Optimization of Biochar Quality from Palm and Cacao Waste through Variation of Pyrolysis Temperature and Duration as a Soil Amendment Material

Abstract

Palm and cacao waste are high-quality raw materials for producing quality biochar that enhances soil fertility, provided that the biochar production process takes into account various aspects of pyrolysis. The pyrolysis conditions, such as temperature and duration, significantly impact the quality of the biochar produced as a soil amendment. The type of raw material, pyrolysis temperature, duration, and other conditions affect the ash content, pH, functional groups of the biochar, the morphological structure of the surface, and other chemical characteristics of the biochar. The objective of this research is to find the best formulation of biochar made from Palm Kernel Shells (PKS), Palm Oil Empty Bunches (POEB), Cacoa Pod Husks (CPH) and a mixture of PKS: POEB: CPH based on the physicochemical properties of the biochar produced at pyrolysis temperatures of 350, 450 and 550°C with durations of 2 and 4 h. The research used a pyrolysis reactor designed to produce biochar at controlled temperatures, digitally recorded throughout the pyrolysis process. FTIR and SEM analyses were performed to examine changes in functional groups and the morphological structure of the biochar surface. Additionally, the chemical characteristics of the biochar were analyzed, including ash content, pH, organic carbon, total nitrogen, total phosphorus, total potassium, total calcium, total magnesium, Cation Exchange Capacity (CEC), and moisture content. The results provide insights into the quality of biochar produced from different raw materials, temperatures, and durations of pyrolysis. The research shows that shifts in aliphatic and aromatic CH groups occur with increased temperature and duration of pyrolysis across various types of agricultural waste biochar. The surface morphological structure and several physicochemical characteristics of the biochar, such as moisture content, ash content, organic carbon, total nitrogen, total phosphorus, total potassium, total calcium, total magnesium, and CEC, vary due to different temperatures and durations of pyrolysis for each type of palm and cacao raw material.