This study focused on CO₂-triggered phase separation in concentrated dispersions of mono-, di-, and triaminated silica for CO₂ capture, based on the hypothesis of reduced regeneration energy coupled with the formation of a CO₂-rich, water-lean sediment. The sedimentation of the CO₂-rich and CO₂-lean dispersions was studied using time-resolved optical transmittance measurements. The CO₂ capacity, reaction rate, diffusivity, and solubility of the dispersions were also studied. The involved CO₂-amine chemistry was studied by using infrared (IR) and cross-polarization solid-state ¹³C and ¹⁵N NMR spectroscopy, and the fluid behavior of the dispersions was studied by rheology. The aminated silica was of the SBA-15 type and characterized by N₂ adsorption and desorption experiments, thermogravimetric analysis, powder X-ray diffraction, scanning and transmission electron microscopy, and crosspolarization solid-state ²⁹Si NMR spectroscopy. The derived energy balances for a simplified process indicated that the regeneration of the CO₂-rich sediments results in an energy demand similar to that of 30 wt % ethanolamine (MEA) in water. The bounds of the energy balances were found to be limited by the somewhat low CO₂ capacities of the dispersions, which underscores the need for increasing the amino group density of the dispersions in future efforts. The observed changes in transmittance between the CO₂-lean and CO₂-loaded dispersions showed that sedimentation occurred within the first 10 min for the CO₂-loaded dispersions, while the CO₂-lean dispersions exhibited no change in transmittance after 60 min. The analysis of the pressure decay curves of the partial CO₂ pressure showed that the absorption rates of the dispersions were smaller than those of monoethanolamine (MEA) in water but were similar to the absorption rates of 2-amino-2-methyl-1-propanol (AMP) in water. The IR spectroscopic analysis was consistent with the formation of ammonium carbamates at a low CO₂ loading and the subsequent formation of HCO₃^– at a higher loading. The flow curves displayed rich and complex fluid behavior, which was strongly affected by the capture of CO₂ by the dispersions. Phenomena such as shear thinning, jamming, and thixotropy were observed.

Packed-bed CO₂ capture systems often suffer from high pressure drops, limiting their scalability and efficiency. To address this limitation, we developed an aminated, highly filled paper adsorbent designed for a structured configuration with low pressure drop. Four commercial activated carbons (ACs) were screened as paper fillers based on their low-pressure CO₂ uptake at 20°C, identifying DARCO® activated charcoal (AC-DC) as the optimal candidate. Paper sorbents were fabricated using 80wt.% AC-DC as filler and 20wt.% cellulose nanofibrils as binder, followed by polyethyleneimine (PEI) amination. Two amination routes were compared: i) post-impregnation of pristine AC paper (post-PEI-AC paper), and (ii) papermaking from pre-aminated AC-DC (pre-PEI-AC paper). The former markedly outperformed the latter, achieving a static CO₂ uptake of 0.46 mmol/g at p_CO2=0.04 kPa (400 ppm) and 20°C, which decreased by 58 % at 50°C but increased by 77 % at 100 kPa. When structured into alternating flat-corrugated stacks to form channel-like pathways, the post-PEI-AC paper exhibited a 7.5-fold lower pressure drop than loose-fill beds at a superficial velocity of 1.43 m/s. This advantage is expected to grow at higher velocities as the packed beds followed a superlinear pressure-drop-velocity dependence, contrasting with the linear trend for the paper adsorbents under laminar flow. These findings demonstrate the feasibility and potential of aminated and highly filled paper adsorbents for efficient CO₂ capture. The structured design combines high sorbent productivity with low pressure drop, offering a promising and scalable pathway toward energy-efficient direct air capture technologies.

Engineering the building blocks in metal–organic materials is an effective strategy for tuning their dynamical properties and can affect their response to external guest molecules. Tailoring the interaction and diffusion of molecules into these structures is highly important, particularly for applications related to gas separation. Herein, we report a vanadium-based hybrid ultramicroporous material, VOFFIVE-1-Ni, with temperature-dependent dynamical properties and a strong affinity to effectively capture and separate carbon dioxide (CO₂) from methane (CH₄). VOFFIVE-1-Ni exhibits a CO₂ uptake of 12.08 wt % (2.75 mmol g^–1), a negligible CH₄ uptake at 293 K (0.5 bar), and an excellent CO₂-over-CH₄ uptake ratio of 2280, far exceeding that of similar materials. The material also exhibits a favorable CO₂ enthalpy of adsorption below −50 kJ mol^–1, as well as fast CO₂ adsorption rates (90% uptake reached within 20 s) that render the hydrolytically stable VOFFIVE-1-Ni a promising sorbent for applications such as biogas upgrading.

