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CO 2 is the main pollutant in biogas, reducing its calorific value. Among various technological methods to eliminate carbon dioxide from biogas, membrane separation technology stands out for large-scale industrial biogas purification due to its advantages. The selection of membrane material and preparation process are key factors in membrane separation technology. In this study, a premixing process was initially used to blend different masses of packed molecular sieves TS-1 (or ZSM-5) and cellulose derivatives (ethyl cellulose, cellulose acetate) separately. These mixtures were then coated onto porous PVDF substrates using a coating process to create various bilayer hybrid composite membranes. Among these, PVDF/EC-ZSM-5 (containing 15 % ZSM-5) bilayer hybrid composite membrane is the most fitting. For CO 2 /CH 4 gas mixtures, the gas selectivity of this membrane surpassed Robeson's 1991 standard line (the CO 2 permeability was 597.48 Barrer, and the CO 2 /CH 4 selectivity was 9.14). Overall, this composite membrane, made for the first time from PVDF, ZSM-5, and EC, is expected to be a promising CO 2 selective separation membrane material for biogas purification in large-scale industrial processes due to its simple production process., Competing Interests: Declaration of competing interest The authors report no declarations of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Developing artificial leaves to address the environmental burden of CO 2 is pivotal for advancing our Net Zero Future. In this study, we introduce EcoLeaf, an artificial leaf that closely mimics the characteristics of natural leaves. It harnesses visible light as its sole energy source and orchestrates the controlled expansion and contraction of stomata and the exchange of petiole materials to govern the rate of CO 2 sequestration from the atmosphere. Furthermore, EcoLeaf has a cellulose composition and mechanical strength similar to those of natural leaves, allowing it to seamlessly integrate into the ecosystem during use and participate in natural degradation and nutrient cycling processes at the end of its life. We propose that the carbon sequestration pathway within EcoLeaf is adaptable and can serve as a versatile biomimetic platform for diverse biogenic carbon sequestration pathways in the future., (© 2024. The Author(s).)

Reuse of biochar residues after lignin degradation will not only save costs but also reduce the pollution, protect and improve the environment. In this study, biochar residue (BR) after peanut shell lignin selective depolymerization on ZSM-5 were recycled, and characterized by Scanning Electron Microscopy, Surface area & pore size distribution analyzers, Thermogravimetric Analysis. Subsequently, a series of hybrid matrix membranes were prepared using ethyl cellulose as the matrix and biochar residue after depolymerization under different reaction conditions as the filler. The separation performance of BR/EC membranes for CO 2 /CH 4 mixed gas and CO 2 /N 2 mixed gas was measured. The results showed that the gas separation membranes prepared with biochar residue (3 h, 300 °C) as filler had good gas separation characteristics. The resulting mixed-matrix membrane exhibited a permeability of 66.00 Barrer for CO 2 and selectivities of 9.97 for CO 2 /CH 4 . Meanwhile, the resulting mixed-matrix membrane exhibited a permeability of 79.53 Barrer for CO 2 and selectivities of 20.01 for CO 2 /N 2 . Both exceed the upper limit of known pure EC membranes. Therefore, the use of biochar residue after ZSM-5 depolymerization as a filler for gas separation membranes is a feasible way. Furthermore, the membrane is well stabilized, proving its good potential for industrial applications., (Copyright © 2022. Published by Elsevier B.V.)

Old corrugated containers with low recyclability were used as raw materials to synthesize a series of aerogels with varying cellulose concentrations in NaOH/urea solution via a freeze-drying process. The resulting aerogels had a rich porous structure with specific surface areas in the range of 132.72-245.19 m 2 .g -1 and mesopore volumes in the range of 0.73-1.53 cm 3 .g -1 , and were tested for CO 2 sorption at ambient temperature and pressure, displaying excellent CO 2 adsorption capacities in the range of 1.96-11.78 mmol.g -1 . Furthermore, the CO 2 /N 2 selectivity of aerogels decreased with decreasing specific surface area, which was mainly caused by the decrease in CO 2 capture. In addition, the CO 2 sorption capacity of the sample with 2% cellulose content, CA-2, exceeded the values reported so far for many other sorbents with higher specific surface areas, and showed reasonable cyclic stability for CO 2 capture. Therefore, this adsorbent represents an attractive prospect for CO 2 uptake at room temperature., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Carbon dioxide (CO 2 ), an important gas molecule metabolite produced by the tricarboxylic acid cycle, is a direct signal for identifying cancers in cells and tissues. Herein, design and synthesis of a novel "breathable" block polymer supramolecular assembly probe consisting of a hydrophilic block, an amidine-containing CO 2 -responsive block, and an aggregation-induced emission (AIE) luminescence block to detect CO 2 metabolized by cancer cells is reported. The triblock copolymer poly-(4-undecoxy tetraphenyl ethylene methacrylate)- b -poly-(( N -amidino)-(2,3-dihydro-1 H -1, 4-methyl-1, 2,3-triazole)-(ethenylbenzene))- b -poly(ethylene oxide) (PTPE- b -PAD- b -PEO) was successfully synthesized and characterized. This triblock copolymer could be self-assembled into "breathable" aqueous solution vesicles. In the presence of CO 2 , the amidine-containing CO 2 -responsive block (PAD block) of the vesicle "inhales" an amount of CO 2 , which causes the volume of the vesicle to expand. The expansion of the vesicle induces the aggregation of the AIE luminescence block (PTPE block), which resulted in the fluorescence intensity enhancement. The supramolecular vesicles "exhale" CO 2 , and the volume and AIE phenomenon of the vesicles decrease when N 2 is passed into the solution. On the basis of this reversible change of fluorescence intensity, HeLa cervical cancer cells, CNE1 nasopharynx cancer cells, 5-8F nasopharynx cancer cells, 16HBE human bronchial epithelial cells, and GES-1 human gastric mucosa epithelial cells have all been successfully detected and identified.

