Adsorption Film Research Articles

Research on the Anti-corrosion Performance of Corrosion Inhibitor under Salt Freeze-Thaw Cycles

In this study, a multifunctional corrosion inhibitor (referred to as CI) was incorporated into C30 concrete. The effect of CI on the free chloride content, Tafel curves of reinforcement, and quality loss rate (QLR) were investigated under salt freeze-thaw cycles (SFTCs). Additionally, the scanning electron microscope (SEM) was employed to examine the corrosion of the reinforcement surface. The results indicated that CI was beneficial in reducing the internal free chloride content within the concrete. It could also form an adsorption film on the reinforcement surface, effectively lowering the corrosion rate and minimizing QLR, and providing excellent protection for the steel reinforcement.

Friction and Corrosion Properties of Phytic Acid Ionic Liquid-water Mixtures.

The study involved the preparation of mixtures of phytic acid ionic liquid and water, which were analyzed for their rheological, frictional, and electrochemical properties. The viscosity and friction characteristics of the mixtures are significantly affected by the water content. Mixtures with low water content (below 30%) result in low friction and negligible wear because of the generation of a close adsorption film and high viscosity. Especially, steel tribo-pairs lubricated with mixtures containing 25% water exhibited friction coefficients lower than 0.06. However, when the water content exceeds 35%, the friction coefficient increases dramatically, and the tribo-surface suffers from severe corrosive wear due to the predominance of tribocorrosion in the frictional properties. These results were confirmed through XPS and electrochemical testing.

The effect of aromatic side chains on the dilational rheological properties of N-acyltaurate amphiphiles at water-decane interfaces.

To elucidate the effect of aromatic side chains on dilational rheological properties of N-acyltaurate amphiphiles at the decane-water interface, the interfacial rheological properties of sodium N-2-(2-naphthoxy)-tetradecanoyltaurinate (12+N-T) and sodium N-2-(p-butylphenoxy)-tetradecanoyltaurinate (12+4B-T) were investigated utilizing the drop shape analysis method. The effects of adsorption time, interfacial pressure, oscillating frequency, and bulk concentration on the interfacial dilational modulus and phase angle were explored. The results show that the 12+4B-T molecule with a longer hydrophobic chain shows a higher ability for reducing the interfacial tension (IFT). In addition, the interfacial films of both 12+N-T and 12+4B-T are dominated by diffusion exchange at high concentrations. The rigidity of molecules controls the diffusion exchange at low concentrations, while the molecular hydrodynamic radius determines the diffusion exchange at high concentrations. Thus, at low concentrations, the stronger intermolecular interaction between 12+4B-T molecules results in higher dilational modulus values than 12+N-T. When approaching the CMC (critical micelle concentration) value, the rapid diffusion exchange of 12+4B-T between the sublayer micelles and the interface causes a significant decrease in the dilational modulus, while the relatively rigid structure of 12+N-T enables a higher dilational modulus than 12+4B-T. What's more, the longer hydrophobic chain allows 12+4B-T molecules to escape from the interface more easily, resulting in a higher phase angle at low concentrations. However, the diffusion exchange of 12+4B-T is slower than that of 12+N-T, which results in lower phase angles for 12+4B-T than 12+N-T at high concentrations. In general, the introduction of a rigid naphthalene ring in the molecular structure gives the interfacial film greater strength at high concentration. The research results in this paper provide a new technique for the strength regulation of interfacial surfactant adsorption films.

Multi-time scale thermal tribological dynamics coupling model of the helicopter intermediate reducer under severe loss of lubrication

There is no lubrication in the contact area, which leads to a significant influence of the thermal characteristics on the friction dynamics and life of the helicopter intermediate reducer because the helicopter experiences severe loss of lubrication. In this study, for evaluating the non-linear friction dynamics and transient thermal network models of the intermediate gearbox, a multi-time scale coupling method was proposed to establish a proportional allocation method between the oil film region and the rough peak contact region of the tooth surface by considering the effect of temperature and to study the adsorption film under the condition of severe lubrication loss. The coupled thermal and kinetic characteristics of the severe lubrication loss condition were obtained by calculating the friction coefficients in the lubricated and dry-friction regions. The results showed that the friction coefficient of the bevel gear tooth surface fluctuated between 0.1 and 0.6, and the degree of the gear axis trajectory shift was more evident owing to the increase in the friction force excitation caused by the increase in the friction coefficient.

