Photo-catalytic pretreatment of biomass for anaerobic digestion using visible light and Nickle oxide (NiOx) nanoparticles prepared by sol gel method

The biodegradability of lignocellulosic biomass in anaerobic digesters is the key factor that limits the biogas production. Therefore, scientists are finding the possible ways to reduce the recalcitrant lignin content of biomass that greatly hinder the digestion process. The Photo-oxidation considered advanced oxidation of organic polymers in the presence of optically active catalyst preferably metal oxide. Hence, the present study was designed to report the effects of NiOx along with visible light (350–780 nm) to oxidize the highly lignified wheat straw (WS). Specifically, the experiment was designed to pretreat WS with four different NiOx concentrations under three different exposure times. Consequently, the differentially pretreated samples were subjected to biochemical methane potentials (BMPs) and continuously stirred tank reactors (CSTRs). Further, the pretreatment with 3 wt% NiOx at 4 h light exposure showed 40% (p