Efficient Extraction and Analysis of Wheat Straw Lignin by Response Surface Methodology

Area of Science:

• Biomass valorization
• Green chemistry
• Materials science

Background:

• Straw waste presents a significant disposal challenge.
• Efficient lignin extraction is key to unlocking the high-value potential of lignocellulosic biomass.
• Developing sustainable methods for lignin recovery is crucial for the circular economy.

Purpose of the Study:

• To optimize lignin extraction from wheat straw using a formic acid/acetic acid solvent system.
• To investigate the impact of key reaction parameters on lignin yield.
• To characterize the extracted lignin and analyze extraction kinetics.

Main Methods:

• Single-factor experiments and response surface methodology for optimization.
• Formic acid/acetic acid solvent system for lignin extraction.
• Fourier-transform infrared (FTIR) spectroscopy, UV spectroscopy, and thermogravimetric analysis (TGA) for lignin characterization.
• Kinetic modeling of the extraction process.

Main Results:

• Optimized conditions (90 °C, 3.5 h, 1:16.5 solid-liquid ratio, 86.2 wt.% formic acid) yielded 79.83% lignin.
• Reaction temperature was the most significant factor influencing lignin yield, followed by solid-liquid ratio, reaction time, and formic acid content.
• Extracted lignin maintained structural integrity and demonstrated good thermal stability.

Conclusions:

• The formic acid/acetic acid system provides an efficient method for high-yield lignin extraction from wheat straw.
• The extracted lignin is suitable for various high-value applications due to its preserved structure and thermal stability.
• This study contributes to sustainable biomass utilization and waste valorization strategies.