Chemical modification of betel nut husk prepared by sodium hydroxide for methylene blue adsorption

Abstract

Abstract In recent years, different biomaterials have garnered more research attention due to their usefulness as adsorbents. The present study focuses on a chemical treatment process to improve the adsorption capacity of betel nut husk fibers for a textile effluent (methylene blue). The fibers of chemically modified material were assessed using Fourier transform infrared (FTIR) spectrometer and Brunauer–Emmett–Teller (BET) analyzer to determine the existing surface functional groups and surface area, respectively. Parameters including contact time, dye concentration, temperature, effects of pH and desorption efficiency were also evaluated to identify optimum adsorption performance. Adsorption followed the Freundlich isotherm model and pseudo-first-order kinetics, indicating physisorption was responsible for adsorption and its occurrence on multilayers. Adsorption capacity was 149.921 mg/g, 149.874 mg/g and 145.462 mg/g at 30, 40 and 50, respectively, and was best at 30 °C. ΔH° was found to be − 1.494 which suggests adsorption is exothermic in nature and thus satisfying the findings that the physical process of adsorption took place in this study.

Keywords

• Adsorption
• Betel nut husk
• Dye removal
• Isotherms
• Chemical modification