Adsorption Of Amines Research Articles

Adsorption and hydrophobic action of different surfactants on montmorillonite Na-001 surface: a molecular simulation study

Montmorillonite (Mt) is a typical clay mineral in tailings, and its strong hydrophilicity is easy to lead to the instability of tailings dam structure and the difficulty of tailings wastewater treatment. The influence of different types of surfactants on the Mt Na-001 surface hydrophobicity was analysed from the perspective of adsorption energy, electron transfer and concentration distribution. DFT simulation results showed that the adsorption effect of surfactant was cationic > anionic > non-ionic, and the best surfactant were methyl primary amine, methyl sulfonic acid and methyl formate. The MD simulation results of the adsorption of dodecyl primary amine (DDA) and sodium dodecyl sulfonate (SDS) with different coverage on the surface of Mt Na-001 showed that the adsorption effect of DDA and SDS was significantly improved with the increase of coverage, and DDA was significantly better than SDS, and the optimal coverage of DDA was 1 ML. Finally, the reason why DDA is superior to SDS was explained from the concentration distribution of water and Na+ on Mt surface. This simulation calculation study can provide micro-level insights for solving practical engineering problems.

Feasibility and Effectivity of an Amine-Grafted Alumina Adsorbent for Direct Air Capture.

Direct air capture (DAC) has been identified as a necessary negative emission technology (NET) to solve global warming. DAC methods have been divided into two major types: solvent absorption and sorbent adsorption. Aqueous amine absorption is the major method in postcombustion carbon capture, not in DAC because contactors blow large volumes of air over the solvent, which results in high evaporation of solvents. Solid amine adsorption has been one of the primary methods of DAC due to its low volatility of amine. Therefore, the development of DAC adsorbents is the key to improve CO2 capture efficiency. Nowadays, the research on adsorbents mainly focuses on amine impregnation and grafting. The grafting adsorbents generally have better stability than impregnation adsorbents. Silica is the most common support material for amine-grafted adsorbents. Nonetheless, silica has some defects, such as poor hydrothermal stability, which limits its employment. Alumina is a promising support material with excellent hydrothermal stability, but studies on amine-grafted alumina are still scarce. Herein, a method of 3-[2-(2-aminoethylamino)ethylamino] propyltrimethoxysilane (TRI) grafting onto γ-alumina is presented. The results of this paper suggest that alumina is a potential support material for amine grafting. The CO2 adsorption capacity of the adsorbent is 0.39 mmol g-1 at 400 ppm and 25 °C. The amine-grafted alumina has excellent thermal stability than the amine-impregnation silica adsorbent. Besides, the adsorbent exhibits stable performance during cycles, with the working capacity maintained at 83% of that of the first cycle after 60 cycles. Water adsorption capacity and selectivity indicate that TRI-Al2O3 has good selectivity at high relative humidity. These findings make amine-grafted alumina a promising DAC adsorbent.

Effect of Pre-Sulfidization on the Octadecyl Amine Adsorption on the Smithsonite Surface and Its Flotation.

The low-grade zinc oxide ore was sulfidized to increase the efficiency of flotation, but the effect of pre-sulfidization on the adsorption mechanism of octadecyl amine (ODA) on the smithsonite surface is currently unclear. In this study, the effect of pre-sulfidization on the adsorption mechanism of ODA and the flotation behavior was studied using smithsonite and pre-sulfidized smithsonite as the samples by zeta potential, contact angle measurement, total organic carbon analyzer (TOC), quartz microcrystalline balance (QCM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and micro-flotation tests. Micro-flotation tests showed that the pretreatment of sulfidization could improve the floatability of smithsonite. Zeta potential and contact angle measurements demonstrated that pre-sulfidization could favor the adsorption of ODA, which is further confirmed by the adsorption tests of ODA using TOC and QCM. Furthermore, FTIR and XPS analysis showed that pre-sulfidization changes the adsorption mode of ODA, changing it from physical adsorption to chemical adsorption. These results suggested that the favorable effect of pre-sulfidization on the adsorption of ODA and the flotation of smithsonite might provide important guidance for industrial application.

