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 acid precipitation method. In the following step, powdered carbon was sensitized through 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 ratio (R) of 2 and 3 on activated carbon (AC) structure were investigated. To study the physical and morphological properties of the sensitized carbons, BET, SEM, and FTIR methods were used. The potential application of synthesized ACs was investigated by measuring their adsorption capacity in adsorption process of Methylene blue (MB) from aqueous solution. The AC sensitized 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 the most correspondence with the experimental data. Maximum adsorption capacity was 188 mg/g. The study proved that a high potential for conversion of black liquor to greatly porous Lignin-based adsorbents. Moreover, the considerable maximum adsorption capacity suggested that a noteworthy potential of Lignin-based AC for wastewater treatment.

Keywords

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