Triethanolamine Aqueous Solution Research Articles

Modeling CO2 loading capacity of triethanolamine (TEA) aqueous solutions via a deep learning approach

Capturing carbon dioxide (CO2) from natural gas is essential for reducing CO2 emissions as a greenhouse gas as well as increasing the gas heating value. Absorption of CO2 by amine solutions is a method that has seen a widespread use as a CO2 collection technique. In this research, advanced ML approaches are utilized to simulate the CO2 loading capacity of triethanolamine (TEA) aqueous solutions as a function of system temperature, CO2 partial pressure, and amine concentration in the aqueous phase. Deep neural network (DNN), Gaussian process regressor (GPR), deep belief network (DBN) and bagging regressor (BR) are the models that have been developed. The DNN model with the coefficient of determination (R2) of 0.9990 as well as the root mean square error (RMSE) of 0.0073 outperformed other models in terms of accuracy and validity. The R2 values of 0.9911, 0.9861, and 0.9745 for DBN, BR, and GPR, accordingly, showed that other models could likewise perform with high accuracy. Moreover, trend analysis of the results confirmed that the DNN method can correctly estimate the behavior of CO2 loading with variations in the input parameters. Furthermore, a sensitivity analysis showed that temperature has a decreasing effect on the CO2 loading, while amine concentration and CO2 partial pressure exhibited to have an incremental effect. Herein, the temperature had the greatest influence on the amount of CO2 loading. The final stage of the research was the leverage approach, which stated that about 99% of the data are statistically valid and the DNN model is reliable to be replaced by experimental approaches in the prediction of CO2 absorption into certain type of solutions.

AgCl co-catalyst modified g-C3N4 nanosheets for highly efficient photocatalytic hydrogen evolution

This article uses a co-precipitation method to prepare AgCl/g-C3N4 photocatalysts, and the different loading amounts of AgCl on the g-C3N4 surface photocatalysts have a major effect on the efficiency of photocatalysis. AgCl/g-C3N4 photocatalysts can reduce charge transfer efficiency and enhance photocatalytic performance by loading a significant amount of AgCl onto their surface, which results in a wide interface contact area, excellent charge transfer efficiency, and an increase in numerous surface active sites. In ideal circumstances, 15 % AgCl/g-C3N4 (15 % AgCl/CN) photocatalyst exhibits visible light in triethanolamine aqueous solution (λ > 420) the hydrogen production is as high as 721.34 μmol h−1 g−1 is 15.6 times greater than traditional g-C3N4 photocatalysts. The result show that photocatalysts based on g-C3N4 are capable of producing hydrogen with good efficiency.

Enhanced Photocatalytic Activity of Surface‐Modified TiO2 with Bimetallic AuPd Nanoalloys for Hydrogen Generation

Herein, commercial titania (TiO2‐P25) is modified with mono‐ and bi‐metallic (Au, Pd, and AuPd) nanoparticles synthesized by chemical reduction method using NaBH4 as a strong reducing agent at room temperature. Bimetallic AuPd nanoalloys homogeneous in size and well dispersed on the TiO2 surface are obtained. The charge‐carrier dynamics, which is a key factor in photocatalysis, is studied by time‐resolved microwave conductivity. The results reveal that surface modification plays a crucial role in charge‐carrier separation, increasing the activity under UV–vis light irradiation. The bimetallic AuPd nanoalloys formation is confirmed by high‐angle annular dark field scanning transmission electron microscopy and corroborated by semiempirical molecular dynamics simulations (Gupta‐LAMMPS). The surface‐modified TiO2 with bimetallic AuPd nanoalloys exhibits higher photocatalytic activity compared to TiO2 modified with their monometallic counterparts. The experimental results are also supported by density functional theory and density functional tight binding calculations, which show that alloying AuPd with low Pd content presents significant synergetic effects for hydrogen generation under UV–vis light from aqueous triethanolamine solutions. Additionally, the AuPd/TiO2 photocatalysts are stable with cycling.

Nb2O5 and Nb based oxides as redox photocatalysts: Partial oxidation of 2-propanol and H2 generation by photoreforming

The structural and chemical properties of niobium oxide catalysts have been under scientific scrutiny for the last fifty years; however, their application in photocatalytic processes is very recent and still little studied. In this research, pristine Nb2O5 and its composites containing Ti, Ce, or Zr oxides have been used as photocatalysts in redox reactions such as 2-propanol oxidation in gas-solid regime and in aqueous phase triethanolamine photo-reforming to yield H2. All the materials were active in the oxidation of 2-propanol under simulated sunlight irradiation. The substrate was oxidised in the presence of all of the solids resulting in formation of propanone as the major intermediate product and CO2 as the final product. In liquid solid regime, the H2 production by UV-assisted photoreforming of aqueous solution of triethanolamine reached ca. 6 μmol h−1 g−1 for the best performing material, the bare Nb2O5, which increases up to 592 μmol h−1 g−1 in the presence of 1 % of Pt co-catalyst.

