Enhanced methane production kinetics by graphene oxide in fed-batch tests

Abstract

The study aims to prove that the addition of graphene oxide (GO) improves anaerobic digestion (AD) kinetic performance. Classical batch tests were modified to a fed-batch strategy at four GO levels while using two substrates (glucose and microcrystalline cellulose (MCC)). First-order and modified Gompertz models were respectively applied to evaluate the kinetic performance. The results showed significantly (p < 0.05) improved kinetic from the third refeeding step for both substrates. 20 mg GO per g of volatile solids (VS) led to an increase of up to 210% for the first-order rate constant (k) and up to 120% for maximum biochemical methane potential (BMP) rate (RMAX) compared to control for glucose and MCC, respectively. The findings of this work suggest the implementation of GO in continuously operated systems to accelerate the AD process