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Arango Hoyos, B. E., Franco Osorio, H., Valencia Gomez, E. K., Guerrero Sanchez, J., Del Canto Palominos, A. P., Larrain, F. A., et al. (2023). Exploring the capture and desorption of CO2 on graphene oxide foams supported by computational calculations. Sci. Rep., 13(1), 14476.
Abstract: In the last decade, the highest levels of greenhouse gases (GHG) in the atmosphere have been recorded, with carbon dioxide (CO2) being one of the GHGs that most concerns mankind due to the rate at which it is generated on the planet. Given its long time of permanence in the atmosphere (between 100 to 150 years); this has deployed research in the scientific field focused on the absorption and desorption of CO2 in the atmosphere. This work presents the study of CO2 adsorption employing
materials based on graphene oxide (GO), such as GO foams with different oxidation percentages (3.00%, 5.25%, and 9.00%) in their structure, obtained via an environmentally friendly method. The characterization of CO2 adsorption was carried out in a closed system, within which were placed the GO foams and other CO2 adsorbent materials (zeolite and silica gel). Through a controlled chemical reaction, production of CO2 was conducted to obtain CO2 concentration curves inside the system and calculate from these the efficiency, obtained between 86.28 and 92.20%, yield between 60.10 and 99.50%, and effectiveness of CO2 adsorption of the materials under study. The results obtained suggest that GO foams are a promising material for carbon capture and the future development of a new clean technology, given their highest CO2 adsorption efficiency and yield. Keywords: CARBON-DIOXIDE; AB-INITIOFLUE-GAS; ADSORPTION; AIR; SEPARATION; SILICA; ADSORBENT; EXTRACTION; SORBENTS
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Clavero-Leon, C., Ruiz, D., Cillero, J., Orlando, J., & Gonzalez, B. (2021). The multi metal-resistant bacterium Cupriavidus metallidurans CH34 affects growth and metal mobilization in Arabidopsis thaliana plants exposed to copper. PeerJ, 9, e11373.
Abstract: Copper (Cu) is important for plant growth, but high concentrations can lead to detrimental effects such as primary root length inhibition, vegetative tissue chlorosis, and even plant death. The interaction between plant-soil microbiota and roots can potentially affect metal mobility and availability, and, therefore, overall plant metal concentration. Cupriavidus metallidurans CH34 is a multi metal-resistant bacterial model that alters metal mobility and bioavailability through ion pumping, metal complexation, and reduction processes. The interactions between strain CH34 and plants may affect the growth, metal uptake, and translocation of Arabidopsis thaliana plants that are exposed to or not exposed to Cu. In this study, we looked also at the specific gene expression changes in C. metallidurans when co-cultured with Cu-exposed A. thaliana. We found that A. thaliana's rosette area, primary and secondary root growth, and dry weight were affected by strain CH34, and that beneficial or detrimental effects depended on Cu concentration. An increase in some plant growth parameters was observed at copper concentrations lower than 50 mM and significant detrimental effects were found at concentrations higher than 50 mM Cu. We also observed up to a 90% increase and 60% decrease in metal accumulation and mobilization in inoculated A. thaliana. In turn, copper-stressed A. thaliana altered C. metallidurans colonization, and cop genes that encoded copper resistance in strain CH34 were induced by the combination of A. thaliana and Cu. These results reveal the complexity of the plant-bacteria-metal triad and will contribute to our understanding of their applications in plant growth promotion, protection, and phytoremediation strategies.
Keywords: SOIL; PHYTOEXTRACTION; COLONIZATION; ACCUMULATION; BIOSORPTION; HOMEOSTASIS; MICROBES; CADMIUM; SYSTEMS; EXCESS
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Harrison, R., & Lagunoff, R. (2019). Tipping points and business-as-usual in a global commons. J. Econ. Behav. Organ., 163, 386–408.
Abstract: This paper analyzes a dynamic strategic model of resource extraction from a global commons. Countries derive benefits from both direct extraction and aggregate conservation of an open access resource. Each period, a country's output depends both on its resource usage and on the global stock of the resource stored within the ecosystem. Leading examples are ocean fisheries, habitat preservation, forestry, and land carbon biomass. The production coefficients on these inputs vary across countries and evolve stochastically over time. A Business-as-usual (BAU) equilibrium characterizes each country's resource usage in the absence of an effective international agreement. Under non-concave resource dynamics, depletion of the resource in a BAU equilibrium may reach a tipping point below which the stock spirals downward toward a steady state of marginal sustainability. Under the assumptions of the model, the tipping points emerge endogenously. If the number of extractors exceeds some fixed, finite bound, the commons always tips regardless of the initial stock. We find that countries will accelerate their rates of extraction the closer they are to reaching the low-end steady state. By contrast, in the socially efficient plan the commons never tips if the initial stock is large. (C) 2019 Elsevier B.V. All rights reserved.
