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Abstract: Hydrogel presents great potential for dehydrating fuel, although several 13 challenges must be addressed to advance this technology for commercial use. The 14 essential attributes for industrial application include robust mechanical strength, high 15 hydrophilicity, and rapid water removal kinetics. This study aimed to design composite 16 hydrogels that concurrently meet these requirements. The addition of cellulose 17 significantly improved the compressive strength, with microfibrillated cellulose (MFC) 18 surpassing cellulose nanocrystals (CNC), resulting in a fivefold increase in 19 compressive strength. Notably, the inclusion of MFC had no significant impact on water 20 removal from biodiesel, as supported by a 95% confidence level. To enhance 21 hydrophilicity, ionizable charges were introduced through hydrolysis of the composite. 22 This process substantially improved water removal from biodiesel, increasing it from 36% to 49%. Moreover, the swelling degree increased from 27 to 714 g.g 23 -1 when using 24 the hydrolyzed composite and oven-dried hydrogel compared to non-hydrolyzed 25 polyacrylamide. The drying method influenced the water uptake kinetics, with freeze26 dried hydrogels exhibiting better initial performance but ultimately reaching equilibrium 27 values similar to oven-dried hydrogels. Equilibrium was achieved after 1440 minutes 28 for hydrolyzed composite hydrogels, with the kinetic data fitting the pseudo-second29 order model. With approximately 200 mg of hydrogel per mL of biodiesel, the water 30 content in the biodiesel decreased from 1,497 ppm to 303 ppm, meeting regulatory 31 agency specifications. Furthermore, the material proved to be reusable for at least 32 three cycles of biodiesel treatment. Summing up, this research demonstrates that 33 cellulose-polyacrylamide composite hydrogels are a promising solution for effectively 2 1 removing trace amounts of water from biodiesel, achieving efficiency comparable to 2 established technologies

Abstract: The ability to calculate how different compounds diffuse within microporous structures is paramount for a number of applications in the oil & gas sector, from oil exploration to separation, and even for the design of Carbon Capture, Utilization, and Storage (CCUS) processes. Molecular Dynamics simulations entail an excellent alternative to cases for which an experimental determination is unfeasible or extremely difficult, as it happens for fluids in micropores. Nonetheless, being confined within a mineral micropore makes the fluid spatial distribution inhomogeneous, requiring appropriate methods to compute the diffusion coefficients. Recently, some of us presented a new method for this purpose (Franco et al., J. Chem. Theory Comput., 12, 5247-5255, 2016). In this work, we present a detailed study on how to apply such a method exploring fluids confined within calcite walls, which is a mineral representative of carbonate rocks found in several geological formations. From our results, we were able to map the evolution of the self-diffusion tensor components throughout the pore, showing the anisotropy among the components at different directions. We also show the influence of confinement and observe a significant effect at the center of the pore for small micropores (< 7.5 nm), where the density distribution is constant. This is an unexpected result that shows how the confinement effect is manifested even at the so-called "bulk-like" region at the center of the pore

Abstract: The N-[3-(Dimethylamino)propyl] hexadecanamide molecule is an important intermediate for synthesizing amphoteric and quaternary ammonium surfactants. Despite its importance for the household and personal care sectors, little to no information about its enthalpy of formation is found in the NIST database or literature, which hinders many industrial operations, especially its chemical production, by consuming much more energy than what is necessary. In this work, we present a first estimative of N-[3- (Dimethylamino)propyl] hexadecanamide's standard enthalpy of formation with a simple procedure that can be used to obtain similar parameters in chemical industry laboratories. The enthalpy estimative was obtained by reacting palmitic acid and dimethylaminopropylamine (DMAPA), yielding the desired compound. Hess's law was used to determine the enthalpy of the reaction through the heat associated with the extent of the reaction. The reagents were contacted in a simple calorimeter at room temperature (diluted with acetone) and 100 ºC (without acetone). The extent of the reaction was obtained by quantitative determination of the reaction medium in gas chromatography. The room temperature experiment led to an insignificant reaction extent which generated an unreliable result for the compound's enthalpy of formation. In contrast, at 100 ºC, the estimated standard enthalpy of the reaction was adequately calculated, leading to an enthalpy of formation of -703.93?±?9.17 kJ/mol for the N- [3-(Dimethylamino)propyl] hexadecanamide. With this simple procedure, the industrial reactor's more precise heat consumption can be calculated, yielding economic and environmental benefits