Synergistic effect of surfactant and 1,10-decanedithiol as corrosion inhibitor for zinc anode in alkaline electrolyte of zinc-air batteries

The self-discharge by corrosion of zinc-air batteries (ZABs) will result in the reduced coulombic efficiency and lower energy efficiency. The additives in electrolyte should not only inhibit the occurrence of self-corrosion during battery dormancy, but also achieve a stable cycle of adsorption–desorption during battery operation, improving the durability of discharge cycles. But the former requires strong binding between additives and zinc to form a dense protective film, while the latter requires easy desorption of additives and zinc without affecting discharge power, which is contradictory to balance. In this study, a dynamic combination of additives and zinc, as well as a design of multi-channel strategy for the corresponding protective layer, have been proposed to solve the issues of self-corrosion and discharge cycle stability. Specifically, the surfactant (octylphenol polyoxyethylene ether phosphate (OP-10P)) and 1,10-decanedithiol (DD) have been selected as the combined anti-corrosion additives in ZABs with concentrated alkaline solution. The synergistic inhibition mechanism and the stabilization mechanism in zinc-air full cells have been studied systematically. The results indicated that the combined inhibitors inhibited the self-corrosion of Zn efficiently in the dormancy, and the inhibition efficiency reached 99.9 % at the optimized proportion. OP-10P achieve the preferential adsorption on the zinc surface, and then the chelates of DD with Zn2+ deposit on the outer layer to form the protective film with fine hydrophobic performance. The stability of ZABs in discharge and charging cycles has been improved owing to the multilayer adsorption film on zinc surface, which retains ion transport channels with the homogeneously pores to weaken the dendrites and side reactions during galvanostatic cycles. A probable model on zinc surface was established to discuss the actual working mechanism.

Effect of the Molecular Structure of 1,3-Diketones on the Realization of Oil-Based Superlubricity on Steel/Steel Friction Pairs.

In this article, five kinds of 1,3-diketones and their chelates with different molecular structures were prepared, and their tribological properties were tested. The experimental results show that the running-in time and friction coefficient of the friction pairs lubricated by 1,3-diketones containing a benzene ring increased with the increase of the carbon chain length. In addition, only the friction pair lubricated by 1-(4-ethylphenyl)-butane-1,3-dione (0201) and 1-(4-ethylphenyl)-nonane-1,3-dione (0206) could achieve stable superlubricity. When the benzene ring was replaced with a carbon six-membered ring, it was found that although the friction pair lubricated by this lubricant could achieve superlubricity, the wear of the friction pair was severe, and obvious abrasive wear occurred. In addition, the lubricants prepared by mixing 1,3-diketones and the corresponding chelates in a ratio of 4:6 had greatly improved lubricating properties compared to 1,3-diketones. Through X-ray photoelectron spectroscopy (XPS) analysis of the surface of the friction pair after the test and Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses of 1,3-diketones before and after the experiment, we found that the necessary conditions for the friction pair lubricated by 1,3-diketone to achieve superlubricity were formation of tribochemical adsorption films and the presence of chelates in solution.

Synergistic effect between two quaternary ammonium salts and thiourea as corrosion inhibitors for X70 steels in CO2 saturated 3.5% NaCl solution

Pyridine and quinoline quaternary ammonium salts (1-CPN and 1-CQN) were synthesized. The synergistic effects with different molar ratios of TU were investigated using weight loss, electrochemical measurements, surface characterization and theoretical calculations. The results showed that 1-CPN and 1-CQN had significant synergistic corrosion inhibition effects when combined with TU. The best synergistic effect occurred at 1-CPN/1-CQN:TU = 3:1, which had been proved by weight loss, electrochemical measurements and theoretical calculations. The mixture of 1-CPN/1-CQN with TU produced a denser adsorption film on the X70 steels surface, effectively inhibiting the corrosion process. Additionally, an intermolecular synergistic mechanism was proposed.

