Triethanolamine Solution Research Articles

Adsorption of molybdate on molybdate-imprinted chitosan/triethanolamine gel beads

Mo (VI)-imprinted chitosan (CTS)/triethanolamine (TEA) gel beads (Mo (VI)-ICTGBs) (ICTGBs=imprinted chitosan triethanolamine gel beads) were prepared by using ion-imprinted technology, in which TEA and molybdate solution were used in coagulation bath. The spectrum of FT-IR implies that bonding are formed between TEA and the primary hydroxyl of CTS, and ion gel reaction happen between CTS and molybdate; XRD patterns also prove the change among CTS, TEA and molybdate. SEM images and N2 adsorption show that the surface area increases obviously after eluting Mo (VI) ions. The adsorption isotherm of Mo (VI)-ICTGBs imply that the adsorption process is according with Freundlich model. Adsorption kinetics suggests that the pseudo-second order adsorption mechanism is predominant for this adsorbent system of Mo (VI)-ICTGBs. The Mo (VI)-ICTGBs show high adsorption capacity and good selectivity for Mo (VI) anions in the coexistence system at pH=6.0. The Mo (VI)-ICTGBs have a good application prospect, because it is with a simple and rapid technique and good durance.

Modeling and Experimental Study of CO2 Removal by Alkanolamines in a Packed Bed

Absorption of CO2 by monoethanolamine, diethanolamine, and triethanolamine solutions in a lab–scale packed bed tower was investigated. A model for analyzing the heat and mass transfer mechanism in the presence of reaction was developed and validated using the measured data for MEA and TEA solutions and the results were compared with the others' experimental data. The well-known correlations for determining Henry's constant, as a critical parameter in the presented model, were evaluated and it was shown that the available correlations are often limited to a narrow range of operating conditions which could limit the applicability of the available models.

Synthesis of magnesium oxysulfate whiskers using triethanolamine as a morphology control agent

Whisker shaped magnesium oxysulfate (MOS, 5Mg(OH)2 MgSO4·3H2O) was synthesized form MgSO4·7H2O and triethanolamine (TEA) using a hydrothermal method at 80°C for 24h. An aqueous solution of 2M MgSO4·7H2O was used as the precursor and TEA was used as the chelating ligand. The experimental results indicate that the TEA promotes the formation of the desirable whisker morphology during the hydrothermal synthesis. The Mg atom coordinates with an O atom of SO42− in another layer to form a multi layer crystal structure. The thermal analytical curve of this compound was recorded, and its decomposition mechanism was discussed. In particular, the use of this TEA solution led to the simple and economical synthesis of magnesium oxysulfate whiskers with lengths of 100–200μm and diameters of 80–200nm. The product characteristics were investigated by making XRD, FT-IR, TG, FE-SEM, EDS and TEM observations.

Hydrogen Production over Eosin Y-Sensitized Pt-Loaded Layered Lanthanum Niobate under Visible Light Irradiation

A novel and highly efficient photocatalyst, Eosin Y-sensitized Pt-intercalated nanotube Pt/HLa Nb2O7, was found to be very active for hydrogen generation within triethanolamine (TEOA) solution as the electron donor under visible-light irradiation (λ420 nm). The photocatalysts were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), scan electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the significant enhancement of photocatalytic activity was achieved via Pt intercalating and subsequent dye sensitization of Pt/HLaNb2O7. The highest rate for hydrogen evolution was 4.45 mmol·g-1·h-1under irradiation with a wavelength longer than 420 nm, and the probable mechanism of photosensitized hydrogen evolution have also been discussed.

Low-temperature vacuum stripping of CO2 from aqueous amine solutions using thin-film silicalite-filled PDMS composite membranes

Carbon dioxide (CO2) recovery by vacuum stripping technology using membranes was studied as an alternative to the desorption process at low temperatures (below 120°C) in conventional aqueous amine absorption process. Composite membranes were prepared by coating hydrophobic silicalite-filled polydimethylsiloxane (PDMS) layers on polyethylene (PE) porous supports and used as new membrane strippers for CO2 recovery to prevent the typical pore wetting problem of hydrophobic porous membranes. Aqueous 30wt% solutions of monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) were used as absorbents in the desorption process. CO2 fluxes were measured under various operation conditions, such as different vacuum pressures, stripping temperatures, CO2 loadings, types of amine solutions and operation time. CO2 stripping fluxes increased with increasing temperature and CO2 loading of amine solutions as well as with decreasing stripping pressures because of the enhanced upstream and downstream driving forces. CO2 stripping fluxes were much higher in the TEA and DEA solutions than in the MEA solutions. The thin-film silicalite-filled PDMS composite membranes showed excellent long-term stability in the vacuum stripping process when compared with porous polytetrafluoroethylene (PTFE) membranes.

