Diethylenetriamine Research Articles

Evaluation of Nitrogen-Doped Adsorbents Based on Reduced Graphene Oxide as Platforms for CO2 Capture

CO2 emissions into the atmosphere have been rapidly rising due to human activities, resulting in the escalation of global warming. To mitigate climate change, it is imperative to develop materials for CO2 capture with high CO2 capacity and low production costs. Herein, we developed a facile method to obtain adsorbents based on reduced graphene oxide (rGO) sheets, NrGO(1 - X)700, where X represents the mass of diethylenetriamine (DETA) (X = 1, 2 and 4 g) used in the preparation. The materials NrGO(1 - 1)700, NrGO (1 - 2)700, and NrGO(1 - 4)700 were obtained from graphene oxide dispersions, followed by DETA impregnation and chemical activation with K2CO3. N2 isotherms demonstrated that the materials simultaneously presented micro and mesopores with similar values of specific surface area (280.16 to 310.32 m2 g-1), pore volume (0.26 to 0.28 cm3 g-1) and pore size (3.78 to 3.80 nm). CO2 sorption experiments revealed that the material NrGO(1 - 4)700, containing the highest amount of pyridinic, graphitic, and amino nitrogen functionalities, showed the best CO2 adsorption capacity. Diffuse reflectance Fourier transformed infrared spectroscopy experiments indicated stronger solid-gas interactions for NrGO(1 - 4)700 than for the other materials.

SOIL FERTILITY STATUS AS INFLUENCED BY CROPPING SYSTEM IN EASTERN DRY ZONE OF KOLAR DISTRICT IN KARNATAKA

The current investigation was carried out to determine how farming systems under rainfed and irrigated conditions affected the soil’s fertility. Thimmasandra of Bangarpet Taluka, Yadahalli of Kolar Taluka, Gaddur of Mulbagal Taluka, Thippasandra of Malur Taluka, and Kadudevandahalli of Srinivaspurua Taluka were the four villages from where the soil samples (0–15 cm) were gather. As a consequence of chemical examination, the samples’ pH and electrical conductivity were found to be between 5.8 and 7.5 and below 0.4 and 08 dS/m, respectively. The percentage of soil organic carbon in soil samples from irrigated systems was higher than that of rainfed systems, where no soil sample fell into this group. In a similar vein, soils from tomato other vegetable-based cropping systems (irrigated) have lower accessible N, P, K, and Diethylene Triamine Penta Acetic acid extractable Zn, Cu, Mn, and Fe than soils from finger millet-fallow systems (rainfed).

Target-specific modification of diethylenetriamine with hydroxyalkyls: Efficient absorbents for CO2 capture

Chemical absorption of CO2 by amine solutions is an industrialized operation and currently represents the most practical technology worldwide. However, the development of amine absorbents with high efficiency and energy-saving benefits remains a major challenge. Here, we developed a novel class of amines through the target-specific modification of the secondary amine group in diethylenetriamine (DETA) with various hydroxyalkyls. The obtained amines present enhanced overall efficiency for CO2 capture, especially with regards to the absorption/desorption rates and recyclability. Significantly, the regeneration energy consumption for the developed amines can be reduced to a remarkable low value of 2.78 GJ t-1 CO2. Moreover, the CO2 absorption and desorption processes were closely monitored by nuclear magnetic resonance (NMR). Combined with density functional theory (DFT) calculations, the mechanism of the developed amine for CO2 capture was fully elucidated. This targeted modification strategy provides a new avenue for the development of efficient amine absorbents for practical CO2 capture.

A generic machine learning model for CO2 equilibrium solubility into blended amine solutions

In this work, three machine learning methods were employed to predict carbon dioxide (CO2) equilibrium solubility in blended amine solutions consisting of ethanolamine (MEA), N,N-diethylethanolamine (DEEA) and methyldiethanolamine (MDEA). Three machine learning algorithms, Radial Basis Function Neural Network (RBFNN), Support Vector Machine Regression (SVR) and Extreme Gradient Boosting (XGBoost), were used to fit the experimental results. We found that the predicted values of the three models developed for the CO2 equilibrium solubility were in good agreement with the experimental results, and the comparison of the mean absolute percentage error (MAPE) and root mean square error (RMSE) results showed that XGBoost had the best prediction accuracy with the MAPE of less than 1%. Four different amine blends were then used to evaluate the expandability of the XGBoost model, namely MEA and 1-dimethylamino-2-propanol (1DMA2P), MDEA and piperazine (PZ), diethylenetriamine (DETA) and PZ, and MEA and triethanolamine (TEA); the MAPE between the experimental and predicted results were 0.30%, 0.91%, 0.86% and 1.63%, respectively. The results obtained showed that the XGBoost model has enormous potential for application in dealing with the CO2 equilibrium solubility in blended amine solutions.