Dynamic host-guest interfacial recognition of alginate-based β-cyclodextrin/cholic acid supra-amphiphiles for stabilizing multi-type Pickering emulsion

The multi-type Pickering emulsions were formed by macromolecule-based soft colloidal emulsifiers due to its great architectural tailorability. Herein, the supramolecular β-cyclodextrin-modified alginate/cholic acid-grafted alkyl chain (SA-CD/CA-C12) system was designed by β-CD/CA-engineered host-guest molecular recognition at oil-water interface. Especially, supra-amphiphilic SA-CD/CA-C12 self-assemblies acted as excellent colloidal surfactant with high interfacial activity (0.74 mN/m), and the interfacial adsorption films exhibited higher coverages and thickness in contrast to that of alone amphiphilic SA-CD, and CA-C12 system, further preventing interdroplets aggregation, collision, and coalescence. Furthermore, the W/O, bicontinuous, and O/W emulsions were generated by altering the oil/water volume ratio due to the dynamical host-guest recognition-induced self-regulated flexibility of macromolecular architectonics. Additionally, the microstructures of supramolecular host-guest emulsion-templated aerogel were regulated by tuning the aggregation behaviors of supramolecular host-guest interfacial system, providing a new strategy for engineering soft materials.

Constructing a viscoelastic film for enhanced oil recovery via self-adsorption of amphiphilic nanosheets at oil-water interface

Immiscible liquid-liquid interfaces have widespread applications in drug delivery, oil-water separation, oil recovery, emulsion and foam stability, etc. Here, a dense viscoelastic interface film is constructed via the self-adsorption of amphiphilic molybdenum disulfide nanosheets at the oil-water interface, which has significant implications for enhanced oil recovery. The microscopic dispersion characteristics of amphiphilic nanosheets in water phase are characterized using Cryo-EM, and the adsorption regularities of amphiphilic nanosheets in horizontal and vertical directions of oil-water interface are also revealed. Besides the mechanical response and rheological properties of interface adsorption film are systematically studied. Experimental results demonstrate that the amphiphilic nanosheet can self-curl to form a single amphiphilic nanosheet with a size of 30 nm in the water phase as the amphiphilic nanosheets concentration is lower than 50 mg/L. When the amphiphilic nanosheets concentration reaches 100 mg/L, obvious water-phase aggregation behaviors happen. The amphiphilic nanosheets can reduce the oil-water interfacial tension from 18.47 mN/m to 0.27 mN/m by forming multilayer adsorption at the oil-water interface. The adsorption ratio of amphiphilic nanosheets from bulk phase to oil-water interface can reach 97.50 %. In addition, the oil-water interface adsorption film exhibits excellent elastic properties and higher strength because the amphiphilic nanosheets can form a planar network structure at the oil-water interface which can be also directly observed in microfluidic pores. The storage modulus and interface shear viscosity of interface adsorption film are 1.65 Pa and 1.38 mN·s/m, respectively. In theory, the required desorption energy of a single amphiphilic nanosheet from oil-water interface to bulk phase is deduced to be 587 KBT. This work is expected to provide amphiphilic molybdenum disulfide nanosheet as an effective candidate for enhanced oil recovery.

Low-viscosity oligoether esters (OEEs) as high-efficiency lubricating oils: Insight on their structure–lubricity relationship

Development of energy-efficient lubricants is a way to reduce energy consumption for transportation, with the tendency to design molecules that are beneficial in reducing the viscosity of synthetic oils. Oligoether esters (OEEs), as a low-viscosity ester base oil, have characteristics such as simple synthesis and excellent lubrication effect, however, the application of OEEs in tribology field has rarely been investigated. The objective of the present study is to investigate the effect of structure on the lubricating performance of OEEs and to develop a predictive model for OEEs based on quantitative structure-property relationship (QSPR) through a combination of experiment and statistical modeling. Results showed that glycol chains contribute positively to lubrication with the ether functional groups increasing the sites of adsorption. Compared to branched-chain OEEs, straight-chain OEEs exhibited reduced wear, which was mainly due to the thicker adsorption film formed by the straight-chain structure. Furthermore, carbon films were detected on lightly worn surfaces, indicating that OEEs underwent oxidation during the friction process. Based on the results of principal component analysis (PCA) and partial least squares (PLS), it could be found that the predictive models of viscosity–temperature performance, thermal stability performance, coefficient of friction (COF), and wear volume (WV) performed well and robustly. Among them, COF and WV can be best predicted with an R2 of about 0.90.

