Cyclic Absorption Research Articles

Integrated CO2 absorption-mineralization process by the MEA + MDEA system coupled with Ba(OH)2: Absorption kinetics and mechanisms

In order to address the problems of poor performance of a single amine solvent in CO2 absorption and high regeneration energy consumption for thermal desorption, an integrated process was proposed in this study for CO2 absorption and mineralization using MEA + MDEA mixed amines coupled with Ba(OH)2 to produce high value-added BaCO3. The results showed that the optimal CO2 absorption performance was achieved with the use of 5 wt% of MEA and 2 wt% of MDEA. The Arrhenius activation energy Ea was 1.63 × 104 kJ/kmol, and the interaction coefficient β between MEA and MDEA reached up to 0.5, which had a positive effect on the absorption kinetics. The density functional theory (DFT) confirmed the reaction between the electron-donating group (−R3N¨) of MDEA and the strong electron withdrawing H+ of MEAH+, which contributed to the synergistic absorption mechanism involving proton transfer and formation of new bonds. The BaCO3 synthesized under conditions of 40 ℃, 60 min, and Ba(OH)2 addition ratio of 1: 1 was sphere-like and had a particle size of 150–200 nm and a specific surface area of 6.4430 m2/g, which aligned with the industry standard (1.5–15 m2/g) for opto-electronic level BaCO3. The FTIR spectra elucidated the CO2 absorption-mineralization mechanism that Ba(OH)2 could mineralize carbamate, CO32–/HCO3– and simultaneously regenerate free amine. The chemically regenerated MEA + MDEA solution performed stably in cyclic CO2 absorption and mineralization. This research sheds light on carbon emission reduction and CO2 resource utilization.

Tailoring the Wettability of Bacterial Cellulose Magnetobots via the Assembly of In Situ Synthesized and Surfactant-Coated Magnetic Nanoparticles.

This study showcases the possibility of tailoring the wettability of magnetic bacterial cellulose (m-BC) composites by the combined effect of in situ synthesized magnetic nanoparticles (MNPs) distribution and simultaneous oleic acid (OA) coating within the BC matrix. This combined effect of MNPs and OA resulted in m-BC composites exhibiting solvent-dependent and time-dependent surface-wetting behavior, which was not observed in either individual cases of BC that have been modified with OA or BC that has MNPs adsorbed on its fibers. This tailored wettability in m-BCs was achieved via varying the concentrations of iron precursors, which governed the arrangement and morphology of MNPs (uniformly or clustered) on the BC membrane, although the same fraction of MNPs was observed in both the m-BCs. Finally, we have achieved delayed water absorption in m-BC_x (synthesized in a comparatively lower precursor concentration) and no absorption of water in m-BC_4x (synthesized in a 4-times-higher precursor concentration). The m-BC_4x composite maintained its hydrophobic characteristics in diverse environments, ranging from highly acidic conditions (pH 1.2) to physiological environments at pH 4, 5.5, and 7.4. The MNP agglomerates on the BC nanofibers in the m-BC_4x composite were found to be instrumental in attaining a stable cyclic absorption performance with structural integrity. Additionally, the magnetic-inducing heat generation efficiency of the m-BCs can be extended for evaporating low-boiling-point solvents. The present study expands the frontiers of BC-based magnetic composites by emphasizing the assembly of surfactant-coated magnetic nanostructures in their responsiveness to polar/nonpolar liquids with stable performance even in complex scenarios.

Synthesis and Structure-Property Relationship of meso-Substituted Porphyrin- and Benzoporphyrin-Thiophene Conjugates toward Electrochemical Reduction of Carbon Dioxide.