Abstract: Mixing degree in microdevices has been herein investigated by enhancing the angular momentum in a truncated cone-shaped micromixer via side-feedings. However, flows in microchannels are preferentially characterized by molecular transport which streamlines flow in parallel, hindering a fast response for the quality of mixing in a process. Thus, a micromixer with side-feedings coupled to a 2D truncated cone with subsequent wavy microchannel has been evaluated. Therefore, this work assesses the arrangement of feeds in this entrance section, as well as the Reynolds number (Re) and the curvatures of bumps in the wavy microchannel. The symmetrical lateral feeds favored a homogeneous mixing in the flow in the inlet section where the streamlines intersect. At the device outlet, all bump curvatures have contributed to a mixing index higher than 0.90 in a Reynolds number range of 20 to 40. Furthermore, lower Reynolds numbers have also resulted in a mixing index above 0.90, but the flow is slower and predominantly diffusive. Finally, a sharper curvature geometry generates smaller pressure drops with a similar mixing index when compared to other geometries, which indicates that it is the best option for bump curvature

Abstract: Nitrogen-doped carbon nanodots synthesized from l-arginine and ethylenediamine (NCNDs); citric acid-derived carbon nanodots with carboxylic surface groups (a-CDs); and Silica-Cdots hybrids produced through coupling a-CDs to SiO2 nanoparticles were used for the fabrication of fluorescent PMMA-CDs optical films. The nanoparticles occlusion allows the conversion of a broader UV bandwidth to the visible by enhancing PMMA’s natural fluorescence. This UV-to-Visible conversion boost can enhance the efficiency of solar energy concentrators and generators and, as a proof-of-concept, photovoltaic cells were coated with NCNDs-doped PMMA films. Experiments show an 11.3% cell efficiency increase after film application, which can be further enhanced by optimizing film production and deployment, what shows the feasibility and potential of these low-cost environmentally friendly materials

Abstract: Polymeric hydrogels are a promising new technology for removing water from fuels. This work critically analyzes the effect of hydrolysis post treatment and drying method on polyacrylamide hydrogels for removing diluted water from biodiesel. The material was characterized by FTIR, SEM, DVS, compressive strength and swelling degree. The water diffusion profile during swelling was observed using an innovative method described in this work. Hydrolysis improved the hydrophilicity of the material, resulting in a doubling of water absorption and reaching a swelling degree between 987-1,095 g.g-1. Freeze-drying benefited the kinetic of water uptake. Using hydrolyzed polyacrylamide hydrogel, the water content in biodiesel decreased from 1497 ppm to 978 ppm in only 30 minutes, and within 72 hours, 49% of the water was removed from the biofuel. This demonstrates the efficiency of hydrogel systems, which could become a competitive alternative to traditional desiccants of fuels, capable of removing even traces of moisture

Abstract: Recycling and upcycling waste polyvinyl chloride (PVC) poses a major challenge to the footwear industry due to its short lifecycle and the environmental impact of destructive trends. This study aimed to recycle thermoplastic polyvinyl chloride (rPVC) from used sports shoes of the most varied kind, obtained from a recycling company. The rPVC and thermoplastic polyurethane (TPU) were melt-blended, prepared by industrial injection molding with different compositions, and the polymer blends were characterized by morphological, thermal, and mechanical means. The overall properties of the recycled polymer blends were improved compared to their parent commercial materials. When TPU and rPVC were blended, the resulting material displayed a remarkable hardness. The abrasion resistance of the TPU/rPVC polymer blends (67/33 and 50/50 wt.%) was enhanced twice compared to PVC, and the rPVC rupture strength (14.73 MPa) was 1.6 times greater than virgin PVC (9.11 MPa). Likewise, The TPU/rPVC blend (50/50% wt.%) also offered significantly greater deformation resistance, indicating that rPVC has a more entangled structure with greater resistance and, thus, greater tensile strength. Polymer blending is accelerating research and development in the footwear industry, and the outcomes have qualified the TPU/rPVC (67/33 and 50/50 wt.%) polymer blends to meet the growing consumer demand for environmentally friendly footwear

