TiO2 supported natural zeolites as biogas enhancers through photocatalytic pre-treatment of Miscanthus x giganteous crops. (15th August 2020)

• Record Type: Journal Article
• Authors: Tedesco, S.; Hurst, G.; Imtiaz, A.; Ratova, M.; Tosheva, L.; Kelly, P.
• Is Part Of: Energy. Volume 205(2020)
• Publication Date: 2020-08-15
• Subjects: Biogas -- Anaerobic digestion -- Lignocellulosic -- Photocatalysis -- Pretreatment -- Zeolites; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.117954
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Miscanthus giganteous is probably the most fast growing and low nutrient bioenergy crop among lignocellulosic feedstocks. Despite its significant content in fermentable sugars, currently Miscanthus biomass is not used for biogas/methane production due to the high-lignin and low moisture content in the winter/spring harvest as well as cellulose crystallinity, which limit access to enzymatic action for all lignocellulosic feedstock. This study identified that a photocatalytic pretreatment prior to anaerobic digestion helps increase the substrate's biodegradability by oxidising the lignin fraction, leading to increased methane yield up to 46% compared to the untreated. A novel photocatalyst was manufactured by reactive magnetron-sputtering deposition of TiO2 particles onto natural zeolite supports, which provided important trace elements for the anaerobic digestion process and retained a large surface area that acted as biofilm to boost growth of the microbial community. A load of 2% w/w catalyst in the bioreactor after 3 h of photocatalytic treatment led to 220 mLN gVS −1, with a net energy balance that is achieved for the whole process when treating the dispersed phase suspension at concentrations above 10 g m − 3 . Highlights: Photolysed Miscanthus giganteous can yield up to 100 ml gVS −1 extra CH4 . TiO2 coated zeolites as photocatalysts help reduce NH3 in the reactor. Natural zeolites provide microbial nutrients such as Na, Mg, Al, Si, K, Ca, and Fe. A positive energy balance of UV treatment is found for substrate above 10.1 g m −3 .