A novel series of ZnII-trans-A2B2 porphyrins and benzoporphyrins bearing phenyl and thiophene-based meso-substituents was successfully synthesized and characterized by spectroscopic and electrochemical techniques. Systematic comparison among the compounds in this series, together with the corresponding A4 analogs previously studied by our group, led to the understanding of the effects of π-conjugated system extension of a porphyrin core through β-fused rings, replacement of the phenyl with the thiophene-based meso-groups, and introduction of additional thiophene rings on thienyl substituents on photophysical and electrochemical properties. Oxidative electropolymerization through bithiophenyl units of both A4 and trans-A2B2 analogs was achieved, resulting in porphyrin- and benzoporphyrin-oligothiophene conjugated polymers, which were characterized by cyclic voltammetry and absorption spectrophotometry. Preliminary studies on catalytic performance toward electrochemical reduction of carbon dioxide (CO2) was described herein to demonstrate the potential of the selected compounds for serving as homogeneous and heterogeneous electrocatalysts for the conversion of CO2 to carbon monoxide (CO).

Development of a high-pressure 700 bar metal hydride hydrogen compressor

HySA Systems and TF Design have recently developed a single-stage prototype high-pressure metal hydride hydrogen compressor (MHHC) which is able to compress hydrogen from 100 to >700 bar at the working temperatures from 20 to 150 °C, with estimated productivity about 1 Nm3/h. The MHHC comprises of two 2 m-long fibre-wound high-pressure MH containers developed by the authors earlier and assembled in two modules operating in a mode of a cyclic lower-pressure H2 absorption (on cooling) and high-pressure H2 desorption (on heating). The containers operate using a self-developed multicomponent C14 Laves type Ti–based AB2 intermetallic alloy. The article considers phase-structural and hydrogen sorption properties of the utilized metal hydride material, hydrogen compression performances of the metal hydride container, as well as layout and the expected performance characteristics of the compressor assembly.

Effects of cyclic ageing frequencies on the ageing and mechanical behaviour of adhesive materials: Experimental analysis and numerical study

In marine structures adhesive joint structures are often exposed to cyclic conditioning where the ambient humidity changes cyclically during their service. Though some comprehensive studies on the aging of adhesives exist, these researches mainly focus on monotonic aging conditions where the adhesive joints are exposed to a wet condition continuously for a long time. However, the few investigations performed on the cyclic moisture absorption of adhesive materials show that the parameters obtained in monotonic aging conditions are not suitable for estimation of the aging behaviour of adhesive exposed to alternating humidity. An important question that can arise is whether or not this frequency affects the mechanical behaviour of adhesive joints under cyclic aging condition. In this investigation bulk dogbone and square samples were manufactured, subjected to cyclic aging conditions with four different aging frequencies and tested. The results show that the moisture diffusion constant of adhesives exposed to higher aging frequencies increase more than those exposed to lower aging frequency conditions. In addition, the moisture content only affects the degradation of strength and stiffness of the tested adhesives in different aging frequencies.

Catalytic behavior of aluminum-modified SAPO-34 catalysts for reducing the energy penalty of CO2-rich amine solutions regeneration

The goal of this research is to develop a potential strategy to significantly decrease the heat duty for the amine-based CO2 capture process. Here, a variety of Al2O3-modified SAPO-34 composite catalysts with varying Al2O3 contents are synthesized and utilized to catalytically facilitate the CO2 desorption process. The catalytic CO2 desorption characteristics of various catalysts, Al-SAPO-34, SAPO-34, and γ-Al2O3 are investigated in a CO2-loaded 5 M monoethanolamine (MEA) solution. The results indicate that all catalysts accelerate CO2 desorption, while the Al-SAPO-34 catalysts work better than the parent Al2O3 and SAPO-34 catalysts. Especially, the 15 % Al-SAPO-34 increases the CO2 desorption rate by 78.4 % and reduces the relative energy requirement by 37 % at a desorption time of 1440 s. The catalysts are characterized by different methods and their structure–activity relationship is analyzed. The increased acid sites and mesoporous surface area of the Al-SAPO-34 catalyst may be responsible for its greater catalytic activity. The intermediates of the catalytic CO2 desorption process are identified by FT-IR and NMR, and then a possible catalytic regeneration mechanism is put forward. Additionally, the cyclic stability of the Al-SAPO-34 catalyst for cyclic CO2 absorption–desorption is evaluated. This work demonstrates that the Al-SAPO-34 exhibits greater catalytic CO2 desorption performance, and outstanding stability, and has the opportunity to become an attractive industrial catalyst for the amine-based CO2 capture process.

