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1.
The influence of the specific surface area of air bubbles in the process of bubbling on the oxidation rate of Fe2+ ions of model solutions prepared using distilled water with the addition of Fe2+ ions in the form of iron(II) sulfate (pure grade). The dependences of the rate of Fe2+ oxidation in water during air bubbling have been found. 相似文献
2.
Lan-Huong Tran Patrick Drogui Guy Mercier Jean-François Blais 《Journal of Applied Electrochemistry》2010,40(8):1493-1510
The decomposition of polycyclic aromatic hydrocarbons in a creosote oily solution and in synthetic solutions containing naphthalene
and pyrene was investigated in the presence of an amphoteric surfactant using electrooxidation by comparison to Fenton oxidation
process. Electrolysis was carried out using a parallelepipedic electrolytic 1.5-L cell containing five anodes (expanded titanium
covered with ruthenium) and five cathodes (stainless steel) alternated in the electrode pack, whereas Fenton oxidation process
was carried out in 500 mL Erlenmeyer glass-flasks in which H2O2 and Fe2+ were added. Using electrochemical oxidation, the sum concentration of 16 polycyclic aromatic hydrocarbons investigated could
be optimally diminished by up to 80–82% by applying a current density of 9.23 mA cm−2 and a pH of 4.0 or 7.0 for 90-min reaction period. By comparison, the best yield (46%) of Fenton oxidation process for polycyclic
aromatic hydrocarbons degradation was recorded by using H2O2/Fe2+ molar ratio of 11.0 and a pH of 4.0. 相似文献
3.
Javeed Mohammed Abdul Mahintha Kumar Saravanamuthu Vigneswaran Jaya Kandasamy 《Journal of Industrial and Engineering Chemistry》2012,18(1):137-144
The removal of metsulfuron methyl (MeS)—a sulfonyl urea herbicide from contaminated water was investigated by advanced oxidation process (AOP) using Fenton method. The optimum dose of Fenton reagent (Fe2+/H2O2) was 10 mg/L Fe2+ and 60 mg/L H2O2 for an initial MeS concentration ([MeS]0) range of 0–80 mg/L. The Fenton process was effective under pH 3. The degradation efficiency of MeS decreased by more than 70% at pH > 3 (pH 4.5 and 7). The initial Fe2+ concentration ([Fe2+]0) in the Fenton reagent affected the degradation efficiency, rate and kinetics. The degradation of MeS at optimum dose of Fenton reagent was more than 95% for [MeS] 0 of 0–40 mg/L and the degradation time was less than 30 min. The determination of residual MeS concentration after Fenton oxidation by UV spectrophotometry was affected by the interferences from Fenton reagent. The estimation of residual MeS concentration after Fenton oxidation by high pressure/performance liquid chromatograph (HPLC) was interference free and represented the actual concentration of MeS and does not include the by-products of Fenton oxidation. The degradation kinetics of MeS was modelled by second order reactions involving 8 rate constants. The two reaction constants directly involving MeS were fitted using the experimental data and the remaining constants were selected from previously reported values. The model fit for MeS and the subsequent prediction of H2O2 were found to be within experimental error tolerances. 相似文献
4.
An acrylic monomer bearing xanthene group, acryloylfluorescein (Ac-Flu) was synthesized from fluorescein and acryloyl chloride
in the presence of triethylamine in dry dichloromethane (CH2Cl2) at room temperature. The synthesized Ac-Flu was identified by IR, MS and 1HNMR spectra. Copolymer of Ac-Flu and acrylamide (AM) was synthesized with thermal initiator and it was characterized by the
method of IR, UV–Vis and DSC. The photophysical behaviors of Ac-Flu and its copolymer were explored by recording the fluorescence
spectra in solution, solid state and film in detail. In addition, the ability of the copolymer to detect different metal cations
(Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) in aqueous solution was investigated. The results showed that poly(Ac-Flu-co-AM) had a good linear response between the logarithm of concentration of Fe3+ (lg[Fe3+]) against the relative fluorescence intensity for Fe3+ concentration. The results suggest that this copolymer may offer potential as a reusable polymer sensor for Fe3+ ion in aqueous solution. 相似文献
5.