Assembly of primary secondary amine over magnetic graphitized carbon black material for selective cleansing of sample matrices

Pigments and organic acids are among the most common impurities in complex sample matrices. Their presence in the samples often interferes with the detection of trace analytes. This study aimed to design and develop magnetic materials (GCB/Fe3O4-PSA) for the efficient purification of organic acids and pigment impurities in sample matrices. We employed the acid modification method to enhance the modification of magnetic Fe3O4 by the primary secondary amine adsorption group (PSA), effectively boosting its adsorption performance. This modification technique not only retains the inherent adsorption characteristics of Fe3O4 but also avoids the irreversible damage to Fe3O4′s own adsorption by traditional grafting methods. Subsequently, Fe3O4-PSA and graphitized carbon black (GCB) were combined through a simple physical assembly method to prepare GCB/Fe3O4-PSA, which was used for the purification of pigments and organic acids in complex matrices. During the purification process, GCB/Fe3O4-PSA can be rapidly magnetically separated. After six reuses, the adsorption performance remains above 80 %, fully demonstrating the rapid purification ability and reusability potential of GCB/Fe3O4-PSA. Compared with unmodified Fe3O4, GCB/Fe3O4-PSA significantly enhanced the purification effect of complex matrices. Its adsorption capacities for chlorophyll and ascorbic acid increased by 276.9 % and 263.9 % respectively. After combining with the GCB/Fe3O4-PSA purification material, cathinones in complex matrix samples (tea, apples, carrots) were determined using UPLC-MS/MS. The recoveries in spiked samples ranged from 96.35 % to 104.17 %, with the RSDs < 3.02 %. Simultaneously, characterization methods such as SEM, FTIR, XRD, VSM, XPS, and BET were used to study the surface structure and chemical composition of GCB/Fe3O4-PSA. The above results highlight the outstanding performance of GCB/Fe3O4-PSA in the efficient purification of organic acids and pigments in complex matrices and also show its considerable application potential in the pretreatment of complex matrix samples.

Use of Ball Drop Casting and Surface Modification for the Development of Amine-Functionalized Silica Aerogel Globules for Dynamic and Efficient Direct Air Capture.

Amine-functionalized silica aerogel globules (AFSAGs) were first synthesized via a simple ball drop casting method followed by amine grafting. The effect of grafting time on the structure and CO2 adsorption performance of the AFSAGs was investigated. The CO2 adsorption performance was comprehensively studied by breakthrough curves, adsorption capacity and rates, surface amine loading and density, amine efficiency, adsorption halftime, and cyclic stability. The results demonstrate that prolonging the grafting time does not lead to a significant increase in surface amine content owing to pore space blockage by superabundant amine groups. The CO2 adsorption performance shows obvious dependence on surface amine density, determined by both the surface amine content and specific surface area, and working temperature. AFSAGs with a grafting time of 24 h (AFSAG24) with a moderate surface amine density have optimal CO2 adsorption capacities, which are 1.78 and 2.14 mmol/g at 25 °C with dry and humid 400 ppm CO2, respectively. The amine efficiency of AFSAG24 with low CO2 concentrations, 0.38-0.63 with dry 400 ppm-1% CO2, is the highest among the reported amine-functionalized adsorbents. After estimation with different diffusion models, the CO2 adsorption process of AFSAG24 is governed by film diffusion and intraparticle diffusion. In the range of 1-4 mm, the ball size does not affect the CO2 adsorption capacity of AFSAG24 obviously. AFSAG24 offers significant advantages for practical direct air capture compared with its state-of-the-art counterparts, such as high dynamic adsorption capacity and amine efficiency, excellent stability, and outstanding adaptation to the environment.

Polyamine functionalized cage hollow mesoporous SiO2 microspheres for CO2 capture over a wide temperature range

Hollow SiO2 microspheres have become attractive materials for nanotechnology applications owing to their biological inertness and high functionality. In this study, hydrophobic spherical hollow cages were formed using the soft stencil method with Pluronic F127 and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent, and hollow nanoporous SiO2 microspheres (FHMS) were prepared using the soft template method. Various of amine functionalization modes were further employed to demonstrate the complexity of the relationship between pore structure/amidation mode/amine content and adsorption capacity. The hollow morphology of the porous silica was revealed using field-emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and its porous properties were revealed using nitrogen adsorption-desorption isotherm measurements. Experiments on the fixed-bed dynamic adsorption process at 15% CO2 showed that the high specific surface area, high pore volume and amine content of the carriers had a positive effect on the adsorption performance. However, the accessibility of the adsorption centre was affected at high loadings, and the amine efficiency and adsorption capacity were reduced. The dual amine functionalized FHMS-G-I60 maintained the integrity and order of the hollow mesoporous carrier structure, and overcame the dilemma of easy loss in the cycle process of the impregnation method and the low adsorption capacity of the grafting method. It possessed an adsorption capacity of 3.62 mmol/g, high adsorption cycling stability (more than 99.5% adsorption maintained after 10 cycles) and high amine efficiency (0.2852 mmol CO2/mmol N). CO2-TPD analysis (Thermal Programmed Desorption) further showed that FHMS-G-I60 had a faster desorption rate and lower regeneration energy consumption. In general, such structure-directed prepared matrices and functionalized with different amines are promising and low-cost adsorbents that can be used to capture CO2 from ambient air and flue gases under different demands.

