Adsorption Of Glycol Research Articles

Interactions involved in the adsorption of ethylene glycol and 2-hydroxyethoxide on the Au(111) surface: a Density Functional Theory study

Context: The monolayers of ethylene glycol and 2-hydroxyethoxide on gold surfaces have been used in hybrid materials as biosensors. In this article, the adsorption of ethylene glycol and 2-hydroxyethoxide on the Au(111) surface was analyzed. For the first system, ethylene glycol on Au(111), there are Au···\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\cdot \\cdot \\cdot $$\\end{document}O and Au···\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\cdot \\cdot \\cdot $$\\end{document}H interactions. To the best of our knowledge, the Au···\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\cdot \\cdot \\cdot $$\\end{document}H interaction has been overlooked until now. However, in this work, there is strong evidence that this interaction is important to stabilize the system. For the second system, the atomic interactions mentioned previously are also predicted, although there is an additional interaction between 2-hydroxyethoxide molecules. Such an interaction induces the link -O-H-O-, with high values of the electron density at the critical points of the corresponding bond path of the O-H interaction. These links suggest the forming of ethylene glycol chains. Methods: The calculations were performed using two exchange-correlation functionals: BEEF-vdW and C09x\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{x}$$\\end{document}-vdW; both functionals incorporate dispersion effects within the Kohn-Sham approach in Density Functional Theory as implemented in GPAW code and ASE computational packages. The contacts between the molecules considered in this article and the Au(111) surface were analyzed through the Quantum Theory of Atoms in Molecules implemented in GPUAM code.

Advancing BiVO4 Photoanode Activity for Ethylene Glycol Oxidation via Strategic pH Control.

The photoelectrochemical (PEC) conversion of organic small molecules offers a dual benefit of synthesizing value-added chemicals and concurrently producing hydrogen (H2). Ethylene glycol, with its dual hydroxyl groups, stands out as a versatile organic substrate capable of yielding various C1 and C2 chemicals. In this study, we demonstrate that pH modulation markedly enhances the photocurrent of BiVO4 photoanodes, thus facilitating the efficient oxidation of ethylene glycol while simultaneously generating H2. Our findings reveal that in a pH = 1 ethylene glycol solution, the photocurrent density at 1.23 V vs. RHE can attain an impressive 7.1 mA cm-2, significantly surpassing the outputs in neutral and highly alkaline environments. The increase in photocurrent is attributed to the augmented adsorption of ethylene glycol on BiVO4 under acidic conditions, which in turn elevates the activity of the oxidation reaction, culminating in the maximal production of formic acid. This investigation sheds light on the pivotal role of electrolyte pH in the PEC oxidation process and underscores the potential of the PEC strategy for biomass valorization into value-added products alongside H2 fuel generation.

Au nanoparticles decorated ZnIn2S4/WO3 core-shell heterostructures as highly sensitive and selective ethylene glycol gas sensors

Ethylene glycol (EG) is extensively utilized as anti-freezer and deicer, which would bring potential health risk under unintentional exposures especially with hazardous inhalation of EG aerosols or vapors. In this study, ZnIn2S4 (ZIS)/WO3 core-shell nanofibrous heterostructure loaded with optimized Au nanoparticles (NPs) was prepared for superiorly sensitive and selective EG gas sensing. The ternary Au/ZIS/WO3 heterostructures exhibited an excellent response (Ra/Rg=98.92) to 50 ppm EG, demonstrating an enhancement of 3.5 times compared to the binary ZIS/WO3, and a substantial improvement of 59.5 and 24.1 times compared to pure WO3 and ZIS, respectively. The ternary Au/ZIS/WO3 heterostructures also possessed an extremely low detection limit of 6 ppb, as well as excellent selectivity, repeatability, and long-term stability. This exceptional gas sensing performance can be attributed to its distinctive ternary Au/ZIS/WO3 heterostructures with high specific surface areas. This unique structure not only facilitate the activation of abundant active oxygen species, but also promote the spillover effect of Au and enhance effective electronic distribution, thereby providing more EG adsorption sites, which was confirmed by density functional theory calculation. The synergistic effect arising from the metal-semiconductor interface and the core-shell heterostructure presents a novel avenue for advancing high-performance sensor technologies.

