Amount Of Formic Acid Research Articles

Probing the sites on metal oxide cluster nodes of metal organic framework MIL-96, MIL-100 and MIL-110

Metal oxide cluster MOF nodes are a good platform to understand the reactivities and catalysis. MIL-96, MIL-100 and MIL-110 are drastically different in their node structures. Following our previous reported results for MIL-100, we report the modified synthesis and characterization of the node sites of MIL-110 and MIL-96 and their catalytic sites by using methanol dehydration as probe reaction. We show that these MOFs can be synthesized from the same solution by adding various amounts of formic acid as modulator. Herein, the chemistry of hydroxyl, formate and methoxy groups were used to probe the three MOFs’ node sites. IR data show the bonding structures of these ligands are highly diverse, with reactivities and flexibilities depending on node sites. We identified terminal OH group and various µ2-OH groups in single, paired or hydrogen bonded modes on the MOF nodes. Formate ligands were introduced to the node sites during the synthesis or by a post treatment in formic acid/DMF solution. Surprisingly, the bonding modes of formate ligands on Al3(OH)3 node structure of MIL-96 can be reversibly switched between monodentate and bidentate through a process induced by water molecules. Further, methoxy ligands—likely to be the intermediate for catalytic reaction—were also observed on the node sites under methanol dehydration conditions at 250 ℃. The activities of MIL-100 and MIL-96 for methanol dehydration determined by TOF per node were similar, both approximately 3-fold higher than that of MIL-110. The data suggests that catalytic sites incorporate adjacent vacancy and defect node sites, which constitute a minority among all observed MOF node sites. We foresee the opportunities in expanding the chemistry and understanding into other MOFs with metal oxide cluster nodes.

Neutron and gamma-ray shielding effectiveness of novel polyaniline composites

This study uses experimental, theoretical, and Monte Carlo simulation techniques to investigate the neutron and gamma-ray shielding performances of polyaniline-based composites filled with different amounts of formic acid, boron nitride, and boric acid. The radiation shielding performances of composites were evaluated at neutron energies of 0.025 eV, 1 keV, and 10 MeV, and gamma-ray energy of 662 keV. The study found that the composite material made of polyaniline and boron nitride with a higher percentage of boron has better thermal neutron shielding properties than other polyaniline composites. The research also showed that a polyaniline-boric acid composite with a thickness of 1.6 mm can reduce thermal neutrons by 64.5%. As a result, the composite containing equal amounts of polyaniline and boric acid was identified as the most promising material for shielding. The macroscopic cross-sections of neutrons and mass attenuation coefficients of gamma-rays were found to have expanded uncertainties up to 13.47% and 7.11%, respectively. The factors contributing to the uncertainty of the experimental, theoretical, and simulation results were identified, evaluated, and shown how to include uncertainty components in the uncertainty budget.

Construction of defective zirconium-based metal–organic frameworks for enhanced removal of toxic selenite: performance and mechanism studies

The development of effective adsorbents for the adsorption and removal of toxic selenite (SeO32−) from wastewater is urgently required but challenging. Herein, formic acid (FA), a monocarboxylic acid, was used as a template to construct serial defective Zr-Fumarate (Fum) -FA based on a green and facile preparation method. Physicochemical characterization shows that the defect degree of Zr-Fum-FA can be flexibly controlled by regulating the amount of FA to be added. Owing to rich defect units, the diffusion and mass transfer of guest SeO32− into the channel can be boosted. Particularly, Zr-Fum-FA-6 with the most defects exhibits superior adsorption capacity (519.6 mg g−1) and rapid adsorption equilibrium (∼200 min). The adsorption isotherms and kinetics can be well described by the Langmuir and pseudo-second-order kinetic models. Moreover, this adsorbent possesses excellent resistance towards co-existing ions, high chemical stability and good applicability in a broad pH range of 3–10. Thus, our study provides a promising adsorbent for SeO32−, and more importantly, it proposes a strategy for rationally tailoring the adsorption behavior of adsorbents via defect construction.