Development of Monoethanolamine Chloride-Ethylene Diamine Deep Eutectic Solvent for Ffficient Carbon Dioxide Capture

Deep eutectic solvents (DES) emerge as a compelling class of ionic liquids, with distinct advantages over traditional solvents, particularly in the realm of CO2 capture. In the present study, [MEACl][EDA] is synthesized across various molar ratios (1:3 to 1:10) and combined with the results of Differential Scanning Calorimetry (DSC) to identify DESs. The DESs are further characterized using Fourier Transform Infrared Spectroscopy (FTIR), and the properties and performance of the DESs with diverse water contents (30–60 wt%) are systematically studied for CO2 capture. The optimal aqueous solution is identified based on the CO2 uptake and viscosity, followed by the evaluation of the cyclic absorption experiments. Results demonstrate that 40 wt% of [MEACl][EDA] DES with (1:5) molar ratio exhibits higher CO2 uptake (22.09 wt%) and comparable viscosity (4.401 mPa·s before and 13.330 mPa·s after CO2 capture at 25 °C) compared to aqueous 40 wt% MEA (15.74 wt% CO2 capture capacity, viscosity of 3.318 mPa·s before and 8.413 mPa·s after CO2 capture), and its absorption rate is also more favorable than the aqueous MEA. Furthermore, recycling studies reveal ∼ 88 % regeneration of the aqueous DES solution at 100 °C.

Experimental and neural network prediction of the cyclic stability and light absorption characteristics of supercritical CO2 based CNTs nanofluids

Traditional working fluids face challenges including constrained heat transfer efficiency and inadequate thermal stability, which are detrimental to the thermal efficiency of energy conversion systems. To overcome these limitations and achieve a profound breakthrough in the field of energy conversion, it is imperative to develop innovative working fluids. Consequently, this study builds a nanofluid circulation flow experimental platform and prepares a supercritical carbon dioxide/hydroxylated multi-walled carbon nanotubes nanofluid. The study conducts a series of meaningful experimental tests and performance predictions, including stability analysis, deposition characterization research, light absorption potential investigation, and artificial neural network prediction. Remarkably, the artificial neural network model exhibits excellent learning capacity in training, validation, and testing, with root mean square error of only 9.069 W/m2, 8.9996 W/m2, and 13.0143 W/m2, respectively. Test results indicate that the nanofluid reaches a steady state after 4 min, with a fluctuation amplitude of only 2.13 %. Furthermore, the deposition density of the nanofluid on nickel sheet saturates after 4 h, confirming its considerable potential for promotion and application. The light absorption capacity and power decay rate of the nanofluid are enhanced by 606–881 W/m2 and 32.3–46.99 %, compared to other typical substances. The transmittance is reduced by 8.51–22.96 % compared to other nanofluids. The nanofluid proves to be an effective alternative to conventional working fluids, providing a practical reference solution for researchers aiming to improve working fluids in the field of energy conversion.

Structural and electrochemical properties of mononuclear copper(II) complexes with pentadentate ethylenediamine-based ligands with pyridine/quinoline/isoquinoline/quinoxaline binding sites.

