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CO2 uptake by activated hydrochar derived from orange peel (Citrus reticulata): Influence of carbonization
K R Deepak1, Sooraj Mohan2, P Dinesha1
1Department of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, India.
Abstract:
In this study, activated hydrochar was prepared from orange peel (OP) waste using KOH for the first time for potential environmental applications. The influence of hydrothermal carbonization temperature (180 °C, 200 °C, and 220 °C) on the CO2 adsorption capacity of OP-derived activated hydrochar (OP-180, OP-200, and OP-220) was investigated. Scanning electron microscope (SEM) images revealed that the activated OP hydrochar has high microporosity, a desired attribute for effective adsorption. The yield and the oxygen content of the hydrochar decreased with the increasing process temperature whereas the carbon content showed an increase. Fourier-transform infrared spectroscopy showed the presence of various functional groups including ketone, aldehydes, esters, and carboxyl in the hydrochar. CO2 adsorption isotherm was determined for all hydrochar samples. At 25 °C and 1 bar, OP-220 showed the highest CO2 uptake at 3.045 mmol/g. The use of OP waste for CO2 adsorption applications contributes to carbon neutrality and a circular economy.
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