Significantly enhanced tribological properties of PTFE/PEEK fabric composites by macroporous metal − organic frameworks with solid–liquid synergistic lubrication

In this work, a macroporous oil-containing metal–organic framework material (CuBTCO) was prepared by a solvothermal method and vacuum impregnation. The tribological behaviors of PTFE/PEEK fabric composites (PFC) filled with CuBTCO were evaluated by the pin-on-disk tribometer under different loads. The coefficient of friction and mass wear rate of PFC containing 6 wt% CuBTCO (PFC-CuBTCO-6 %) were 0.017 and 1.1 × 10-9 g/(Nm), respectively, which were reduced by 63.8 % and 76.3 % in comparison to PFC containing 6 wt% CuBTC under the same conditions. The excellent tribological properties of PFC-CuBTCO-6 % are attributed to the solid–liquid synergistic lubrication between the adsorption film formed by the oleylamine released from CuBTCO and the PTFE-based transfer film. This work provides a novel approach for the structural design of solid–liquid synergistic lubrication of fabric liner composites.

Corrosion Inhibition Mechanism of Water-Soluble Imidazoline on A572 Gr.65 Steel in 3.5 wt % NaCl Solution.

To optimize the economic advantages and corrosion-resisting property of A572 Gr.65 steels, the inhibition effect of water-soluble imidazoline on the sample surface with rare earth was explored in a 3.5 wt % NaCl solution. In this paper, the mechanism of corrosion and the adsorptive behavior of water-soluble imidazoline inhibitors on A572 Gr.65 steels with 47 ppm of rare earth in saltwater solution were discussed, along with the establishment of the adsorption model. Achievements proposed that the inhibition efficiency of water-soluble imidazoline was as high as 95.73% at 80 mg L-1 dosage following an anodic-dominated mixed-type inhibition mechanism. Besides, the scanning electron microscopy and X-ray diffraction analysis revealed that the corrosion inhibitor resulted in a smoother and more stable rust layer with a significant reduction of the γ-FeOOH. Theoretical calculations confirmed that imidazoline formed a unimolecular layer adsorption film on the steel surface, exhibiting adherence to both Langmuir and Frumkin adsorption isotherms, involving physical and chemical adsorption.

Synthesis of oxidized carboxymethyl cellulose-chitosan and its composite films with SiC and SiC@SiO2 nanoparticles for methylene blue dye adsorption

The cationic methylene blue (MB) dye sequestration was studied by using oxidized carboxymethyl cellulose-chitosan (OCMC-CS) and its composite films with silicon carbide (OCMC-CS-SiC), and silica-coated SiC nanoparticles (OCMC-CS-SiC@SiO2). The resulting composite films were characterized through various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). The dye adsorption properties of the synthesized composite films were comprehensively investigated in batch experiments and the effect of parameters such as contact time, initial dye concentration, catalyst dosages, temperature, and pH were systematically evaluated. The results indicated that the film's adsorption efficiency was increased by increasing the contact time, catalyst amount, and temperature, and with a decreased initial concentration of dye solution. The adsorption efficiency was highest at neutral pH. The experimental results demonstrated that OCMC-CS films have high dye adsorption capabilities as compared to OCMC-CS-SiC, and OCMC-CS-SiC@SiO2. Additionally, the desorption investigation suggested that the adsorbents are successfully regenerated. Overall, this study contributes to the development of sustainable and effective adsorbent materials for dye removal applications. These films present a promising and environmentally friendly approach to mitigate dye pollution from aqueous systems.

