Development of an ammonia production method for carbon-free energy generation

Ammonia has great prospects in the context of the transition to carbon-free energy. It can be used as fuel in gas turbines, fuel cells, internal combustion engines, and burned together with coal. However, industrial production of ammonia is based on the Haber-Bosh process, which involves the use of natural gas and coal, which, in this case, does not make it really carbon-free. This study proposes a method to produce ammonia, which is environmentally friendly and does not require the use of fossil fuels. It is based on the approach to adjusting the concentration of ammonium nitrogen in a biogas reactor and implies the sorption of ammonia from the gas phase with a solution of monoammonium phosphate, obtaining diammonium phosphate, and subsequently heating it with the release of ammonia. The factors influencing the extraction of ammonia from waste have been considered, as well as the influence of temperature on the release of ammonia from the solution of diammonium phosphate; the energy efficiency of the method has been assessed. With increasing temperature, the degree of ammonia and the degree of sorbent regeneration increased. Under laboratory conditions, 111 J/g of ammonia energy was spent. The higher the concentration of (NH4)2HPO4 in the solution, the less energy is required to obtain a unit of ammonia mass. The total amount of ammonia released varies depending on the temperature. Sorbent regeneration can be carried out using thermal energy obtained at a cogeneration plant. The possibility of using this method to produce ammonia at an industrial scale has been estimated by analyzing the ways of ammonia utilization as a fuel. The potential for ammonia production in the main livestock industries in Europe and the United States is up to 11,482,651.15 and 11,582,169.5 tons per year, respectively. Applying this solution also makes it possible to improve the efficiency of biogas production from waste with high nitrogen content. The proposed method of ammonia production could potentially contribute to the development of carbon-free energy

Chromatographic separation of mannitol from mixtures of other carbohydrates in aqueous solutions

The isolation of mannitol from natural sources, e.g. from plant extracts or broths, requires considerable time and effort. The separation of mannitol from aqueous solutions containing also glucose, fructose, and sucrose was tested using discontinuous preparative anion- and cation-exchange chromatography. The suitability of the application in the separation of carbohydrates and especially mannitol was tested under various conditions and using three different types of ion-exchangers. The effect of sorbent regeneration and modification on the separation was also examined using different concentrations and volumes of chemical agents. The fractions collected after the discontinuous chromatography were analysed on the content of mannitol by the high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method. The successful isolation of pure mannitol fraction, using water as a mobile phase and a combination of sodium chloride and hydroxide for sorbent regeneration, was achieved only on anion-exchange chromatography.

Direct Air Capture of CO2 with Aqueous Peptides and Crystalline Guanidines

Negative emission technologies, including direct air capture (DAC) of carbon dioxide, are now considered essential for mitigating climate change, but existing DAC processes tend to have excessively high energy requirements, mostly associated with sorbent regeneration. Here we demonstrate a new approach to DAC that combines atmospheric CO₂ absorption by an aqueous oligopeptide (i.e., glycylglycine) with bicarbonate crystallization by a simple guanidine compound (i.e., glyoxal-bis-iminoguanidine). In this phase-changing system, the peptide and the guanidine compounds work in synergy, and the cyclic CO₂ capacity can be maximized by matching the p<i>K</i>_a values of the two components. The resulting DAC process has a significantly lower regeneration energy compared to state-of-the-art solvent-based DAC technologies.

Direct Air Capture of CO2 with Aqueous Peptides and Crystalline Guanidines

Negative emission technologies, including direct air capture (DAC) of carbon dioxide, are now considered essential for mitigating climate change, but existing DAC processes tend to have excessively high energy requirements, mostly associated with sorbent regeneration. Here we demonstrate a new approach to DAC that combines atmospheric CO₂ absorption by an aqueous oligopeptide (i.e., glycylglycine) with bicarbonate crystallization by a simple guanidine compound (i.e., glyoxal-bis-iminoguanidine). In this phase-changing system, the peptide and the guanidine compounds work in synergy, and the cyclic CO₂ capacity can be maximized by matching the p<i>K</i>_a values of the two components. The resulting DAC process has a significantly lower regeneration energy compared to state-of-the-art solvent-based DAC technologies.

Unexpected Selective Gas Adsorption on a ‘Non-Porous’ Metal Organic Framework

A metal organic framework Cu(tpt)BF4·¾H2O was synthesized as a potential carbon capture material, with the aim being to exploit the Lewis base interaction of the incorporated ligand functionalities with acidic gas. The material displays high thermal stability but an exceptionally low surface area; however, this contrasts starkly with its ability to capture carbon dioxide, demonstrating significant activated diffusion within the framework. The full characterization of the material shows a robust structure, where the CO2 sorption is 120% greater than current industrial methods using liquid amine solutions; the thermal energy required for sorbent regeneration is reduced by 65%, indicating the true industrial potential of the synthesized material.