Hydrothermal Sulfonation of Palm Empty Fruit Bunch Carbon as Solid Acid Catalyst and Its Hydrolysis Catalytic Activity
Abstract The sulfonated carbon solid acid catalyst (C-SO3H) was successfully generated from palm empty fruit bunch (PEFB) carbon via hydrothermal sulfonation by addition of hydroxyethylsulfonic acid and citric acid. The C-SO3H was identified contain of 1.75 mmol/g of acidity and 40.2% of sulphur. The surface morphology of C-SO3H showed pores with diameters of 3-6 µm and crystalline index (CrI) of material was decreased to 63.8% due to changed structure become carbon. The surface area of carbon was increased significantly from 11.5 to 239.65 m2g-1 after hydrothermal treatment. The identification of functional groups of -SO3H, COOH and -OH were detected by Fourier Transform Infra-Red (FT-IR). The optimum catalytic activity of C-SO3H was achieved via hydrolysis reaction with 60.4% of total reducing sugar (TRS) yield. The both concentrations of C-SO3H and cassava peel starch is 5% at 100 oC for 1 h. Stability of C-SO3H showed good performance for 4th repeated used; it showed insignificant of activity that decreased only of 6%. Thus, the C-SO3H is a candidate for green and potential sulfonated solid acid catalyst for wide range applications.