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

Area of Science:

• Environmental Science
• Biotechnology
• Chemical Engineering

Background:

• Anaerobic digestion (AD) is a key process for waste treatment and biogas production.
• Optimizing AD kinetics is crucial for efficient biogas generation.
• Graphene oxide (GO) has emerged as a potential additive to enhance biological processes.

Purpose of the Study:

• To investigate the impact of graphene oxide (GO) on the kinetic performance of anaerobic digestion (AD).
• To evaluate the effectiveness of GO across different substrates and concentrations.
• To determine the optimal conditions for GO-enhanced AD.

Main Methods:

• Modified classical batch tests to a fed-batch strategy with four GO levels.
• Utilized glucose and microcrystalline cellulose (MCC) as substrates.
• Applied first-order and modified Gompertz models to analyze kinetic performance.

Main Results:

• Significant improvement in AD kinetic performance observed from the third refeeding step for both glucose and MCC.
• 20 mg GO per g of volatile solids (VS) resulted in up to a 210% increase in the first-order rate constant (k).
• A 120% increase in maximum biochemical methane potential (BMP) rate (RMAX) was observed for MCC at the optimal GO concentration.

Conclusions:

• Graphene oxide (GO) addition demonstrably improves anaerobic digestion (AD) kinetic performance.
• The findings support the implementation of GO in continuously operated AD systems to accelerate biogas production.
• Optimized GO dosage can significantly enhance methane yield and process efficiency.