Synthesis and characterisation of activated carbon from organic waste by hydrothermal method

Today's increasing environmental problems and the need for sustainable material production have made the utilization of agricultural wastes an important research topic. The conversion of agricultural wastes with high carbon content into activated carbon, which is widely used in industrial applications, carries great importance in terms of both waste management and economic aspects. In our study, active carbon production was carried out using hydrothermal carbonization method from apricot kernel shell, which is an organic waste. The apricot kernel shells were powdered and prepared for the hydrothermal reaction. The hydrothermal carbonization process was carried out at three different temperatures of 240°C, 260°C, and 300°C, under 10 Bar pressure for 24 hours. The obtained hydro chars were then activated with potassium hydroxide (KOH) and subjected to heat treatment under inert atmosphere at 700°C. To determine the properties of the produced hydrochar and activated carbon samples, analyses such as Brunauer-Emmett-Teller (BET) surface area measurement, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were performed. According to BET analysis results, the surface area, which was initially 6.752 m²/g, increased after hydrothermal carbonization and rose up to 658.5564 m²/g after KOH activation. SEM images showed that micro and meso pores were formed after the activation process and the surface morphology changed significantly. EDS analyses revealed that the carbon content increased as a result of the processes, and the carbon ratio, which was initially 59.83%, increased above 85% after activation. The study demonstrated that apricot kernel shell could be successfully converted into activated carbon with high surface area through hydrothermal carbonization and KOH activation. The results offer valuable insights into the conversion of agricultural waste into high-value materials and the production of sustainable resources.