Method for determining nitrogen dioxide in workplace air by ion-exchange chromatography

To evaluate the method for collecting NO2 in workplace air using a solid adsorbent and determining the concentration of NO2 by ion-exchange chromatography. NO2 in workplace air was collected using sampling tubes filled with 13X molecular sieve soaked with triethanolamine, and the samples were desorbed with a certain concentration of triethanolamine solution to obtain NO2(-). NO2(-) was separated with an anion exchange chromatography column and quantified by a conductivity detector. The concentration of NO2 was determined based on the conversion coefficient of NO2 and NO2(-). Different concentrations of NO2 (standard gas) was collected using the sampling tubes at different time points, and the sampling efficiency and desorption efficiency could reach more than 90%. The penetrating capacity of sampling tubes was more than 1.1 mg. The comparative test shows that there was no significant difference between the new method and national standard method (solution absorption) (P > 0.05). The samples could be stored at room temperature for more than 16 days. The calibration curve plotted in the new method was linear in the range of 0.1∼20.0 µg/ml, with a correlation coefficient of 0.9998; the detection limit was 0.01 µg/ml; the minimum detectable concentration was 0.05 mg/m(3) (V0 = 3.0 L). This determination method meets the requirements of Guide for establishing occupational heath standards-Part 4 Determination methods of air chemicals in workplace (GBZ/T 210.4-2008) and shows obvious advantages for determination of NO2 in workplace air.

ChemInform Abstract: Electrodeposition of CoxFe3‐xO4 Epitaxial Films and Superlattices.

AbstractCoxFe3‐xO4 (0 < x < 1) thin films are prepared by a one‐step electrodeposition from alkaline Fe3+‐ and Co2+‐triethanolamine solutions.

Comparison of Carbon Dioxide Absorption in Aqueous MEA, DEA, TEA, and AMP Solutions

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for CO2 capture. The solubility of CO2 in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption (−ΔHabs) between the absorbent and CO2 molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of CO2 absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and CO2 loading.

Electrodeposition of CoxFe3–xO4 Epitaxial Films and Superlattices

Spinel ferrites are of interest because of their potential applications in spintronics (spin-based electronics) and solid-state memories. Cobalt ferrite (CoFe2O4) is an inverse spinel ferrite. Currently, the utility of CoFe2O4 is mainly based on its high coercivity and magnetocrystalline anisotropy. The magnetic and electrical properties of CoFe2O4 depend on its Co:Fe ratio. In this paper, a one-step electrodeposition of CoxFe3-xO4 (0 < x < 1) thin films from an alkaline Fe3+- and Co2+-triethanolamine solution is presented. The Co:Fe ratio in the CoxFe3–xO4 thin films can be tuned by controlling the deposition potential. That is, CoxFe3–xO4 thin films with tunable chemical and physical properties can be produced from a single solution. Superlattices in the CoxFe3–xO4 system were also electrodeposited from the same solution by simply pulsing between two potentials. Compared to CoxFe3–xO4 individual films, superlattices exhibit resistance switching and a more pronounced negative differential resistance (NDR) feature at lower current during perpendicular transport measurements, which could be used in resistive random access memories.

Carbon nitride nanosheets for photocatalytic hydrogen evolution: remarkably enhanced activity by dye sensitization

Carbon nitride (CN) nanosheets with a thickness of around 3 nm were prepared by pyrolysis of urea. Well-dispersed Pt nanoparticles of about 3 nm were pre-loaded on CN nanosheets as the co-catalyst by chemical reduction in ethylene glycol. The Pt/CN sample showed a H2 evolution rate of 45.1 μmol h−1 from an aqueous solution of triethanolamine (TEOA) under visible light irradiation (λ > 420 nm). By simply adding a low-cost dye Erythrosin B (ErB) in the photoreaction suspension, a remarkably enhanced H2 evolution rate of 652.5 μmol h−1 was observed. Efficient electron transfer from excited ErB to the conduction band of CN is expected due to the energy difference between the LUMO level of excited ErB (−3.59 eV vs. vacuum level) and the conduction band potential of CN (−3.71 eV vs. vacuum level). A dye sensitization mechanism between ErB and CN is proposed. Upon irradiation with light of long wavelength (λ > 550 nm), the Pt/CN–ErB photocatalyst system still exhibited a high H2 evolution rate of 162.5 μmol h−1. The highest quantum efficiency of 33.4% was obtained at 460 nm. Moreover, the Pt/CN photocatalyst could be easily recycled by simple filtration and 90% of the activity was still kept after five consecutive runs.