Invasive weed of Mikania micrantha extract as a novel efficient inhibitor for the corrosion of aluminum in HNO3 solution

The inhibition effect of Mikania micrantha extract (MME) on 1060 aluminum corrosion in 0.10 M HNO3 was investigated by both experimental and theoretical methods. The results demonstrate that MME performs excellent inhibition with the maximum inhibition efficiency of 97.6% at 0.50 g L-1. The adsorption of MME on aluminum surface obeys Langmuir, Freundlich, Temkin, El-Awady thermodynamic-dynamics, Flory-Huggins isotherm, and it is a mixed-type inhibitor. Nyquist consists of a capacitive loop at high frequency, an inductive loop at medium frequency, and a small capacitive section at low frequency. The impedance of EIS is gradually enhanced along with the increase of MME concentration. SEM and AFM images confirm that MME can efficiently retard the metallic corrosion. XPS demonstrates that the adsorptive inhibition film is composed of polar functional groups containing C and O elements of CO, C─OH/C─O─C, C─H/C─C from MME. LC-MS illustrates that MME contains multiple active ingredients of quercetin, caffeic acid, vanillin and guanine. The anti-corrosion effect of MME is mainly attributed to the synergistic effect of multi-components. Quantum chemical calculations and MD simulations indicate that the presence of multiple active sites in quercetin, caffeic acid, vanillin and guanine, including benzene/heterocyclic and carboxyl groups, facilitates their interaction with aluminum surface.

Chloride transportation and electrochemical behavior of concrete containing corrosion-inhibiting admixture and its inhibition mechanism under compound salt and drying-wetting cycles

The purpose of this study is to provide an ecological corrosion-inhibiting admixture (CIA) for retarding the degradation of reinforced concrete under compound salt attack and drying-wetting cycles. The effects of CIA on the mechanical behavior, chloride transportation, and electrochemical behavior of concrete under compound salt and drying-wetting cycles were investigated. The pore contents with different sizes in concrete and the micro-morphology of rebars were analyzed by the bubble spacing coefficient analyzer and the scanning electron microscopy (SEM), respectively. The findings showed that the addition of CIA retarded the deterioration of concrete under compound salt and drying-wetting cycles. After exposure for 150 d, the weight loss rate and average free chloride concentration of concrete containing 5 % CIA decreased by 74.14 % and 51.53 % respectively, and the compressive strength was 1.49 times that of concrete without CIA. Chloride transportation was primarily dominated by diffusion and convection. Additionally, CIA significantly reduced the content of larger pores, prevented the diffusion of chloride and sulfate into the interior concrete, and formed adsorption films through a combination of physical and chemical effects, thus improving the electrochemical performance of rebars. This study is of great significance to provide new perspectives and improvement measures for mitigating the deterioration of reinforced concrete under compound salts and drying-wetting cycles.

Mechanochemical in-situ construction of ionic liquid-functionalized covalent organic frameworks for anti-wear and friction reduction

Herein, ionic liquid-functionalized covalent organic frameworks (COFs) were prepared via mechanochemical reaction. The rich-aldehyde terminated COFs (LZU1) was firstly synthesized via the excess aldehyde monomer and amino monomer. Then, the ionic liquid (NH2-IL) with amino group can graft onto the aldehyde terminated-COFs through Schiff base reaction between amino and aldehyde group driven by ball milling, and then through anion-exchange with NTf2- resulting in the ionic liquid-functionalized COFs (LZU1-NH2IL-NTf2). The LZU1-NH2IL-NTf2 displays good lubricating performance as lubricant additive, the friction coefficient is maintained at 0.106 and the wear volume is reduced by 85.4% compared with 500SN. The remarkable lubrication performance is mainly due to the physical adsorption film promoted by ionic liquid and the robust protective film formed by tribochemical reaction.

Investigation of the Nonionic Acidizing Retarder AAO for Reservoir Stimulation.

In the process of matrix acidizing, reducing the reaction rate between hydrochloric acid and carbonate rock to increase oil and gas production has become one of the biggest challenges in reservoir stimulation. An adsorption film formed on rocks can effectively postpone the contact between the hydrogen ion and rock, which is of great significance in decreasing the rate of an acid-rock reaction. In this study, nonionic acidizing retarder AAO was synthesized by acrylamide, allyl poly(ethylene glycol), and octadecyl methacrylate. The structure of AAO was characterized by Fourier transform infrared (FT-IR) spectrometry and 1H nuclear magnetic resonance (1H NMR). The reaction of AAO retard acid and 20% hydrochloric acid with CaCO3 was studied at 50 °C, and the amount of CO2 generated at different times was recorded. The etching time of 0.8% AAO retard acid to CaCO3 could be up to 120 min, whereas 20% hydrochloric acid (without AAO) ended at 45 min, which showed that AAO had the potential to defer the acid-rock reaction. The adsorption behavior of AAO on CaCO3 matched the pseudo-second-order kinetic model well. Meanwhile, the addition of urea greatly reduced the adsorption amount of AAO on CaCO3, which showed that the hydrogen bond was the driving force for the adsorption process. Additionally, the results of X-ray photoelectron spectroscopy (XPS) showed that the N element from acrylamide appeared on the surface of CaCO3 after adsorption. Scanning electron microscopy (SEM) demonstrated that a smooth and dense thin film existed on the surface of CaCO3 treated with AAO retard acid. The change in the vibration peak of C=O from 1720 to 1650 cm-1 indicated that the ester groups in AAO had been hydrolyzed, which was beneficial to film desorption and the reduction of reservoir damage. Therefore, this paper could help with research on carbonate acidizing for reservoir stimulation.

