Every year, massive amounts of oil-contaminated water are produced, particularly in the petrochemical industry. Accidental oil spills, in particular, represent a serious threat to human and marine life. As a result, eliminating oils from water is critical to avoiding environmental harm. Previous studies have demonstrated that activated carbon is a good adsorbent for extracting oil from polluted water. However, because of the high treatment costs, some researchers seek a replacement adsorbent for activated carbon. Biochar (BPBC) generated from discarded saba banana peels (Musa acuminata balbisiana) was utilized as an adsorbent in this study to remove diesel oil from water. 

The BPBC was synthesized using a slow pyrolysis method and characterized using SEM, EDX, FTIR, DSC, TGA, BET, contact angle analyzer, and XRD. The results showed that BPBC exhibited high porosity, thermal stability, and hydrophilic character, making it a promising adsorbent for oil-water separation and environmental remediation. The adsorption capacity of BPBC for diesel oil removal was examined in terms of adsorbent dose, pH level, salinity, and contact time. Lowering the BPBC dosage enhanced the sorption capacity. However, pH variations had little effect on adsorption. Longer contact times increased BPBC sorption capacity, emphasizing the relevance of contact time. Adsorption parameters were optimized using a reduced cubic model, and an adsorbent dose of 2.5 g, pH of 7.0, a salinity of 44,999.954 mg/L, and contact time of 240 minutes was found to be optimal for producing a sorption capacity of 5.6 mg/g.