Insights into the Impacts of Synthesis Parameters on Lignin-based Activated Carbon and Its Application for: Methylene Blue Adsorption

Abstract

In the current research, lignin was successfully extracted from industrial waste Kraft black liquor using the acid precipitation method. In the following step, powdered carbon was synthesized through the H3PO4-chemical activation method. The effects of synthesis parameters, including activation temperature (T) within the range of 400-600 ⁰C and two H3PO4/Lignin mass ratios (R) of 2 and 3 on activated carbon (AC) structure, were investigated. The physical and morphological properties of the ACs were obtained through BET, SEM, and FTIR analyses. The potential application of ACs was studied by measuring their adsorption capacity in the adsorption process of Methylene blue (MB) from an aqueous solution. The sensitized AC at R=2, and T= 500 ⁰C (AC-2-500) showed the highest specific surface area (1573.31 m2/g) and the pore volume (0.89 cm3/g), as well as the highest adsorption capacity of MB. This adsorbent was applied in the equilibrium adsorption experiments and kinetic description. The results from kinetic experiments and adsorption isotherms indicated that the pseudo-first-order model and Langmuir model were in correspondence with the experimental data most. The maximum adsorption capacity was 188 mg/g. The study proved there is a high potential for the conversion of black liquor to greatly porous Lignin-based adsorbents. Moreover, the considerable maximum adsorption capacity suggested a significant potential of Lignin-based AC for wastewater treatment.

Keywords

• aqueous solution
• black liquor
• equilibrium
• kinetic
• wastewater treatment