Culture contamination, end-product toxicity, and energy efficient product recovery are long-standing bioprocess challenges. To solve these problems, we propose a high-pressure fermentation strategy, coupled with in situ extraction using the abundant and renewable solvent supercritical carbon dioxide (scCO 2 ), which is also known for its broad microbial lethality. Towards this goal, we report the domestication and engineering of a scCO 2 -tolerant strain of Bacillus megaterium, previously isolated from formation waters from the McElmo Dome CO 2 field, to produce branched alcohols that have potential use as biofuels. After establishing induced-expression under scCO 2 , isobutanol production from 2-ketoisovalerate is observed with greater than 40% yield with co-produced isopentanol. Finally, we present a process model to compare the energy required for our process to other in situ extraction methods, such as gas stripping, finding scCO 2 extraction to be potentially competitive, if not superior.

To overcome the natural recalcitrance of cellulose for glucose production in aqueous media catalyzed by enzyme, in this study, a dissolution pretreatment strategy was developed by using in situ formed CO 2 -based reversible ionic compounds (RICs)/DMSO mixed organic electrolytes under mild conditions. The influences of the constitution of RICs, CO 2 pressure, dissolution pretreatment time on the physic-chemical structure of cellulose were investigated systematically by FTIR, XRD, SEM, AFM towards in-depth understanding of the correlations between the pretreatment conditions, micro-scale structure and enzymatic saccharification of cellulose. The results showed that the tetramethyl guanidine (TMG) based RICs solvent system [TMGH] 2 + [O 2 COCH 2 CH 2 OCO 2 ] 2- /DMSO (X RICs  = 0.1, X RICs : the mole fraction of the formed RICs in the mixture) presented the best performance, which was evidenced by 100% glucose yield after the dissolution-regeneration pretreatment strategy under mild conditions (T = 60 °C, Pco 2  = 2.0 MPa, t = 2 h). Furthermore, the solvent system have good recyclability and usability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This paper introduces a convenient approach for determining iodate in iodized salt by headspace gas chromatography (HS-GC). The analytical technique can measure the generated carbon dioxide from the redox reaction between iodate and sodium oxalate in the presence of strong acid. The formed carbon dioxide from this reaction in a closed vial is measured by GC. It was observed that the redox reaction in the vial was completed in 40 min at 95 °C. The results indicated that this analytical technique is precise (RSD ≤ 2.69%) and accurate (relative errors ≤ 7.21%). The present approach is fast and simple, providing a robust avenue to the routine estimation of iodate in iodized salt in a wide variety of applications from processing to quality monitoring., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of this work was to study promotion of ball milling and CO 2 assistance on cellulose hydrolysis kinetics in water medium. Kinetic behaviors were analyzed based on first-order and shrinking core models. The results showed that cellulose hydrolysis is enhanced by ball milling and CO 2 assistance. Ball milling reduced crystallinity and particle size of cellulose, resulting in high cellulose conversion, while hydrolysis promoted by CO 2 assistance was weaker. Double-layer hydrolysis was observed for ball-milled cellulose, and rate constant in active layer is higher. Based on double-layer shrinking core model (DL-SCM), activation energy of cellulose conversion decreased from 73.6 to 39.8 kJ/mol when ball milling and CO 2 assistance were applied. Hydrolysis active layer was about 0.9 μm, representing activated thickness of ball-milled cellulose. Hydrolysis promotion by crystallinity and particle size reduction was distinguished via DL-SCM, and crystal evolution possesses greater improvement than particle size decrease on hydrolysis of ball-milled cellulose., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Most biomass pretreatment processes for sugar production are run at low-solid concentration (<10 wt.%). Subcritical carbon dioxide (CO2) could provide a more sustainable pretreatment medium while using relative high-solid contents (15 wt.%). The effects of subcritical CO2 pretreatment of sugarcane bagasse to the solid and glucan recoveries at different pretreatment conditions were investigated. Subsequently, enzymatic hydrolysis at different hydrolysis time was applied to obtain maximal glucose yield, which can be used for ethanol fermentation. The maximum glucose yield in enzyme hydrolyzate reached 38.5 g based on 100g raw material after 72 h of enzymatic hydrolysis, representing 93.0% glucose in sugarcane bagasse. The enhanced digestibilities of subcritical CO2 pretreated sugarcane bagasse were due to the removal of hemicellulose, which were confirmed by XRD, FTIR, SEM, and TGA analyses., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The present work investigated the effects of subcritical CO2 pretreatment of sugarcane bagasse at different CO2 pressure, pretreatment time, and temperature with relative high-solid concentration (15% w/v) to the composition of prehydrolyzate and the enzymatic hydrolysis. The results indicated that the maximum xylose yields in prehydrolyzate liquid were 15.78 g (combined 3.16 g xylose and 12.62 g xylo-oligosaccharides per 100g raw material). Due to the effective removal of hemicellulose, the maximum glucose yield in enzyme hydrolyzate reached 37.99 g per 100g raw material, representing 91.87% of glucose in the sugarcane bagasse. The maximal total sugars yield (combined xylose and glucose both in prehydrolyzate and enzymatic hydrolyzate) were 52.95 g based on 100g raw material. These results indicated that subcritical CO2 pretreatment can effectively improve the enzymatic hydrolysis, so it could be successfully applied to sugarcane bagasse., (Copyright © 2013 Elsevier Ltd. All rights reserved.)