A modulator-induced defect strategy to construct different mesopore ratios Zr-based metal-organic frameworks for ultrafast adsorption of heterocyclic aromatic amines

The platform of isostructural crystalline metal-organic frameworks (MOFs) with structural defects and additional pores is an emerging technology for rapidly removing hazardous small molecules. Herein, this paper designed a series of Zr-based MOFs (UiO-66) with different mesopore ratios by inducing linker/cluster missing through monocarboxylic acid modulators; besides their adsorption capacity and mechanism for heterocyclic aromatic amines (HAAs) were investigated. The UiO-66 defected with lauric acid (UiO-66-12A) showed the best adsorption performance and its adsorption capacity and rate for HAAs were 1.25–5.63 and 1.74–5.82 times higher than UiO-66, respectively. The zeta potentials of adsorbents in the presence of HAAs aqueous solutions underscore the pivotal role of electrostatic interactions during adsorption. Fourier Transform Infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) demonstrated that π-π stacking, coordination and hydrogen bonding interactions were also critical factors in promoting adsorption. Moreover, simulation calculations revealed that UiO-66 with missing clusters can provide more active sites and stronger interactions. These findings provided a novel and feasible strategy for the rapid removal of hazardous small molecules from complex food environments, which could improve the adsorption capacity and convenient processes of MOFs through building appropriate inherent microporous structures. The comprehensive and systematic understanding of the adsorption mechanism in this paper is conducive to the future advancement of nanomaterials.

Crystal transformation of metal–organic frameworks to boost visible-light photocatalysis via amine adsorption

A novel metal–organic framework (MOF) photocatalyst was synthesized via crystal transformation. It exhibited intrapore adsorption of organic amine due to host–guest interaction, resulting in high-efficiency amine-triggered perfluoroalkylation.

Synergy tetraethylenepentamine and diethanolamine impregnated within silica nanotubes derived from natural halloysite for efficient CO2 capture

Amine-impregnated porous solid adsorbents are promising commercial CO2 capture adsorbents for CO2 mitigation due to relatively large CO2 capacity and high CO2 selectivity. However, the intrinsic viscosity and aggregation of the polyamine leads to low amine efficiency and greatly limits its further development. In this work, a facile and efficient approach was carried out to manipulate the porosity of natural halloysite (HNTs) support with hollow tubular structure and impregnate mixed-polyamines, i.e., both tetraethylenepentamine (TEPA) and diethanolamine (DEA) to synergistically enhance CO2 adsorption capacity, fast adsorption kinetics and thermal/chemical stability compared to the individual supported TEPA and DEA. The effects of the blend amount for TEPA and DEA, adsorption temperature and CO2 partial pressure on CO2 adsorption capacity and adsorption kinetics were specifically discussed. Due to the auxiliary effect of DEA, the chemical reaction between non-hydroxylated TEPA and CO2 was altered thus improving amine efficiency and the agglomeration layer between protonated TEPA molecules and carbamate, which existed due to electrostatic interaction when TEPA was loaded alone, was loosened thus improving amine efficiency and adsorption kinetics. Therefore, the maximum CO2 adsorption capacity of MHNTs loaded with 20 wt% TEPA and 20 wt% DEA was 3.25 mmol/g at 75 °C in the flow of 40 vol% N2/60 vol% CO2. Compared with loading individual TEPA with multiple amino groups on MHNTs, individual DEA with hydroxyl groups could increase the utilization efficiency of the amino groups of TEPA and ultimately obtain excellent CO2 capture capacity and adsorption kinetics. The experimental results show that the adsorbents obtained in this study using mixed amine impregnated silica nanotubes derived from natural minerals have a promising application in practical CO2 capture and separation processes.