Modeling CO2 loading capacity of triethanolamine aqueous solutions using advanced white-box approaches: GMDH, GEP, and GP

The equilibrium solubility of carbon dioxide (CO2) in the solvents is a key essential characteristic that has to be evaluated for successful absorption-based CO2 capture procedures. In this study, the CO2 loading capacity of triethanolamine (TEA) aqueous solutions was estimated using three famous white-box algorithms namely gene expression programming (GEP), genetic programming (GP), and group method of data handling (GMDH). For achieving the aim of this study, 258 data in a wide range of pressure, temperature, and amine concentration were collected from literature. Temperature, partial pressure of CO2, and amine concentration were used as input parameters. The results demonstrated that GMDH correlation is more accurate than GEP and GP with a determination coefficient (R2) of 0.9813 and root mean square error of 0.0222. The R2 values of 0.9713 and 0.9664 for the GEP and GP, respectively, demonstrated that the GEP and GP also showed accurate predictions. In addition, GMDH approach accurately predicted the anticipated trends of the CO2 loading in response to changes in the partial pressure of CO2 and temperature. The Pearson and Spearman correlation analyses were also incorporated in this research which showed that temperature and CO2 partial pressure have almost the same relative effect on CO2 loading, while amine concentration has the lowest effect on it.

Highly efficient hydrogen production and selective CO2 reduction by the C3N5 photocatalyst using only visible light.

The production of energy sources by metal-free photocatalysts based on graphitic carbon nitride (g-C3N4) has garnered substantial attention. In this study, nitrogen-rich carbon nitride (C3N5) was successfully synthesized through the thermal polycondensation of 3-amino-1,2,4-triazole. The structural and physical characterization has suggested that a portion of the triazine rings, which constitute the structural framework of g-C3N4, may be substituted with five-membered rings in C3N5. Furthermore, the polymerization of C3N5 proceeded more extensively than that of g-C3N4 from melamine precursors. The increased nitrogen content in C3N5 resulted in a heightened number of π-electrons and a narrowed energy bandgap, with the potential of the valence band maximum being negatively shifted. Additionally, photocatalytic assessments encompassing nitro blue tetrazolium reduction, H2 production from triethanolamine aqueous solution, and CO2 reduction in the liquid phase were performed. All findings demonstrated that C3N5 exhibits significantly superior photocatalytic properties compared to g-C3N4. It is particularly noteworthy that C3N5 selectively generates methanol and H2 from oversaturated CO2 solutions under visible light irradiation, while g-C3N4 selectively generates formaldehyde. These outcomes strongly indicate that C3N5 serves as a metal-free, visible-light-responsive photocatalyst, capable of contributing to both the production of renewable energy sources and the reduction of greenhouse effect gases.

Atomic‐Scale Defected HfS2 Nanosheets: A Novel Platform Enhancing Photocatalysis

AbstractRecently, novel 2D materials with fascinating characteristics are extensively applied to design/fabricate high‐activity and cost‐effective photocatalysts for solar‐driven fuels/chemicals generation. Among these 2D materials, HfS2 nanosheets (NSs) exhibit excellent features of large surface area, short bulk‐to‐surface distance, alterable band structures, and vast catalytic sites. Despite these features, no realistic experimental works on HfS2‐based materials are reported in photocatalysis field. Moreover, it is interesting but challenging to realize atomic‐scale engineering of compositions/structures for novel 2D materials and to relate these atomic‐scale characteristics with the element/space/time‐resolved charge kinetics of 2D materials‐based photocatalysts. Herein, for the first time, atomic‐scale defected HfS2 NSs are designed/synthesized. The as‐synthesized HfS2 NSs are combined with various photocatalysts to acquire novel HfS2‐TiO2, HfS2‐CdS, HfS2‐ZnIn2S4, and HfS2‐C3N4 composites, respectively. Among them, HfS2‐CdS exhibits the highest rate (5971 µmol g−1 h−1) on hydrogen (H2) evolution in triethanolamine aqueous solution, together with obviously‐enhanced rates on H2 (2419 µmol g−1 h−1) and benzaldehyde (5.11 mmol g−1 h−1) evolution in benzyl alcohol aqueous solution. Various state‐of‐art characterizations reveal the element/space/time‐resolved electron/hole kinetics in HfS2‐CdS composites, disclosing that these atomic‐scale S vacancies temporarily trapping electrons to facilitate spatiotemporal electron–hole separation/transfer. This work paves avenues to atomic‐scale design/synthesis of new 2D‐materials‐based photocatalysts for sunlight utilization.

