Aman, Aan Mohammad Nusrat
(2025)
Evaluation of biochar from palm oil waste as a carbon sink and as sustainable cement replacement in building materials.
PhD thesis, University of Nottingham.
Abstract
Over the years, there has been a high demand of concrete in the construction industry due to its strength and durability. However, the production of cement, a key component of concrete, has caused high carbon dioxide emissions, negatively affecting the environment. To address this issue, recent research has explored sustainable supplementary cementitious material such as biochar, which offers increased strength and enhanced properties for concrete and mortar composites. This research focuses on the usability, efficiency, and sustainability of palm oil waste biochar as a cement replacement for carbon sequestration. The selected biochar palm kernel shell and empty fruit bunch were produced through pyrolysis. By recycling palm oil waste and converting it into biochar for construction, this approach promotes sustainable practices within the palm oil industry. This study investigates both the optimisation of biochar production through pyrolysis and its utilisation as a supplementary cementitious material. Response surface methodology was used to optimise pyrolysis parameters. The optimised pyrolysis parameters are 409°C, 15°C/min, 120 minutes for palm kernel shells and 455°C, 15°C/min, 20 minutes for empty fruit bunch. Cement replacement from 1 to 8% was casted with biochar mortar composites and mechanically tested through compressive strength, density, porosity, water absorption and flexural strength to understand the behaviour of biochar with cement. Mortar composites with 4% empty fruit bunch biochar pyrolysed at 455°C were found to be the optimum percentage with improved mechanical properties. Concrete composites with 4% biochar were compared and evaluated by the same mechanical tests. The concrete composites with 4% palm kernel shells pyrolysed at 409°C proved to be the optimum mix.
The carbon dioxide sequestration potential of the biochar, biochar concrete and the mortar composites were tested and analysed. The results show that palm kernel shell biochar, which was pyrolysed at 409°C had the highest carbon dioxide sequestration potential. Both biochar mortar and concrete composites also showed potential, but this was mainly due to physical adsorption rather than chemical adsorption within the tested time frame. Finally, to assess the environmental impact, life cycle assessment was conducted for the biochar mortar and concrete composite using the OpenLCA software. All composites showed a decrease in environmental impact compared to the control. The composite with 4% empty fruit bunch pyrolysed at 500°C had the lowest impact of 17.2% for mortar and 38.1% for concrete in reference to the control. Based on the combined evaluation of enhanced mechanical properties and carbon sequestration potential, the optimised biochar from both biomass sources, palm kernel shells and empty fruit bunch are proposed as an effective sustainable replacement of cement. The approach by this research determines the importance and feasibility of using a specific type of biochar as a carbon sink and as a supplementary cementitious material. The findings highlight that the utilisation of palm oil waste biochar as a supplementary cementitious material will enhance mechanical properties, promote waste management and additionally reduce the use of landfill.
Actions (Archive Staff Only)
 |
Edit View |
Tools
Tools
![[thumbnail of Aman, Aan_20005899_Final.pdf]](https://eprints.nottingham.ac.uk/style/images/fileicons/application_pdf.png "Aman, Aan_20005899_Final.pdf")