Oxidation of CrIII aminocarboxylate complexes by hydrous manganese oxide: products and time course behaviour

2015 ◽  
Vol 12 (1) ◽  
pp. 33 ◽  
Author(s):  
Richard F. Carbonaro ◽  
Alan T. Stone
Keyword(s):  
Manganese Oxide ◽  
Time Course ◽  
Ethylenediaminetetraacetic Acid ◽  
Environmental Concern ◽  
Iminodiacetic Acid ◽  
Nitrilotriacetic Acid ◽  
Product Distribution ◽  
Hydrous Manganese Oxide ◽  
Wide Ph Range ◽  
Ph Range

Environmental context Oxidation of CrIII (trivalent chromium) to CrVI (hexavalent chromium) is of environmental concern because CrVI is a known mutagen and carcinogen. Our results show that hydrous manganese oxide (HMO) is capable of oxidising soluble CrIII complexed with iminodiacetic acid and nitrilotriacetic acid to CrVI at appreciable rates. CrVI production from soluble CrIII organic complexes is therefore expected to occur in natural and engineered systems that contain HMO. Abstract MnIII,IV (hydr)oxides are believed to be the principal oxidants of CrIII in the subsurface. In nearly all previous work on this subject, the CrIII reactant was prepared from inorganic salts (e.g. nitrate, chloride, sulfate). In our present work, CrIII complexes with the synthetic chelating agents iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) were reacted with hydrous manganese oxide (HMO) over a wide pH range to examine rates of reaction and product distribution. Capillary electrophoresis was used to quantify changes in reactant (CrIII–IDA and CrIII–NTA) and product (CrVI, free IDA and free NTA) concentrations as a function of time. In addition, a small number of experiments were performed using solutions prepared from CrIII alum (KCr(SO4)2·12H2O(s)) as the CrIII reactant. CrIII–IDA and CrIII–NTA were oxidised to CrVI, but rates were considerably lower than those obtained using inorganic CrIII. Within the timescales of our experiments, complete conversion of CrIII–NTA occurred at pH >7, but not under moderately acidic conditions, even when there was a large stoichiometric excess of HMO. MnCl2 addition experiments indicated that the observed reaction inhibition was attributable to MnII generation during the reaction. Our previous work has shown that citric acid, IDA, NTA and ethylenediaminetetraacetic acid solubilise CrIII from amorphous Cr(OH)3(s) at appreciable rates. The results of this study show that HMO is capable of oxidising the resulting soluble CrIII complexes, providing a viable mechanism for CrIII oxidation to CrVI over a wide pH range.

scholarly journals Adsorption of As(V) by the Novel and Efficient Adsorbent Cerium-Manganese Modified Biochar

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2720
Author(s):  
Ting Liang ◽  
Lianfang Li ◽  
Changxiong Zhu ◽  
Xue Liu ◽  
Hongna Li ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Photoelectron Spectroscopy ◽  
Water Environment ◽  
Polluted Water ◽  
X Ray ◽  
Modified Biochar ◽  
Wide Ph Range ◽  
Infrared Spectrometer ◽  
Pseudo Second Order ◽  
Ph Range

Arsenic has become a global concern in water environment, and it is essential to develop efficient remediation methods. In this study, a novel adsorbent by loading cerium and manganese oxide onto wheat straw-modified biochar (MBC) was manufactured successfully aiming to remove arsenic from polluted water. Through scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FT-IR), and other techniques, it was found the loading of cerium and manganese oxide on MBC played a significant role in As(V) adsorption. The results of the batch test showed that the adsorption of MBC followed the pseudo-second order kinetics and Langmuir equation. The adsorption capacity of MBC was 108.88 mg As(V)/g at pH = 5.0 (C0 = 100 mg/L, dosage = 0.5 g/L, T = 298 K) with considerable improvement compared to the original biochar. Moreover, MBC exhibited excellent performance over a wide pH range (2.0~11.0). Thermodynamics of the sorption reaction showed that the entropy (ΔS), changes of enthalpy (ΔH) and Gibbs free energy (ΔG), respectively, were 85.88 J/(moL·K), 22.54 kJ/mol and −1.33 to −5.20 kJ/mol at T = 278~323 K. During the adsorption, the formation of multiple complexes under the influence of its abundant surface M-OH (M represents the Ce/Mn) groups involving multiple mechanisms that included electrostatic interaction forces, surface adsorption, redox reaction, and surface complexation. This study indicated that MBC is a promising adsorbent to remove As(V) from polluted water and has great potential in remediating of arsenic contaminated environment.

