Effectiveness of CO2 - Sorbent Coated Membrane for Improving Dark Fermentative Hydrogen Production

Dark fermentative hydrogen production (bioH₂) can be significantly impaired by hydrogen accumulation in the reactor headspace and its re-dissolution in the culture medium, where CO₂ and NADH may be diverted to succinate and fumarate formation, reducing hydrogen yields. To mitigate this, the study investigated the effect of removing headspace CO₂ using calcium oxide (CaO) sorbent impregnated into polyvinylidene fluoride (PVDF) membranes during dark fermentation of banana-based feedstock. Reactors equipped with membranes impregnated with 1 M CaO produced 15.6% and 11.6% higher hydrogen yields than those with non-impregnated membranes and with 2 M CaO-impregnated membranes, respectively. CO₂ yield and loss in membrane storage modulus were 74.5 ml/g VS and 40% for 1 M CaO-impregnated membranes, compared to 79.9 ml/g VS and 28% for 2 M CaO-impregnated membranes, indicating that 1 M CaO loading provided more efficient CO₂ adsorption. The improved hydrogen yield with CaO-impregnated membranes demonstrates the effectiveness of membrane-based headspace CO₂ capture and suggests possible commercial applicability if further optimized. These findings contribute to advancing hydrogen energy technology via more efficient biohydrogen production.