Effectiveness of banana peels as an affordable biosorbent for heavy metals and microbial pathogens removal from municipal wastewater

Abstract Conventional heavy metal and pathogen removal processes may be costly and inefficient; thus, natural, environmentally friendly alternatives are becoming more popular. Therefore, this study evaluates banana peels as efficient and cost-effective biosorbent to remove copper (Cu), zinc (Zn), lead (Pb), and microbial pathogens from municipal wastewater using batch adsorption at two pyrolysis temperatures (600 °C and 800 °C). The pH, contact length, and peel dosage were all carefully adjusted to optimize removal efficiency. The biosorbent’s surface was characterized using the BET surface area analyzer, thermo gravimetric analysis (TGA), Fourier‑transform infrared spectroscopy (FTIR) peak analysis, and energy dispersive X-Ray spectroscopy (EDS). The banana peel biosorbent demonstrated high adsorption capacity, particularly for Cu, Pb, and Zn, with removal rates above 99.9% under optimal conditions. The banana peel biosorbent showed high removal efficiency for the three heavy metals (Cu + 2 , Zn + 2 , and Pb + 2 ), achieving 86.6, 97.5, and 100%, respectively, under optimal conditions from municipal and 100% removal efficiency for all three heavy metals from industrial wastewater. EDS revealed the presence of carbon, oxygen, magnesium, potassium, silica, and other minor elements on the peels’ surfaces. FTIR spectrometry findings demonstrate the occurrence of carboxylic acid and aliphatic groups on the peels’ surfaces. TGA traces indicated moisture loss and the development of several light molecules, including water. The removal efficiency of total coliforms (TC), fecal coliforms (FC), E. coli , Staphylococci , and Candida species was 47.27, 41.66, 41.66, 45, and 23%, respectively, from real sewage using 700 mg/L of the prepared banana peels biosorbent with a one-hour contact time. These findings suggest that banana peels might be a viable green solution for heavy metal detoxification and pathogen removal in water treatment, offering a more sustainable alternative to standard methods while saving electricity, time, and cost.