Preparation and Characterisation of Modified Biochar from Vitex Doniana (Black Plum) Seeds Using Chemical and Thermal Treatments

Abstract

Agricultural wastes from plant have continued to be a huge contributor to the global biomass generation and their utilization for biochar is growing. The goal of this research was to produce and characterize modified biochar of Vitex doniana (Black plum) seeds using chemical and thermal treatments. To achieve this, the vitex seed was carbonized for 2 hours at 400°C in a pyrolysis reactor. The resulting char was then impregnated for 24 hours with Phosphoric Acid (H₃PO₄) and potassium hydroxide (KOH) as chemical activating agents before being thermally activated at 400°C, 500°C, 600°C, and 700°C respectively. The purpose of the characterization was to see how the activators and activation temperature affected the adsorbents generated. The quality of absorbents produced was affected by the treatment of char with chemical agents and the activation temperature, according to the results. The samples had distinct functional groups on the surface, according to FTIR analysis, and SEM analysis via microscopy revealed the presence of pores on the surface. Iodine absorption testing reveals that materials activated with KOH had a higher absorption value, peaking at 950mg/g for KOH treated and 600°C activation temperature. The pore diameters and pore volume of KOH samples were determined using BET analysis. The results demonstrate that KOH activated at 600°C has larger pores and a higher pore volume, implying that KOH at 600°C has a higher adsorption capacity. The char sample was also subjected to TGA analysis in order to better understand its behavior in temperature settings.