Periodic Reporting for period 1 - CONFETI (Green valorization of CO2 and Nitrogen compounds for making fertilizers)
Reporting period: 2023-11-01 to 2024-10-31
CONFETI proposes a more sustainable and cost-effective approach for fertiliser production, reducing reliance on traditional fossil fuel-based methods and mitigating the harmful environmental effects caused by CO2 and nitrogen pollutants. To do so, CONFETI aims to develop a self-sustaining system using photo- and electrochemical technologies that capture CO2 and nitrogen compounds directly from air, flue gas and/or residual water, converts them into urea in situ using sustainable energy sources, and delivers the resulting fertiliser autonomously without the need of storage and transport. As a result, CONFETI promotes circular economy and sustainable agricultural practices, while tackling four critical global challenges that are major contributors to climate change, environmental degradation and the inequality between countries: rising CO2 emissions, energy demand, food scarcity and nitrogen pollution.
During the 1st year of the project, work on the different components of the CONFETI’s prototype for fertilizer production has been conducted in parallel:
(1) We have developed several key components of the electrolyser for urea production from CO2 and N-compounds. Three families of green solvents combining good CO2 sorption properties with high ionic conductivities based on Ionic Liquids (ILs) were examined for this purpose: 7 commercially available ILs, 1 bio-based IL, and 15 synthesised ILs based on aprotic heterocyclic anions (AHA ILs), which were then immobilised into solid (bio)polymer membranes. After implementing different methodologies for determining the CO2 capture efficiency and speciation of these materials, we obtained very positive results for AHA IL-based membranes (capture up to 4.0 mg CO2/g membrane directly from air in about 5 min and long-term stability). Second, different classes of liquid and solid electrolytes have been explored for electrolyser operation. Liquid aqueous electrolytes have been optimised to favour urea production (1.34 µmol/cm²·h at Eapp = -1.5 V vs Ag/AgCl). Interestingly, for NO₃⁻-containing ILs and membranes, urea production could be observed at relatively low voltages (-1.77 V vs Ag/AgCl) and with significant current densities (up to 85 mA/cm²). Third, a range of electrocatalysts have been prepared, including metal-containing N-doped carbon materials (Ni, Ag, Cu and In), VO-InOOH, quaternary chalcohalide semiconductors, and ternary II-III2-VI4 colloidal nanocrystals. Combined experimental and computational efforts are under way to design and produce better electrocatalysts.
(2) For powering the electrolyser, work has been carried out to optimise the performance of soil microbial fuel cells (SMFCs) in terms of soil type, bioanode preparation (co-immobilisation of bacteria and redox mediators in silk) and cell configuration (parallel stacks). Moreover, printed circuit boards have been successfully developed and tested for both storing the energy provided by SMFCs and, if necessary, solar panels as well as powering and controlling the electrolyser at low voltage ranges.
(3) For valorising the residual nitrates generated upon soil fertilisation, a library of photocatalysts were synthesised at a large scale (> 5 g). The photocatalytic activity for nitrate reduction of most of these materials has been tested at the lab and pilot reactor scales, obtaining very successful results for the TiO2-CuO system: total NO₃⁻ conversion with 78.7% selectivity for NH₄⁺ formation after 4 hours of irradiation (50 kJ/L).
In parallel to these scientific-technological activities, a life cycle assessment of the materials and technologies developed is under progress to allow identification and minimisation of their environmental impact, which so far has focused on the CO2 sorbents prepared.
