Chemical oxidation of anthracite with hydrogen peroxide via the Fenton reaction

doi:10.1016/0016-2361(84)90041-3

Fuel

Volume 63, Issue 2, February 1984, Pages 221-226

https://doi.org/10.1016/0016-2361(84)90041-3 Get rights and content

Abstract

Solutions of 30% H₂O₂ ranging from pH = 0 to pH = 11.5 have been used to oxidize anthracite at room temperature. The inorganic impurities, primarily pyrite, catalysed the oxidation and reduction of H₂O₂ (the Fenton reaction) to form the hydroxyl radical; the oxidation of the organic matter was minimal and was observed only in strong acidic solutions (pH < 1.5). After acid demineralization, samples of the same anthracite underwent a significant enhancement of oxidation in both acid and alkaline solutions (pH = 0.4–11.5). As all the iron had been removed from the surface and the reactions were completed in a much shorter time, the oxidation mechanism must have been of a different nature than that for the untreated anthracite. A qualitative model based on the catalytic decomposition of H₂O₂ by activated carbon sites in the coal surface is used to explain the oxidation of the demineralized anthracite.

References (27)

C.R. Ward
Fuel
(1974)
D.J. Boron et al.
Fuel
(1981)
F.E. Senftle et al.
Fuel
(1981)
D.E. Lowenhaupt et al.
Int. J. Coal Geol.
(1980)
W.S. Kramers
G.R. Yohe
Oxidation of Coal
Ill. State Geol. Survey Rept. of Invest. No. 207
(1958)
I. Dryden
A.J. Nalwalk et al.
Energy Sources
(1974)
E. Stack et al.
Coal Petrology
(1975)
T. Matsue et al.
J. Electrochem. Soc.
(1981)

G.H. Wood

Geologic map of anthracite-bearing rocks in the Nesquehoning quadrangle

J.K. Kuhn et al.

Geochemical evaluation and characterization of a Pittsburgh No. 8 and a Rosebud seam coal

H.J.H. Fenton et al.

J. Chem. Soc. (London)

(1899)

Cited by (25)

