Characterization of Diluted-acid Pretreatment of Water Hyacinth

Abstract

Water hyacinth (WH) is an abundant renewable lignocellulosic biomass. The renewable resources are widely studied to produce bioenergy and high value added products. The obstacle of converting the lignocellulosic biomass to products due to its recalcitrant structure, required disruption to enhance the chemical or enzyme accessibility. The aim of this study is to investigate the possibility of WH pretreatment with dilute sulfuric acid (DSA). The addition of sulfuric acid in pretreatment process was varied concentration at 1, 2, 3, and 4% (v/v). The chemical component was analyzed to optimize the pretreatment condition. The results showed that the 2% sulfuric acid had effect on cellulose recovery. The morphological changes of WH due to pretreatment were determined by Scanning Electron Microscopy (SEM). The images showed the destructive surface of all treated samples. The intact surface of native WH was destroyed after pretreatment process while the increment of acid concentration increased the rough surfaces. The Fourier Transform Infrared Spectrometer (FTIR) and X-ray diffraction (XRD) were used for analyzing functional groups and crystallinity, respectively. The FTIR patterns of DSA treated WH were slightly different due to the remained components in samples. The results showed the highest crystallinity index was 55% which was obtained from pretreated WH with 2% sulfuric acid, 80°C, 60 min. In the present study, it was found that DSA pretreatment is possible to modify the chemical structure of WH for developing economical processes.