Lignin is a group of cell wall localised heterophenolic polymers varying in the chemistry of the aromatic and aliphatic parts of its units. The lignin residues common to all vascular plants have an aromatic ring with one para hydroxy group and one meta methoxy group, also called guaiacyl (G). The terminal function of the aliphatic part of these G units, however, varies from alcohols, which are generally abundant, to aldehydes, which represent a smaller proportion of lignin monomers. The proportions of aldehyde to alcohol G units in lignin are, nevertheless, precisely controlled to respond to environmental and development cues. These G aldehyde to alcohol unit proportions differ between each cell wall layer of each cell type to fine-tune the cell wall biomechanical and physico-chemical properties. To precisely determine changes in lignin composition, we, herein, describe the various methods to detect and quantify the levels and positions of G aldehyde units, also called coniferaldehyde residues, of lignin polymers in ground plant samples as well as in situ in histological cross-sections.

Volatile organic compounds (VOCs) are often hazardous and need commonly to be removed from gas mixtures. Capture on activated carbon (AC) is one approach to achieving this. We hypothesized that the smallest pores on ACs and the inclusion of inorganic phosphates could enhance the low gas pressure uptake of two typical VOCs (acetone and isopropanol). To test this hypothesis, ACs were prepared by chemical activation of hydrochars with H3PO4 or a mixture of FeCl3 and H3PO4. The hydrochars had been prepared by hydrothermal carbonization of glucose. The ACs were characterized by XRD, IR, TGA, and the adsorption of N2, CO2, H2O, acetone, and isopropanol. The results showed that the ACs had comparably high adsorption of acetone and isopropanol at low vapor pressures. The low-pressure uptake (at 0.03 kPa) of isopropanol and acetone had values of up to 3.4 mmol/g and 2.2 mmol/g, respectively. This suggests that ACs containing iron phosphate could be of relevance for adsorption driven removal of VOC. It was also observed that the external surface area of the ACs containing iron phosphates increased upon secondary heat treatment in N2.

Analyses for organic fingerprints on fossilized plant cuticles and pollen hold valuable chemotaxonomic and palaeoclimatic information, and are thus becoming more utilized by palaeobotanists. Plant cuticle and pollen composition are generally analyzed after standard treatments with several chemical reagents for mineral and mesophyll removal. However, the potential alterations on the fossil composition caused by the different cleaning reagents used are still poorly understood. We tested the effects of commonly used palaeobotanical processing methods on the spectra of fossilized cuticles from successions of Late Triassic to Early Jurassic age, including the gymnosperms Lepidopteris , Ginkgoites , Podozamites , Ptilozamites and Pterophyllum astartense. Our study shows that standard chemical processing caused chemical alterations that might lead to erroneous interpretation of the infrared (IR) spectra. The difference in pH caused by HCl induces changes in the proportion between the two bands at similar to 1720 and 1600 cm(-1) (carboxylate and C-C stretch of aromatic compounds) indicating that the band at similar to 1610 cm(-1) at least partially corresponds to carboxylate instead of C-C stretch of aromatic compounds. Interestingly, despite being used in high concentration, HF did not cause changes in the chemical composition of the cuticles. The most alarming changes were caused by the use of Schulze's solution, which resulted in the addition of both NO2 and (O)NO2 compounds in the cuticle. Consequently, a new protocol using H2CO3 , HF, and H2O2 for preparing fossil plant cuticles aimed for chemical analyses is proposed, which provides an effective substitute to the conventional methods. In particular, a less aggressive and more sustainable alternative to Schulze's solution is shown to be hydrogen peroxide, which causes only minor alteration of the fossil cuticle's chemical composition. Future work should carefully follow protocols, having in mind the impacts of different solutions used to treat leaves and other palaeobotanical material such as palynomorphs with aims to enable the direct comparison of spectra obtained in different studies.