Glycogen for lysosome-targeted CpG ODNs delivery and enhanced cancer immunotherapy

CpG oligodeoxynucleotides (ODNs) strongly activate the immune system after binding to toll-like receptor 9 (TLR9) in lysosome, which demonstrated significant potential in cancer immunotherapy. However, their therapeutic efficacy is limited by drawbacks such as rapid degradation and poor cellular uptake. Although encouraging progress have been made on developing various delivery systems for CpG ODNs, safety risks of the synthetic nanocarriers as well as the deficient CpG ODNs release within lysosome remain big obstacles. Herein, we developed a novel nanovector for lysosome-targeted CpG ODNs delivery and enhanced cancer immunotherapy. Natural glycogen was simply aminated (NH2-Gly) through grafting with diethylenetriamine (DETA), which was spherical in shape with diameter of approximately 40 nm. NH2-Gly possessed good biocompatibility. Cationic NH2-Gly complexed CpG ODNs well and protected them from nuclease digestion. NH2-Gly significantly enhanced the cellular uptake of CpG ODNs. Efficient CpG ODNs release was observed in the presence of α-glucosidase that mimicking the environment of lysosome. Consequently, NH2-Gly/CpG complexes triggered potent antitumor immunity and effectively inhibit the tumor growth without causing any toxic effect or tissue damages. This work highlights the promise of glycogen for lysosome-targeted on-command delivery of CpG ODNs, which brings new hope for precision cancer immunotherapy.

The new Schiff‐base complex of copper(II) grafted on mesoporous KIT‐6 as an effective nanostructure catalyst for the homoselective synthesis of various tetrazoles

In this work, KIT‐6 mesoporous silica material was used to create heterogeneous catalyst due to its excellent surface area, substantial pore volume, and highly functionalized surface. A copper(II) Schiff‐base complex was fabricated on the surface of KIT‐6. For this purpose, (3‐iodopropyl)trimethoxysilane (IPTMS) was synthesized as a linker from (3‐choloropropyl)trimethoxysilane through a simple SN2 reaction using NaI. On the other hand, ligand (a) was synthesized from condensation of diethylenetriamine (DETA) and salicylaldehyde (SA), which was identified by IR and 1H‐NMR techniques. In order to, prepare Sal(PMeOSi)DETA (b), ligand (a) was reacted with IPTMS. One of the challenges of this synthesis was to prove the linkage between the ligand (a) and the IPTMS, which was proved by 1H‐NMR technique. In the next step, the Schiff base complex of copper(Cu(II)[Sal(PMeOSi)DETA]) (c) was synthesized using a complexation reaction of Cu(NO3)2.3 H2O and b. Finally, the obtained copper complex was fixed on KIT‐6, {Cu(II)[Sal(PMeOSi)DETA]} as the new reusable and practical catalyst. This catalyst has been identified using IR, BET, EDS, XRD, SEM, and TGA methods and employed in the synthesis of different tetrazoles for the first time. All tetrazoles were prepared with high yields, and good TOF and TON values, indicating excellent catalytic performance. This catalyst shows excellent homoselectivity in the synthesis of five‐substituted 1H‐tetrazoles. Also, it can be recovered and reused several times without a significant decrease in its catalytic activity or copper leaching.

Research of novel polyamine-based biphasic absorbents for CO2 capture using alkanolamine to regulate the viscosity and mechanism analysis