《Fuel》2007,86(7-8):993-999
The oxidation of ferrous iron in solution using Acidithiobacillus ferrooxidans has industrial applications in the regeneration of ferric iron as an oxidant agent for the removal of hydrogen sulfide from waste gases, desulphurization of coal, leaching of non-ferrous metallic sulfides and treatment of acid mine drainage. The aim of this attempt was to increase the biooxidation rate of ferrous sulfate by using immobilized cells. Rate of ferrous iron oxidation was determined in a packed-bed reactor configuration with low density polyethylene (LDPE) particles as support material in order to find the most practical system for scale-up. The present work studies the influence of basic parameters on the ferrous iron biooxidation process using an indigenous iron-oxidizing microorganism, namely A. ferrooxidans, in a 2 L packed-bed bioreactor. Effects of several process variables such as initial pH, temperature, dilution rate, initial concentrations of ferrous and ferric ions on oxidation of ferrous sulfate were investigated. Experimental results indicate that in the temperature range of 31–34 °C the biooxidation of ferrous ions to ferric ions could be resulted efficiently. A pH range of 2–2.2 was optimum for the growth of the culture and effective bacterial activity for oxidation of ferrous ions to ferric ions. The highest oxidation rate of 2.9 g Fe2+ L−1 h−1 was obtained using a culture initially containing 25 g L−1 Fe+2 at the dilution rate of 0.4 h−1. This rate is very high compared to that achieved in other bioreactors found in the literature. In addition the biooxidation of Fe2+ to Fe3+ conversion could be achieved effectively in the presence of the Fe3+ in the concentration range of 0.1–0.7 g/L. 相似文献
6.
《Journal of Industrial and Engineering Chemistry》2014,20(3):848-857
This study focused on the application of RSM on the Fenton process and the adsorption of vegetal carbon (VC) to obtain the optimal conditions for the minimization of the colored synthetic wastewater. Methyl orange (MO) with an azo dye was used as the model organic compound. Fenton processes were investigated to establish the optimal conditions. The Fe2+/H2O2 ratio was studied to establish the major MO degradation when 100 and 200 mg/L of MO were treated. For the adsorption process, to determine the optimal conditions, the principal variables studied were the vegetal carbon mass dosage, degradation time and dye concentration. 相似文献
7.
Miao-Jing Chen Xue-Min Weng Lei-Qing He Shidang Xu Hong Li 《Journal of Applied Electrochemistry》2011,41(7):795-801
The homogeneous and mediated oxidation of guanine by [Ru(bpy)3]2+ (2,2′-bipypyridine) in the presence of surfactants and single-walled carbon nanotubes (SWCNTs) has been investigated using
cyclic voltammetry, repetitive differential pulse voltammetry and rotating electrode method. In acidic medium, the oxidation
of guanine was controlled by mass transport process of [Ru(bpy)3]2+ in solution, leading to a homogeneous electrocatalysis. In neutral medium, the result from emission spectroscopy suggested
the formation of the aggregates containing [Ru(bpy)3]2+, dihexadecyl phosphate (DHP) and guanine. The electrocatalysis of [Ru(bpy)3]2+ toward guanine oxidation was promoted by anionic surfactant DHP and, however, hindered by an excess amount of hexadecyl trismethyl
ammonium chloride (HTAC) or SWCNTs added to solutions. The electrocatalytic mechanism of [Ru(bpy)3]2+ for guanine oxidation becomes evident, strongly depending on the presence of anionic or cationic surfactants and SWCNTs. 相似文献
8.
Elena Guinea Francesc Centellas Jos Antonio Garrido Rosa María Rodríguez Conchita Arias Pere-Lluís Cabot Enric Brillas 《Applied catalysis. B, Environmental》2009,89(3-4):459-468
This paper reports a comparative study on the anodic oxidation of 2.5 l of 50 mg l−1 TOC of formic, oxalic, acetic, pyruvic or maleic acid in 0.1 M Na2SO4 solutions of pH 3.0 with and without 1.0 mM Fe3+ as catalyst in the dark or under solar irradiation. Experiments have been performed with a batch recirculation flow plant containing a one-compartment filter-press electrolytic reactor equipped with a 20 cm2 boron-doped diamond (BDD) anode and a 20 cm2 stainless steel cathode, and coupled to a solar photoreactor. This system gradually accumulates H2O2 from dimerization of hydroxyl radical (OH) formed at the anode surface from water oxidation. Carboxylic acids in direct anodic oxidation are mainly oxidized by direct charge transfer and/or OH produced on BDD, while their Fe(III) complexes formed in presence of Fe3+ can also react with OH produced from Fenton reaction between regenerated Fe2+ with electrosynthesized H2O2 and/or photo-Fenton reaction. Fast photolysis of Fe(III)-oxalate and Fe(III)-pyruvate complexes under the action of sunlight also takes place. Chemical and photochemical trials of the same solutions have been made to better clarify the role of the different catalysts. Solar photoassisted anodic oxidation in presence of Fe3+ strongly accelerates the removal of all carboxylic acids in comparison with direct anodic oxidation, except for acetic acid that is removed at similar rate in both cases. This novel electrochemical advanced oxidation process allows more rapid mineralization of formic, oxalic and maleic acids, without any significant effect on the conversion of acetic acid into CO2. The synergistic action of Fe3+ and sunlight in anodic oxidation can then be useful for wastewater remediation when oxalic and formic acids are formed as ultimate carboxylic acids of organic pollutants, but its performance is expected to strongly decay in the case of generation of persistent acetic acid during the degradation process. 相似文献
9.
