OPTIMISATION OF THE PRODUCTION OF BIOGAS FROM COW DUNG USING IRON OXIDE NANOPARTICLES

Due to the global concern about climate and environmental issues, there has been a shift to using more sustainable energy alternatives. Biogas is a major point of interest because it is produced from waste materials which are readily available. This study focuses on the production and optimisation of biogas from cow dung using magnetite (Fe₃O₄) nanoparticles. Fe₃O₄ were synthesised using the co-precipitation method with FeSO₄ and FeCl₃ solutions, and it was characterised using the Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX) analysis. The experiment was designed to get the optimal parameters using Design-Expert 7.0.0 software, giving a range of concentration of Fe₃O₄ nanoparticle concentration (–12.43 to 72.43 mg) and retention time (4–23.9 days). 13 experimental runs were conducted using 200g of cowdung in a 1:1 mixture with water to form the slurry. The results obtained indicated that the magnetite nanoparticles increased the yield of biogas for the digesters that included the NP, compared to the control. Also, it was observed that the highest gas yield was obtained at the moderate NP concentration of 30mg, indicating that excessive addition of NP may inhibit methanogenic activities. The quadratic model generated by Design- Expert revealed a good correlation between the predicted and experimental results, giving R² as 0.6423. This confirms the adequacy of the model for process optimisation. Overall, this study successfully indicated that magnetite nanoparticles can enhance the production of biogas, and the optimal conditions for this mass of cow dung are 30mg in NP concentration and a 21- day retention period