Parametric optimization of ozonolysis pretreatment of empty fruit bunch by response surface methodology and its characterization

Empty fruit bunch (EFB) from palm oil mills offers potential for advanced material development of cellulose derivatives due to its high cellulose content. However, recalcitrant lignin in EFB hinders cellulose isolation, necessitating ozonolysis pretreatment for delignification and further extracting cellulose fiber. In this study, the influence of moisture content, ozone concentration and reaction time on lignin degradation, cellulose and hemicellulose contents were investigated by Response Surface Methodology (RSM) using Box-Behnken Design (BBD). The physico-chemical effects of ozonolysis treatment on EFB are scrutinized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). RSM analysis shows the influence of the process parameter was different for each responses. The moisture content was important for lignin degradation, while ozone concentration and the interaction between the process parameter controlled the hemicellulose degradation. But, none of the process parameter affected cellulose degradation. A 99.39 %, 60 %, and 26.20 %, of lignin degradation, cellulose and hemicellulose content were projected with below 10 % error, respectively. These suggested that ozonolysis could effectively degrade lignin and slightly degraded hemicellulose but cellulose was not affected. Thus, decreasing the lignin and hemicellulose content increased the cellulose content in treated EFB. The findings were confirmed by TGA, FTIR, XRD and SEM, and have proved the reduction/absence of lignin from untreated EFB without affecting the cellulose structure after ozonolysis pretreatment. The findings of this study could be employed in the future to isolate the cellulose fiber from other agricultural waste biomass that is ecologically benign and sustainable with the aim to produce products with added value.