Abstract: A deeper understanding of the kinetics and thermodynamics parameters of sugarcane bagasse (SCB) thermal degradation could define appropriate conditions for primary biorefining in the production of renewable fuels. In this work, the kinetics of thermal degradation of SCB’s high polymers are investigated through thermogravimetric data. From this data, model-free and model fitting methods are used to calculate apparent activation energies (Ea) and other related kinetic parameters. DTG curves present three major peaks associated with pseudo-components (PSEs): PSE 1 (hemicelluloses?+?extractives and lignin), PSE 2 (cellulose?+?extractives and lignin), and PSE 3 (lignin?+?extractives and residual holocelluloses). An essential advance is related to the quantitative interpretation of the degradation process by multi-stage modeling governed by diffusion-controlled reactions and order-based models. The Kissinger-Akahira-Sunose method provided Ea ranges of 124–154, 147–153, and 230–530 kJ?mol-1, while the ranges obtained by the Flynn-Wall-Ozawa method were 120–152, 144–150, and 232–545 kJ?mol-1, both for PSE 1, PSE 2, and PSE 3, respectively. Data could support the calculation of many critical operating parameters in biorefinery process, such as the pretreatment minimum temperature. SCB biorefining could lead to a degradation of up to 10, 0.5, and 11% for PSE 1, PSE 2, and PSE 3, respectively, at 473.15 K for 200 min. Thermodynamic parameters (?H, ?G, and ?S) determined SCB endothermic and non-spontaneous thermal degradation

Abstract: A bstract Simultaneous intracellular depolymerization of xylo-oligosaccharides (XOS) and acetate fermentation by engineered Saccharomyces cerevisiae offers an advance towards more cost-effective second-generation (2G) ethanol production. As xylan is one of the most abundant polysaccharides present in lignocellulosic residues, the transport and breakdown of XOS in an intracellular environment might bring a competitive advantage for recombinant strains in competition with contaminating microbes, which are always present in fermentation tanks; furthermore, acetic acid is a ubiquitous toxic component in lignocellulosic hydrolysates, deriving from hemicellulose and lignin breakdown. In the present work, the previously engineered S. cerevisiae strain, SR8A6S3, expressing NADPH-linked xylose reductase (XR), NAD + -linked xylitol dehydrogenase (XDH) (for xylose assimilation), as well as NADH-linked acetylating acetaldehyde dehydrogenase (AADH) and acetyl-CoA synthetase (ACS) (for an NADH-dependent acetate reduction pathway), was used as the host for expressing of two ß-xylosidases, GH43-2 and GH43-7 , and a xylodextrin transporter, CDT-2 , from Neurospora crassa , yielding the engineered strain SR8A6S3-CDT 2 -GH43 2/7 . Both ß-xylosidases and the transporter were introduced by replacing two endogenous genes, GRE3 and SOR1 , that encode aldose reductase and sorbitol (xylitol) dehydrogenase, respectively, which catalyse steps in xylitol production. Xylitol accumulation during xylose fermentation is a problem for 2G ethanol production since it reduces final ethanol yield. The engineered strain, SR8A6S3-CDT 2 -GH43 2/7 , produced ethanol through simultaneous co-utilization of XOS, xylose, and acetate. The mutant strain produced 60% more ethanol and 12% less xylitol than the control strain when a hemicellulosic hydrolysate was used as a mono- and oligosaccharide source. Similarly, the ethanol yield was 84% higher for the engineered strain using hydrolysed xylan compared with the parental strain. The consumption of XOS, xylose, and acetate expands the capabilities of S. cerevisiae for utilization of all of the carbohydrate in lignocellulose, potentially increasing the efficiency of 2G biofuel production. Highlights Integration of XOS pathway in an acetate-xylose-consuming S. cerevisiae strain; Intracellular fermentation of XOS, acetate and xylose improved ethanol production; Deletion of both sor1 ? and gre3 ? reduced xylitol production

Abstract: The rising biodiesel content in diesel, driven by global policies, intensifies the challenge of maintaining fuel quality, particularly regarding water content. Elevated water levels in fuels can cause mechanical failures, corrosion, microbial growth, and reduced fuel performance, leading to increased maintenance costs and environmental concerns. Composite hydrogel packings offer significant potential for fuel dehydration, particularly in continuous processes, where essential characteristics include robust mechanical strength, high hydrophilicity, rapid kinetics, and geometry that facilitates fluid flow without causing pressure drops. This study addresses these challenges by employing hydrolyzed and non-hydrolyzed polyacrylamide/cellulose microfibril (PAM/MFC) hydrogels, shaped into Raschig rings, as packing materials in fixed-bed columns for continuous water removal from biodiesel and B15 diesel. For biodiesel, hydrolyzed PAM/MFC reduced water content from 952.8 ppm to 463.6 ppm (51%26 removal) after a 2.3-hour residence time, meeting EN 14214 standards. When connected in series with a column containing hydrolyzed and lyophilized PAM/MFC hydrogels, water content was further reduced to approximately 350 ppm. Hydrolyzed PAM/MFC maintained performance over seven cycles, including four with regenerated material, demonstrating its reusability and durability. Conversely, non-hydrolyzed PAM/MFC hydrogels removed 40% of water during a 2.3-hour residence time, highlighting the need for anionic hydrogels to achieve faster water removal kinetics from biodiesel. For B15 diesel, the same non-hydrolyzed material achieved a 36% reduction in 17 minutes of residence time, lowering water content to below 200 ppm, in compliance with EN 590 standards. This study also optimized the production of Raschig ring-shaped hydrolyzed PAM/MFC hydrogels, demonstrating the feasibility of reusing the twice, reducing specific sodium hydroxide consumption by approximately 44%. Additionally, washing hydrolyzed hydrogels in a cascade system significantly improved washing efficiency. An economic evaluation revealed that hydrolyzed PAM/MFC hydrogels provided a cost advantage over other anionic hydrogels with similar performance in removing water from biodiesel, being 17% and 50% less expensive than acrylamide-sodium acrylate copolymers and sodium polyacrylate hydrogels, respectively. Overall, this study presents a scalable and technically viable solution for industrial fuel dehydration, offering an integrated approach that combines operational efficiency in packing production and compliance with global fuel quality standards

