Microalgae, renowned for their high photosynthetic efficiency and minimal competition with land-based crops, hold great promise in the biofixation of CO2 from waste sources, making them valuable for diverse applications, including biofuels, food production, and biomaterials. An innovative technology, the integrated carbonate-based carbon capture and algae biofixation system is emerging as an alternative to traditional carbon capture and sequestration (CCS) methods. This closed-loop system utilizes bicarbonates as inorganic carbon sources, which can directly enter microalgae photosynthesis, subsequently regenerating carbonates for another cycle of carbon capture. This system offers significant advantages, including cost savings in carbon supply, simplified photobioreactor development, and reduced labor and energy requirements. Nevertheless, further research is essential to evaluate the suitability of various microorganisms and search for optimal growth conditions. In this study, we assessed the performance of two strains of Spirulina within the integrated system. Employing a Design of Experiments approach, we simultaneously varied temperature, bicarbonate concentration, and light irradiation while operating within a lab-scale photobioreactor. We achieved remarkable results, with a biomass productivity of 875 mg/L·d and an impressive CO2 utilization efficiency of 58%. These findings indicate a genuine opportunity for further exploration and scaling of this approach in industrial settings.
The increasing demand for sustainable agricultural practices aimed at reducing carbon dioxide emissions has driven the exploration of converting viticulture residues into biochar. This study investigates the potential technological applications of biochar as a filler for the production of electrically conductive composite materials, suitable to Bipolar Plate (BP) manufacturing. Grape seeds (GSs), defatted grape seeds (DGSs), wood stems (WSs), and whole grape seeds (WGSs) were converted into biochar samples through low-temperature (300 °C) pyrolysis for 3 or 24 h. The composition and thermal stability of biochar were evaluated through thermogravimetric analysis (TG), which provided valuable insights into interpreting the in-plane conductivity (IPC) values of the BP samples. Pyrolyzed GS and DGS biochar samples demonstrated enhanced thermal stability and conferred higher IPC values compared to WS counterparts. This indicates a clear correlation between the formation of carbon-rich structures during pyrolysis and overall electrical conductivity. In contrast, pyrolyzed WGSs produced BP samples with lower IPC values due to the presence of lipids, which were not effectively degraded by the low-temperature pyrolysis.
The new polynucleating tripodal proligand , containing thirteen nitrogen donors of four different types, was designed, synthesized, and isolated in good yield ( 60%) via a transition-metal-free triple N-arylation of tren with HXdpa (X Br or F), using or as a base ( tren tris(2-aminoethyl)amine, HXdpa 6-halogeno- -(pyridin-2-yl)pyridin-2-amine). HFdpa was prepared with excellent yield (90–92%) by reaction of 2,6-difluoropyridine with 2-aminopyridine in LiH/toluene/pyridine and was found more reactive than HBrdpa, affording higher conversion and higher yield. Use of turned out to be essential for achieving high regioselectivity and eliminating overarylation almost completely.
14 May 2024 in Beilstein Journal of Organic Chemistry
Both aryl and benzyl polybromides have gained significant importance as reactive building blocks in polymer and materials chemistry. Their preparation primarily relies on established synthetic methods using molecular bromine or N-bromosuccinimide, known for their reliability and effectiveness. However, from a sustainability perspective, these methods suffer from the generation of stoichiometric amounts of byproducts and often encounter selectivity troubles. To mitigate these issues, we extended the greener peroxide-bromide halogenation method, initially developed for monobromides, to afford aryl-cored polybromides in high yields. The same method can be employed in two variants modulated by light irradiation. This external switch can be used to selectively trigger side-chain or core halogenation.
With regards to oil-based diesel fuel, the adoption of bio-derived diesel fuel was estimated to reduce CO2 emissions by approximately 75%, considering the whole life cycle. In this paper, we present a novel continuous-flow process able to transfer an equimolar amount of CO2 (through urea) to glycerol, producing glycerol carbonate. This represents a convenient tool, able to both improve the efficiency of the biodiesel production through the conversion of waste streams into added-value chemicals and to beneficially contribute to the whole carbon cycle. By means of a Design of Experiments approach, the influence of key operating variables on the product yield was studied and statistically modeled.
In this study, we demonstrate the direct preparation of dihalo-γ-lactams featuring two distinct halogens from dichloroamides using a novel atom exchange radical cyclization (AERC) procedure. This method integrates the established atom transfer radical cyclization (ATRC) with halogen exchange in solution. The technique operates under mild conditions and requires small amounts of metallic copper, serving as both a supplemental activator and reducing agent.