Eosin Y-sensitized graphitic carbon nitride fabricated by heating urea for visible light photocatalytic hydrogen evolution: the effect of the pyrolysis temperature of urea

Graphitic carbon nitride (g-C3N4) was prepared by pyrolysis of urea at different temperatures (450-650 °C), and characterized by thermogravimetric and differential thermal analysis (TG-DTA), elemental analysis (C/H/N), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), Brunauer-Emmett-Teller (BET) analysis, Fourier transform-infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectra. The samples prepared at low temperatures (450 and 500 °C) are a mixture of g-C3N4 and impurities, whereas the samples prepared at high temperatures (550, 600 and 650 °C) should be g-C3N4 (polymeric carbon nitride). The polymerization degree of g-C3N4 for the prepared samples increases to a maximum at 600 °C with increasing pyrolysis temperature and then decreases, whereas the defect concentration changes conversely, that is, g-C3N4 prepared at 600 °C has the lowest defect concentration. Using Eosin Y (EY) and the prepared sample as the sensitizer and the matrix, respectively, the photocatalytic activity for hydrogen evolution from aqueous triethanolamine solution was investigated. The g-C3N4 prepared at 600 °C exhibits the highest sensitization activity. Under optimum conditions (1.25 × 10(-5) mol L(-1) EY and 7.0 wt% Pt), the maximal apparent quantum yield of EY-sensitized g-C3N4 prepared at 600 °C for hydrogen evolution is 18.8%. The highest activity can be attributed to the pure composition, the higher dye adsorption amount and the lowest defect concentration.

Enthalpy of Solution of Carbon Dioxide in Aqueous Solutions of Triethanolamine at Temperatures of 322.5 K and 372.9 K and Pressures up to 5 MPa

Enthalpy of Solution of Carbon Dioxide in Aqueous Solutions of Triethanolamine at Temperatures of 322.5 K and 372.9 K and Pressures up to 5 MPa

Synthesis of CuS nanorods grown at room temperature by electrodeposition method

CuS thin films were deposited on stainless steel substrates from an aqueous solution of CuSO4, Na2S2O3 and Triethanolamine. Deposited films were characterized by XRD, SEM, EDAX, Raman and Optical measurements. The electrodeposition bath concentration can be used to control the diameter of the electrodeposited nanorods within the range of 35–40 nm. The formation of complexes of copper ions and TEA was found to be a key factor in the nanorods growth process. Films are polycrystalline with hexagonal crystal structure. SEM images indicate that the film surfaces are smooth, homogeneous and well-covered. A new structure of CuS nanorods having length of 5–10 μm and diameter from 35 to 40 nm has been demonstrated. By changing bath concentration and keeping deposition time fixed the agglomeration of rods is enhanced due to the formation of large number of particles during growth process. Raman shifts of samples are detected at wave numbers 473 cm−1. Typical film deposited with optimized bath concentration shows optical band gap of about 2.73 eV.

Simultaneous mineralization of CO2 and recovery of soluble potassium using earth-abundant potassium feldspar

CO2 capture and storage (CCS) is an important strategy in combatting anthropogenic climate change. However, commercial application of the CCS technique is currently hampered by its high energy expenditure and costs. To overcome this issue, CO2 capture and utilization (CCU) is a promising CO2 disposal method. We, for the first time, developed a promising method to mineralize CO2 using earth-abundant potassium feldspar in order to effectively reduce CO2 emissions. Our experiments demonstrate that, after adding calcium chloride hexahydrate as an additive, the K-feldspar can be transformed to Ca-silicates at 800°C, which can easily mineralize CO2 to form stable calcium carbonate and recover soluble potassium. The conversion of this process reached 84.7%. With further study, the pretreatment temperature can be reduced to 250°C using hydrothermal method by adding the solution of triethanolamine (TEA). The highest conversion can be reached 40.1%. The process of simultaneous mineralization of CO2 and recovery of soluble potassium can be easily implemented in practice and may provide an economically feasible way to tackle global anthropogenic climate change.

A physicochemical model of sorption processes in NO2 passive sampling with air humidity effects

Aqueous triethanolamine (TEA) solutions are widely used as sorption medium for passive sampling of ambient NO(2), with NO(2) trapped and accumulated as nitrite ion. The results of test measurements of ambient NO(2) concentrations using passive sampling method showed that the simple approach commonly used to describe passive sampling process might lead to substantial systematic errors. Presented in the article is a new physicochemical model of the process of passive sampling of gaseous NO(2), with aqueous TEA solution used as a trapping medium. The model is based on the available results of experimental studies of interaction of gaseous NO(2) with TEA/water solutions. The key principles underlying the model are: (1) when absorbed by a trapping solution, NO(2) forms nitrite ion only on the condition that TEA is hydrated; (2) coefficient of conversion of NO(2) to NO(2)(-) is equal to one when reacting with hydrated TEA; and (3) the fraction of hydrated TEA molecules depends on air humidity at the moment of measurement. Validation of the model was made using the data of the field measurements carried out in the Middle Urals in 2007-2009. The new model was used to calculate average NO(2) concentrations. Concentrations calculated agreed well with the results obtained by reference methods. The difference between the datasets was statistically insignificant.