N-Monosubstituted ethylenediamine derivatives with three methylene-tethered aromatic groups ((ArCH2)2NCH2CH2N(R)CH2Ar (R-ArArAr), where Ar = 2-pyridyl, 2-quinolyl, 1- and 3-isoquinolyl and 2-quinoxalyl; R = methyl, benzyl and phenyl) were utilized as pentadentate ligands for copper(II) complexation. Fifteen mononuclear copper(II) complexes were synthesized and exhibit differences in cyclic voltammetry, absorption spectroscopy and solid state geometries, depending on the aromatic group (Ar) and the substituent on the aliphatic nitrogen atom (R) of the ligand. Compared with the pyridine and isoquinoline complexes, the quinoline and quinoxaline derivatives exhibit distinct Cu(II)/Cu(I) redox potentials and d-d transition absorption wavelengths. Similarly, the phenyl derivatives are different from their methyl and benzyl counterparts. These characteristic trends are discussed in relation to the square-pyramidal/trigonal-bipyramidal structure of the complexes which is perturbed by the location of quinoline moieties in the penta- or hexacoordinate complexes with Jahn-Teller distortion. In addition, the results are compared to the copper(II) complexes with pyridine/quinoline mixed ligands, Ph-Ar1Ar2Ar3 ((Ar1CH2)(Ar2CH2)NCH2CH2N(Ph)CH2Ar3).

Preparation of Open-Cell Long-Chain Branched Polypropylene Foams for Oil Absorption.

This study aimed to prepare open-cell foams using a blend of long-chain branched polypropylene and polyolefin elastomer (LCBPP/POE) for the production of reusable oil absorbents. The supercritical CO2 foaming process was conducted using a two-step batch rapid depressurization method. This unique two-step foaming approach significantly expanded the temperature and pressure windows, resulting in more uniform cells with smaller sizes, ultimately leading to higher expansion ratios and an increased open cell content. The foaming process was optimized by adjusting parameters, such as the LCBPP/POE ratio, foaming temperature, and foaming pressure, reaching a maximum open cell content of 97.6% and a maximum expansion ratio of 48. The influence of polypropylene (PP) crystallization was investigated with the aid of scanning electron microscopy and differential scanning calorimetry. Furthermore, the hydrophobic and lipophilic characteristics of the LCBPP/POE open-cell foam were determined via contact angle measurements and oil/water separation tests. Oil absorption tests revealed that the blended LCBPP/POE foam has a higher oil absorption capacity than that of the pure LCBPP foam. The cyclic oil absorption tests demonstrated the outstanding ductility and recoverability of the LCBPP/POE open-cell foam in comparison to those of the pure LCBPP foam. Over 10 cycles, the LCBPP/POE foam maintained a substantial adsorption capacity, retaining 99.3% of its initial oil absorption capacity. With its notable features, including a high open cell content, excellent hydrophobic and lipophilic characteristics, superior oil absorption capacity, impressive cyclic oil absorption performance, and robust reusability, LCBPP/POE open-cell foams exhibit significant promise as potential oil adsorbents for use in oil spill cleanup applications.

Highly efficient CO2 capture using 2-methylimidazole aqueous solution on laboratory and pilot-scale

To date, the primary industrial carbon capture approach is still absorption using aqueous solutions of alkanolamines. Here, to pursue a substitute for the amine-based approach to improve the CO2 capture efficiency and decrease the energy cost further, we report a new carbon capture approach using a 2-methylimidazole (mIm) aqueous solution. The properties and sorption behaviors of this approach have been experimentally investigated. The results show that the mIm solution has higher CO2 absorption capacity under relatively higher equilibrium pressure (>130 kPa) and lower desorption heat than the methyldiethanolamine solution. 91.6% sorption capacity of mIm solution can be recovered at 353.15 K and 80 kPa. The selectivity for CO2/N2 and CO2/CH4 can reach an exceptional 7609 and 4324, respectively. Furthermore, the pilot-scale tests were also performed, and the results demonstrate that more than 98% of CO2 in the feed gas could be removed and cyclic absorption capacity can reach 1 mol·L–1. This work indicates that mIm is an excellent alternative to alkanolamines for carbon capture in the industry.

