Abstract
A sulfonated carbon acid catalyst (C-SO(3)H) was successfully generated from palm empty fruit bunch (PEFB) carbon via hydrothermal sulfonation via the addition of hydroxyethylsulfonic acid and citric acid. The C-SO(3)H catalyst was identified as containing 1.75 mmol g(-1) of acid and 40.2% sulphur. The surface morphology of C-SO(3)H shows pores on its surface and the crystalline index (CrI) of PEFB was decreased to 63.8% due to the change structure as it became carbon. The surface area of the carbon was increased significantly from 11.5 to 239.65 m(2) g(-1) after sulfonation via hydrothermal treatment. The identification of -SO(3)H, COOH and -OH functional groups was achieved using Fourier-transform infrared spectroscopy. The optimal catalytic activity of C-SO(3)H was achieved via hydrolysis reaction with a yield of 60.4% of total reducing sugar (TRS) using concentrations of 5% (w/v) of both C-SO(3)H and cassava peel starch at 100 °C for 1 h. The stability of C-SO(3)H shows good performance over five repeated uses, making it a good potential candidate as a green and sulfonated solid acid catalyst for use in a wide range of applications.