Separation of ethylene glycol from propylene glycol via selective adsorption with basic anion-exchange resin

Ethylene glycol (EG) is a common impurity in bio-derived 1,2-propylene glycol (PG). EG was isolated from PG via selective adsorption on basic ion-exchange resin. A small amount of moisture improved the porosity of resin, thereby reinforcing the intraparticle diffusion and adsorption performance. The adsorption equilibrium could be reached within 1 min, indicating that EG can be instantly removed. The real adsorption capacity for PG was much lower than that for EG, and the selectivity was up to 5.5 at 60 °C due to the susceptibility of PG adsorption to temperature. The PG content was increased from 90 to 95.7 wt% in a continuous-flow process with low bed pressure drop. The EG adsorption process agreed with the Langmuir isotherm model, and the apparent EG adsorption capacity reached 250.6 mg/g at 60 °C, while real PG adsorption capacity was negligible. The different interactions between diols and OH− ions were proven by UV and surface-tension measurements, and the stronger acidity of hydroxyl group in EG contributed to its stronger acid-base interaction with basic materials. The resin adsorbent could be reused and completely regenerated without leaching via elution with 20 wt% NaOH. Based on the acidity of EG, this work presents an unprecedented cost-effective strategy to separate diols.

Inspiration of Bimetallic Peroxide for Controllable Electrooxidizing Ethylene Glycol Through Modulating Surficial Intermediates

AbstractBiomass feedstock ethylene glycol (EG) can be anodically oxidized to the high‐value glycolic acid (GA), which is widely considered as one critical raw material of biodegradable plastics. Developing low‐cost electrocatalyst to economically produce GA with high selectivity still meeting challenges. Herein, a non‐precious Co‐Ni bimetal catalysts are developed for controllable electrooxidizing EG to GA (EGOR). Through regulating the generation of key intermediate (CH2OH‐CO*) on the low‐cost catalyst surface, a successive electrooxidation from EG to GA has been achieved with high selective (96.3%) and conversion rate (>85%) at current density of 150 mA cm−2, which is on par with the reported precious metal catalysts. Through coupling with hydrogen evolution reaction (EGOR‐HER), 2.759 mmol H2 and 7.48 mmol of GA are generated at 80 mA cm−2, which also can save 27% energy comparing with a water splitting system. The synergistic effect between Co and Ni in the bimetallic catalyst has been exploited: high‐valent CoOOH sites catalyzed the generation of CH2OH‐CO* and reduce the energy barrier during GA formation; Whereas, Ni sites can effectively facilitate the formation of CoOOH and improve the adsorption of EG.

Elucidation of polyethylene glycol adsorption at the solid–H2O(l) interfaces of anatase TiO2(101) using density functional theory and molecular dynamics simulations

Polyethylene glycol adsorption on anatase TiO2(101) in the presence of liquid water was investigated using the free energy analysis of a combined density functional theory and classical molecular dynamics simulations.

Corrosion behavior of AA3003 friction stir welded joints

This work focuses on the corrosion behavior of the friction stir welded joint of aluminum alloy 3003. In order to quantify the quality of FSW joints, the corrosion in the welded joint and the base metal was compared. A gravimetric and thermodynamic study was carried out to determine corrosion resistance. Three aggressive media based on three solutions (sodium chloride, hydrogen chloride, and ethylene glycol) at four temperatures (25°, 45°, 65°, and 85 °C) were tested. The results showed that temperature has a strong influence on corrosion rates, which are higher in the metal than in the FSW joint. The presence of ethylene glycol considerably reduces the rate of corrosion, its effect is more marked on the FSW joint. The adsorption of ethylene glycol on the surface of the base metal and that of the FSW joint follows the Langmuir isotherm to form a monolayer on the surface of both samples.

Immunohematological evaluation of red cell alloimmunization and statistical assessment of various adsorption techniques in warm autoimmune hemolytic anemia

Adsorption techniques are widely applied to detect underlying masked alloantibodies in warm autoimmune hemolytic anemia (WAIHA). We established various adsorption techniques with an aim to detect alloimmunization in WAIHA This study conducted over a period of nine years included 298 patients of WAIHA. Complete immunohematological evaluation was performed on these 298 samples following departmental protocols. Clinical and laboratory details of patients were obtained from patient files. Various adsorption methods were performed and statistically evaluated in the study. Out of 479 cases of autoimmune hemolytic anemia, WAIHA comprised of 62.2 % (N = 298). A total of 139 (46.6 %) serum samples revealed autoantibodies. Adsorption study was performed in 101 (72.7 %) indicated samples and 24 (23.8 %) of these showed 26 alloantibodies. Among the patients subjected to adsorption study hemolytic marker were significantly deranged in the alloimmunization group (p < 0.01). Polyethylene glycol (PEG) adsorption was the quickest (52.2–54.6 min) of all adsorption techniques with minimum (1.3–1.5) numbers of adsorptions needing for complete removal of serum antibodies. The LISS-papain (LP) technique was found to be more sensitive and specific compared to the other two techniques. The agreement between PEG adsorption and LP adsorption was found to be ‘perfect’ (96.4 %) with a Cohen’s kappa (k) value of 0.9. We conclude that identification of alloantibody specificities underlying a warm autoantibody is critical for a safe and effective transfusion. All WAIHA patients with history of blood transfusion, pregnancy or both should be subjected to adsorption study. Selection of a suitable adsorption technique depends on multiple important factors.

