Comprehensive CO2 reduction and methane purification in anaerobic fermentation bioreactors via a hybrid approach of photosynthetic bacteria and chemical adsorbents
Comprehensive CO2 reduction and methane purification in anaerobic fermentation bioreactors via a hybrid approach of photosynthetic bacteria and chemical adsorbents
Technology title
Comprehensive CO2 reduction and methane purification in anaerobic fermentation bioreactors via a hybrid approach of photosynthetic bacteria and chemical adsorbents
Technology overview
The technology invention approach: to prevent MgCO3 shell formation, a biomimetic strategy inspired by the Namib Desert beetle was employed, utilising a mix of hydrophilic and hydrophobic surface properties to enhance CO2 diffusion and capture efficiency. Experimental Validation and Efficiency – CO2 removal rate: The aqueous MgO-Mg(OH)2 solution (S2) demonstrated a 100% CO2 removal within 24 hours, compared to the solid MgO powder (S3) which retained only 5% CH4 after 10 hours, and PNSB (S1) achieving a 40% CO2 reduction over 10 days.
Comparison with Existing Technologies and Hybrid Approach – Efficiency Improvement: the study’s hybrid strategy, combining rapid CO2 removal (S2) with nutrient recovery (S1 PNSB), potentially reduces bioreactor processing time from 10 days (using S1 alone) to just 1 day with S2, marking a 1000% efficiency improvement.
Practical Implications and Future Directions -integration into Existing Systems: The MgO-Mg(OH)2 composites can be seamlessly integrated into existing bioreactor setups, offering a scalable and efficient solution for biogas purification without compromising methane content.
By focusing on the critical parameters and summarising the core achievements of the study, this condensed overview highlights the technological advancements and potential of MgO-Mg(OH)2 composites in methane purification processes.
Technology specifications
MgO-based composites have been identified as a viable CO2 absorbent, due to its high theoretical CO2 capture capacity (1100 mg CO2/g adsorbent). However, the unmodified MgO has a relatively low CO2 adsorption capacity, for example, 8.8 mg/g for commercial MgO at 50藲C, whereas the porous MgO generated by thermal breakdown of Mg(OH)2 show CO2 removal capability of 33 mg/g.
By reacting with CO2, MgO particles produce MgCO3, which forms an impermeable barrier around the unreacted MgO particles and hinders CO2 molecule diffusion. We took a cue from a genus of Namib Desert beetles’ water-harvesting techniques to get around the carbonate blocking effect. The back of the Stenocara beetle is covered with a variety of non-waxy hydrophilic bumps that are surrounded by a hydrophobic wax-coated background. Water production and adsorption are facilitated by the alternative hydrophobic and hydrophilic surface domains. According to recent findings, combining strong CO2 adsorbents (e.g., MgO) and weak CO2 adsorbents (e.g., Mg(OH)2) in a well-structured manner can significantly enhance the practical CO2 adsorption capacity. However, due to the limited interaction between CH4 and the surface OH– group on the Mg(OH)2 surface, the adsorption of CH4 is expected to remain low.
Considering these insights, the present study proposes the application of MgO-Mg(OH)2 composite as chemical absorbents for CO2 and CH4 separation in biogas. The interweaving of these materials offers the potential for improved CO2 capture efficiency while acknowledging the inherent limitations in CH4 adsorption resulting from the weaker interaction with the Mg(OH)2 surface. Besides, as CO2 assimilation by microalgae or anaerobic photosynthetic bacteria is a rapidly growing technology for energy saving and environmentally friendly. We conducted our research in photobioreactors using purple non sulphur bacteria (PNSB) and MgO-Mg(OH)2 composite materials to upgrading methane gas produced by a pig farm.
Sector
This invention is applicable to the agriculture sector, particularly pig farming and bioenergy.
Market opportunity
- Rapid-growth biogas upgrading market: Increasing demand for low-cost, low-energy CO鈧 removal technologies in agricultural biogas plants
- Seamless integration into existing bioreactor and gas-cleaning systems lowers capital barriers
Applications
Key applications include enhancing CO鈧 removal, methane purification, and nutrient recovery in biogas plants, agricultural facilities, and waste-treatment centres. The technology can also be adapted for customised biogas-upgrading solutions in sectors such as food processing, breweries, and wastewater treatment, supported by monitoring systems, replenishment packs, and integration services for optimal performance.
Customer benefits
The technology enhances methane purity, supports nutrient recovery, and improves overall operational efficiency.
Technology readiness level
TRL 7
Ideal collaboration partner聽
Ideal collaboration partners include biogas technology providers and system integrators, as well as agri-tech or energy operators.
Collaboration mode
This technology is suitable for multiple collaboration modes, including R&D Collaboration, licensing and IP acquisition.