The impact of water soaking on physicochemical activated carbon produced by various thermal cracking temperature

Abstract

The feedstock and processing technology determined the quality of activated carbon. The ulin wood (Eusideroxylon zwageri) waste was used as activated carbon feedstock. The aim of this study was to analyze the physicochemical properties of activated carbon produced by water soaking activation at low thermal cracking temperature. At first, ulin wood was characterized by Thermal Gravimetric/Differential Scanning Calorimetry (TGA/DSC). Ulin wood waste was pyrolyzed for two hours in the absence of oxygen at 350 °C, 450 °C, and 550 °C of thermal cracking temperature. The hot char produced was then water soaked for thirty minutes to activate the char. The characteristics of activated carbon were performed by ultimate-proximate analyses, Scanning Electron Microscopy (SEM), Fourier-Transform Infra-Red spectroscopy (FT-IR), Brunauer, Emmett, and Teller (BET), and XRD (X-Ray Diffraction) analyses. To compare the activated carbon properties, it was also analyzed the conventional carbon produced without water soaking. Based on TGA/DSC, the components of lignocellulose in wood powders have decomposed at all pyrolysis temperature. The result showed that in the 550 °C thermal cracking temperature, the fixed carbon, total carbon, ash content, and pH were increased, but volatile matter, yield, oxygen, and hydrogen were decreased. Carbon activation by water soaking could clean the char from the surface dust. Based on SEM analysis, the higher the thermal cracking temperature, the more ordered macroporous char. There was a functional group similarity between activated and conventional char. As increasing thermal cracking temperature, the organic functional groups had a high aromatic of C-H, C=C, C=O groups. BET surface areas of activated carbon of ulin wood were ranged between 175.97m2/g - 218.88m2/g. The calorific value was increased from 6,728.67 cal/g to 7,128.14 cal/g as increased pyrolysis temperature. The sharp diffraction peaks based on XRD analysis indicated that there was the structure of the graphite crystalline in activated carbon.