Experimental Study of Bio-Hydrogen Production by Clostridium beijerinckii from Different Substrates

Glucose, alcohol stillage and glycerol were used as substrates for bio-hydrogen production by the newly isolated strain Clostridium beijerinckii 6A1 under batch conditions. High molar yields of hydrogen from the studied organic substrates were observed. There was a neat difference in the metabolic pathways of substrate digestion when hexose-based substrate or glycerol were used. The products of glycerol digestion showed that a pathway with no formic acid formation as intermediate was probable. In this case, considerable concentrations of acetic and propionic acid (up to 6 g dm−3) and small amounts of butanol were observed after 48 h. When glucose or hexose-based substrates were used, considerable amounts of formic acid (up to 6 g dm−3), i.e., the pathway proposed for Clostridia mixed cultures, were appropriate for the observed process of hydrogen release. For these substrates, considerable amounts of propionic acid in concentrations up to 1 g dm−3 were observed. That is why the pathway proposed for mixed cultures seemed more appropriate for our experiments carried out with hexose-based substrates. When hexoses were used, substrate digestion stopped the formation of acetic acid, propionic acid and ethanol. Probably, these intermediates are inhibitors to the further digestion to other products.

Treatment of pyridine in industrial liquid waste by atmospheric DC water plasma

Pyridine is a basic heterocyclic compound with high toxicity, widely found in liquid waste from industrial processes. The treatment of highly-concentrated pyridine was demonstrated using a novel mist-type water thermal plasma torch. Decomposition rate and TOC removal rate were more than 94% in all conditions, while the max energy efficiency reached about 23 g/kWh. With a high temperature of 5500–7500 K, more than 95% of carbon content in pyridine was converted into valuable gas products, while a little amount of formic acid and acetic acid were observed as liquid by-products. The production of hydrogen cyanide (HCN) during the thermal decomposition of pyridine was observed, which can be inhibited by increasing the input power. Based on the experimental results, detailed decomposition mechanisms in the high-temperature and the downstream region were discussed respectively. Water plasma shows significant potential in the treatment of non-biodegradable industrial liquid waste.

Electrospun Silk Fibroin Scaffolds for Tissue Regeneration: Chemical, Structural, and Toxicological Implications of the Formic Acid-Silk Fibroin Interaction.

The dissolution of Bombyx mori silk fibroin (SF) films in formic acid (FA) for the preparation of electrospinning dopes is widely exploited to produce electrospun SF scaffolds. The SILKBridge® nerve conduit is an example of medical device having in its wall structure an electrospun component produced from an FA spinning dope. Though highly volatile, residual FA remains trapped into the bulk of the SF nanofibers. The purpose of this work is to investigate the type and strength of the interaction between FA and SF in electrospun mats, to quantify its amount and to evaluate its possible toxicological impact on human health. The presence of residual FA in SF mats was detected by FTIR and Raman spectroscopy (new carbonyl peak at about 1,725 cm−1) and by solid state NMR, which revealed a new carbonyl signal at about 164.3 ppm, attributed to FA by isotopic 13C substitution. Changes occurred also in the spectral ranges of hydroxylated amino acids (Ser and Thr), demonstrating that FA interacted with SF by forming formyl esters. The total amount of FA was determined by HS-GC/MS analysis and accounted for 247 ± 20 μmol/g. The greatest part was present as formyl ester, a small part (about 3%) as free FA. Approximately 17% of the 1,500 μmol/g of hydroxy amino acids (Ser and Thr) theoretically available were involved in the formation of formyl esters. Treatment with alkali (Na2CO3) succeeded to remove the greatest part of FA, but not all. Alkali-treated electrospun SF mats underwent morphological, physical, and mechanical changes. The average diameter of the fibers increased from about 440 nm to about 480 nm, the mat shrunk, became stiffer (the modulus increased from about 5.5 MPa to about 7 MPa), and lost elasticity (the strain decreased from about 1 mm/mm to about 0.8 mm/mm). Biocompatibility studies with human adult dermal fibroblasts did not show significant difference in cell proliferation (313 ± 18 and 309 ± 23 cells/mm2 for untreated and alkali-treated SF mat, respectively) and metabolic activity. An in-depth evaluation of the possible toxicological impact of residual FA was made using the SILKBridge® nerve conduit as case study, following the provisions of the ISO 10993-1 standard. The Potential Patient Daily Intake, calculated from the total amount of FA determined by HS-GC/MS, was 2.4 mg/day and the Tolerable Exposure level was set to 35.4 mg/day. This allowed to obtain a value of the Margin of Safety of 15, indicating that the amount of FA left on SF mats after electrospinning does not raise concerns for human health.

