Biochar from Oil Palm Frond to Reduce Fe Ions in Artificial Solution and Peat Water

Raw oil palm fronds (OPF-R) converted into biochar (OPF-B) by torrefaction processes at temperatures range of 200 °C to 300 °C. This study aims to evaluate OPF-B performance to reduce iron ions in artificial solutions and peat water. Batch adsorption carried out at room temperature by stirring (175 rpm) using an orbital shaker. Some parameters observed included optimum torrefaction temperature, optimum conditions of Fe ions adsorption (optimum pH and contact time) and sorption isotherm. Metal content measured using atomic absorption spectroscopy (AAS). Functional groups on material surface characterized using Fourier Transform Infrared (FT-IR). Torrefaction at 260 °C produces biochar with the highest efficiency in removing iron ions. Both functional groups C=O and C-O attributed to lignocellulose on OPF-B were diminished and absorption band of aromatic (C=C) increased which caused by torrefaction. The optimum conditions for removal of Fe ions at pH 5 and 30 minutes contact time. Adsorption process follows the Langmuir Isotherm which indicates the formation of a monolayer with qmax 111.11 mg/g. Amount of 0.025 g OPF-B able to reduce iron concentration from 13.960 mg/L to 0.746 mg/L in 100 mL peat water (has complied with Indonesian clean water standard for iron concentration).