Chemical speciation and risk assessment of Cu and Zn in biochars derived from co-pyrolysis of pig manure with rice straw
2018, Chemosphere
Citation Excerpt :
All the analyses were performed in two replicates and reagent blanks were included in each digestion batch. A chemical oxidant (H2O2) is commonly used to assess the recalcitrance of chars (Heard and Senftle, 1984; Enders et al., 2012; Guo and Chen, 2014), which is relevant to the decomposition of biochar under field conditions (Knicker et al., 2013). For this study, the relatively low concentration of H2O2 was 6% and the oxidation was performed in a thermostatic water bath (Guo and Chen, 2014).
Pig manure has been utilized as a good feedstock to produce biochar. However, the pig manure-derived biochar from intensive pig cultivation contains high levels of total and bioavailable heavy metals. In this study, the co-pyrolysis of pig manure with other biomass (e.g. rice straw) at 300–700 °C was investigated to solve the above-mentioned topic. The ammonium acetate (CH₃COONH₄), Tessier sequential extraction procedure and hydrogen peroxide were adopted to evaluate the bioavailability, chemical speciation, and potential risk of Cu and Zn in the biochars. Results showed that the addition of rice straw significantly reduced the concentrations of total, exchangeable and carbonate-associated Cu and Zn in the biochars compared to the single pig manure biochars. Co-pyrolysis of pig manure with rice straw at a mass ratio of 1:3 and at 600 °C could be most effective to reduce the concentrations of CH₃COONH₄-extractable and potential released Cu and Zn in the biochars. In conclusion, the co-pyrolysis process is a feasible management for the safe disposal of metal-polluted pig manure in an attempt to reduce the bioavailability and potential risk of heavy metals at relatively high pyrolysis temperatures.
Long-Term Aging of Biochar: A Molecular Understanding With Agricultural and Environmental Implications
2017, Advances in Agronomy
Biochar has unveiled a new avenue for carbon (C) sequestration and has shown the potential to increase agricultural productivity. Although there is still debate about the mineralization rate of biochar and its role in sustaining soil fertility after fresh biochar amendment, oxidized or aged biochar has shown strong positive effects on crop productivity. Aging of biochar changes its physiochemical properties, while a range of biochar-derived organic materials (BDOMs) can be formed. These changes have significant consequences for the bioavailability and transport of nutrients and contaminants. In this review, we provide an overview of biochar aging, focusing on its change in structure, surface chemical properties, and the interactions of biochar and BDOMs with nutrients and contaminants in the soil. Synthesis of spectroscopic data from nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and near edge X-ray fine structure (NEXAFS) showed that with progressive aging, either artificially or naturally, biochar undergoes structural and chemical changes leading to progressive formation of surface functional groups such as carboxyl, phenolic, and carbonyl groups. As a result, the O:C ratio, negative surface charge, and cation exchange capacity increase with increased level of aging. The surface oxidized biochar and BDOMs may interact with soil minerals, nutrients, and contaminants resulting in increased mineral-stabilized organic matter, cation retention, anion bioavailability, and reduced organic contaminants’ sorption. Therefore, application of aged biochar could potentially increase agricultural productivity with increased capacities to retain nutrients while serving the role of C sequestration.
The formation of alpha-FeOOH onto hydrothermal biochar through H<inf>2</inf>O<inf>2</inf> and its photocatalytic disinfection
2016, Chemical Engineering Journal
Citation Excerpt :
Fang et al. claimed that persistent free radicals were contained on biochar surface and could produce carboxylic groups when H2O2 was added [17]. However, carbon loss was more and more larger with the increase of H2O2 levels [18], which could mainly be due to aromatic carbons decomposed by H2O2 [19]. Kumar [20] reported that the decomposition of aromatic carbons by H2O2 was comprised of two different products: (i) aliphatic carboxylic acids; (ii) CO2 and H2O.
Effect of H₂O₂ levels on the formation of alpha-FeOOH (goethite) on the modified hydrothermal biochar and its photocatalytic disinfection performance were investigated in this study. Chemical composition analysis indicated that goethite formed successfully on biochars using hydrothermal carbonization (HTC) with H₂O₂ modification. The investigation for the relationship of oxygen-rich functional groups with H₂O₂ levels and Fe (III) mass balance during goethite formation implied that carboxylic group on biochars increased obviously with the increase of H₂O₂ levels, while both hydroxyl and lactone groups increased firstly and then decreased with increase of H₂O₂ levels. Fe (III) could approximately meet mass balance during the second HTC. Goethite level on goethite coated biochar (GCB) by 20% H₂O₂ modification was higher than the one for 30% H₂O₂ modification due to the potential phase transformation. The application of GCB in photocatalytic disinfection systems showed that Escherichia coli inactivation by GCB photocatalysis (solar or UVA irradiation) was evidently greater than the one by the control. The inactivation of E. coli by GCB4 (20% H₂O₂ modification) photocatalytic disinfection was the best with close to 4.5 log reduction for solar irradiation and about 4 log reduction for UVA irradiation, which had little changes after five cycle experiments, suggesting that the application of GCB4 photocatalysis with solar or UVA to inactivate E. coli was feasible and desirable in this study.
