Modelling studies of methylene blue dye removal using activated corn husk waste: Isotherm, kinetic and thermodynamic evaluation

Abstract

Corn husk waste (CHW) was evaluated as an alternative simple treatment strategy to remove methylene blue dyes (MB). Various experimental factors, such as pH, concentration, contact time, and temperature, were studied during the adsorption process. Optimum conditions were obtained at pH 6, initial concentration of 800 mgL−1, contact time of 60 min, and temperature 298 K with an adsorption capacity of 41.06 mgg−1. The kinetics study was analyzed using pseudo-first-order, pseudo-second-order, intra-particle diffusion, and Elovich models. Moreover, the pseudo-second-order process model can characterize the MB chemisorption kinetics. The experimental results were fitted to the Langmuir isotherm model. The obtained thermodynamic parameters (ΔHo,ΔSo,ΔGo) revealed that MB adsorption was spontaneous and exothermic. The optimum conditions for removing MB on laboratory wastewater was 99.79 %, while for MB on batik industry water was 51.40 %. CHW had an excellent capability to be used for 4 times cycle.

Keywords

• Adsorption
• Corn husk waste
• Low-cost
• Methylene blue
• Waste