Enzymatic hydrolysis lignin dissolution and low-temperature solvolysis in ethylene glycol

The dissolution and solvolysis processes of enzymatic hydrolysis lignin (EHL) in ethylene glycol are investigated. Ethylene glycol exhibits high EHL solubility and achieves complete EHL dissolution at room temperature. Gaussian simulation reveals that van de Waals interactions between ethylene glycol and EHL, including C-H⋯O and lone pair⋯π interactions, break the π-π stacking in EHL, achieving complete EHL dissolution. EHL is partly depolymerized in ethylene glycol at 200 °C even without a catalyst due to the strong van de Waals interactions. When NaOH and Ni are used as co-catalysts, EHL is efficiently depolymerized at 200 °C, and the overall monomer yield reaches 18.8 wt%. Fourier transform infrared spectroscopy (FT-IR) and molecular dynamics simulation results indicate that the adsorption of ethylene glycol over Ni surface hinders the adsorption of lignin fragments and monomers. Hence, EHL catalytic solvolysis in ethylene glycol occurs in the liquid phase, where OH− of NaOH promotes the EHL linkage breakage and active hydrogen atoms formed on Ni surface stabilize the active monomers.

High Speed Atomic Force Microscope Observation of Polyethylene Glycol Adsorption on Au(100)

Polyethylene glycol (PEG) plays an important role as an inhibitor of the electrodeposition. In this study, we investigated the potential dependence of PEG (molecular weight: 3000) adsorption and desorption processes on the gold single crystal substrate. High speed atomic force microscope (HS-AFM) was applied for observing the dynamic behaviors of the nucleation and the growth of PEG adsorption. The in situ observation was conducted at the several potentials where the cyclic voltammogram measurement showed the broad peak of the reduction current. As the applied potential became more cathodic, the adsorption morphology changed from film-like, through the sphere, to the large irregular cluster. When the potential was switched to anodic potential, HS-AFM could show the dissolution process of PEG. Finally we demonstrated the effect of the tip force by modifying the feed-back circuit of AFM.

Inhibition of multi-site adsorption of polyethylene glycol during copper via-filling process

The inhibitory effect of molecular weight (Mw) of polyethylene glycol (PEG) on the through-hole filling by copper electroplating was investigated by the electrochemical testing method and energy change with DFT. The cathodic polarization, electron transfer resistance, and diffusion coefficient of PEG with different Mw and concentration were assayed by cyclic voltammetry and electrochemical impedance spectroscopy; The inhibitory effect of different PEG Mw was demonstrated and examined by cross-sectional images using OLYMPUS confocal laser microscope, and the thickness of the copper layer and TP value were important measurement standards. The adsorption behavior on copper surfaces was calculated using the first principles. As PEG Mw and concentration are increased, the best TP value and diffusion coefficient of the plating formula is gained when PEG Mw and concentration are 20000 g/mol and 250 mg/L, they are 148.56% and 2.34 × 10-7, respectively. Better adsorption energy can be obtained as the adsorption sites of PEG increases, and the adsorption energy of PEG5 is − 1.99 eV. The experimental and theoretical results show that PEG with small Mw has no inhibitory effect, and even accelerates the deposition rate of Cu2+/1+. Only when the Mw and concentration exceed 2000 g/mol and 150 mg/L, PEG can inhibit the deposition of Cu2+/1+, and the best effect of through-hole electroplating is 20000 g/mol and 250 mg/L.

Adsorption of the Polymer on a Clay Matrix : Theoretical Study

Adsorption of polymers is a phenomenon of great importance in a number of areas of our daily life. However, understanding this phenomenon is essential. This work focuses on the theoretical study of the polyethylene glycol (PEG) adsorption phenomenon on thenatural clay-layer surface. Clay is considered as a matrix. Different adsorption regimes have been presented. The expressions of the surface coverage ratio as a function of the volume fraction of monomer for each regime were calculated. A strong adsorption was noted for the first two regimes (dilute surface, and bidimensional semi-dilute surface) confirmed by the exponential term. When the surface becomes saturated, we are in the plateau regime for which the adsorption varies logarithmically, due to the occupation of most of the sites available on the clay-layer surface. Finally, we presented the variation of the volume fraction as a function of 𝑧(axis perpendicular to the surface), we have shown that a layer of polyethylene glycol (PEG) adsorbed on a natural clay-layer surface is composed of three zones (proximal, central and distal) with different volume fractions.

