Adsorption of ammonium and phosphates by biochar produced from oil palm shells: Effects of production conditions

• Published in: Results in Chemistry 2021-01, Vol.3, p.100119, Article 100119
• Main Authors: Munar-Florez, David Arturo, Varón-Cardenas, Darlis Adriana, Ramírez-Contreras, Nidia Elizabeth, García-Núñez, Jesús Alberto
• Format: Article
• Language: English
• Subjects: Biochar; Chemical activation; Eutrophication; Oxidation; Pyrolysis
• ISSN: 2211-7156; 2211-7156
• DOI: 10.1016/j.rechem.2021.100119

•Biochar production conditions could affect the adsorption properties.•Biochar surface properties depend on the temperature of carbonization.•Biochar is a versatile material to use as both adsorbent and soil conditioner.•Biochar is eco-friendly by capturing carbon and improving soil quality. This study investigated the effects of production conditions on the ammonium and phosphate adsorption capacity of oil-palm-shell-biochar. Biochar was prepared at three pyrolysis temperatures (350, 650, and 750 °C), under three activation conditions (no oxidation, partial oxidation at 250 °C, and chemical activation with K2CO3), and using three washing methods (no washing, acid washing, and hot water). Physicochemical properties of certain biochar samples were characterized by SEM, CHON-S, XRF, FTIR, and area BET. The highest ammonium adsorption capacity (1.49 mg/g) was observed for chemically activated biochar pyrolyzed at 650 °C without washing. The best phosphate adsorption capacity (0.89 mg/g) was observed for partially oxidized biochar pyrolyzed at 650 °C with acid washing. The BET surface area ranged from 4 to 253 m2/g. The biochar produced at 350 °C without washing had more surface functional groups than that produced at higher temperatures. The chemical activation process promoted the development of numerous functional groups on the biochar surface.