초록
Hydrogen (H<SUB>2</SUB>) has become a promising energy source because it is clean and has high-energy potential. The aim of this research was to enhance the H<SUB>2</SUB> production efficiency under anaerobic condition by addition of calcium ions (Ca<SUP>2+</SUP>) in a fluidized bed reactor (FBR) with immobilized cells. Ca<SUP>2+</SUP> ions were added either in the form of Ca(OH)<SUB>2</SUB> or CaCl<SUB>2</SUB>. Immobilized cells were prepared by physical adsorption with activated carbon (AC). The experiments were carried out in a FBR system. The H<SUB>2</SUB> production performance of the FBR fed with sucrose-based synthetic medium, was evaluated under various influent Ca<SUP>2+</SUP> concentrations [Ca<SUP>2+</SUP>] (50, 100 and 200 ppm) and hydraulic retention times (HRTs) (8, 6, 4 and 2 h). The peak value of 1.22 L/h-L was obtained at [Ca<SUP>2+</SUP>] 100 ppm, irrespective of the form of Ca<SUP>2+</SUP> ion added, and at the HRT of 2 h. Although the results were similar for different forms of Ca<SUP>2+</SUP> ions, the presence of Ca<SUP>2+</SUP> ions enhanced the H<SUB>2</SUB> producing bioprocess by 12-18%.