinetics