Effects of pyrolysis temperature on chemical composition of coconut-husk biochar for agricultural applications: a characterization study

Abstract

Coconut husk, a plentiful agricultural waste, rich in cellulose and lignin, is abundant in tropical and subtropical regions worldwide. The emergence of new green energy technologies harnessing coconut husk has intensified interest in biochar production due to its affordability and low energy requirements. The effectiveness of biochar varies based on the raw materials and production process. Hence, this study aimed to evaluate the chemical and structural properties of coconut-husk biochar produced at different pyrolysis temperatures, focusing on its agricultural benefits. In this research, biochar derived from coconut husk was generated at varying pyrolysis temperatures 325, 350, 400, 500, 600, and 700 °C under limited oxygen supply and a heating rate of 7 °C/min for 3 h. The chemical and structural properties of the produced biochar were meticulously examined using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) techniques. The findings underscored the significant impact of pyrolysis temperature on the chemical properties and structure of coconut-husk biochar, especially at lower heating rates. Remarkably, the highest yield, recorded at 42.79% (at p < 0.05), was achieved at 325 °C, emphasizing the suitability of lower pyrolysis temperatures for biochar production using coconut husk. Furthermore, alterations in pyrolysis temperature resulted in notable differences in elemental concentrations and significant changes in the biochar structure. These modifications enhance plant and leaf water use efficiencies, boost plant photosynthesis efficiency, modify soil properties, reduce greenhouse gas emissions, and contribute to mitigating global warming.

Keywords

• agricultural waste
• coconut husk
• global warming
• photosynthesis
• pyrolysis