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This work aims to advance the biocarbonate concept by developing the first process to produce limonene carbonate based on ionic liquids (ILs). Conventional petroleum-derived cyclic carbonates are recognized products partially composed of CO 2 with the main drawback of the high energy consumption that imposes epoxide production. In contrast, natural epoxidable compounds, such as terpenes, stand out in the literature as a more sustainable open research line to enable CO 2 conversion processes with better sustainable indicators. Limonene, an abundant natural compound, is identified as a key terpene in the aforementioned discussion. Ammonium-based ILs are experimentally selected and optimized, after covering massive anion and cation substituent tuning, achieving high selectivity and competitive yields to limonene carbonate. The reaction-extraction platform concept, which recovers the catalyst by liquid-liquid extraction, is envisioned and developed using a rational experimental-computational approach. The work concludes with a novel process to effectively produce limonene carbonate by using an IL catalyst and water as an extracting solvent. Ultimately, taking advance of the process simulation, a CO 2 emissions assessment was conducted. Using renewable raw materials enhances the sustainability of CO 2 conversion to cyclic carbonate, reducing global warming impact compared to fossil-based epoxides. However, limonene extraction and epoxidation have a tangible impact on the overall result of CO 2 balance, turning efforts outside battery limits of the CO 2 conversion process in the search of a limonene carbonate production line with negative neat CO 2 emissions that may change the paradigm in the fixation of CO 2 through cycloaddition reactions. [Display omitted] • Effective use of terpenes as feedstock in substitution of petroleum-derived epoxides. • Development of an efficient ad hoc process to produce limonene biocarbonate to reduce energy consumption. • Development of LCA-based scenarios for limonene-based process. • New criteria to guide future CCU developments in the search of zero neat CO 2. [ABSTRACT FROM AUTHOR]

In order to use livestock manure digester liquor (LMDL) as liquid fertilizer, NaH2PO4was evaluated for its effectiveness as pH buffer in an anaerobic ammonium oxidation (anammox) reactor treating high-strength LMDL. The results show that influent total nitrogen (TN) concentration was increased from 500 to 2,200 mg/L with the addition of NaH2PO4as a pH buffer. To the best of our knowledge, this is the highest influent TN concentration for anammox reactor in treating LMDL. An average TN removal efficiency of 85% was observed in LMDL treatment without dilution. The treated effluent may be applied directly as a terrestrial liquid fertilizer, as the effluent has a suitable balance of nitrogen and phosphorus (approximately 1:1). 16S rRNA gene analysis showed thatKuenenia stuttgartiensisandUncultured bacterium clone KIST-JJY001, known as anammox bacteria, shared approximately 26% in genus level in the reactor.Uncultured bacterium clone Dok53,Uncultured bacterium clone KIST-JJY024,Uncultured bacterium clone FN-11,Uncultured bacterium clone KIST-JJY012, andUncultured bacterium clone AnSal-09, which are often detected as co-occurring bacteria, were also found in this study. [ABSTRACT FROM AUTHOR]

Abstract: We report here a concept converting carbon dioxide to biocarbonate in a biomimetic nanoconfiguration. Carbonic anhydrase (CA), the fastest enzyme that can covert carbon dioxide to bicarbonate, can be spontaneously entrapped in carboxylic acid group-functionalized mesoporous silica (HOOC-FMS) with super-high loading density (up to 0.5mg of protein/mg of FMS) in sharp contrast to normal porous silica. The binding of CA to HOOC-FMS resulted in a partial conformational change comparing to the enzyme free in solution, but it can be overcome with increased protein loading density. The higher the protein loading density, the less conformational change, hence the higher enzymatic activity and the higher enzyme immobilization efficiency (up to >60%). The released enzyme still displayed the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment, indicating that the conformational change resulted from the electrostatic interaction of CA with HOOC-FMS was not permanent. This work may provide a new approach converting carbon dioxide to biocarbonate that can be integrated with the other part of biosynthesis process for the assimilation of carbon dioxide. [Copyright &y& Elsevier]

Abstract: A pluridisciplinary approach was used to define iodine immobilization mechanisms by biocarbonates in a natural marine carbonate-bearing clayey formation. For this purpose, different techniques of observation (optical microscope, scanning electron microscope (SEM), cathodoluminescence (CL)) and of analyses (infrared spectrometry (IR), electron microprobe (EPMA), spatially resolved synchrotron-based X-ray fluorescence (μ-XRF) and X-ray diffraction (μ-XRD)) were performed on two entire and centimeter-sized carbonate shells of the Callovian–Oxfordian (160Ma) clayey formation from the ANDRA (French Radioactive Waste Management Agency) Underground Research Laboratory (Meuse/Haute Marne, France), in the Eastern part of the Paris Basin. Combined (SEM, CL, IR and μ-XRD) data indicates that the biostructure of the Rhynchonella shell is relatively well-preserved but bio-aragonite slowly transforms into calcite, whereas the bivalve shell is entirely recrystallized into diagenetic calcite and celestite. EPMA and μ-XRF data show bioaccumulation of iodine in carbonate shells, confirming previous work on present-day mollusks. EPMA analyses give evidence of iodine content up to 1200ppm in the preserved Rhynchonella shell and up to 2000ppm in recrystallized bivalve shell. μ-XRF elemental mapping shows that iodine is more homogeneously distributed in bio-calcite of the Rhynchonella shell than in recrystallized calcite of the bivalve shell, suggesting a loss of iodine during re-crystallization processes, but not a total exclusion of iodine from the carbonate structure. Combined EPMA data and μ-XRF elemental maps do not give evidence of any correlation between the iodine location and the distribution of other elements. [ABSTRACT FROM AUTHOR]