Char properties and pollutant adsorption capability of oil palm shell using hydrothermal process

Abstract

Hydrothermal carbonization (HTC) for lignocellulosic biomass has many advantages in terms of environmentally friendly, non-toxic, and low energy use. The products produced from HTC process can be used for various materials such as chemicals, adsorbents, energy, and agriculture fertilizer. In this study, HTC process has been done by using the oil palm shell (OPS). The purposes of this study were to evaluate the characteristics of the hydrochar, as well as to determine the effect of temperature and processing time on hydrochar properties resulting from the HTC process. The process was carried out using a temperature of 200 °C, 225 °C, and 250 °C, with a processing time of 4, 6, and 8 h. The ratio of biomass to water was 15:100 based on weight. The characterization that performed on the hydrochar and its raw OPS were elemental analysis, proximate analysis, Brunauer Emmett and Teller (BET), fourier transform infrared (FTIR), pyrolysis–gas chromatography–mass spectroscopy (Pyr–GC–MS), and X-ray diffraction (XRD). The determination of iodine number test, methylene blue number test, and some pollutants adsorption tests were also performed to characterize the product. The results showed that the surface area, fixed carbon, and carbon content of hydrochars were increased as compared with the raw OPS. The structure of hydrochar also differs with raw OPS structure based on XRD analysis. The hydrochar that produced by the temperature of 225 °C for 8 h selected as the best properties based on the determination of iodine, some gaseous pollutant adsorption, and surface area of materials.