Lubrication Performances of Polyalkylene Glycols at Steel Interface under External Electric Fields.

This work studied the lubrication performances of polyalkylene glycols, which are insulating oils, at the steel interface under external electric fields. The results show that external electric fields greatly affect the lubrication performances of polyalkylene glycols, and there is an optimal voltage (−1.0 V) for the improvement in friction reduction performance. The surface analysis and experiment results indicate that the polyalkylene glycol adsorption film and the reduction in the amount of FexOy and FeOOH in the tribochemical film contribute to improved friction performance under the negative voltage condition. This work proves that the lubrication performances of insulating oils can be affected by external electric fields as well. A lubrication model was proposed, hoping to provide a basic understanding of the lubrication mechanisms of ether-bond-containing insulating oils in the electric environment.

Electrochemical and leaching studies to better understand the role of ethylene glycol in the oxidative acid dissolution of chalcopyrite

It has been demonstrated that the combined use of organic compounds and acidic peroxide solutions greatly improves the dissolution kinetics of chalcopyrite. Among the additives employed, ethylene glycol (EG) is one of the most attractive for operating at moderate temperatures (20–50 °C). However, the role of EG in the leaching process is still not clearly understood, which limits optimization and industrial scale-up. For this reason, in this investigation, an electrochemical study was undertaken, using both a solid chalcopyrite (SE-Cp) electrode coupled to a rotating disk, as well as a chalcopyrite concentrate carbon paste electrode (CPE-CCp). Leaching experiments were also performed with EG and several other organic compounds, comparing the copper dissolved in each case. The results, in the mixed potential range of 0.55–0.75 V, showed that the presence of EG did not increase chalcopyrite oxidation. However, EG adsorption on the surface of the sulfide is sufficient to hinder hydrogen peroxide dismutation, the main cause of H2O2 decomposition in EG-free acidic solutions; at the same time, decreasing the interfacial tension favors chalcopyrite contact with the solution. Finally, the formation of similar products on the chalcopyrite surface, suggest that the organics additives do not alter the dissolution mechanism.

Modifier Effect in Silica-Supported FePO4 and Fe-Mo-O Catalysts for Propylene Glycol Oxidation.

Currently, catalytic processing of biorenewable raw materials into valuable products attracts more and more attention. In the present work, silica-supported FePO4 and Fe-Mo-O catalysts are prepared, their phase composition, and catalytic properties are studied in the process of selective oxidation of propylene glycol into valuable mono- and bicarbonyl compounds, namely, hydroxyacetone and methylglyoxal. A comparative analysis of the main routes of propylene glycol adsorption with its subsequent oxidative conversion into carbonyl products is carried out. The DFT calculations show that in the presence of adsorbed oxygen atom, the introduction of the phosphate moiety to the Fe-containing site strengthens the alcohol adsorption on the catalyst surface with the formation of the 1,2-propanedioxy (–OCH(CH3)CH2O–) intermediate at the active site. The introduction of the molybdenum moiety to the Fe-containing site in the presence of the adsorbed oxygen atom is also energetically favorable, however, the interaction energy is found by 100 kJ/mol higher compared to the case with phosphate moiety that leads to an increase in the propylene glycol conversion while maintaining high selectivity towards C3 products. The catalytic properties of the synthesized iron-containing catalysts are experimentally compared with those of Ag/SiO2 sample. The synthesized FePO4/SiO2 and Fe-Mo-O/SiO2 catalysts are not inferior to the silver-containing catalyst and provide ~70% selectivity towards C3 products, while the main part of propylene glycol is converted into methylglyoxal in contrast to the Ag/SiO2 catalyst featuring the selective transformation of only the secondary C-OH group in the substrate molecule under the studied conditions with the formation of hydroxyacetone. Thus, supported Fe-Mo-O/SiO2 catalysts are promising for the selective oxidation of polyatomic alcohols under low-temperature conditions.

Through Silicon Via Filling with Suppression Breakdown of PEG–Br– in Absence of Accelerator

The effects of halide ions on the adsorption of polyethylene glycol (PEG) and through-silicon via (TSV) filling were investigated. Halide ions on a Cu surface assist the adsorption of PEG, and the suppression effect of PEG–halide ion layers increases in the order of Cl– < Br– < I−. For all halide ions, suppression breakdown and negative differential resistance were observed, suggesting that the three halide ions with PEG potentially induce Cu bottom-up filling. However, we confirmed that only Br− enables Cu bottom-up filling, whereas Cl– results in conformal deposition and I– cannot complete bottom-up filling due to the low Faradaic efficiency. The PEG-Br– provides sufficient suppression strength, facilitating the formation of passive–active regions and enabling defect-free Cu filling without an accelerator. This study indicates that the property of the suppression layer contributes significantly to Cu bottom-up filling based on a passive–active filling mechanism.