Biphasic solvent has attracted widespread attention in CO2 chemical absorption technology due to its significant potential for reducing capture energy consumption. However, the high viscosity of CO2-rich phase after phase split could lead to issues such as high flow resistance, low heat transfer efficiency, and phase separation instability in application. To address these limitations, a strategy of using alkanolamine as a viscosity regulator for biphasic solvents was proposed. Diethanolamine(DEA), an alkanolamine regulator, was introduced to a system of polyamine/amide absorbent, and then a novel biphasic solvent of diethylenetriamine (DETA)/diethanolamine(DEA)/N, N-Dimethylacetamide(DMAC)/water(H2O) was developed. The viscosity of the CO2-rich phase solvent was reduced to 19.02 mPa⋅s, a significant decrease compared to the solution without DEA regulation. The novel solvent exhibited a high cyclic capacity of 2.08 mol/kg, which was 43.4 % higher than that of the solution without DEA, and a desorption rate twice as high as 30 wt% monoethanolamine(MEA). Quantitative 13C Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD) simulations revealed the phase split and viscosity regulation mechanisms. It was proved that DETA species, especially carbamates, tend to self-aggregate with each other due to intermolecular hydrogen bonding with the CO2 loading increases, which leads to phase split and high viscosity of the saturated solution. Through DEA regulation, the protonation of carbamates and the generation of HCO3–/CO32– were promoted, which weakened the self-aggregation of carbamates species, decreasing the viscosity and the regeneration energy of saturated CO2-rich phase solution. The regeneration energy reached 2.19 GJ/ton CO2, which exhibited a 42.4 % reduction compared with that of 30 wt% MEA.

Amine-bridged periodic mesoporous organosilica adsorbents for CO2 capture

Novel periodic mesoporous organosilica (PMOs) were synthesized using different commercial non-aminated and aminated bisilanes in order to incorporate aminated sites within the silica walls. Three different commercial bisilanes were employed: i)without amine groups, ii)with one amine group, and iii)with two amine groups. Moreover, materials were prepared with different molar ratios of non-aminated and aminated bisilanes. P123 was used as structure directing agent for the mesoporosity. The amino functional groups of the PMOs so prepared were incorporated within the silica walls of the obtained solid particles. Moreover, for comparative purposes, BEBA-0, that is a non-aminated PMO, was functionalized via grafting with N1-(3-trimethoxysilylpropyl)diethylenetriamine (DT) and impregnation with polyethyleneimine (PEI) to produce amino functionalized materials. All these materials were tested for CO2 capture through CO2 adsorption/desorption isotherms and TGA studies. It was observed that increasing the concentration of amine containing bisilane increased the CO2 capture capacity significantly from 21.4 mg/g to 47.3 mg/g. The PMO synthesized with the bisilane containing two amine groups had higher CO2 uptake than the one containing one amine group from 47.3 to 62.6 mg/g due to the presence of more functional groups in the final material (6.0 versus 9.4% wt N, respectively). The cyclic capacity of the adsorbents via a series of adsorption/desorption tests has also been determined, the results showing the low reactivity decay (less than 3%) of the novel PMOs and materials prepared by grafting during the first 10 cycles, when compared with the 13% of PEI-impregnated material.

An ultra-sensitive detection of Melamine in milk using Rare-earth doped Graphene Quantum Dots- Synthesis and Optical Spectroscopic approach

This work focuses on a rapid and sensitive spectroscopic approach for detecting melamine in food products based on rare-earth Terbium-doped Graphene Quantum Dots (Tb-GQDs) synthesized using microwave and simple chemical conjugation methods. Citric acid and diethylene triamine (DETA) are the precursors of synthesizing GQDs. Terbium, a rare earth element with exceptional fluorescence properties, is doped onto the surface of the GQD to obtain dual photoemission with a broad spectral window and to provide excellent photo-stable characteristics. The as-synthesized Tb-GQDs were characterized using various spectroscopic and microscopic techniques. The synthesized Tb-GQD were spherical with a size of around 6 nm, showing approximately a quantum yield of 52 %, concerning the Standard-Quinine sulfate quantum yield of 54 %. Further, Tb-doped GQDs act as a fluorescent probe, were used to detect and quantify the concentration of melamine (0––5 µM) used as an adulterant in milk and milk products and obtained a maximum detection limit of 0.31 µM. This work concludes that the reported dual emitting Tb-GQDs provide a sensitive and effective platform for detecting melamine in real-time samples, especially in milk, and show promising potential in food industries.

Preparation of barium sulfate chelating agent DTPA-5Na and molecular dynamics simulation of chelating mechanism.