UV‐initiated preparation and absorption properties of pseudo‐polyrotaxane cyclodextrin‐based PVA/poly (acrylamide‐co‐acrylic acid) hydrogel

AbstractThe recycling of dyes from dye wastewater is one of the most challenging problems in wastewater treatment. In this study, a pseudo‐polyrotaxane cyclodextrin based PVA/poly (acrylamide‐co‐acrylic acid) hydrogel was prepared by UV‐initiated polymerization. The network structure of the hydrogel and the performance on the dye absorption were adjusted by controlling the content of cyclodextrin. The study was mainly focused on the absorption of methylene blue (MB) in different environments, selectivity of absorption in mixed solutions and the cyclic absorption behavior. At room temperature, the absorption efficiency of this hydrogel for MB and methylene green reached 91.37% and 94.23%, respectively. In addition, the hydrogel exhibited highly selective absorption towards MB in mixed dye solutions. In the absorption‐desorption cyclic experiments, a more cost‐effective and environmental friendly solvent, a mixture of ethanol and water, was used, and after ten cycles, the highest absorption efficiency was basically maintained. Hence, the hydrogel is expected to be a candidate for more efficient and economical absorbent material in dye wastewater treatment.

Aminosiloxane having double absorption sites with low viscosity for efficient SO2 capture

The viscosity and absorption capacity are important factors in evaluate the performance of SO2 absorbent, but it is not an easy task to balance the contradiction between them. Herein, we designed and synthesized a novel aminosiloxane (3-diethylaminomethyl-1,1,3,3-tetramethyl-disiloxyalkyl methyl)-diethylamine (DTDA) with double absorption sites. This absorbent has low viscosity before and after absorption, with 3.41 mPa·s and 180.00 mPa·s at 303.15 K, respectively. The absorption capacities of DTDA can reach 3.42 mol/mol (303.15 K, 1.00 atm) and 1.71 mol/mol (303.15 K, 0.02 atm). The desorption of SO2 can be realized at 363.15 K with good cyclic absorption performance. Moreover, with the introduction of dimethyl silicone oil (DSO), a mixed absorption system (DTDA-DSO) with liquid-liquid phase-change behaviors was obtained. The mixed absorption system not only shows better thermal stability but also needs lower thermal desorption energy consumption. The excellent absorption performance of DTDA-DSO system makes them have great potential in the field of SO2 capture and could provide strong support for their industrial application.

Electrochemistry of Selected Acetaminophen Derivatives

Acetaminophen (N-(4-hydroxyphenyl)acetamide, APAP) belongs to the most frequently used pharmaceuticals with analgesic and antipyretic effect [1]. The metabolization of APAP via oxidation pathway lead to formation of highly reactive intermediate N-acetyl-p-benzoquinone imine (NAPQI). It immediately reacts with a nucleophile e.g. with glutathione by formation of respective conjugate. The level of such conjugates can be directly linked to the toxicity of APAP in humans.Hence, three derivatives of acetaminophen were synthesized and characterized [2]. In this contribution, we focus on the characterization of redox properties of selected acetaminophen derivatives (see scheme 1) which were studied by means of cyclic voltammetry, rotating-disk voltammetry and UV-VIS absorption spectrometry. The oxidation mechanism was studied in phosphate buffers of different pH as well as in non-aqueous environment of N,N-dimethylformamide The influence of substituents on the electron transfer mechanism was estimated and corresponding rate constants were evaluated. We found that the protonation/deprotonation of acetaminophen derivatives act as a rate determining steps in aqueous media. The obtained electrochemical results were accompanied by chemical ones using reaction of the conjugates with diphenylpicrylhydrazyl (DPPH radical assay) in order to examine their interaction with radical, hence radical scavenging ability. Acknowledgement This work was supported by the Czech Science Foundation (GA19-11867S). References L. O. Boreus, F. Sandberg, Acta physiologica Scandinavica 1953, 28, 261-265.J. Vanova, D. Malinak, R. Andrys, M. Kubat, T. Mikysek, E. Rousarova, K. Musilek, T. Rousar, P. Cesla, J. Chromatogr. A 2022, 1669, 11. Figure 1

Thermodynamics and kinetics hydrogen isotope effects of hydrogen/deuterium absorption in Pd-5wt.%Pt alloy