Abstract: Over the past few years, eutectic solvents (ESs) have been drawing the scientific community's attention because they are usually more environmentally friendly than traditional organic solvents. One of the applications of ESs is in the gas capture field, where they are considered promising absorbers to replace amine- (MEA, DEA, or MDEA processes), methanol- (Retinol process), dimethyl ethers of polyethylene glycol- (Selexol process), N-methyl-2-pyrrolidone- (Purisol process), propylene carbonate- (Fluor solvent process), or morpholine-based (Morphysorb process) solvents on CO2 capture of atmosphere. Although several studies have reported experimental gas solubility data in ESs, especially for CO2, only a small number of the existing options are covered. In fact, resorting to experimental methods to obtain the solubility data seems unfeasible considering the vast number of possible eutectic mixtures. Therewith, theoretical predictions of gas solubility in ESs are valuable for the fast pre-screening of prospective solvents. In this work, the ability of the COSMO-RS thermodynamic model to represent solubility data of CO2, CH4, and H2S in 17 Choline Chloride-based (ChCl) ESs was evaluated. The experimental data were collected from the literature at different molar ratios, at 298.15 K or 313.15 K, and in the pressure range from 1 to 125 bar. COSMO-RS offers a qualitative description of these gases' solubility, which was expected due to the model's fully predictive character

Abstract: The study of transport properties of unconventional oil reservoirs such as shale gas is crucial to optimize production, enhance oil extraction, and decrease costs and environmental hazards. One important dynamical property of fluids is diffusion, which is necessary to determine the oil mobility and rate of oil production from the reservoir, and can be obtained through the self-diffusion coefficient. To obtain the transport properties of fluids under confinement, one must take into account the surface and the confinement effects. Moreover, approaches that consider the position-dependency and the nonlinear particle distribution are required. Applying methods based on probability density function, the self-diffusion components of methane-ethane mixtures confined within calcite nanopores were calculated, using molecular dynamics simulations. The anisotropy between xx, yy, and zz components of the self-diffusion tensor has different effects depending on the position inside the nanopore. A surface effect causes an anisotropic behavior between parallel self-diffusion coefficients for this mixture close to the calcite walls. And at the center of the pore, the confinement effect is manifested by lowering the value of the perpendicular self-diffusion coefficient when compared to the parallel ones. Mixture composition plays an important role, since a higher ethane content shows greater anisotropy between parallel components

Abstract: Thermodynamic perturbation theories are indispensable in the development of equations of state based on Statistical Mechanics. Recently, a new statistical thermodynamic model has been proposed in which molecules are represented as cylindrically symmetric hard bodies (ellipsoids of revolution, spherocylinders, and cylinders) interacting with identical neighboring molecules through a spherically symmetric square-well potential. This novel equation of state embeds at least two approximations to the Onsager’s second virial theory: one restrains the equation of state to systems with an isotropic (disordered) orientation distribution, while the other decouples the translational and orientational degrees of freedom, being only valid at low densities. Using canonical Monte Carlo simulations, we investigated the feasibility of such approximations by determining the uniaxial nematic order parameter of the systems and calculating the first- and second-order perturbation coefficients of the high-temperature series expansion (HTSE) of the Helmholtz free energy. Our results indicate that both approximations are reasonable for a certain range of packing fractions and molecular anisotropies. We have also calculated the full Helmholtz free energy of the perturbed system, which can be used for determining high-order perturbation terms to improve the predictive capability of the equation of state