Gel self-assembly of lanthanum aminopolycarboxylates with skeleton structures and adsorptions of gases

2021 ◽  
Author(s):  
Si-Yuan Wang ◽  
Zhenlang Xie ◽  
Xin Dong ◽  
Zhao-Hui Zhou
Keyword(s):  
Self Assembly ◽  
Ethylenediaminetetraacetic Acid ◽  
Iminodiacetic Acid ◽  
Nitrilotriacetic Acid ◽  
Edta Ethylenediaminetetraacetic Acid

Three lanthanum aminopolycarboxylates [La(Hida)2(H2O)2]n·nCl·4nH2O (1), K2n[La(nta)2]n·nH2O (2) and (H2en)n[La(edta)(H2O)]2n·10nH2O (3) (H2ida = iminodiacetic acid; H3nta = nitrilotriacetic acid; H4edta = ethylenediaminetetraacetic acid; en = ethylenediamine, NH2CH2CH2NH2) have been isolated by...

An Environmentally Friendly Stimulation Fluid for High-Temperature Applications

SPE Journal ◽  
2010 ◽  
Vol 16 (01) ◽  
pp. 104-110 ◽  
Author(s):  
J.N.. N. LePage ◽  
C.A.. A. De Wolf ◽  
J.H.. H. Bemelaar ◽  
H.A.. A. Nasr-El-Din
Keyword(s):  
Glutamic Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Aquatic Toxicity ◽  
Monosodium Glutamate ◽  
Nitrilotriacetic Acid ◽  
Raw Material ◽  
Well Performance ◽  
Deep Wells ◽  
Ph Range ◽  
Carbonate Formations

Summary Matrix acidizing is used in carbonate formations to create flow channels from the formation to the wellbore; in sandstone formations, however, the goal is to dissolve materials that impair well performance. However, the use of acids in deep wells has some major drawbacks, including high reaction rate and corrosion to well tubulars. We have discovered a new stimulation chemical that can be used as a replacement for or in combination with acid treatments in deep wells. A polyacid whose structure allows for acidification is described. The polyacidic chelate L-glutamic acid, N, N-diacetic acid (GLDA) is manufactured from L-glutamic acid (MSG). The chelate-based fluid very effectively dissolves CaCO3, and it is less corrosive to the equipment and easy to handle. This paper discusses the reaction of the new chelate, GLDA, with calcite and compares its performance with other available chelates, including ethylenediaminetetraacetic acid (EDTA), hydroxy-ethylethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and ethanoldiglycine (EDG). GLDA dissolves calcite over a wide pH interval, although it is less effective than HEDTA at pH > 5. A unique property of GLDA is its high solubility; solutions exceeding 40 wt% can be achieved at a pH of approximately 2, whereas HEDTA solubility is limited to approximately 10 wt%. A mole of GLDA with a natural pH of approximately 1.5 is capable of dissolving up to two moles of CaCO3. Throughout the pH range, GLDA appears to be as thermally stable as HEDTA. As an additive to hydrochloric acid (HCl), GLDA is as effective as HEDTA in preventing precipitation of moderate levels of Fe3+ in spent acids. At high Fe3+ concentrations, GLDA is slightly less effective than HEDTA on a molar basis; but, to deal with high Fe3+ levels, GLDA may be better because significantly higher concentrations of it are possible in various acids. In 28 wt% HCl, HEDTA has limited solubility while GLDA's solubility exceeds 40 wt%. From an environmental standpoint, GLDA is readily biodegradable and is made from a renewable raw material, monosodium glutamate. GLDA has low toxicity and aquatic toxicity characteristics. As a replacement for HCl, GLDA is significantly safer and less corrosive.