Barium sulfate (BaSO4) scale is dense and hard, making it difficult to remove using conventional acid and alkali treatments. Diethylenetriaminepentaacetic acid (DTPA) and its complexes have been identified as important chelating agents for the removal of BaSO4 scale. However, DTPA has good solubility only under strong alkali conditions, which in turn exacerbate scaling. To improve the solubility and chelation effectiveness of DTPA, penta sodium diethylenetriamine-pentaacetate (DTPA-5Na) was synthesized using chloroacetic acid, diethylenetriamine, sodium carbonate, and sodium hydroxide as raw materials. The structure of DTPA-5Na was characterized by infrared spectroscopy and 1H-NMR, and its chelation effectiveness was evaluated. Experimentation demonstrated that under conditions of 50 °C and with a molar ratio of chloroacetic acid (ClCH2COOH), sodium carbonate (Na2CO3), sodium hydroxide (NaOH), and diethylenetriamine (DETA) of 5.00 : 2.50 : 5.25 : 1.00, the reaction for 6 hours resulted in the optimal chelation value of DTPA-5Na at 76.8 mg CaCO3·per g. Analysis of the chelation and dissolution of BaSO4 scale using DTPA-5Na and microstructural scanning electron microscopy of the BaSO4 crystal indicate that DTPA-5Na functions through solubilization, lattice distortion, and flaking dispersion to remove BaSO4. Molecular dynamics simulation software was used to simulate the chelation mechanism of DTPA-5Na, where the results indicated strong adsorption of DTPA-5Na to the surface of BaSO4. The adsorption energy follows the order of (120) surface > (001) surface > (100) surface > (210) surface. The adsorption is mainly a result of the interaction between the carboxylic "O" atom in DTPA-5Na and the (001), (100), and (120) surfaces of BaSO4 scale, while N atoms in DTPA-5Na structure primarily interact with the (210) surface. The adsorption of "O" atoms is stronger than that of "N" atoms in the DTPA-5Na structure.

Surface functionalization of magnetite nanoparticles for remediation enhancement of phenol from aqueous solutions

Phenol is a toxic pollutant generated by industries. It can diminish the supply of clean water and is hazardous to human health. Hence, an effective abatement method is important to remove phenol from water sources. The following amine-functionalized magnetite nanoparticles, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and polyethylenehexamine (PEHA), were used to study the adsorption performances of phenol from the prepared samples. The morphological study revealed long rod shapes with rough and sharp edges, while the elemental analysis presented the addition of two elements, C and N atoms. In addition, the TETA@MNP possessed weaker magnetism compared to MNPs, showing that the surface functionalization of MNPs was successful. TETA@MNP showed the highest percentage for phenol removal compared to others. The TETA@MNP achieved a removal efficiency of 99.2% at optimum conditions of 60 mg dosage, contact time of 25 min, and pH of 7. TETA@MNP obeyed the pseudo-second-order kinetic model and the Freundlich isotherm model, with coefficients of determination (R2) of 0.9765 and 0.9682, respectively. The reusability study has demonstrated that TETA@MNP can be reused approximately 6 times with extremely minor loss. Therefore, TETA@MNP is a good adsorbent for the adsorption of phenol from prepared sample solutions.

Synthesis of dynamic polymers by amino-yne click reaction using multifunctional amine

Covalent adaptable networks (CANs) have become sustainable alternatives to traditional thermosetting materials due to their powerful reprocessing and rearrangement capabilities. Therefore, developing and investigating reversible reactions that can be used in the construction of CANs is a popular research topic. Amino-yne click chemistry is known for its green characteristics—it is a catalyst-free and efficient reaction—and is widely applied in the synthesis of bio-organic molecules, but there have been few reports on CANs, especially multifunctional amine-based amino-yne click reactions. In this study, various CANs were synthesized via the amino-yne click reaction using multifunctional amines (diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA)), and they were compared with CANs that were prepared from a primary amine (tris(2-aminoethyl) amine (TREN) and a secondary amine (tris[2-(methylamino)ethyl]amine (TMEN)) under the same conditions. The results showed that H-DETA CANs exhibited the smallest glass transition temperature Tg (15 °C) and Young's modulus (105 MPa) because the crosslinker (DETA) contained a low content of primary amine and secondary amine, but its crosslinking density followed the trend of H-TMEN < H-DETA < H-TREN. In addition, the relaxation time, activation energy, and creep rate results for the CANs followed the same trend as the crosslinking density. With the increase in the secondary amine content of the multifunctional amines, the Tg of the CANs increased from 15 °C to 57 °C, the Young's modulus increased from 105 to 666 MPa, and the crosslinking density increased from 955 to 2690 mol/m3. Notably, the increase in the secondary amine content led to the weaker dynamics of the material, namely, prolonged relaxation time, increased activation energy, and decreased creep rate. This work also verified the dynamic exchange mechanism of the materials by the molecular model reaction and the amine solvent dissolution tests. Finally, hot-pressing experiments demonstrated the good plasticity and recovery ability of prepared CANs. This work provides an elegant path for preparing materials in energy and chemical fields such as coatings and rubber.