Rapid and large-capacity adsorption of heterocyclic aromatic amines on heat resistant two-dimensional metal organic layer/cellulose nanofiber aerogels constructed by a thawing cross-linking strategy

Composite aerogels, formed by the combination of nanoscale polymers and highly efficient adsorbents, offer the potential to deploy adsorbent distinct separation properties into a processable matrix. This paper presents a method for the fabrication of low energy bio-aerogels with high ductility, excellent wet strength and favorable heat resistance, based on cellulose nanofibers (CNFs) bound by calcium carbonate particles (CaCO3) via a simple process of ice induction, cross-linking during freezing and freeze-drying. Due to induced defects, two-dimensional metal-organic layers (MOLs) were rich in mesoporous structure and embedded in the aerogel (AGCa-MOL), which exhibited a powerful adsorption capacity. AGCa-MOL could take full advantage of their hierarchical pores and available surface area to obtain high adsorption capacity (0.694–5.470 μmol/g) and rapid adsorption kinetics (5 min) for 14 heterocyclic aromatic amines (HAAs). Moreover, the CaCO3 particles and MOLs gave the AGCa-MOL excellent thermal stability, so that it could maintain excellent adsorption capacity at a high temperature (100 °C) and be applied as an adsorbent to remove HAAs in the boiling marinade. The intrinsic potential of composite aerogels was revealed due to the synergistic properties of the various components in the composite aerogel.

Au/Nb2O5-catalyzed N-Formylation of Amines Utilizing High Selectivity to Formate Intermediate in CO2 Hydrogenation

Abstract Deformed orthorhombic niobium oxide-supported Au nanoparticles (Au/Nb2O5-DO) exhibited high catalytic activity for N-formylation of amines using CO2 and H2 compared to other Au/Nb2O5 catalysts having different crystalline structures. Au/Nb2O5-DO also showed high selectivity to methyl formate in CO2 hydrogenation. Nb2O5-DO possessed a greater amount of acid sites than Au/Nb2O5-T (orthorhombic) and Au/Nb2O5-A (amorphous), which would be beneficial for formate activation and amine adsorption.

Selective adsorption of volatile compounds of oyster peptides by V-type starch for effective deodorization

Oyster peptides extracted from oysters have strong off-odors, which hinders consumer acceptance. The “empty” V-type starches (V6a, V6h, V7a, V7h, V8a, and V8h) prepared from high amylose maize starch were used as adsorbents to improve the flavor of oyster peptides. The total adsorption rates measured through headspace gas chromatography mass spectrometry (HS-GC-MS) follow the order of V6a > V7a > V6h > V7h > V8a > V8h. Moreover, the V-type starches with different structures exhibit adsorption selectivity. The V6- and V7-type starches with a smaller cavity size show selective adsorption capacity for alcohols, acids, ketones and other similar classes of volatile compounds, while the V8-type starches with a larger cavity selectively adsorb amines. In addition, successful preparation of “empty” V-type starches were confirmed through X-ray diffraction (XRD), and the inclusion complexes (ICs) between V-type starches and volatile compounds of oyster peptides were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). It was found that the O/C ratio of V6a-ICs, V6h-ICs, and V7a-ICs increased, while that of V7h-ICs, V8a-ICs, and V8h-ICs decreased after the deodorization. Pearson's correlations indicated that the adsorption rates of aldehydes, alcohols, ketones, and alkanes have a significant negative correlation with temperature range (ΔT) and enthalpy change (ΔH). While a significant positive correlation was observed between the ratio of peak intensity at 1047/1022 cm−1 and the amine adsorption rate. These results suggested that V-type starch can improve the flavor of aquatic products effectively.

Model-Assisted Interpretation of 4,4'-Methylene Dianiline Adsorption on Soils at Micromolar Concentrations.

Adsorption kinetics and isotherms were determined for 4,4'-methylene dianiline (MDA) on five diverse soils at nominal concentrations of 0.01-1.0 mg L-1 (nominal soil loading 0.1-40 μg gs -1 ). The data were used to model the adsorption process based on the two-step mechanism that is characteristic of the adsorption of aromatic amines, consisting of a physical equilibrium between the aqueous phase and the soil organic matter and a chemical reaction between the adsorbed MDA and reactive sites in the soil organic matter. Generic parameters were determined that enabled application of the model to other soils, which was checked against previously published data for MDA adsorption. At the low concentrations evaluated, the adsorption process took place almost exclusively in the organic matter without the need to account for a separate ion exchange process with the soil mineral fraction. Physical adsorption was found to be mainly dependent on the protonation state of MDA and increased with decreasing pH of the soils. Because of the chemical reaction taking place, adsorption equilibrium constants (organic-carbon partition coefficient [KOC ]) normalized to the organic carbon content in the soil gradually increased with time; and it was demonstrated that, at steady-state conditions, values of log KOC > 3.5 can be expected for most any soil at conservatively estimated potential environmental MDA concentrations. Environ Toxicol Chem 2023;42:2580-2588. © 2023 SETAC.

