TITLE:
Synthesis of Waste-Derived Biochar-Based Phase Change Material for Thermal Energy Storage Applications
AUTHORS:
Himangshu Bhowmik, Mahadi Hasan Mahim, Mandira Bhowmik, Shaon Talukdar
KEYWORDS:
Paraffin Wax, Biochar, Alumina Powder, Thermal Conductivity, PCM
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.14 No.4,
September
11,
2026
ABSTRACT: This study analyzes the transformation of organic waste into biochar, used as a supporting matrix for phase change materials (PCMs). This approach not only valorizes waste but also aligns with sustainability and the circular economy by reducing waste and offering a cost-effective solution for energy storage applications in areas such as building energy management, electronics cooling, and solar thermal systems. The work contributes not just technically but also environmentally by reducing reliance on petrochemical or synthetic supports for PCMs. Nanocomposites were synthesized using a melt blending technique by adding 1% of aluminum oxide (Al2O3) nanoparticles and 10% of biochar by weight, derived from biomass wastes: coconut fiber and water hyacinth. The composites were characterized using Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), thermal conductivity analysis and moisture absorption test. FTIR results confirmed the structural integrity and chemical compatibility of the composite, with the integration of Al2O3 nanoparticles and biochar into paraffin, which can be suitable for long-term thermal cycling applications. SEM micrographs revealed the uniform dispersion of the additives and the structural stability of the matrix. The coconut fiber biochar composite exhibited the highest thermal conductivity of 0.24 W/m·K, followed by the water hyacinth biochar of 0.23 W/m·K, and the paraffin-Al2O3 composite of 0.17 W/m·K. The moisture absorption test showed negligible weight gain after 12 hours of immersion, indicating a strong moisture resistance. Finally, the integration of agricultural and aquatic waste with PCMs not only improves thermal performance but also contributes to the sustainable waste management solution.