Visible‐Light‐Induced Photocatalytic Hydrogen Production over Binuclear RuII–Bipyridyl Dye‐Sensitized TiO2 without Noble Metal Loading

Highly efficient, visible light induced photocatalytic H(2) production was achieved over a TiO(2) system sensitized by binuclear Ru(II) bipyridyl (bpy) complex [Ru(2)(bpy)(4)(BL)](ClO(4))(2) (BL = bridging ligand) without Pt loading, which is almost unaffected by pH in aqueous solution in the wide range from pH 5.00 to 10.50, although the dye molecules can only be loosely attached to TiO(2) due to the absence of terminal carboxyl groups. The photocatalyst shows remarkable long-term stability and reproducibility of H(2) evolution even after exchanging the aqueous triethanolamine solution. The amount of H(2) evolved over 100 mg of photocatalyst in 27 h of irradiation corresponds to a turnover number of about 75,340, and the apparent quantum yields are estimated to be 16.8 and 7.3 % under 420 and 475 nm monochromatic light irradiation, respectively. A comparative study shows that the loosely attached dye [Ru(2)(bpy)(4)(BL)](ClO(4))(2) has higher photosensitization efficiency than tightly linked dyes with terminal carboxyl groups, such as [Ru(2)(dcbpy)(4)(BL)](ClO(4))(2) and N719. It can be rationalized by their different coordination, physicochemical, electron-injection, and back-transfer properties.

Kinetic Study of the Absorption of Carbon Dioxide by Aqueous Triethanolamine Solutions

Abstract In this work, the absorption of pure carbon dioxide by aqueous triethanolamine solutions (TEA) was studied in terms of the kinetic process. The process was made in a stirred tank reactor with a flat and known interfacial area, the operating variables being temperature (288 to 313 K) and concentration in the range 0.1-2.0 M. From the results, it was deduced that the absorption of pure carbon dioxide by aqueous triethanolamine takes place under isothermal conditions in which there is an instantaneous reaction regime at low concentrations, while at higher concentrations it takes place in a moderately fast reaction regime, following a first-order kinetic with respect to alkanolamine. In these conditions of concentrations and temperatures essayed, an expression for the constant kinetic was deduced.

Facile synthesis of cysteine and triethanolamine capped CdTe nanoparticles

Cysteine and triethanolamine capped CdTe nanoparticles have been synthesized using a simple aqueous solution based method. This method involves the reaction of tellurium powder with sodium borohydride (NaBH4) in water to produce telluride ions (Te2−), followed by the simultaneous addition of an aqueous solution of cadmium chloride or other cadmium source (acetate, carbonate and nitrate) and solution of l-cysteine ethyl ester hydrochloride or triethanolamine. The effect of capping agent on the size, structure and morphology of the as-synthesized nanoparticles was investigated. The particles were characterized using optical spectroscopy, transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.

Worm-Like Ag/ZnO Core–Shell Heterostructural Composites: Fabrication, Characterization, and Photocatalysis

Novel worm-like Ag/ZnO core–shell heterostructural composites were fabricated using a two-step chemical method. As-prepared silver nanowires were soaked in a solution of zinc acetate and triethanolamine to form worm-like Ag/ZnO core–shell composites under ultrasonic irradiation. Samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, and UV–vis spectrophotometer. The results show that the core–shell composites are composed of single-crystal Ag nanowires serving as the core, on which dense ZnO particles grow as the shell. The surface plasmon absorption band of Ag/ZnO composites is distinctly broadened and red shifted to monometallic Ag nanowires. The PL intensity of Ag/ZnO heterostructural composites varies and has the minimum intensity for the sample prepared with Ag of 2.8 atom %. Moreover, photocatalytic tests show that the Ag/ZnO composites ...

Preparation and properties of TiCxN1 − x coatings containing calcium on titanium surface by plasma electrolytic carbonitriding

The TiCxN1−x coatings containing calcium (Ca–TiCxN1−x) were prepared on the surface of titanium through plasma electrolytic carbonitriding (PEC/N) technique in a certain concentration of electrolyte solution of triethanolamine, urea and calcium nitrate. The effects of parameters, such as discharge time, on the Ca–TiCxN1−x coatings were investigated, and the phase composition, morphologies, surface chemical components, anticorrosion and hardness were also examined, respectively. The results show that the plasma discharge time significantly affects the microstructure and composition of the coatings. In addition, introduction of the Ca–TiCxN1−x coatings into the Ti surface can clearly improve the wear resistance and anticorrosion. Moreover, MTT assay demonstrates that the Ca–TiCxN1−x coatings can improve the cell viability, showing excellent cytocompatibility.