A NEW STRATEGY FOR THE SYNTHESIS OF HIGHLY ACTIVE CATALYSTS BASED ON <i>g-</i>C<sub>3</sub>N<sub>4</sub> FOR THE PHOTOCATALYTIC PRODUCTION OF HYDROGEN UNDER VISIBLE LIGHT

In this work, materials based on graphite-like carbon nitride were synthesized by thermal treatment of a mixture of melamine and urea and the effect of synthesis conditions on the photocatalytic activity of the samples was studied. As a cocatalyst, platinum (1 wt. %) was deposited on the surface of the synthesized g‑C3N4 samples. The photocatalysts were characterized by X-ray phase analysis, diffuse reflectance UV-vis spectro-scopy in the UV and visible range, and low-temperature nitrogen adsorption. Photocatalytic activity was determined in the reaction of hydrogen evolution from an aqueous solution of triethanolamine (10 vol. %) under visible light irradiation (λ = 425 nm). The optimal conditions for the synthesis of the photocatalyst 1% Pt/g-C3N4, obtained by calcination of a mixture of melamine and urea (1 : 3), were found, using which the rate of H2 evolution was 5.0 mmol g–1 h–1 with an apparent quantum efficiency of 2.5%. The developed synthetic approach makes it possible to obtain highly active catalysts due to the formation of an intermediate supramolecular melamine-cyanuric acid complex during the synthesis, which, upon further heating, turns into g-C3N4, which is characterized by a high specific surface area exceeding 100 m2 g–1.

Ohmic-functionalized type I heterojunction: Improved alkaline water splitting and photocatalytic conversion from CO2 to C2H2

A hollow dodecahedron-shaped N-doped carbon (N-C) coated with CoSe2 nanoparticles are fabricated via MOF-derived self-sacrificing strategy based on Kirkendall Effect. By coupling with CdS nanodots, the optimal Ohmic-type functionalized type I heterojunction CdS/N-C/CoSe2 (CCE50) exhibits a significant photocatalytic hydrogen evolution reaction (PHER) rate of 19317.3 μmol h−1 gcat−1 that is 15.7 and 33.7 folds higher than type I CdS/N-C heterojunction (1230.3 μmol h−1 gcat−1) and pure CdS respectively, and successfully transfers the source of photo-corrosion to obtain stable PHER for 5 cycles. Moreover, the CCE50 in alkaline media (pH = 12) achieves a 1.6-fold PHER rate higher than that in the original triethanolamine (TEOA) aqueous solution (pH≈8), where electron paramagnetic resonance (EPR) result shows that it is attributed to the accumulation of O2–. The effective PHER rate can be attributed to the synergistic effect of higher light absorption in hollow CCE50 with multiple scattering and the introduction of Ohmic contact. Besides, the successful conversion from CO2 to C2H2 under 80 kPa CO2 pressure is detected firstly on CdS-based photocatalyst (the conversion rate is 2.8 μmol h−1 gcat−1) without other C1 or C2 gas products. EPR, in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) tests, Kelvin Probe Force Microscopy (KPFM) and density functional theory calculations, etc. have illustrated and verified the photocatalytic mechanism for Ohmic contact-enhancing type I heterojunction, which promotes hydrogen production in alkaline media and C2H2 generation from CO2.

Carbon dioxide absorption by Ammonia-promoted aqueous triethanolamine solution in a packed bed

Carbon dioxide absorption by Ammonia-promoted aqueous triethanolamine solution in a packed bed

Effect of Ethane on the Solubility of CO2 in Aqueous Triethanolamine Solutions

Effect of Ethane on the Solubility of CO2 in Aqueous Triethanolamine Solutions

C3N4/reduced graphene oxide photocatalysts loaded with Ag or Ag/Pt for H2 evolution from aqueous solution of triethanolamine

Composites of C3N4/reduced graphene oxide have been used as photocatalysts for triethanolamine photo-reforming with H2 generation in aqueous solution. The rate of H2 production over the Ag loaded best performing photocatalyst reached 525 μmol·h−1·g−1 which increases to ca. 88,000 μmol·h−1·g−1 in the presence also of 1% of Pt. The apparent quantum efficiency (AQE) of the optimal material was ca. 9% by using both visible LED or natural sunlight irradiation.

Influence of Cocatalysts (Ni, Co, and Cu) and Synthesis Method on the Photocatalytic Activity of Exfoliated Graphitic Carbon Nitride for Hydrogen Production.