Nanostructured allophane clays supported with iron oxide (AlSi2Fe6) were characterized by X-ray photoelectron spectroscopy (XPS) and Mössbauer spectroscopy showing the presence of both Fe3 + and Fe2 + species on the allophane surface. A glassy carbon disk (GC) modified with a film obtained by the deposition of drops of a dispersion formed by graphite and AlSi2Fe6 in water was used as working electrode in a heterogeneous electro-Fenton system (HE-Fenton) for the oxidation of atrazine. The effect of the initial pHs and the proportion of AlSi2Fe6/graphite in the mixture were studied and compared with the heterogeneous Fenton process. The HE-Fenton system using AlSi2Fe6-GC electrodes showed higher efficiency towards the oxidation of atrazine than the heterogeneous Fenton one; mainly due to the continuous and simultaneous electro-regeneration of iron species (Fe3 +/Fe2 +) and electro-generation of hydrogen peroxide by the oxygen reduction process. The degradation of atrazine in this HE-Fenton system reached almost 100% at pH 3.0 after 8 h, whereas at more neutral pH (~ 6) a 76% of degradation was obtained. Two reaction products were identified by HPLC: desethyl-atrazine (DEA) and desethyl-desisopropyl-atrazine (DEIA). 相似文献
10.
Luminescence functionalization of the ordered mesoporous SBA-15 silica is realized by depositing a CeF3: Eu3+ phosphor layer on its surface (denoted as CeF3: Eu3+/SBA-15/IS, CeF3: Eu3+/SBA-15/SI and CeF3: Eu3+/SBA-15/SS) using three different methods, which are reaction in situ (I-S), solution impregnation (S-I) and solid phase grinding
synthesis (S-S), respectively. The structure, morphology, porosity, and optical properties of the materials are well characterized
by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, N2 adsorption, and photoluminescence spectra. These materials all have high surface area, uniformity in the mesostructure and
crystallinity. As expected, the pore volume, surface area, and pore size of SBA-15 decrease in sequence after deposition of
the CeF3: Eu3+ nanophosphors. Furthermore, the efficient energy transfer in mesoporous material mainly occurs between the Ce3+ and the central Eu3+ ion. They show the characteristic emission of Ce3+ 5d → 4f (200–320 nm) and Eu3+
5D0 → 7F
J
(J = 1–4, with 5D0 → 7F1 orange emission at 588 nm as the strongest one) transitions, respectively. In addition, for comparison, the mesoporous material
CeF3: Eu3+/SBA-15/SS exhibits the characteristic emission of Eu3+ ion under UV irradiation with higher luminescence intensity than the other materials. 相似文献
11.
Background
It has been shown that several extracts and compounds derived from garlic are able to inhibit Cu2+-induced low density lipoprotein oxidation. In this work we explored if the ability of aqueous garlic extract to prevent in vitro Cu2+-induced lipoprotein oxidation in human serum is affected by heating (a) aqueous garlic extracts or (b) garlic cloves. In the first case, aqueous extract of raw garlic and garlic powder were studied. In the second case, aqueous extract of boiled garlic cloves, microwave-treated garlic cloves, and pickled garlic were studied. It was also studied if the above mentioned preparations were able to chelate Cu2+. 相似文献12.