Microwave-assisted depolymerization of lignin and a biphasic extraction method for the recovery of bio-oil and phenolic monomers

Alkaline lignin and de-alkaline lignin were depolymerized under microwave irradiation in the presence of formic acid and ethanol to produce bio-oil and phenolic monomers. The amount of formic acid was identified as the most critical factor influencing product yields among variables of temperature, retention time, feedstock concentration, and formic acid to feedstock mass ratio. Formic acid acted as both catalyst and in-situ hydrogen donor and it is economically and environmentally advantageous over metal catalysts. An ethyl acetate-water extraction method was developed, which was suitable to recover bio-oil from the depolymerization of lignin with high ash content. Acidic extraction condition favored the product recovery than neutral or basic conditions, giving bio-oil product with much improved quality. This is attributed to the fact that pH adjustment induced ionization of solutes and thus altered the affinity between the solutes and the extraction solvents. This work also revealed that alkaline and de-alkaline lignin feedstocks gave comparable bio-oil yield (ash-free basis) and chemical composition. The bio-oil derived from the de-alkaline lignin has a lower average molecular mass than the alkaline lignin-based bio-oil, likely caused by the presence of alkaline compounds in the alkaline lignin, which could neutralize some formic acid (FA) catalyst, leading to a reduced degree of de-polymerization with the alkaline lignin.

Evaluation of Dye Fixatives – A Comparative Study

Dyeing is the important unit process in leather manufacturing, which adds value to the leather. Although formic acid is used for fixing of dyes in leather processing, difficulties do arise in fixation of certain dye stuffs. Further high quantities of formic acid used do create health issues and adds to high cost of production. Compounds such as formic acid, acetic acid, mixture of organic acids and quaternary ammonium compounds have been found to function as dye fixatives. The efficacy of these compounds to function as dye fixatives for various dye stuffs and substances either alone or along with formic acid has been studied in detail in this work. The physical and color characteristics of leather and spent liquor analysis have been carried out.

Magnetic Ru Nanocatalysts for Sustainable Hydrogenation of CO2 Gas to Formic Acid

We performed the Ru nanoparticles encapsulation using silica-coated carbon-cobalt nanostructure (with and without amine functionality). The physicochemical properties of the above structures were evaluated using the following analytical techniques such as XPS, EDX, XRD, HR-TEM, and ICP-AES. The analytical data received from the above analysis were found in good correlation to each other and confirm the uniform distribution of ruthenium nanoparticles over the surface of the silica–carbon coated magnetic cobalt system. The uniform Ru dispersion confirms the high catalytic activity during CO2 hydrogenation reaction to formic acid. We also studied the effect of water and correlated the same with the quantity of formic acid. Easy catalyst preparation, hassle-free catalyst isolation under an applied magnetic field, and good catalyst recycling is the major outcome of this proposed work. The effect of the ionic liquid solvent system was also noticed in terms of high reaction rate, good catalyst stability, and nine times catalyst recycling.

Hydrothermal liquefaction of macroalgae with in-situ-hydrogen donor formic acid: Effects of process parameters on products yield and characterizations

Catalytic Hydrothermal liquefaction (HTL) of Ulva lactuca (UL) macroalgae over various amount of formic acid (FA) with solvents (water, ethanol and methanol) at different reaction temperatures (260, 280 and 300 °C), reaction holding times (15, 30 and 45 min.) with acidic ZSM-5 and basic MgO catalyst were investigated. Without catalyst, the maximum bio-oil yield was obtained 43.8 wt.% in ethanol-FA mixture at 280 °C for 30 min reaction time. However, the maximum bio-oil (55.2 wt.%) was obtained with basic metal MgO catalyst in the ethanol-FA solvent mixture compared to the acidic ZSM-5 catalyst (48.7 wt.%). When ethanol solvent used with MgO and ZSM-5 catalyst, the highest bio-oil yield 46.7 and 48.7 wt.% were observed. Selectively higher derivatives of hydrocarbon compounds were obtained with MgO in ethanol-FA solvent. However the phenolic compounds majorly were found with ZSM-5 catalyst. The higher carbon (69.5 %) and higher high heating value (HHV) (35.8 MJ/kg) was observed in case of MgO catalytic HTL bio-oil compared to the other HTL bio-oil. The use of catalysts in HTL increased the boiling point range of bio-oil and the higher boiling point range was observed in case of MgO and ZSM-5 catalytic bio-oil.