(1) We have developed several key components of the electrolyser for urea production from CO2 and N-compounds. Three families of green solvents combining good CO2 sorption properties with high ionic conductivities based on Ionic Liquids (ILs) were examined for this purpose: 7 commercially available ILs, 1 bio-based IL, and 15 synthesised ILs based on aprotic heterocyclic anions (AHA ILs), which were then immobilised into solid (bio)polymer membranes. After implementing different methodologies for determining the CO2 capture efficiency and speciation of these materials, we obtained very positive results for AHA IL-based membranes (capture up to 4.0 mg CO2/g membrane directly from air in about 5 min and long-term stability). Second, different classes of liquid and solid electrolytes have been explored for electrolyser operation. Liquid aqueous electrolytes have been optimised to favour urea production (1.34 µmol/cm²·h at Eapp = -1.5 V vs Ag/AgCl). Interestingly, for NO₃⁻-containing ILs and membranes, urea production could be observed at relatively low voltages (-1.77 V vs Ag/AgCl) and with significant current densities (up to 85 mA/cm²). Third, a range of electrocatalysts have been prepared, including metal-containing N-doped carbon materials (Ni, Ag, Cu and In), VO-InOOH, quaternary chalcohalide semiconductors, and ternary II-III2-VI4 colloidal nanocrystals. Combined experimental and computational efforts are under way to design and produce better electrocatalysts.
(2) For powering the electrolyser, work has been carried out to optimise the performance of soil microbial fuel cells (SMFCs) in terms of soil type, bioanode preparation (co-immobilisation of bacteria and redox mediators in silk) and cell configuration (parallel stacks). Moreover, printed circuit boards have been successfully developed and tested for both storing the energy provided by SMFCs and, if necessary, solar panels as well as powering and controlling the electrolyser at low voltage ranges.
(3) For valorising the residual nitrates generated upon soil fertilisation, a library of photocatalysts were synthesised at a large scale (> 5 g). The photocatalytic activity for nitrate reduction of most of these materials has been tested at the lab and pilot reactor scales, obtaining very successful results for the TiO2-CuO system: total NO₃⁻ conversion with 78.7% selectivity for NH₄⁺ formation after 4 hours of irradiation (50 kJ/L).
In parallel to these scientific-technological activities, a life cycle assessment of the materials and technologies developed is under progress to allow identification and minimisation of their environmental impact, which so far has focused on the CO2 sorbents prepared.
From a scientific perspective, key innovations have been realised in the capture and valorisation of CO2 and N-compounds through the development of advanced materials and technological systems. CONFETI team has already prepared several solid-state materials for CO2 that can directly capture CO2 from air based on polymeric ionic liquid membranes, developed new electrolyte formulations compatible with CO2 capture and reduction as well as NO3- diffusion and urea production, and synthesised electrocatalysts and electrode materials for urea production. To integrate these components, two lab-scale portable electrolysers have been designed and are currently under fabrication, which will be self-powered by soil microbial fuel cells (SMFCs). For this, the performance of state-of-the-art SMFCs must be enhanced, for which we have identified optimised soils, microorganisms, bioanodes and cell configuration. In addition, the electronics that allows electrolyser control with SMFCs has been manufactured and tested. As for the sun-driven valorisation of residual N-compounds, a series of photocatalysts to reduce NO3- into NH4+ have been satisfactorily tested on the lab and pilot plant scales. The first semi-portable component parabolic collector (CPC) photoreactor to implement this process has been designed and is being assembled for operating on the field. Based on these results, IPR protection through three patent applications is under progress, for which the support from the technology transfer offices from each partner is crucial.
Once CONFETI is completed, important efforts will be devoted to tackling technological, market and investment barriers as well as to identify of a list of potential customers interested in the technology. In parallel with close-to-market development, the main goal will be to improve and scale up the technology for in-field production and delivery of fertilisers. To reach this goal, CONFETI will seek to benefit from EU funding programs such as EIC Transition/Accelerator, as well as national
Once CONFETI is completed, important efforts will be devoted to tackling technological, market and investment barriers as well as to identify of a list of potential customers interested in the technology. In parallel with close-to-market development, the main goal will be to improve and scale up the technology for in-field production and delivery of fertilisers. To reach this goal, CONFETI will seek to benefit from EU funding programs such as EIC Transition/Accelerator, as well as national