Anchor Group Bottlebrush Polymers as Oil Additive Friction Modifiers.

Surface-tethered polymers have been shown to be an efficient lubrication strategy for boundary and mixed lubrication by providing a solvated film between solid surfaces. We have assessed the performance of various graft copolymers as friction modifier additives in oil and revealed important structure-property relationships for this application. The polymers consisted of an oil-soluble, grafted poly(lauryl acrylate) segment and a polar, linear poly(4-acryloylmorpholine) anchor group. Reversible addition-fragmentation chain transfer polymerization was used to access various architectures with control of the grafting density and position of the anchor group. Macrotribological studies displayed promising results with ≈50% reduction in friction coefficient at low polymer treatment rates. QCM-D experiments, neutron reflectometry, small-angle neutron scattering, and atomic force microscopy were used to gather detailed information on these polymers' surface adsorption characteristics, film structure, and solution behavior.

Adsorption Dynamics of Uremic Toxins to Novel Modified Magnetic Nanoparticles.

Kidney dysfunction leads to the retention of metabolites in the blood compartment, some of which reach toxic levels. Uremic toxins are associated with the progression of kidney disease and other symptoms of kidney failure (i.e., nausea, itchiness, and hypertension). Toxin removal ameliorates symptoms and reduces further organ damage, but membrane-based methods are inadequate for this purpose. Engineered adsorbents may facilitate enhanced removal of retained toxins, especially those bound strongly by proteins. Poly 2-(methacryloyloxy)ethyl phosphorylcholine-co-β-cyclodextrin (p(MPC-co-PMβCD)) coated magnetic nanoparticles are synthesized, characterized for their physicochemical properties (Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetric analysis(TGA), gel permeation chromatography(GPC), and transmission electron microscope (TEM), and evaluated toxin adsorption from a complex solution for the first time to quantify the effects of film chemistry and incubation time on the adsorbed toxinome (the collection of toxins). Uremic toxins are bound by even "low-fouling" polymer films themselves; providing further insight into how small molecule interactions with "low-fouling" films may affect protein-surface interactions. These results suggest a dynamic interaction between toxins and surfaces that is not driven by solution concentration alone. This knowledge will help advance the design of novel adsorbent films for clearing uremic toxins.

Inhibition effect of nano-silica synergistic corrosion inhibitor on 110SSsteel in ultra-high temperature organic acidic environment

ABSTRACT Compared to hydrochloric acid, organic acids can reduce the acid rock reaction rate in high-temperature reservoir acidification. Although corrosion inhibitors can reduce the corrosion of acid on the pipe string, the ultra-high temperature makes the effectiveness of corrosion inhibitors unsatisfactory. We found that the use of nano-silica can improve the effectiveness of corrosion inhibitors in organic acid systems. Some interesting findings are as follows. Firstly, the ultra-high temperature made the adsorption film of LD-H uneven or incomplete. Next, the high-temperature corrosion inhibition ability of corrosion inhibitors was enhanced by adding nano-silica to organic acids, with a corrosion inhibition rate of up to 99%. Furthermore, the addition of nano-silica made the adsorption membrane of LD-H more complete or uniform, which more effectively inhibited corrosion reactions. By enhancing the adsorption capacity of corrosion inhibitors and filling adsorption membranes, nano-silica enhanced the corrosion inhibition effect of LD-H in organic acid systems.