Exfoliated graphitic carbon nitride (ex-g-CN) was synthesized and loaded with non-noble metals (Ni, Cu, and Co). The synthesized catalysts were tested for hydrogen production using a 300-W Xe lamp equipped with a 395 nm cutoff filter. A noncommercial double-walled quartz-glass reactor irradiated from the side was used with a 1 g/L catalyst in 20 mL of a 10 vol% triethanolamine aqueous solution. For preliminary screening, the metal-loaded ex-g-CN was synthesized using the incipient wetness impregnation method. The highest hydrogen production was observed on the Ni-loaded ex-g-CN, which was selected to assess the impact of the synthesis method on hydrogen production. Ni-loaded ex-g-CN was synthesized using different synthesis methods: incipient wetness impregnation, colloidal deposition, and precipitation deposition. The catalysts were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption using the Brunauer-Emmett-Teller method, and transmission electron microscopy. The Ni-loaded ex-g-CN synthesized using the colloidal method performed best with a hydrogen production rate of 43.6 µmol h-1 g-1. By contrast, the catalysts synthesized using the impregnation and precipitation methods were less active, with 28.2 and 10.1 µmol h-1 g-1, respectively. The hydrogen production performance of the suspended catalyst (440 µmol m-2 g-1) showed to be superior to that of the corresponding immobilized catalyst (236 µmol m-2 g-1).

Carbon Dioxide Absorption by Ammonia Promoted Aqueous Triethanolamine Solution in a Packed Bed

Carbon Dioxide Absorption by Ammonia Promoted Aqueous Triethanolamine Solution in a Packed Bed

A ZnFe2O4/C3N4 composite with the assistance of multifunctional Au-nanoparticle to generate hydrogen under visible-light

Design a composite photocatalyst for a photocatalytic reaction is a powerful way to improve the photocatalytic performance. Herein, we reported a three-component composite 2Au@1%-ZFO/CN for H2 evolution in the triethanolamine aqueous solution under visible-light. ZnFe2O4 and C3N4 prepared by solid-state method are the main components of the composite, which was prepared via a hydrothermal method. And then, the Au-nanoparticles were dispersed on it by a photodeposition method. The morphology of the sample is that particle ZnFe2O4 is wrapped by particle C3N4. The Au-nanoparticles with a size of ∼ 6 nm were dispersed over sample C3N4, which acts as an active site, hot electron provider, and electronic channel. The photocatalytic performances of H2 evolution for these composites were studied in detail. The H2 evolution rate of the optimal sample 2Au@1%-ZFO/CN is 1622.3 and 1846.4 μmol/h/g under ultraviolet-light, simulated sunlight irradiation, respectively, which are 10.7-folds and 128.2-folds higher than that of the unloaded sample. The unloaded sample has no detectable photocatalytic performance under visible light. However, the optimal sample has an H2 evolution rate of 36.6 μmol/h/g. Moreover, its apparent quantum yield is 47.6% at 400 nm. The construction of three-component composites is a promising strategy for the study of photocatalytic properties.

One-step preparation of cobalt phosphate at room temperature for effective photocatalytic H2 evolution

Cobalt phosphate materials were prepared in the present work in one step at room temperature using different raw materials and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and N2 gas adsorption. Cobalt phosphates exhibit 3D flower-like structures, and the assembly of nanosheets (petals of the "flowers") of cobalt phosphate prepared with sodium phosphate and cobalt acetate as raw materials (denoted as Co-P(A)) is more incompact than that of cobalt phosphate prepared with diammonium hydrogen phosphate and cobalt nitrate as raw materials (denoted as Co-P(B)) due to the former's mildly basic environment. The cobalt phosphates show relatively high photocatalytic activity for H2 evolution reaction (HER) in the presence of Eosin Y as a sensitizer in an aqueous triethanolamine solution. The activity of Co-P(A) (0.40 mmol h-1 g-1) exceeds that of Co-P(B) (0.19 mmol h-1 g-1), which can be attributed to a more dispersive nanosheet and larger BET-specific surface area of Co-P(A). The mechanisms of photocatalytic HER and the formation of flower-like Co3(PO4)2 were discussed. The present system comprising of only abundant elements contributes toward the development of cost-efficient solar HER to achieve sustainable development.