Engineering Pt-Mn2O3 interface to boost selective oxidation of ethylene glycol to glycolic acid

Rational design of desirable active sites is still a grand challenge for the efficient conversion of polyols to value-added products. Herein, we successfully constructed the Pt-Mn2O3 interfacial sites rather than Pt-MnOx solid solution to boost selective oxidation of ethylene glycol to glycolic acid under mild conditions. X-ray absorption spectroscopy and high-resolution transmission electron microscope revealed that the pre-distribution of Mn2O3 inside support unexpectedly induced the formation of Pt-Mn2O3 interfacial active sites with strong electron coupling effect, leading to an unprecedented catalytic activity (turnover frequency: 3196.9 h−1) and glycolic acid yield (86.4 %). In addition, quantitative analysis of the intrinsic active sites was performed, and a “volcano-shape” relationship was established between initial reaction rate and Pt/Mn ratio. Moreover, the structure-dependent reaction kinetics and density functional theory calculation revealed that the synergistic effect between the Mn2O3 redox cycle and Pt promotes the adsorption of ethylene glycol and the activation of CH bond, resulting in the lower activation energy of ethylene glycol oxidation. The outcome of this work offers a promising avenue for the direct construction of efficient Pt-based catalysts with desired active sites.

Template-free synthesis and photocatalytic activity of hierarchical hollow ZnO microspheres composed of radially aligned nanorods

In this work, hierarchical hollow ZnO microspheres with an average diameter of 3.5 μm are successfully synthesized via a simple template-free solvothermal route. And these microspheres are constructed by anisotropic single-crystalline ZnO nanorods which grows along the [0001] c-axis direction because of the selective adsorption of ethylene glycol. It is noted that ethylene glycol plays a crucial role in promoting the growth and aggregation of nanorod by comparing the effect of other solvents, such as water, ethanol, isopropanol and glycerol. Furthermore, the photocatalytic activity of as-obtained hollow ZnO microspheres is evaluated by the degradation of methylene blue (MB) in aqueous solution. The photocatalytic performance reveals that these hollow ZnO microspheres can not only efficiently degradate the dye, but also show good stability during the cycling photodegradation.

Study of synergistic effect mechanism of compound polymer inhibitors adsorption on the surface of beta-dicalcium silicate based on molecular dynamics simulation

In the process of alumina clinker leaching, the effect of inhibiting the secondary reaction of compound polymer inhibitors composed of polyacrylic acid (PAA) and polyethylene glycol (PEG) adsorption on the surface of β-dicalcium silicate (β-C2S) was better than that of single polymer inhibitor (PAA or PEG). It was shown that there is a synergistic effect between PAA and PEG in the compound inhibitors, but the synergistic effect mechanism is not still clear. In this paper, molecular dynamics simulation (MD) was used to study the adsorption behavior of the compound inhibitors of PAA and PEG on the surface of β-C2S and synergistic mechanism between them during the adsorption process. The results showed that the density and stability of the polymer adsorption layer formed by the compound inhibitors on the surface of β - C2S and its ability to remove water molecules are better than that of the single inhibitor. The inhibition effect of the polymer adsorption layer formed by the compound inhibitors of PAA and PEG with a mass ratio of 2:2 is the best, which is consistent with the experimental results in the literature. During the adsorption process of the compound inhibitors on the surface of β-C2S, on the one hand, the compound inhibitors adsorbed on the surface of β-C2S depending on the interaction between functional groups of PAA and PEG with calcium and oxygen ions of the surface of β-C2S. On the other hand, the molecular chains of PAA and PEG polymer are mainly connected with each other by hydrogen bond, which was formed by the interaction between the hydroxyl hydrogen (Hhydroxy) in PAA and the etheryl oxygen (Oether) in PEG. The interaction of all of those can produce the synergistic effect between PAA and PEG in the adsorption process, which strengthen the adsorption of the compound inhibitors on the surface of β-C2S.

Suppressive Effects on Copper Electrodeposition, Induced by Adsorption of Polyethylene Glycol and Pluronic Surfactants

Suppressive Effects on Copper Electrodeposition, Induced by Adsorption of Polyethylene Glycol and Pluronic Surfactants