The production of biochar from orange pomace by hydrothermal method

In this study, orange pomace, a food industry waste, was studied by hydrothermal carbonization (HTC) method for the production of ''biochar'' which was used as a soil amendatory. For this purpose, the carbonization of orange pomace was carried out at different temperatures (175, 190, 225 and 260 °C) and at different reaction times (30, 60, 90 and 120 minutes). The products of HTC are the solid product (''biochar''/hydrochar) with high carbon content, the liquid product (aqueous solution) and in trace of gaseous product. In this study, the hydrochars were analyzed for elemental composition, PAH content and water holding capacity properties. The determinations of sugar, aldehyde, organic acid and phenolic compounds, chemical oxygen demand and total organic carbon, pH and electrical conductivity analyses of aqueous solution were carried out as well. By considering C/N, O/C and H/C ratios of hydrochars, pH conditions, heavy metal analyses and nutrient contents, hydrochars can be convenient for soil amendment applications.