Development of dual-functionalized ionic liquids for biphasic solvents: Enhancing the CO2 absorption through two-stage reaction and promoting the energy-saving regeneration

A dual-functionalized ionic liquid was synthesized by facile neutralizing routes from Diethylenetriamine (DETA) and lysine (Lys), which was designated as [DETA]Lys. It could absorb CO2 through a two-stage reaction, achieving a CO2 capacity of up to 2.16 mol CO2/mol ILs. And N-methyl-2-pyrrolidone (NMP) was validated as a good phase splitting agent for [DETA]Lys-based biphasic solvent by tailoring the polarity and hydrogen bonding effect. Thus, DETA-carbamate, Lys-carbamate, and HCO3−/CO32− were formed during CO2 absorption and gathered in the lower layer, while most of the NMP stayed in the upper layer. Finally, the CO2-rich phase took up 53.84 % of the total volume and 99.03 % of the captured CO2, exhibiting a CO2 loading of 4.78 mol CO2/L. The significantly enhanced CO2 loading (4.78 mol/L), decreased stripping volume (53.84 %), and reduced desorption energy (1.28 GJ/ton CO2) allowed for a great reduction in regeneration energy to 1.89 GJ/ton CO2, which was merely 47.37 % of 5 M MEA (3.80 GJ/ton CO2). The regeneration efficiency of the solvent remained at 91.5 % after the 3rd absorption/desorption cycle. Furthermore, the corrosion speeds of the rich and lean phases were merely 0.18 % and 12.35 % of 5 M MEA. The excellent CO2 capture performance and good energy-saving potential enabled the [DETA]Lys + NMP + H2O system an effective absorbent for carbon capture.

Post‐Synthetic Covalent Grafting of Amines to NH2‐MOF for Post‐Combustion Carbon Capture

AbstractHerein, a post‐synthetic modification strategy is used to covalently graft polyamines, including ethylenediamine (ED), diethylenetriamine (DETA), tris(2‐aminoethyl)amine (TAEA), and polyethyleneimine (PEI) to the amino‐ligand inside of a Cr‐MOF, NH2‐Cr‐BDC, for post‐combustion carbon capture applications. X‐ray absorption spectroscopy (XAS), X‐ray photoelectron spectroscopy (XPS), and ion chromatography (IC) reveal that ≈45% of the MOF ligands are grafted with polyamines. Next, assessment of CO2 uptake, CO2/N2 selectivity, isosteric heats of CO2 adsorption, separation performance during humid CO2/N2 (15/85) breakthrough experiments, and cyclability, reveals an enhanced performance for the polyamine‐containing composites and the following performance trend: NH2‐Cr‐BDC&lt;ED&lt;DETA&lt;TAEA&lt;PEI. The best‐performing materials, including the TAEA and PEI‐grafted MOFs, offer CO2 uptakes of 1.0 and 1.55 mmol g−1, respectively, at 0.15 bar and 313 K. Further, these composites also offer a high CO2 capacity after 200 temperature swing adsorption/desorption (TSA) cycles in simulated humid flue gas. Last, after soaking the composites in water, there is no loss of CO2 capacity; on the contrary, when the same MOF is impregnated with polyamines using traditional approaches, there is ≈85% CO2 capacity loss after soaking. Thus, this covalent grafting strategy successfully immobilizes amines in MOF pores preventing leaching and hence can be an effective strategy to extend the adsorbent lifetime.