Effect of H<inf>2</inf>O<inf>2</inf> concentrations on copper removal using the modified hydrothermal biochar
2016, Bioresource Technology
Citation Excerpt :
On the other hand, Fang et al. (2014) claimed that persistent free radicals (PFRs) were contained on biochar surface and could produce carboxylic groups when H2O2 was added. However, carbon loss was also very obvious with the increase of H2O2 concentrations (Guo and Chen, 2014), which could mainly be due to aromatic carbons decomposed by H2O2 (Heard and Senftle, 1984). Kumar (2011) reported that the decomposition of aromatic carbons by H2O2 was comprised of two different products: (i) aliphatic carboxylic acids; (ii) CO2 and H2O.
This study investigated effect of H₂O₂ concentrations on copper removal using H₂O₂ modified hydrothermal carbonization Cymbopogon schoenanthus L. Spreng (HLG). Sorption behaviors of Cu (II) on the modified HLG by 20% H₂O₂ (mHLG2) could be the most desirable. Based on Langmuir isotherm, the maximum amount of Cu (II) uptake was in the sequence of mHLG2 (53.8 mg g⁻¹) > mHLG1 (44.2 mg g⁻¹) > mHLG3 (42.0 mg g⁻¹) > mHLG0 (35.8 mg g⁻¹), which was higher than the results from majority of previous studies, suggesting that H₂O₂ modification advanced sorption capacity of hydrothermal biochars evidently. Effect mechanisms exploration indicated that the difference of Cu (II) removal by biochars before and after the modification was mainly related to functional groups. Carboxylic group was responsible for the best sorption property of Cu (II) by mHLG2, which was attributed to its significant relationships with H₂O₂ modification and Cu (II) removal.
The effect of high power ultrasound on an aqueous suspension of graphite
2010, Ultrasonics Sonochemistry
Citation Excerpt :
Oxidized compounds are mainly monocarboxylic acids and/or alcohols (acetic, propionic, glycolic, butyric, lactic, valeric, caproic, benzoic, caprylic, pelargonic and capric acids or ramified equivalents, and glycerol) and carbonate which is the last species in the oxidation chain of carbon. We easily notice that these compounds like formic acid and some diacids are commonly found in the oxidative degradation chains by HO radicals in the Fenton cycle [33–38]. In this work, only monoacids are detected, maybe due to the CO2 loss in diacids (oxalic → formic; malonic → acetic; succinic → propionic; glutaric → butyric; adipic → valeric, etc.).
Ultrasound treatment was used to study the decrease of the granulometry of graphite, due to the cavitation, which allows the erosion by separating grains. At a smaller scale, cavitation bubble implosion tears apart graphite sheets as shown by HRTEM, while HO and H radicals produced from water sonolysis, generate oxidative and reductive reactions on these sheet fragments. Such reactions form smaller species, e.g. dissolved organic matter. The methodology proposed is very sensitive to unambiguously identifying the in situ composition of organic compounds in water. The use of the atmospheric pressure chemical ionization (APCI) Fourier transform mass spectrometry (FTMS) technique minimizes the perturbation of the organic composition and does not require chemical treatment for analysis. The structural features observed in the narrow range (m/z < 300) were mainly aromatic compounds (phenol, benzene, toluene, xylene, benzenediazonium, etc.), C₄–C₆ alkenes and C₂–C₁₀ carboxylic acids. Synthesis of small compounds from graphite sonication has never been reported and will probably be helpful to understand the mechanisms involved in high energy radical reactions.
Oxidation of high sulphur coal. 3. Desulphurisation of organic sulphur by peroxyacetic acid (produced in situ) in presence of metal ions
2005, Fuel Processing Technology
A chemical oxidative desulphurisation method for coal organic sulphur has been presented using peroxyacetic acid produced in situ as an oxidant. Sulphur is removed to the extent 6.92–10.02 wt.% at 1–4 h while at 24 h, it increases to 13.41 wt.%. To understand the influence of metal ions on desulphurisation, each of six metal ions of variable valence states (Cu⁺, Ni²⁺, Co²⁺, Sn²⁺, Pd²⁺ and Sb³⁺) was externally added. Lowest sulphur loss with Ni²⁺ ion (2.26–9.46 wt.% at 1–4 h and 11.01 wt.% at 24 h) while highest desulphurisation with Pd²⁺ ion (23.15–32.32 wt.% at 1–4 h and 32.75 wt.% at 24 h) are observed. Application of the pseudo-first order kinetics shows rate constants for all the systems in the range (0.70–6.78)×10⁻⁵ s⁻¹. The activation energy and frequency factor for these systems fall in the range (8.46–12.66) kJ/mol and (1.15–2.64)×10⁻³ s⁻¹, respectively. Low frequency factor represents an associated type of desulphurisation reaction involving intermediate activated complexes. The sulphur loss reaction is non-spontaneous in nature and proceeds with the absorption of heat. Occurrence of the reaction is due to the increase in randomness which is governed by the decomposition of activated complex to products and is influenced by the characteristic property of a metal ion. Study of model sulphur compounds (methionine and dibenzothiophene) reveals that the desulphurisation reaction under the experimental conditions is primarily due to aliphatic sulphur compounds. The method described here is simple with low-cost and easily available chemical, and therefore, has considerable technological interest.