Palladium–Platinum (Pd–Pt) alloys have excellent hydrogen isotope separation properties near room temperature compared to pure palladium (Pd), and are expected to be used as filling materials in thermal cyclic absorption (TCAP) columns. However, most studies on the thermodynamic and kinetic hydrogen isotope effects of hydrogen absorption/deuterium in Pd–Pt alloys have been conducted at temperatures of 273 K or above, with few studies involving the performance of TCAP in the cold-cycle operating temperature range (253 K–303 K). In this work, the performance of Pd-5wt.%Pt alloy for the absorption of hydrogen/deuterium at low temperatures (263 K–323 K) was investigated. The results show that the enthalpy and entropy of dissolution of hydrogen and deuterium in the α-phase of Pd-5wt.%Pt alloy are −11.77 kJ/mol (H), 104.00 J mol−1 K−1(H); −5.50 kJ/mol (D), 87.88 J mol−1 K−1 (D), respectively, which are lower than the enthalpy and entropy change values of pure Pd materials. The apparent reaction activation energies of protium and deuterium absorption are −4.14 kJ/mol (H2) and −11.87 kJ/mol (D2), respectively, which are lower than those of pure palladium. The excellent hydrogen isotope separation performance of Pd–Pt alloys may originate from the fast hydrogen absorption and discharge isotope kinetic performance.

Effects of cyclic absorption–desorption of model fuels by aerospace‐grade carbon/epoxy composites

AbstractThe aviation industry is in the process of using several alternative fuels sourced from renewable sources to decrease its impact on the environment. These alternative fuels are mostly comprised of aliphatic hydrocarbons and have low to no aromatic content. The Federal Aviation Administration (FAA) has approved several drop‐in fuels, in which alternative fuels are typically blended with conventional Jet A fuel. Because of blending, the drop‐in fuels consist of both aliphatic and aromatic components. To achieve a fundamental understanding of how individual aliphatic and aromatic components interact with the aerospace‐grade composites, we have considered four model fuels, three aliphatic with varying chain lengths and one aromatic. The absorption of these model fuels by composites in three absorption/desorption cycles was captured and compared to the conventional Jet A fuel. The equilibrium weight gain by the composites due to absorption was low but was different for each model fuel, and the trend could be validated using Hansen solubility parameters. The absorption of model fuels decreased the glass transition temperature of composites. The change in glass transition temperature was not significantly different between the model fuels and the conventional fuel. These results can be translated to alternative fuels, making them a possible substitute for Jet A in the aviation industry.

Solid Waste of Fly Ash toward Energy-Efficient CO2 Capture

Catalytic CO2 absorption–desorption has attracted broad interest due to its potential for improving CO2 absorption efficiency and reducing energy consumption in CO2 separation. However, most utilized catalysts are synthetic and pure, with the development of a natural and hybrid catalyst with acid–base bifunctional catalytic characteristics remaining a significant challenge. In this work, three fly ashes (1-FA, 2-FA, and 3-FA) with different compositions were used as catalysts, and the provided synergistic benefits in the overall MEA-CO2 absorption–desorption processes were evaluated. The results showed that Brønsted acid sites, Lewis acid sites, and Lewis base sites were available on the fly ash surface, which provided proton and electron donation capability. 1-FA exhibited the best catalytic performance by enhancing the CO2 cyclic absorption capacity by 6.7–26.1%, improving the CO2 desorption rate with the highest value of 96.0%, and decreasing the sensible heat by 24–28% compared to MEA as a blank run. Furthermore, 1-FA exhibited comparable catalytic performance to typical HZSM-5. The results of this study demonstrated that fly ash with zero cost and high availability could serve as a good hybrid catalyst candidate for CO2 absorption and desorption.

