Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source babassu

Abstract

Activated carbons (ACs) with well–developed microstructure and high microporosity were obtained from biomass by potassium hydroxide activation. The preparation process consisted in producing carbon materials in the ratios of activating agent to raw material 70:30, 50:50, 30:70 and 25:75 (w/w) characterized by thermal analysis coupled to spectroscopy (TG–DTA / FT–IR), scanning electron microscopy (SEM), N2 adsorption isotherms at –196 ºC and activation isotherm at 500 and 600 ºC for 3.0 h. Specific surface areas (SBET) within 728 and 1712 m2 g-1 and (Smic) within 1054 and 1923 m2 g-1 were obtained, while the micropores surface area was calculated using the Dubinin-Astakhov (DA) equation and the pore size distribution calculated from density functional theory (DFT) was found to be in the range 1.09 – 1.77 nm. Adsorption isotherms were fitted using Langmuir and Freundlich non–linear models and the adsorption capacity determined for methylene blue dye was between 27.13 and 459.20 mg g-1.

Keywords

• babassu
• adsorbent
• thermal analysis
• spectroscopy