Multifunctional, biobased materials processed by means of additive manufacturing technology can behighly applicable within the water treatment industry. This work summarizes a scalable and sustainablemethod of anchoring a green metal–organic framework (MOF) SU-101 onto the surface of 3D printed,biobased matrices built of polylactic acid (PLA)-based composites reinforced with TEMPO-oxidizedcellulose nanofibers (TCNFs). The two tested anchoring methods were hydrolysis via either concentratedhydrochloric acid treatment or via a photooxidation reaction using UV–ozone treatment. Stabledeposition of SU-101 distributed homogenously over the filter surface was achieved and confirmed byFT-IR, XPS and SEM measurements. The obtained 3D printed and functionalized MOF@PLA andMOF@TCNF/PLA (aka MOF@Cell) filters exhibit high efficiency in removing heavy metal ions from mineeffluent and methylene blue from contaminated water, as demonstrated through batch adsorptionexperiments. In addition to their potential for removal of contaminants from water, the MOF@Cell filtersalso exhibit excellent mechanical properties with a Young's modulus value of about 1200 MPa,demonstrating their potential for use in practical water treatment applications. The MOF@Cell filterswere able to maintain their structural integrity and filtration performance even after multiple cycles ofuse and regeneration. This study highlights the potential of multifunctional, biobased materials processedby additive manufacturing technology as a cost-effective alternative to traditional water treatmentmethods. The MOF@Cell filters presented in this study demonstrate high efficiency, durability, andreusability, making them promising candidates for practical applications in the modern water treatmentindustry.

A heterogenized alternative to the homogeneous precapture of CO2 with amines and subsequent hydrogenation to MeOH was developed using aminated silica and a Ru-MACHOTM catalyst. Commercial mesoporous silica was modified with three different amino-silane monomers and used as support for the Ru catalyst. These composites were studied by TEM and solid-state NMR spectroscopy before and after the catalytic reaction. These catalytic reactions were conducted at 155 degrees C at a H-2 and CO2 pressures of 75 and 2 bar, respectively, with the heterogeneous system (gas-solid) being probed with gas-phase infrared spectroscopy used to quantify the resulting products. High turnover number (TON) values were observed for the samples aminated with secondary amines.

Microporous polyureas can be highly stable, but isocyanates or phosgene are normally used for the synthesis. Here, it was postulated and demonstrated that 1,1′-carbonyl diimidazole (CDI) could be used for the synthesis. By reacting tetrakis(4-aminophenyl)methane with CDI, a series of new polyureas with ultramicropores (pores <0.7 nm) were synthesized. To tailor thermal properties and porosity, the ratio of tetraamine-to-CDI and the reaction temperature were varied. The CO₂ adsorption capacities (with values up to 0.74 mmol/g at 0.15 bar/273 K and 1.91 mmol/g at 1 bar/273 K) were ascribed to the ultramicroporosity. The CO₂-based Dubinin-Radushkevich surface areas reached 395 m²/g (at 273 K), while the N₂-based BET surface areas (at 77 K) were small. The apparent CO₂-over-N₂ selectivity was also high for the polymers at 273 K with estimated values of 31–92 for 15/85 v/v mixtures of CO₂ and N₂. This high selectivity was ascribed to the kinetic hindrance of N₂ diffusion. It was noted that one of the polymers changed color irreversibly upon heating. In conclusion, it was shown that CDI and amines could be used to synthesize ultramicroporous polyureas, and that these polymers can exhibit irreversible thermochromism. This thermal effect was attributed to the electron-rich urea moieties, aromatic units, and conjugation.

The biopolymer lignin is deposited in the cell walls of vascular cells and is essential for long-distance water conduction and structural support in plants. Different vascular cell types contain distinct and conserved lignin chemistries, each with specific aromatic and aliphatic substitutions. Yet, the biological role of this conserved and specific lignin chemistry in each cell type remains unclear. Here, we investigated the roles of this lignin biochemical specificity for cellular functions by producing single cell analyses for three cell morphotypes of tracheary elements, which all allow sap conduction but differ in their morphology. We determined that specific lignin chemistries accumulate in each cell type. Moreover, lignin accumulated dynamically, increasing in quantity and changing in composition, to alter the cell wall biomechanics during cell maturation. For similar aromatic substitutions, residues with alcohol aliphatic functions increased stiffness whereas aldehydes increased flexibility of the cell wall. Modifying this lignin biochemical specificity and the sequence of its formation impaired the cell wall biomechanics of each morphotype and consequently hindered sap conduction and drought recovery. Together, our results demonstrate that each sap-conducting vascular cell type distinctly controls their lignin biochemistry to adjust their biomechanics and hydraulic properties to face developmental and environmental constraints.