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Reus, L., Belbeze, M., Feddersen, H., & Rubio, E. (2018). Extraction Planning Under Capacity Uncertainty at the Chuquicamata Underground Mine. Interfaces, 48(6), 543–555.
Abstract: We propose an extraction schedule for the Chuquicamata underground copper mine in Chile. The schedule maximizes profits while adhering to all operational and geomechanical requirements involved in proper removal of the material. We include extraction capacity uncertainties due to failure in equipment, specifically to the overland conveyor, which we find to be the most critical component in the extraction process. First we present the extraction plan based on a deterministic model, which does not assume uncertainty in the extraction capacity and represents the solution that the mine can implement without using the results of this study. Then we extend this model to a stochastic setting by generating different scenarios for capacity values in subsequent periods. We construct a multistage model that handles economic downside risk arising from this uncertainty by penalizing plans that deviate from an ex ante profit target in one or more scenarios. Simulation results show that a stochastic-based solution can achieve the same expected profits as the deterministic-based solution. However, the earnings of the stochastic-based solution average 5% more for scenarios in which earnings are below the 10th percentile. If we choose a target 2% below the expected profit obtained by the deterministic-based solution, this average increases from 5% to 9%.
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Sandoval-Rivas, D., Moczko, E., & Morales, D. V. (2021). Evaluation and characterization of a new method of extracting bark wax from Pinus radiata D. Don. Ind. Crops Prod., 174, 114161.
Abstract: The bark of Pinus radiata D. Don is a bioresource of great worldwide abundance. While various forms of use have been studied, it is still a little-used bioresource. Due to its great accumulation, significant solid emissions of this residue generate environmental problems such as changes in soil chemistry, ecological problems such as the alteration of arthropod communities and fire risk. The opportunity to take advantage of this bioresource could be in its wax content, which could be a replacement for the main raw materials used in the production of cosmetics. These currently correspond to petroleum-derived substances, such as petroleum jelly, paraffin, or mineral oil. The importance of replacing these raw materials is that several studies report that they are the main causes of human skin diseases, such as chemical hypersensitivity syndrome and allergic contact dermatitis. This study seeks to prove that lipophilic extracts (waxes) from pine bark can replace petroleum-derived raw materials used in cosmetics. To achieve this, pine bark at drying conditions was characterized, and the performance of wax extraction by various treatments was studied. The density, viscosity, melting point, and solubility in culture media of the obtained waxes were determined. The waxes were chemically characterized by FT-IR and GC-MS analysis. The results reveal that the maximum moisture of the bark is 14.54 %, the best extraction yields are obtained by using water at 120 degrees C and 1.2 atm, and petroleum ether (3.12 %), alkaline hydrolysis 1 mol L-1 (NaOH) and petroleum ether (3.53 %) ethyl acetate (3.23 %). Values were close to the reference study using the rapid lipid extraction method. The density of the wax is 0.845 g mL-1 and its viscosity of 530 cP (24 degrees C), and the melting point varied according to the extractive treatment at between 25 and 40 degrees C. Solubility tests made it possible to determine that the 10/50/1000 mu L ratio of modified Eagle Dulbecco wax/dimethylsulfoxide/medium allows homogeneous solubilization of the wax without the presence of precipitates. Chemical characterization identified typical functional groups of plant-based waxes such as long-chain alkanes, alkyls, methyl groups, esters, and carbonyls, with the most abundant fatty acids being C:22 and C:24.
Keywords: Pine wax; Extraction; Radiata pine
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Taboada, E., Fisher, P., Jara, R., Zuniga, E., Gidekel, M., Cabrera, J. C., et al. (2010). Isolation and characterisation of pectic substances from murta (Ugni molinae Turcz) fruits. Food Chem., 123(3), 669–678.
Abstract: Cell walls polysaccharides from murta fruit (Ugni molinae Turcz), an endemic Chilean species with relevant food uses, were fractionated by water, ammonium oxalate, hot diluted HCl and cold diluted NaOH extractions. The polysaccharide fractions were analysed for monosaccharide composition and physicochemical properties. Pectic substances were found in all extracts, but mainly in the oxalate and acid soluble fractions, in which they appear as homogalacturonan polymers. Murta pectin was further extracted by hot diluted acid treatment using industrial conditions, yielding 30% by weight of dry fruit. The polymer showed similar composition and physicochemical properties to those of commercial citrus pectin, presenting a galacturonic acid content of 70.9% (w/w), a molecular weight of 597 kDa, and a methoxylation degree of 57%. The FT-IR spectrum of murta pectin suggests the presence of ferulic acid residues on its structure and the NMR analysis confirmed the structure of this polysaccharide. It is concluded that murta fruit can be considered as a valuable source of high quality pectin. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords: Pectin; Murta; Ugni molinae; Polysaccharide extraction; Pectin characterisation
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