Investigation into reversed phase chromatography peptide separation systems part II: An evaluation of the robustness of a protocol for column characterisation

The robustness of the Peptide Reversed Phase Chromatography (RPC) Column Characterisation Protocol was evaluated using reduced factorial design, to ascertain the degree of control required for parameters including temperature, flow rate, dwell volume, a systematic shift in the gradient, amount of formic acid in the aqueous and organic, pH of the ammonium formate and amount of acetonitrile (%MeCN) in the strong solvent, where a loss of MeCN resulted in an unacceptable variation. Mitigations have been introduced to ensure the integrity of the data to allow RPC columns to be characterised using peptides as probes, with the definitive protocol described. In addition, the instrument and column batch to batch variability were assessed with good reproducibility.

Determination of opiates in whole blood using microextraction by packed sorbent and gas chromatography-tandem mass spectrometry

In Portugal, and worldwide, the abuse of psychoactive substances is increasing, with a significant incidence of deaths related to their consumption. Opiates are one of the most prevalent group of substances in that context, and they are responsible for a significant impact of the mentioned harms. Therefore, it becomes necessary to equip labs with faster and effective methods to identify and quantify these substances. This work describes the development and validation of a novel analytical method for the simultaneous determination of morphine, codeine and 6-monoacetylmorphine in blood samples by gas chromatography-tandem mass spectrometry (GC–MS/MS), using microextraction by packed sorbent (MEPS) for sample preparation. Before the MEPS procedure, a precipitation step with acetonitrile was performed. The MEPS parameters were optimized using the fractional factorial planning (2k-1) and surface response methodology. The final optimized conditions were: number of strokes (20), amount of formic acid in the washing solution (3.36%), number of washes of the sorbent (1), amount of ammonium hydroxide in the elution solution (2.36%) and number of elution cycles (11). After the extraction procedure, the analytes were derivatized with MSTFA with 5% TMS. Using a sample volume of 250 μL, the method was validated according to internationally accepted standards. The method proved to be linear in the range of 5-1000 ng/mL with coefficients of determination greater than 0.99 for all analytes. Intra-and inter-day precision and accuracy were in accordance with the above-mentioned criteria, presenting coefficients of variation ≤15% and relative errors within a range of ± 15% of the theoretical concentration. The absolute recoveries ranged from 6 to 23%. The validated method was applied to the analysis of real samples, being an advantageous tool for the detection of those substances in blood. This is the first time that GCMS/MS with MEPS was used for the determination of these compounds in biological fluids.

A two-step approach for producing oxygen-free aromatics from lignin using formic acid as a hydrogen source

A high-calorific-value oil with a high amount of oxygen-free aromatics was produced from highly recalcitrant concentrated-sulfuric-acid-hydrolysis lignin (CSAHL) using a two-step approach. In the first step, lignin-derived bio-oil (LBO) was produced by the liquefaction of CSAHL in a mixture of supercritical ethanol and formic acid. In the second step, hydrodeoxygenation (HDO) of the LBO over sulfided CoMo/γ-Al2O3 (CoMoSx/γ-Al2O3), Pd/Al2O3, and Ru/γ-Al2O3 catalysts was performed to produce upgraded LBO. Although the yield of the LBO was high (70 wt%), its calorific value and the yield of monoaromatics (mainly oxygenated guaiacol- and syringol-type molecules) were low (27.2 MJ kg−1 and 4 wt% (based on CSAHL), respectively). The LBO was separated from the ethanol and used as a feed for HDO in formic acid, which acts as an in-situ hydrogen donating agent. HDO of the LBO over CoMoSx/γ-Al2O3 at 350 °C for 4 h produced oxygen-free aromatics, such as alkylated benzenes, indanes, and tetralins, with the high yield of 6.8 wt% (based on CSAHL). The degree of deoxygenation was high (>90%) and the upgraded LBO exhibited a high calorific value (>40 MJ kg−1). The effects of different HDO parameters, including catalyst loading, amount of formic acid, reaction time, catalyst type, and solvent type were assessed to gain insight into the LBO deoxygenation mechanisms.