Carboxyl-functionalized covalent organic frameworks for the efficient adsorption of foodborne heterocyclic aromatic amines

The development of sorbents with high sensitivity and specificity for the effective extraction and assessment of carcinogenic heterocyclic aromatic amines (HAAs) in thermally processed foods is of utmost significance for food safety monitoring. Herein, we report the design and synthesis of a carboxyl-functionalized covalent organic framework (COF), TpPa-(COOH)2, through the regulation of carboxyl modification and crystallinity. The resulting flower-like TpPa-(COOH)2 exhibited excellent crystallinity and microporosity in an eclipsed stacking structure. Compared to TpPa, the introduction of carboxyl moieties in TpPa-(COOH)2 provided additional binding sites and significantly enhanced adsorption affinity for the 16 target analytes, despite having a smaller BET surface area. The adsorption of HAAs by TpPa-(COOH)2 followed the pseudo-second-order model and exhibited rapid kinetics (10–30 min). The experimental data demonstrated a strong fit with the Freundlich isotherm model, resulting in a maximum adsorption capacity of HAAs ranging from 1.8 to 155.8 mg/g. Additionally, the presence of interfering compounds only caused a slight reduction in both the equilibrium adsorption capacity and HAAs recovery. Notably, TpPa-(COOH)2 maintained its effective adsorption performance even after three adsorption–desorption cycles. Theoretical calculations indicated that the rapid binding of HAAs to TpPa-(COOH)2 could be attributed to the joint effects of electrostatic interaction, π–π interaction, C–H–π interaction, lone pair–π interaction, and hydrogen bonding. This adsorbent exhibits a notable enhancement in both adsorption capacity and mass transfer rates for the adsorption of HAAs, surpassing the performance of the reported adsorbents. This highlights its substantial potential for the precise detection of HAAs within food systems.

Adsorption and flocculation properties of a binary system based on (co)polymers of acrylamide and low- molecular weight amine-containing surfactants in a saline medium

The process of flocculation of a calcium-magnesium solid phase formed in an aqueous-salt solution with the introduction of calcium-containing precipitants using polyacrylamide, cationic and anionic acrylamide copolymers was studied. With the introduction of polymers, an increase in the dispersion settling rate was observed in the concentration range of 0.5–3.0 mg/g, to a greater extent for the anionic copolymer. In the presence of an amine-containing surfactant, the sedimentation rate increased with the introduction of polymers by a factor of 1.1–1.3 compared to dispersions without surfactants. Using an anionic copolymer as an example, it was shown that the adsorption of amine and the sedimentation rate of dispersion increase with the increase of the polymer molecular weight. It was found that the concentration of the anionic copolymer and the pH of the medium also influence the adsorption of amine. Based on the obtained data, an effective method of water-salt solutions purification from amine-containing surfactants and magnesium salts (purification degree 99.5–99.8 %) that can be used at mining and processing enterprises was developed.

Recycling of cathode ray tubes and stone sludge for the synthesis of Al-MCM-41 grafted amine functional group and environmental humidity control material applications

There is a growing need for economical methods by which to reuse industrial waste. This paper reports on the recycling of industrial waste in the preparation of amine functionalized mesoporous molecular sieves (Al-MCM-41), for use as a building material applicable to the energy-free regulation of indoor humidity. The preparation of amine functionalized Al-MCM-41 for experiments involved combining stone sludge, cathode ray tube panel waste glass, an alkali agent (sodium hydroxide), and cetyltrimethylammonium bromide with aminopropyltriethoxysilane in various proportions. The water vapor adsorption of amine functionalized Al-MCM-41 (42.85 g/m2) far exceeded of amine functionalized Al-MCM-41 without surface grafting (28.64 g/m2). Al-MCM-41 with 2.5 vol% amine functional groups achieved the highest 24-h water vapor adsorption performance in compliance with JIS A 1470 standards. This research provides an economical approach to the recovery and recycling of industrial waste that is rich in silicon and aluminum.