Cyril Jose Escopete Bajamundi Maria Lourdes Pascual Dalida Kitirote Wantala Pongtanawat Khemthong Nurak Grisdanurak 《Korean Journal of Chemical Engineering》2011,28(8):1688-1692
Ferric ion was introduced to the commercial photocatalyst P25 (Degussa) by ultrasonic wet impregnation technique. The concentration
of the dopant was varied from 0.0 to 3.0% Fe/Ti ratio. The doped TiO2 was then loaded to alumina balls using mechanical coating technique and followed by calcination in air at 400, 450, 500 and
550 °C. The fabricated photocatalyst was characterized by X-ray diffraction, N2 adsorption-desorption isotherms, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, X-ray adsorption
near edge structure and photoluminescence spectroscopy. The photocatalytic activity was tested by following the degradation
of methylene blue (MB). It was found that the Fe3+ doped TiO2/Al2O3 has a combination of anatase and rutile phase and free of iron oxide phases. The optimum calcination temperature is 400 °C
with 0.1% Fe3+ concentration. The catalyst addresses the entrainment in photocatalytic reactors, eliminating the need for a post filtration
process. 相似文献
13.
Mehdi Ahmadi Farshid Ghanbari Alberto Alvarez Susana Silva Martinez 《Korean Journal of Chemical Engineering》2017,34(8):2154-2161
The performance of UVA-LEDs assisted peroxymonosulfate (PMS)/Fe2+ system was evaluated on carmoisine (E122) decolorization. Complete color removal was obtained under the conditions of pH=3.0, PMS=1.5 mM, Fe2+=1 mM and 25 min reaction time. UVA-LEDs were preferable compared to conventional UVA lamp in terms of decolorization. The functions of Co2+, Cu2+, Mn2+ and Fe2+ were compared and their results showed that Co2+ and Fe2+ had the highest efficiencies. Moreover, the presence of chloride ion showed a double role in different concentrations in which promotional effect was observed in 100 mM Cl?<, while inhibitory effect occurred in 1–10 mM Cl?. However, the high concentration of chloride had no influence on mineralization of E122. The scavenging results demonstrated that the UV irradiation increased the contribution of HO?. In addition, in the presence of chloride ion, HOCl along with sulfate and hydroxyl radicals were the major oxidative agents. 相似文献
14.
Tingzhen Li Yong Yang Zhichao Tao Chenghua Zhang Hongwei Xiang Yongwang Li 《Fuel Processing Technology》2009,90(10):1247-1251
A systematic study was undertaken to investigate the effects of the initial oxidation degree of iron on the bulk phase composition and reduction/carburization behaviors of a Fe–Mn–K/SiO2 catalyst prepared from ferrous sulfate. The catalyst samples were characterized by powder X-ray diffraction (XRD), Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS) and H2 (or CO) temperature-programmed reduction (TPR). The Fischer–Tropsch synthesis (FTS) performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor (CSTR). The characterization results indicated that the fresh catalysts are mainly composed of α-Fe2O3 and Fe3O4, and the crystallite size of iron oxides is decreased with the increase of the initial oxidation degree of iron. The catalyst with high content of α-Fe2O3 in its as-prepared state has high content of iron carbides after being reduced in syngas. However, the catalyst with high content of Fe3O4 in its as-prepared state cannot be easily carburized in CO and syngas. FTS reaction study indicates that Fe-05 (Fe3+/Fetotal = 1.0) has the highest CO conversion, whereas Fe-03 (Fe3+/Fetotal = 0.55) has the lowest activity. The catalyst with high CO conversion has a high selectivity to gaseous hydrocarbons (C1–C4) and low selectivity to heavy hydrocarbons (C5+). 相似文献
15.
Hongzhu Ma Qiongfang Zhuo Bo Wang 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,155(1-2):248-253
The electrochemical oxidation of methylene blue (MB) wastewater assisted by Fe2O3-modified kaolin in a 200 mL electrolytic batch reactor with graphite plate as electrodes was investigated. The catalyst was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of pH, current density and introduction of NaCl on the efficiency of the electrochemical degradation process were also studied. It was found that Fe2O3-modified kaolin has higher catalytic activity in the electrochemical degradation of MB wastewater. 96.47% chemical oxygen demand (COD) removal was obtained in 40 min of electrochemical treatment of MB wastewater at pH 3, current density was equal to 69.23 mA cm−2. 相似文献
16.