Thermal Decomposition of EDTA, NTA, and Nitrilotrimethylenephosphonic Acid in Aqueous Solution

1975 ◽  
Vol 53 (22) ◽  
pp. 3471-3476 ◽  
Author(s):  
A. E. Martell ◽  
R. J. Motekaitis ◽  
A. R. Fried ◽  
J. S. Wilson ◽  
D. T. MacMillan
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Water Solution ◽  
Iminodiacetic Acid ◽  
Nitrilotriacetic Acid ◽  
Decomposition Reaction ◽  
Order Rate Constant ◽  
Hydrolytic Cleavage ◽  
Stable Pair ◽  
Primary Products ◽  
Decarboxylation Reaction

The decomposition of ethylenediaminetetraacetic acid (EDTA) in water solution at 200 and 260 °C, nitrilotriacetic acid (NTA) at 260 and 293 °C, and of nitrilotrimethylenephosphonic acid (NTPO) at 260 °C was studied by n.m.r. as a function of time at pH 9.5 and decomposition rates and products were determined. The primary (fast) decomposition reaction of EDTA involves the hydrolytic cleavage of the ethylenic C—N bond to produce the relatively stable pair: N-(2-hydroxyethyl)iminodiacetic acid and iminodiacetic acid. NTA does not cleave below 260 °C but decomposes at about 290 °C and above through a stepwise decarboxylation reaction. NTPO cleaves hydrolytically at 260 °C at two C—N bonds to produce aminomethylenephosphonic acid and 2 mol of hydroxymethylenephosphonic acid. The further breakdown of the primary products of EDTA at higher temperatures occurs by the loss of carbon dioxide producing the corresponding methylamines, concomitantly with the hydrolytic cleavage of the remaining CH2CH2—N bond giving ethylene glycol. The pseudo first order rate constant kobs for NTA decarboxylation at 293 °C and pH 9.3 is 0.19 ± 0.01 h−1. The value of kobs for EDTA hydrolysis at 200 °C is 1.4 ± 0.2 h−1.

scholarly journals Carbon fibre paper coated by a layered manganese oxide: a nano-structured electrocatalyst for water-oxidation with high activity over a very wide pH range

2019 ◽  
Vol 7 (44) ◽  
pp. 25333-25346 ◽  
Author(s):  
Jens Melder ◽  
Stefan Mebs ◽  
Philipp A. Heizmann ◽  
Rebekka Lang ◽  
Holger Dau ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Manganese Oxide ◽  
High Activity ◽  
Water Oxidation ◽  
Wide Ph Range ◽  
Ph Range ◽  
Coated Carbon ◽  
Layered Manganese Oxide

Manganese oxide coated carbon fibre paper electrodes (MnOx/CFP) exhibit promising water oxidation activities and stabilities for applications in alkaline, neutral and even acidic electrolytes.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

Electroanalytical chemistry of vanadium complexes: Electrochemical oxidation of [V(IV)O(nta)(H2O)]-

1989 ◽  
Vol 54 (1) ◽  
pp. 64-69 ◽  
Author(s):  
Roland Meier ◽  
Gerhard Werner ◽  
Matthias Otto
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Oxidation ◽  
Ph Dependence ◽  
Differential Pulse ◽  
Nitrilotriacetic Acid ◽  
Reduced Form ◽  
Vanadium Complexes ◽  
Differential Pulse Polarography ◽  
Electroanalytical Chemistry ◽  
Ph Range

Electrochemical oxidation of [V(IV)O(nta)(H2O)]- (H3nta nitrilotriacetic acid) was studied in aqueous solution by means of cyclic voltammetry, differential pulse polarography, and current sampled DC polarography on mercury as electrode material. In the pH-range under study (5.5-9.0) the corresponding V(V) complex is produced by one-electron oxidation of the parent V(IV) species. The oxidation product is stable within the time scale of cyclic voltammetry. The evaluation of the pH-dependence of the half-wave potentials leads to a pKa value for [V(IV)O(nta)(H2O)]- which is in a good agreement with previous determinations. The measured value for E1/2 is very close to the formal potential E0 calculated via the Nernst equation on the basis of known literature values for log Kox and log Kred, the complex stability constants for the oxidized and reduced form, respectively.

High degradation efficiency of sulfamethazine with the dual-reaction-center Fe-Mn-SiO2 Fenton-like nanocatalyst in a wide pH range

2021 ◽  
Author(s):  
Manoj Kumar Panjwani ◽  
Qing Wang ◽  
Yueming Ma ◽  
Yuxuan Lin ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Reaction Center ◽  
Degradation Efficiency ◽  
Heterogeneous Fenton ◽  
Wide Ph Range ◽  
Ph Range

The development of a heterogeneous Fenton-like catalyst, possessing high degradation efficiency in a wide pH range, is crucial for wastewater treatment. The Fe-Mn-SiO2 catalyst was designed, and prepared by a...

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