This study reports on the photocatalytic activity of BiFeO3 nanoparticles on the degradation of cationic dye methylene blue (MB). BiFeO3 prepared by using carrageenan as a biotemplating method were characterised using XRD, SEM and EDX analysis. The effect of different parameters such as catalyst dosage, initial concentration of dye, reaction time, pH, and regeneration study on the removal efficiency were investigated. It was found that 12.79 mmol/L BiFeO3 exhibited 96% degradation of methylene blue at basic pH (pH 8 and pH 10) in 180 min. The catalysts were found to be negatively charged in alkaline medium hence the electrostatic charge attracted more cationic dye towards the catalytic site. Kinetic studies showed the degradation can be described according to Langmuir-Hinshelwood expression.