《Ceramics International》2023,49(16):26683-26693
In this work, zero-dimensional (0D) high crystalline PrFeO3 worm nanocrystals were loaded over a three-dimensional (3D) rectangular WO3 to construct a 0D/3D PFO/W Z-scheme heterojunction by an in situ ultrasonic synthetic process. This heterojunction exhibited excellent photocatalytic activities towards the degradation of organic pollutants such as rhodamine B (RhB), Methylene blue (MB), and tetracycline hydrochloride (TC) in the presence of small amounts of H2O2 under visible-light irradiation. For example, the k value of PFO/W + H2O2 was about 67, 107, 45, 27, 11 and 14 times higher than pure H2O2, PrFeO3, WO3, PFO/W nanocomposite, PrFeO3+ H2O2 and WO3+H2O2 respectively during the degradation of MB. The trapping experiments and ESR measurements identified that the generated ·OH, ·O2−, and h+ were the active species involved in the catalysis. Further, the ·OH radical could be continuously generated by Fe3+/Fe2+ and W6+/W5+ conversion and played the dominant role in the degradation of organic pollutants. The superior photocatalytic performance of the PFO/W + H2O2 system was derived from the synergistic effect of the Z-scheme heterostructure and dual photo-Fenton-like oxidation (Fe3+/Fe2+ and W6+/W5+). A possible mechanism was postulated based on the results obtained. In summary, this study provided new insights into synthesizing an effectively heterogeneous 0D/3D Z-scheme dual photo-Fenton-like catalyst for water clarification. 相似文献
17.
Gabriel Favalli Branco Inar Alves Castro 《Journal of the American Oil Chemists' Society》2011,88(11):1747-1758
The oxidative stability of oils is a complex process influenced by several factors, making the evaluation of antioxidant effects
of new compounds difficult. Thus, the objective of this study was to apply a factorial design to obtain the combination of
factors that maximizes the formation of oil oxidation products, and use this model to evaluate the antioxidant activity of
different compounds. Temperature, Fe2+ and ascorbyl palmitate were evaluated in two full-factorial designs (23 and 32). The validated optimized oxidation model was obtained by adding 1.47 mmol/L of Fe2+ and 1.54 mmol/L of ascorbyl palmitate to flaxseed oil stripped of tocopherol kept at 40 °C for 8 days. Antioxidant activities
of six compounds were evaluated using this model. All antioxidant samples were statistically different (p < 0.001) at 200 ppm concentration, indicating the efficiency of the optimized model to evaluate the antioxidant action of
natural and synthetic compounds. 相似文献
18.
《Applied catalysis. B, Environmental》2001,29(2):135-145
Solutions with 1.07 mmol dm−3 aniline or with 1.38 mmol dm−3 4-chlorophenol at pH ca. 3 have been treated with ozone and ozonation catalyzed with Fe2+ and/or UVA. The initial mineralization rate increases as more oxidizing hydroxyl radical is produced in the medium by the catalyzed ozonations. Direct ozone treatment leads to stable oxidation products, which are quickly destroyed under UVA illumination. In the presence of Fe2+ as catalyst, the degradation process is inhibited by the formation of Fe3+ complexes with short organic diacids, being photodecomposed by UVA light. Each initial pollutant is destroyed at similar rate in all processes. p-Benzoquinone and nitrobenzene are identified as intermediates of aniline oxidation. The former product is only detected when high amounts of hydroxyl radical are produced by the action of Fe2+. Ammonium ion released during p-benzoquinone formation is also generated in larger extension under the same conditions. Nitrate ion reaches maximum production under UVA irradiation, indicating that generation of nitrobenzene from selective attack of O3 on the amino group of aniline is photocatalyzed. Reaction of 4-chlorophenol with ozone leads to 4-chloro-1,3-dihydroxybenzene and 4-chloro-1,2-dihydroxybenzene. The last product is produced in larger extension when high amounts of hydroxyl radical can selectively attack the initial pollutant. Chloride ion is completely lost during the further degradation of both dihydroxylated derivatives. Oxidation of all aromatic intermediates detected during aniline and 4-chlorophenol degradation gives maleic acid, which is further mineralized via oxalic acid. A general reaction pathway for the degradation of each pollutant is proposed. 相似文献
19.
Ling Xiao Jinlong Zhang Ye Cong Baozhu Tian Feng Chen Masakazu Anpo 《Catalysis Letters》2006,111(3-4):207-211
Fe3+ doped together with Au deposited TiO2 (Au/Fe3+–TiO2) was successfully prepared, which shows excellent photocatalytic activity for degradation of methyl orange (MO) under both
UV and visible light (λ > 420 nm) illumination. Fe3+ has been confirmed by EPR to substitute for Ti4+ in the TiO2 lattice, and Au exists as Au0 on the surface of the photocatalyst indicated by the results of XRD. Fe3+ and Au have synergistic effects on improving the photocatalytic activity of TiO2. A proposed mechanism concerning the synergistic effects is discussed to explain the improvement of the photocatalytic activities. 相似文献