A novel pH-responsive wormlike micelles combinated sodium dodecyl sulfate (SDS) and diethylenetriamine (DETA) based on noncovalent electrostatic interaction

pH-Responsive wormlike micelles (WLMs) have attracted lots of attention due to their abundant advantages, for example, ease of adjustment and strong reversibility. We have learned that the degree of protonation of diethylenetriamine (DETA) varies with pH, and the anionic sodium dodecyl sulfate (SDS) can connect with cationic groups. Inspired by this, a novel pH-responsive WLMs was prepared based on noncovalent electrostatic interaction with sodium dodecyl sulfate (SDS) and DETA at a molar ratio of 3:1. Properties of the SDS/DETA system were assessed from the aspects of rheology, macro-morphology, aggregates diameter, and micro-morphology. When the pH decreased from 9.98 to 6.80, the SDS/DETA system represented as a weak gel with the viscosity increasing from 7.6 mPa s to 1.4 × 103 mPa·s and the average hydrodynamic radius increasing from 5.6 to 91.3 nm. The phenomenon is attributed to the protonation of DETA when reducing the pH and the formation of WLMs based on electrostatic interaction between DETA and SDS. However, when pH was further reduced by adding HCl, the SDS/DETA system would reach its isoelectric point, thus the solution became turbid with low viscosity. The SDS/DETA solution represents excellent reversibility (at least three cycles) in viscoelasticity by adjusting the pH value, and such pH-responsive WLM holds significant potential for broader applications in biomedical, oilfield chemistry, and other fields.

A Comparative Study on the Properties of Rosin-Based Epoxy Resins with Different Flexible Chains

This study aims to reveal the effects of flexible chain lengths on rosin-based epoxy resin’s properties. Two rosin-based epoxy monomers with varying chain lengths were synthesized: AR-EGDE (derived from ethylene glycol diglycidyl ether-modified acrylic acid rosin) and ARE (derived from acrylic acid rosin and epichlorohydrin). Diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) with different flexible chain lengths were used as curing agents. The adhesion, impact, pencil hardness, flexibility, water and heat resistance, and weatherability of the epoxy resins were systematically examined. It was found that when the flexible chains of rosin-based epoxy monomers were grown from ARE to AR-EGDE, due to the increased space of rosin-based fused rings, the toughness, adhesion, and water resistance of the rosin-based epoxy resins were enhanced, while the pencil hardness and heat resistance decreased. However, when the flexible chains of curing agents were lengthened, the resin’s performance did not change significantly because the space between the fused rings changed little. This indicates that the properties of the rosin-based resins can only be altered when the introduced flexible chain increases the space between the fused rings. The study also compared rosin-based resins to E20, a commercial petroleum-based epoxy of the bisphenol A type. The rosin-based resins demonstrated superior adhesion, water resistance, and weatherability compared to the E20 resins, indicating the remarkable durability of the rosin-based resin.

Preventing crystallization at high concentrated 2-amino-2-methyl-1-propanol for energy-saving CO2 capture

2-amino-2-methyl-1-propanol (AMP) combines the advantages of the faster reaction rate of primary/secondary amines and the high absorption capacity of tertiary amines, making it a highly promising alternative to monoethanolamine (MEA). However, at high AMP concentrations, the absorption products are prone to solid crystallization, resulting in unstable operation of the carbon capture system. In this work, by adding a small amount of diethylenetriamine (DETA) to AMP, the crystallization of reaction products can be effectively controlled and AMP-DETA absorbent possesses a high absorption rate, low regeneration energy, and low metal corrosion rate. Wetted-wall column tests were performed to comprehensively evaluate the mass transfer kinetics and the effect of crucial conditions, and the diffusion coefficient, gas–liquid mass transfer coefficient, enhancement factor, and mass transfer resistance distribution were obtained. The effect of the addition of DETA on the solubility of HCO3− was verified. DETA carbamate was more likely to form intermolecular hydrogen bonds with HCO3−, thus reducing the formation of dimeric or multichain macromolecules between HCO3− molecules through hydrogen bonds and inhibiting the crystallization of high concentration HCO3−. HCO3− can accelerate the desorption rate by participating in the deprotonation of protonation amines. The results demonstrated that the average regeneration energy of the AMP–DETA absorption system was reduced by 21.2 % relative to that of 5 M MEA, and its metal corrosion rate was 0.07 mm/a, which was only 7.9 % of MEA under the same conditions. The results contribute to the industrial application of AMP–DETA.

