Optimization of ultrasonication assisted alkaline delignification of coir pith using response surface methodology

Abstract

Coconut coir pith constituting cellulose, lignin, and hemicellulose is considered as a replenishing and extensively available biomass for the manufacture of value-added chemicals and biofuels. The processability of coir pith has been limited by hemicellulose and lignin content which imparts high recalcitrance to the biomass. The study aims at ultrasonication assisted alkaline treatment of coir pith to attain maximum percent delignification. The process parameters were screened using Plackett Burman Design and the significant parameters were optimized using Central Composite Design tool in Response Surface Methodology. About 70.79 % delignification was achieved when biomass was treated at 180.45 °C for 151.54 min in 3.82 % sodium hypochlorite solution. Scanning electron microscopy (SEM), Fourier transform infra-red (FTIR) spectroscopy and X-ray diffraction (XRD) spectroscopy were employed to characterize the biomass. Water sorption and retention behavior of coir pith was also studied.