Enhancing Biohydrogen Yields: A Comparative Study of Individual and Combined Biomass Pretreatment Techniques.

Abstract

Biohydrogen production from various biomass sources using combined pretreatment methods is an emerging and cost-effective alternative energy technology. To enhance hydrogen production, a batch test was conducted involving heat treatment, ultrasonication, and acid hydrolysis of dairy whey (DW) and sugarcane bagasse (SCB). The heat-treated DW achieved a maximum cumulative hydrogen production of 153.4 ± 2.0 mL H₂/L, which is 20% higher than the untreated biomass. The physicochemical changes in both DW and SCB were analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDAX). The tools used to study the effects of pretreatments on SCB were X-ray diffraction (change in crystalline and amorphous regions) and SEM images. FTIR spectra showed the removal of hemicellulose and lignin content during pretreatments. The presence of cellulose, hemicellulose, and lignin structures in the sample of sugarcane bagasse and cellulosic fractions were indicated by the characteristic absorption bands (cm^-1) of groups shown by the FTIR spectrum for hemicellulose and lignin. SEM images showed extensive degradation of the buddle of fibers of some cellulosic fraction. FTIR spectra indicate that carbohydrates, proteins, and lipids were present in dairy whey. The EDX results indicated that untreated SCB contains 30% carbon, 13.71% oxygen, and 0.50% nitrogen. SCB underwent acid hydrolysis for 90 min at 121 °C using a 2 M concentration of H₂SO₄. The highest cumulative hydrogen production of 189.6 ± 4.3 mL H₂/L was achieved at 37 °C under co-culture conditions. Based on the findings of this study, it may be possible to produce biohydrogen from biomass in a manner that is both efficient and sustainable in the future.