Metal organic framework doped amine-functionalized polymeric beads for selective removal of Uranium (VI) from alkaline leach liquor: Batch and column study

In this work, a diethylenetriamine (DETA) functionalized metal organic framework (ZIF-67) incorporated polyacrylonitrile (PAN) bead (MFB) was developed to capture U efficiently from simulated medium and alkaline leach liquor. The synthesized beads were characterized using suitable analytical methods. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to understand the U uptake mechanism. The process of adsorption was inherently heat-absorbing and spontaneous in nature. The Langmuir sorption capability (Qm) was 835 mg/g, at pH 7 and, 298 K. Surface- grafted abundant amine (–NH2) groups introduce significant coordinative interaction with the U species in aqueous medium. The adsorbent is reusable and structurally robust with >85 % U removal after five consecutive regeneration cycles. The performance of the continuous adsorption columns was simulated by a fundamental adsorption-diffusion model and the relevant transport parameters were evaluated. For real life alkaline leach liquor with U concentration 825 mg/L and 100 to 500 kg of adsorbent, the adsorption column had a breakthrough life of 46 to 108 days with constant flow rate of 500 L/day. This study showed that the synthesized MFB is an excellent adsorbent that is inexpensive, non-toxic, recyclable,environmentally compatible, and selective towards U removal from alkaline leach liquor.

Fabrication of amine-functionalized and multi-layered PAN-(TiO2)-gelatin nanofibrous wound dressing: In-vitro evaluation

The development of advanced multifunctional wound dressings remains a major challenge. Herein, a novel multilayer (ML) electrospun nanofibers (NFs) wound dressing based on diethylenetriamine (DETA) functionalized polyacrylonitrile (PAN), TiO2 nanoparticles (NPs) coating (Ct), and bioderived gelatin (Gel) was developed for potential applications in wound healing. The ML PAN-DETA-Ct-Gel membrane was developed by combining electrospinning, chemical functionalization, synthesis, and electrospray techniques, using a layer-by-layer method. The ML PAN-DETA-Ct-Gel membrane is comprised of an outer layer of PAN-DETA as a barrier to external microorganisms and structural support, an interlayer TiO2 NPs (Ct) as antibacterial function, and a contact layer (Gel) to improve biocompatibility and cell viability. The NFs membranes were characterized by scanning electron microscopy (SEM), surface profilometry, BET analysis, and water contact angle techniques to investigate their morphology, surface roughness, porosity, and wettability. The ML PAN-DETA-Ct-Gel wound dressing exhibited good surface roughness, porosity, and better wettability. Cell morphology, proliferation, and viability were determined using fibroblasts (3T3), and antibacterial assays were performed against six pathogens. The ML PAN-DETA-Ct-Gel NFs membrane showed good cell morphology, proliferation, viability, and antibacterial activity compared with other membranes. This new class of ML NFs membranes offers a multifunctional architecture with adequate biocompatibility, cell viability, and antibacterial activity.

Determination of Critical Limit of Zinc for Lentil (Lens culinaris L.) in Diverse Soils under Intensive Cropping Systems

Determination of the critical limit (CL) for nutritionally essential zinc (Zn) is very important in developing fertilizer recommendations for crops and soils. However, the CL of Zn for the lentil crop has not been determined yet in Bangladesh, leading to the use of a fertilizer rate for the crop estimated on the basis of old critical limit generalised for all crops. A study was conducted in the Greenhouse facilities of the Soil Science Division of BARI, Gazipur, from October to April (Rabi season) of 2018/2019 and 2019/2020, to determine Zinc CL for soils and lentil crop in soils collected at twenty locations encompassing the six Agro-Ecological Zones (AEZs) of Bangladesh. For extraction of available Zn concentrations from soils and lentil biomass, a diethylene triamine penta acetic acid (DTPA) (0.005 M) solution was used. The DTPA-extractable Zn (mg kg-1) in the soils were from 0.43 to 4.10 and from 0.52 to 4.20 in 2018/2019 and 2019/2020, respectively. In all seasons, accessible Zn had negative but substantial correlations with soil pH, soil P, Ca, and Mg in available forms, but the association between available Zn and lentil dry matter was positive and significant (DM). Soil Zn had also a positive significant correlation with Zn concentration of lentil tissue Zn (0.501**). In 2018-2019 and 2019-2020, the CL of EDTA-extractable Zn was determined to be 0.75 mg kg-1 and 0.68 mg kg-1 in soils for lentil crop (0.72 mg kg-1 on an average), respectively, while it was 48.6 mg kg-1 for lentil tissue. The revised CL can be used for fertilizer recommendation for the lentil crop in the entire Gangetic Plains and other Agro-Ecological Zones of Bangladesh. Keywords: Pulse crop, Nutrient management, Micronutrient, Dryland crop, Sustainable agriculture