Two Tungstates Containing Platinum Nanoparticles Prepared by Air-Calcining Keggin-Type Polyoxotungstate-Coordinated Diplatinum(II) Complexes: Effect on Sintering-Resistance and Photocatalysis

Two tungstates containing platinum nanoparticles (Pt Npts) were obtained by air-calcining α-Keggin-type diplatinum(II)-coordinated polyoxotungstates, Cs3[α-PW11O39{cis-Pt(NH3)2}2]⋅8H2O (Cs-P-Pt) and Cs4[α-SiW11O39{cis-Pt(NH3)2}2]⋅11H2O (Cs-Si-Pt), at 700–900 °C for 5 h. The polyoxotungstate Cs-P-Pt was transformed to a mixture of Pt Npts and Cs3PW12O40 upon calcination, while the Cs-Si-Pt structures were transformed to Pt Npts and Cs4W11O35. The Pt Npts generated by air-calcining Cs-P-Pt at 700 °C for 5 h were uniform with an average particle size of 3.6 ± 1.1 nm, which was much smaller than that of the Pt Npts obtained by calcining Cs-Si-Pt (19.9 ± 9.9 nm) under identical conditions. This demonstrated the significant inhibitory effect of Cs-P-Pt on aggregation during high-temperature air-calcination at a high platinum content (10.6 wt.%) and in the absence of a support. During calcination at 700–900 °C, Cs-P-Pt exhibited higher activities than Cs-Si-Pt with respect to hydrogen evolution from aqueous triethanolamine solutions under visible light irradiation in the presence of Eosin Y, α-Keggin-type mono-aluminum-substituted polyoxotungstate, and titanium dioxide. When Cs-P-Pt was calcined at 800 °C for 100 h, no decrease in activity was observed in comparison with that upon calcination for 5 h.Graphical

The method of determination for sulfur dioxide in the air of workplace by ion chromatography without derivatization

Objective: To establish a method for the determination of sulfur dioxide (SO2) in the air of workplace, which including the process of collection by absorption in triethanolamine aqueous solution and the process of analysis and detection by iron chromatography directly without derivatization. Methods: SO2 in the air of workplace was collected at a flow rate of 0.5 L/min for 15 min through 10 ml of 3% triethanolamine aqueous solution filled in a porous glass plate absorption tube. The absorption solution passed through IonPacAS14A analytical column (4 mm×250 mm) and IonPacAG14 protective column (4 mm×50 mm) at a column temperature of 30 ℃, using Na2CO3 (3.0 mmol/L) -NaHCO3 (1.0 mmol/L) as mobile phase with the flow rate of 1.2 ml/min, and was detected by conductivity detector. Results: It showed that SO2 in triethanolamine solution could be stored for at least 7 d at room temperature (25 ℃) and 37 ℃. There was a linear relationship within the determination range of 0-8.00 μg/ml, the linear correlation coefficient was 0.9999. The sampling absorption efficiency was 98.1%-100.0%, the detection limit of the method was 0.018 μg/ml, the minimum detection concentration was 0.024 mg/m3 (based on V0=7.5 L) . The recovery rate was 99.22%-101.69%, the intra batch precision was 0.41%-1.34%, and the inter batch precision was 0.73%-1.77%. Conclusion: The method has the advantages of simple operation, high sensitivity and good accuracy. It can prevent SO2 from being oxidized and realize the direct detection of SO2 in the air of workplace without derivation.

Efficient Electronic Modulation of g-C 3 N 4 Photocatalyst by Implanting Atomically Dispersed Ag 1 -N 3 for Extremely High Hydrogen Evolution Rates

Efficient Electronic Modulation of g-C ₃ N ₄ Photocatalyst by Implanting Atomically Dispersed Ag ₁ -N ₃ for Extremely High Hydrogen Evolution Rates

An improved photocatalytic activity of H2 production: a hydrothermal synthesis of TiO2 nanostructures in aqueous triethanolamine

Abstract In this study, novel hydrothermal synthesis is used to explore the impact of photocatalytic activity on H2 production using an aqueous solution of triethanolamine (TEoA) in TiO2 nanostructures designed with varying molar concentrations of HCl, and the production of molecular hydrogen is explored as a function of molar concentration. A solar simulator is utilized to assess the photocatalytic activities of methyl orange degradation under UV light irradiation and molecular H2 production. Also, XRD patterns and SEM images are explored to show agglomerated nanoparticle formation, and an EDX spectrum is employed to confirm TiO2 compositions. The band gap analysis of produced nanostructures is performed using a UV-Vis spectrometer and is found to be varying in between 2.5 and 3.0 eV, while the maximum methyl orange degradation corresponds to 1.0 M concentration of HCl, indicating an enhanced hydrogen production. To meet the foreseeable future energy crises and worsening environmental challenges, we may need sustainable energy sources, and photocatalysis molecular H2 production offers a viable alternative to fossil fuels that can be employed to tackle future difficulties.