Preparation of biochar from Ketapang shells (Terminalia catappa l.) for dyes adsorbent to support environmental principles

The purpose of this study was to characterize and measure the ability of biochar from ketapang fruit shells to adsorb Naphthol Yellow S. The measurement results of the Fourier Transform Infrared (FTIR) spectrophotometer show that the amine, carbonyl, and hydroxyl groups are a parent in the biochar as evidenced by the presence of C-O bonds at 1190,08 cm⁻¹, C=O at 1421,54 cm⁻¹, and N-H at 1581,63 cm⁻¹ which has the potential to be used as adsorbent. Pore analysis on biochar carbonization results of 500 °C with SEM showed a pore size of 53.7 μm with a magnification of 5000 times and levels of C=87.85% to 93.81%, O=6.19% to 12.15%. The optimum adsorption of Naphthol Yellow S dye on biochar weight variations was obtained at 0.1 gram of biochar weight with an adsorption percentage of 47.875%, for variations in contact time of biochar obtained at 60 minutes contact time with an adsorption percentage of 66.21% and follow the model of the Freundlich isotherm equation with a linear coefficient value of (R²) 0.9983.