High-efficient cyclic absorption of sulfur dioxide in Na-Mg-Ci3- compound system for wet flue gas desulfurization

Sulfur dioxide (SO2), as a primary pollutant in the air, has attracted much attention due to the adverse effects on the atmospheric environment and human health. The wet flue gas desulfurization (WFGD) has been proved to be the most effective method to control the emission of SO2. However, the traditional absorbents in WFGD posed the problems of limited recycling utilization and susceptible to oxidation. In this study, we proposed the Na-Mg-Ci3- compound system to repeatedly absorb SO2 for rounds. The results demonstrated that the compound system can integrate the absorption capacity of Na3Ci absorbent and the regeneration efficiency of Mg3Ci2 absorbent. We compared the performances of the compound systems with different alkaline earth metals (Li, Na, K), and the sodium was most suitable for the circulating desulfurization with the consideration of performance and economy. After that, we investigated the influence of ingredient proportions on the absorbent performance, and the results showed that the 0.4 mol/L Na3Ci and 0.2 mol/L Mg3Ci2 were the best combination for the compound system in these experiments. In this condition, the compound system had the excellent effective sulfur capacity and regeneration speed in the recycling process. Moreover, the anti-oxidation effect of sodium ascorbate was explored, and the reusability performance of compound system can be improved with antioxidants. This study contributes to providing a novel method for the removal and recycling of SO2 in the wet flue gas desulphurization.

Solid base LDH-catalyzed ultrafast and efficient CO2 absorption into a tertiary amine solution

Due to its high capacity, low energy consumption, and low corrosiveness, chemical absorption using aqueous tertiary amine solutions is a potential approach for CO2 capture. The fundamental limitation of this technology is its low CO2 absorption kinetics (rate), which impedes its large-scale use. Here, five typical solid-base catalysts, MgAl-layered double hydroxide (LDH) and its corresponding layered double oxide (LDO), BaCO3, MgCO3, and CaCO3, were adopted to improve the rate of CO2 absorption in an aqueous methyldiethanolamine solution (MDEA). The results indicated that LDH and LDO promoted CO2 absorption, with LDH exhibiting significantly superior catalytic activity. In particular, compared to the non-catalytic absorption, using LDH considerably improved the CO2 absorption rate by 92.7%. The catalytic effects of LDH on CO2 absorption were demonstrated by 13C NMR and FT-IR techniques, and theoretical calculation. A possible catalytic CO2 absorption mechanism over LDH was suggested. Additionally, the stability of LDH was certified with 10 cyclic CO2 absorption–desorption experiments. The excellent catalytic CO2 absorption performance of LDH may be primarily owing to the chemical absorption improvement mechanism of basic sites. Therefore, the LDH-catalyzed CO2 absorption process is a promising option for increasing the CO2 absorption rate in tertiary amine solution. This work may open up a new approach to developing plentiful and affordable solid-base catalysts for CO2 capture technologies with faster absorption kinetics and lower energy requirement.

Optical and Optoelectronic Studies of Binary and Ternary Films of Poly(L-Tryptophane), Poly(5-hydroxy-L-tryptophane), and P(TER-CO-TRI) Doped with Sudan Dye

In this work, the optical properties and optoelectronics parameters of binary and ternary composite films made of two electron acceptors, poly(L-Tryptophane) and poly(5-hydroxy-L-Tryptophane), with an electron donor, P(TER-CO-TRI), doped with Sudan dyes, are comprehensively investigated. The films with different volumetric ratios of the components were deposited onto the glass substrates using spin coating technique. Results showed that with the help of dye doping into the binary systems of poly(L-Tryptophane):P(TRI-co-TER) (1:2) and poly(5-hydroxy-L-Tryptophane):P(TRI-co-TER)(1:2), the refractive index was increased from 2.01 to 2.32. The nature of the electronic transition in the studied films was found to be a direct allowed transition, which was derived from Tauc’s equation. The combination of Cyclic voltammetry (CV) technique and absorption spectroscopy was used to determine the molecular energy levels, HOMO and LUMO of the polymer samples. It was seen that the mixture of poly(L-Tryptophane):P(TRI-co-TER):Sudan dye (1:2:2) has led to increase the energy gap to 2.95 eV and the real optical conductivity ( ) to about 433.11 S.cm-1. According to the findings, the investigated polymers can have a great potential for semitransparent organic solar cells.