Effects of MOFs size and functional group on the pore structure and performance of thin-film nanocomposite membranes

Incorporation of nanomaterials into the selective layer during the interfacial polymerization process was an effective way to improve the perm-selectivity of the membranes. In this study, the piperazine enriched templates assisted interfacial polymerization method was proposed to enhance the salts rejection of thin-film nanocomposite (TFN) membranes. The mono-dispersed UiO-66 type MOFs with high amine adsorption ability were utilized as templates to increase the reaction region and promote the participation of piperazine (PIP) during the interfacial polymerization reaction, resulting in a denser polyamide (PA) layer with weaker surface electronegativity and higher nitrogen-containing group contents. The TFN membranes prepared with 236 nm UiO-66-OH and PIP concentration of 0.35 w/v% exhibited smaller mean pore size (0.636 nm) and reduced surface zeta potential (−26.0 mV) compared to the pristine TFC membranes (0.667 nm and −31.1 mV). Consequently, the rejection of 10 mM MgCl2, MgSO4 and Na2SO4 was increased from 44.7%, 97.7% and 98.3% to 84.3%, 99.2% and 99.5%, respectively, while the pure water flux was slightly decreased from 53.5 L m−1 h−1 to 37.4 L m−1 h−1 at 0.3 MPa. In addition, the size and functional group of the MOFs were found to have significant impacts on the pore structure and performance of the TFN membranes. The increasing of reaction region with relatively large MOFs and higher absorption ability were beneficial to obtain a thicker PA layer, while strong interaction between MOFs and PA oligomers was unfavorable for PA chain packing. Therefore, the TFN membranes prepared with UiO-66-NO2 exhibited a much narrow size distribution and high rejection to all salts, whether by divalent cationic salt or divalent anion salts, i.e., MgCl2 of 95.5%, MgSO4 of 98.9% and Na2SO4 of 99.1%, and the pure water flux was 28.6 L m−1 h−1 at 0.3 MPa. These results illustrated the influences of MOFs size and functional group on the interfacial polymerization process, which was crucial for the TFN membranes preparation.

Understanding the effects of amine and morpholine adsorption on unglazed earthenware using density functional theory

Understanding the effects of amine and morpholine adsorption on unglazed earthenware using density functional theory

Amine Infused Fly Ash Grafted Acrylic Acid/Acrylamide Hydrogel for Carbon Dioxide (CO2) Adsorption and Its Kinetic Analysis.

In most carbon dioxide (CO2) capture processes, chemical absorption using an amine solvent is widely used technology; however, the solvent is prone to solvent degradation and solvent loss which leads to the formation of corrosion. This paper investigates the adsorption performance of amine-infused hydrogels (AIFHs) to increase carbon dioxide (CO2) capture by leveraging the potency of amine absorption and adsorption properties of class F fly ash (FA). The solution polymerization method was used to synthesize the FA-grafted acrylic acid/acrylamide hydrogel (FA-AAc/AAm), which was then immersed in monoethanolamine (MEA) to form amine infused hydrogels (AIHs). The prepared FA-AAc/AAm showed dense matrices morphology with no obvious pore at the dry state but capable of capturing up to 0.71 mol/g CO2 at 0.5 wt% FA content, 2 bar pressure, 30 °C reaction temperature, 60 L/min flow rate, and 30 wt% MEA contents. Cumulative adsorption capacity was calculated and Pseudo-first order kinetic model was used to investigate the CO2 adsorption kinetic at different parameters. Remarkably, this FA-AAc/AAm hydrogel is also capable of absorbing liquid activator that was 1000% more than its original weight. FA-AAc/AAm can be used as an alternative AIHs that employ FA waste to capture CO2 and minimize the GHG impact on the environment.

Film-forming amines adsorption and corrosion kinetics on carbon steel surface in neutral solution investigated by EIS and PM-IRRAS analysis

N-oleyl-1, 3-propanediamine (OLDA) is one of the most used film-forming amines (FFAs) for the corrosion protection of carbon steel circuits of a wide range of industrial plants. The present work focused on the study of OLDA adsorption kinetics onto the carbon steel surface by electrochemical impedance spectroscopy (EIS). The diagrams were obtained in a 200 mg.kg−1 NaCl with and without OLDA for immersion times ranging from 2 min to 140 min and for two temperatures (25°C and 50°C). It was shown that, from the beginning of immersion (2 min), OLDA adsorption and corrosion occurred simultaneously on the carbon steel surface. With increasing immersion time, a dynamic and competitive process between both phenomena was established until a steady-state was reached and the corrosion was slowed down. Ex situ Raman spectroscopy analyses revealed a heterogeneous distribution of the OLDA molecules on the surface with a preferential adsorption on the corrosion products, mainly γ-FeOOH. Ex situ Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) analyses confirmed the formation of mixed barrier layers (OLDA molecules/corrosion products) whose thickness increased with time and temperature.