Abstract:
In this research, the preparation of hidrochar from lignocellulosic nypa frond waste was carried out using the hydrothermal method and its application as adsorption for methylene blue dye. This study aims to determine the effect of the addition of oxalic acid on the characteristics and adsorption ability of hydrochar from nypa frond to adsorption of methylene blue. The hydrothermal process was carried out at 170 ̊C for 2 hours with the addition of oxalic acid at a concentration of 0; 1.5; 3.0; and 4.5% (w/v). Substrates resulting from the hydrothermal process were characterized using FTIR spectroscopy to determine the functional group changes of the nypa frond. The results showed that the nypa fronds decreased in mass and shifted in functional groups after the hydrothermal process with oxalic acid addition. The adsorption capacity of methylene blue increased after the hydrothermal process with the addition of oxalic acid concentrations 1.5; 3.0; and 4.5% (w/v), which were 44.33; 45.10; 45.98; and 46.62 mg/g. The highest adsorption capacity results were obtained for hydrochar with the addition of 4.5% oxalic acid, which was 46.62 mg/g
