Optimization of Biochar Production from Coconut Shell Waste with Pyrolysis Technology with Response Surface Methodology

Coconut shell waste is one of the abundant biomass in Indonesia, but its utilization is still limited. One of its potential uses is as a raw material for making biochar, which is biological charcoal that is useful for improving soil quality. However, the process of making biochar from coconut shells is still not optimal, especially in terms of the yield and characteristics of the biochar produced. This study aims to optimize the process of making biochar from coconut shells through the Response Surface Methodology (RSM) approach. The method used includes the coconut shell pyrolysis process with variations in particle size (8–35 mesh), at atmospheric pressure with a nitrogen gas flow of 5 mL/minute. Pyrolysis was carried out at temperatures ranging from 300°C to 500°C for 30 to 90 minutes. The experimental design was designed using the RSM approach to obtain optimum conditions. The results showed that the optimum pyrolysis conditions were obtained at a temperature of 300°C, a pyrolysis time of 51.211 minutes, and a particle size of 2.38 mm. Under these conditions, the biochar yield was 67.172%, the water content was 2.300%, and the ash content was 1.627%. These values indicate good biochar quality with high production efficiency. In conclusion, the optimum conditions of this research can be used as a basis for the development of a larger-scale biochar production process, with the main focus on increasing yield without sacrificing quality, especially for applications in sustainable planting media.