Investigation of Pyrolyzed Chars from Physic Nut Waste for the Preparation of Activated Carbon

Abstract

Fixed bed pyrolysis of physic nut waste was conducted to investigate the influence of different operating conditions, such as sample size, final temperature and hold time, on properties of the pyrolyzed chars. The obtained chars were characterized by a thermogravimetric analyzer (TGA) for proximate analyses and by Brunauer-Emmett-Teller (BET) for determination of their accelerated surface area. The surface morphology of char was investigated using scanning electron microscopy (SEM). For chemical characterization, an X-ray diffractometer (XRD) and a Fourier transform infrared spectroscope (FTIR) were used to identify inorganic components and surface organic functional groups of the char. In this work, the FTIR analysis indicated the existence of phosphonate groups, carboxyl groups and amine groups on char surface. The XRD pattern of the surface also verified the presence of graphite as main carbon structure. The conditions yielding char with maximum BET surface area of 249.60 m2·g-1 and high fixed carbon are final temperature of 800°C, hold time of 15 minutes, and heating rate of 20°C/min for 0.425-0.5 mm particle. Generally, high temperature pyrolysis of raw materials with short hold time results in char with favorable smooth, porous surface with large cavities.