Lignin Extraction from Coconut Pith by Alkaline and Organosolv Treatment: Characterization and Optimization of Lignin Yield and Purity

Abstract

Effective coconut pith lignin (CPL) extraction remained an obstacle since lignin must be removed without causing significant destruction of cellulose fibers. This work seeks to solve these challenges by improving the extraction procedure for CPL to generate a material appropriate for industrial uses, such as anti-corrosion coatings, that take advantage of lignin’s distinct features. A comprehensive technique based on response surface methodology (RSM) and central composite design (CCD) was used to optimize three critical process parameters: temperature, solvent concentration and time of alkaline treatment (AT) and organosolv treatment (OT) concentration for extracting the lignin. The screening findings showed that the AT produced the highest yield of lignin and purity compared to the OT. This will provide 72.29% CPL-AT and 86.00% purity through RSM analysis. (TGA) and (FTIR) were used to assess the physical qualities of lignin. Fourier transform infrared (FTIR) analysis demonstrated that CPL-AT and CPLOT possess similar spectrums, though the CPL-OT showed more prominent peaks of aromatic rings and phenolic hydroxyl groups. Thermogravimetric analysis (TGA) studies demonstrated that CPL-AT has higher heat stability owing to its higher molecular weight and solubility properties which makes it has potential and economically viable material for industrial applications such as bio-composite materials.