Effects of BTEX on the Removal of Acetone in a Coaxial Non-Thermal Plasma Reactor: Role Analysis of the Methyl Group.

The removal of acetone and benzene series (BTEX) under individual and concurrent conditions is carried out in a coaxial nonthermal plasma (NTP) reactor. The results show that the benzene series has a significant negative impact on acetone conversion and CO2 selectivity under NTP treatment. Furthermore, it is found that p-xylene significantly promotes COx selectivity under co-treatment with acetone because of greater CO generation. Based on the results of transient FTIR, MS, and GC-MS, it is seen that quantities of formic acid, formaldehyde, and ring-opening byproducts from benzene series decomposition are reduced, while quantities of aromatic byproducts with carboxyl, phenolic, and aldehyde groups on the benzene ring increase under coexistence conditions. With the help of theoretical calculation and kinetic analysis, hydrogen abstraction from the methyl group and active hydroxyl radical consumption are proposed as critical factors in the BTEX inhibition effect on acetone degradation.

Influence of washing chemo-thermo-mechanical pulps (CTMP) on the emission of volatile organic acids of medium density fibreboards (MDF) prepared therefrom

Washing of CTMP-pulps ahead of board making decreases the amount of extractable acetate and formate ions from the boards. The decrease in the amount of releasable acetic acid due to washing is enormous, whereas washing seems to have no detectable effect on the releasable amount of formic acid. This is likely due to the fact that formic acid is a much stronger acid than acetic acid.

Studying the effect of formic acid and potassium diformate on performance, immunity and gut health of broiler chickens.

Our trial was conducted to study the effects of formic acid (FA) and potassium di-formate (KDF) in broiler ration on performance, carcass traits, blood biochemical, intestinal microbial load, histological picture of intestine and immune parameters of broilers. In this study 360 one-day-old broiler chicks were divided to 3 groups with 3 replicates of 40 chicks each. The trial continued for 35 days. The control group was fed only basal diet (G1). Group 2 (G2) were fed basal diet supplemented with FA (5 g/kg diet), and group 3 (G3) received basal diet supplemented with KDF (5 g/kg diet). The results showed that both FA and KDF significantly increased body weight gain (BWG), dressing percentage of broilers and significantly decreased feed conversion ratio (FCR) (P < 0.05). The highest percent of breast and thigh was observed in G3. The improvement in villus height was observed in G2 and G3 compared with the control one, and the highest was in G3. The results evidence that the using of FA or KDF in broiler feeds have significant effects on performance, immune parameters, and gut health without having any significant effects on blood biochemical. However, KDF is more effective than FA as little amount of FA reaches the small intestine due to metabolism and absorption, whereas KDF permits a proportion of FA to pass through the fore-gut intact and enter the small intestinal tract. In addition, FA has a strong odor and corrosiveness to gastrointestinal tract which limits its use.

New Solvent System for the Fabrication of Polyvinyl Alcohol – Gelatin Nanofibers via Electrospinning

Polyvinyl Alcohol (PVA) is a biocompatible polymer with high mechanical strength used in the biomedical industry. While its features have biological properties, it lacks cell recognition sites that affect the entirety of cell proliferation and movement. To address this issue, gelatin (GEL) is added to the system to increase biomimetic properties. PVA and GEL nanofibers, produced from electrospinning, could provide new characteristics for tissue engineering applications. At present, aqueous solution of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and many other hazardous organic solutions are used in fabricating both PVA, GEL and PVA-GEL nanofibers, but it poses a great threat on sites that the solvent was unable to evaporate, affecting cell viability and motility. In this study, a new solvent system of deionized water, formic acid and glacial acetic acid was used to replace the current toxic solvent system utilized in electrospinning such polymers. Increasing amounts of formic acid and deionized water decreased further the fiber diameter of the PVA-GEL nanofibers. Further refinement in solution (PVA:GEL ratio) and process parameters (tip-to-collector distance and flow rate) produced much finer nanofibers, leading to a decrease in fiber diameter distribution. It is conclusive that a new alternative solvent system can be used in electrospinning PVA-GEL nanofibers that are non-toxic and exhibits much lower fiber diameter (≈20 nm) than the conventional solvents used before.

