A novel combined method for nitrate removal by chemical Pd–Cu/alumina bimetallic catalyst and biohydrogen produced by Rhodobacter johrii VT1 in an anaerobic, photo-fermentation process

Abstract

In this study, biohydrogen was produced by R. johrii strain VT1 using an anaerobic photo-fermentation process on low-cost industrial wastewater and then used for nitrate reduction in the presence of a chemical catalyst. The effect of substrate, light intensity, and pH on biohydrogen production was investigated. For efficient nitrate reduction, a Pd–Cu/alumina bimetallic catalyst was prepared and analyzed by XRD, FTIR, FESEM, and ICP. Accumulative biohydrogen production was 284.67 ml/h (0.409 ± 0.005 mol/m3h), with molasses, a light intensity of 5300 lux, and a pH of 9. Nitrate removal efficiency was 81.70%, and nitrogen selectivity was 94.25%. The XRD results also showed the stability of the catalyst structure during the reduction. Our study shows that this combined method is effective for nitrate removal and has the potential for large-scale work because of the affordable and sustainable green hydrogen production from wastewater. This is the first report of using biological hydrogen for harmful nitrate removal from drinking water in the presence of a chemical catalyst.