접착제에서 발생하는 휘발성유기화합물(VOCs)에 대한 안정성 연구

ABSTRACT In this study, the stability of the adhesive was de termined through the Oddy Test that is Verification Test for potential damage by various materials. And to find the f actor causing the corrosion of the metal samples, the adhesives and coatings those are usually used in the metal preservation process were selected and treat ed on the samples. Six kinds of adhesives and four kinds of metal sp ecimens Fe, Pb, Cu, Ag were used. As results, the weight change showed high increasement in the rate of weight ch ange 29.87% of Fe sample. The chromatic ity measurement showed the high change value of the Cellulose-based adhesive. In case of the VOCs test from adhesive by using GC-MS, Acetic acid was detected from all six kinds of the adhesives. Compared to cellulose-bas ed adhesives and the other adhesives, the amount of VOCs per 1mg concentration is higher than 900 times and was det ected small amount of Formic acid. This is assumed to be facilitated by acid impurities and the light. This reaction was considered as the result of reducing a large amount of molecular and of generating a large amount of Nox. And thus the reacted sulfur changes wa s considered as the factor for causing corrosion.

A water-born Zr-based porous coordination polymer: Modulated synthesis of Zr-fumarate MOF

In this work, we present the water-based synthesis of the Zr-fumarate MOF (Zr-fum MOF) by applying a monocarboxylic acid as modulator. The original synthesis of Zr-fum MOF was performed in a DMF-based batch at 120°C. The product showed exceptional stability against aqueous solutions. Thus, a water-based synthesis seemed to be promising. Indeed, by adding various amounts of formic acid, acetic acid or propionic acid as modulator, respectively, highly crystalline Zr-fum MOF can be obtained from water at 120°C. The investigation of the influence of modulating molecules with different alkyl chain lengths showed that the particle size decreases when monocarboxylic acids with longer alkyl chains are used, e.g. acetic acid and propionic acid in comparison to formic acid. For the formation of the Zr-fum MOF synthesised with formic acid as modulator, the thermogravimetric and sorption behaviour as well as the stability against various solvents and pH values is discussed in detail. Furthermore, the Zr-fum MOF can also be obtained under very benign reaction conditions at room temperature from water, making this material interesting for various applications, for example as a biomaterial.

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

The inner surface of a metallic tube (i.d. 0.5 mm) was coated with a palladium (Pd)-based thin metallic layer by flow electroless plating. Simultaneous plating of Pd and silver (Ag) from their electroless-plating solution produced a mixed distributed bimetallic layer. Preferential acid leaching of Ag from the Pd–Ag layer produced a porous Pd surface. Hydrogenation of p-nitrophenol was examined in the presence of formic acid simply by passing the reaction solution through the catalytic tubular reactors. p-Aminophenol was the sole product of hydrogenation. No side reaction occurred. Reaction conversion with respect to p-nitrophenol was dependent on the catalyst layer type, the temperature, pH, amount of formic acid, and the residence time. A porous and oxidized Pd (PdO) surface gave the best reaction conversion among the catalytic reactors examined. p-Nitrophenol was converted quantitatively to p-aminophenol within 15 s of residence time in the porous PdO reactor at 40 °C. Evolution of carbon dioxide (CO2) was observed during the reaction, although hydrogen (H2) was not found in the gas phase. Dehydrogenation of formic acid did not occur to any practical degree in the absence of p-nitrophenol. Consequently, the nitro group was reduced via hydrogen transfer from formic acid to p-nitrophenol and not by hydrogen generated by dehydrogenation of formic acid.