Degradation Kinetics of Fe-EDTA in Hydrogen Sulfide Removal Process

Available data on the degradation of Fe-EDTA liquid redox H2S removal processes are reviewed, and the effect of H2S molar flow rate, the initial concentration of Fe(III)EDTA, and the presence of sodium citrate in Fe-EDTA solution were investigated in this study. The semibatch with continuous flow of H2S containing biogas was used under a wide range of experimental conditions; , H2S molar flow rate, (1.08 × 10−3–3.40 × 10−3 mol/h), the initial concentration of Fe(III)EDTA, (2.17–8.16 mol/m3), and the concentration of sodium citrate, (0–300 mol/m3). The result showed that sodium citrate acted as stabilizer with a good ability to reduce the degradation rate. The degradation rate of Fe-EDTA was found to follow pseudo first-order kinetics. Empirical correlations expressed the degradation rate constant as a function of significant H2S molar flow rate, and the initial Fe(III)EDTA and sodium citrate concentration were successfully developed for the prediction of Fe-EDTA degradation rate. Moreover, the precipitated solid, called sulfur cake, was recovered, and its composition was investigated. The result revealed that the sulfur cake contained more than 98% sulfur element and almost balances with iron, and no significant EDTA was degraded into the solid form.

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PHOTOCATALYTIC DEGRADATION OF PYRENE IN POROUS Pt/TiO2–SiO2 PHOTOCATALYST SUSPENSION UNDER UV IRRADIATION

NANO ◽

10.1142/s1793292008001143 ◽

2008 ◽

Vol 03 (05) ◽

pp. 317-322 ◽

Cited By ~ 5

Author(s):

ZHAOHUI LUO ◽

KEIKO KATAYAMA-HIRAYAMA ◽

KIMIAKI HIRAYAMA ◽

TETSUYA AKITSU ◽

HIDEHIRO KANEKO

Keyword(s):

Molecular Weight ◽

Photocatalytic Degradation ◽

High Molecular Weight ◽

Uv Irradiation ◽

Degradation Kinetics ◽

Degradation Process ◽

Bet Surface Area ◽

Experimental Conditions ◽

Initial Concentration ◽

X Ray

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt / TiO 2– SiO 2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was prepared by a simple heat treatment of the compacted powder mixtures of anatase TiO 2 and amorphous SiO 2 with camphor as a pore directing template, followed by coating platinum by the dip-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive analysis of the X-ray (EDX) system, and Brunauer–Emmett–Teller (BET) were used to characterize PPtPC. The degradation kinetics of pyrene in different experimental conditions, such as initial concentration of pyrene, oxygen concentrations, pH, and temperature, were investigated. The durability of PPtPC was also tested. The results indicate that the structure of TiO 2 in PPtPC is anatase. The aggregated size of PPtPC is in the range of 10–100 μm, the mean pore diameter is 3 nm, and the BET surface area is 109 m2 g-1. The photocatalytic degradation process of pyrene follows pseudo-first-order kinetics. The rate constants increase as the initial concentration of pyrene and pH decrease. Higher temperature slightly enhances the rate constant. The dissolved oxygen in the photocatalytic degradation process is not as important as in the photolysis process. The recovered PPtPC still shows high photoactivity. This work suggests that PPtPC offers a promising method for high molecular weight PAH removal.

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Photocatalytic Treatment of MO in Water with BiOBr Photocatalyst

Materials Science Forum ◽

10.4028/www.scientific.net/msf.694.554 ◽

2011 ◽

Vol 694 ◽

pp. 554-558 ◽

Cited By ~ 4

Author(s):

Xiao Xia Zhao ◽

Yan Wang ◽

Zhu Qing Shi ◽

Cai Mei Fan

Keyword(s):

Degradation Rate ◽

Ph Value ◽

Degradation Process ◽

Xenon Lamp ◽

Experimental Conditions ◽

Initial Concentration ◽

X Ray ◽

Hydrolysis Method ◽

Methylene Orange ◽

Initial Ph

The BiOBr catalyst prepared by the hydrolysis method was investigated with the X-ray diffractometry(XRD) and scanning electron microscope (SEM). The results show that the catalyst was the tetragonal primitive crystal structure and composed of homogeneous particles of fine ferrite plates. At the same time, the photocatalytic activity of BiOBr catalyst was evaluated by methylene orange (MO) in aqueous solution illuminated by Xenon lamp, and the degradation process parameters, such as initial concentration of MO, initial pH value and amount of BiOBr catalyst were discussed to the degradation rate of the MO. Under the following experimental conditions of C0=10mg/L, pH=8, m(BiOBr)=1.0g/L, MO can be entirely degraded after 2.5 hours.

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Degradation Kinetics of 2,4,6-Trinitrophenol from Water Using Atmospheric Air Cold Plasma

Asian Journal of Chemistry ◽

10.14233/ajchem.2020.22557 ◽

2020 ◽

Vol 32 (5) ◽

pp. 1116-1120

Author(s):

Nguyen Van Hoang ◽

Nguyen Cao Tuan

Keyword(s):

Cold Plasma ◽

Degradation Rate ◽

Degradation Kinetics ◽

Picric Acid ◽

Air Plasma ◽

Dielectric Barrier ◽

Initial Concentration ◽

Atmospheric Air ◽

Kinetics Of ◽

Initial Degradation Rate

The degradation studies of picric acid (2,4,6-trinitrophenol, TNP) in water sample through a dielectric barrier discharge (DBD) of atmospheric air cold plasma was carried out. The used DBD reactor consisted of comprised two electrodes that were separated by using an insulating dielectric barrier having a electric discharge voltage varying from of 7.0 to 22.0 kV. The effects of the initial concentration of TNP on the initial degradation rate was investigated methodically. The initial degradation rate was determined experimentally by changing the initial concentrations of TNP between 91.02 and 210.17 mg/L using the DBD of cold air plasma. From experimental results, a kinetic equation for TNP degradation was established based on varying initial concentration as –R = 0.0252CTNP/(1+0.0076CTNP). When 0.0076CTNP << 1, the kinetics of TNP degradation complied with the pseudo-first-order reaction. For TNP degradation kinetics, such as ln (Ct/C0) = 0.0269t + 0.1605, ln (Ct/C0) = 0.0197t + 0.0792, and ln (Ct/C0) = 0.014t + 0.0623, the initial concentrations of TNP were 91.02, 153.3 and 210.17 mg/L, respectively. Moreover, the effect of initial concentration of TNP and the electric power on the degradation efficiency of TNP were determined.

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Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽

10.32964/tj17.03.167 ◽

2018 ◽

Vol 17 (03) ◽

pp. 167-178 ◽

Cited By ~ 2

Author(s):

Xin Tong ◽

Jiao Li ◽

Jun Ma ◽

Xiaoquan Chen ◽

Wenhao Shen

Keyword(s):

Degradation Rate ◽

Southern China ◽

Catalytic Degradation ◽

Pulp And Paper ◽

Gaseous Pollutants ◽

Pulp And Paper Mills ◽

Paper Mills ◽

Initial Concentration ◽

First Order ◽

First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

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Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

10.26434/chemrxiv.9461462 ◽

2019 ◽

Author(s):

Christopher John ◽

Greg M. Swain ◽

Robert P. Hausinger ◽

Denis A. Proshlyakov

Keyword(s):

Active Site ◽

Structural Model ◽

Heme Iron ◽

Chemical Transformations ◽

Experimental Conditions ◽

Strongly Coupled ◽

Non Heme Iron ◽

Reversible Redox ◽

Wide Range ◽

Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

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Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

International Journal of Molecular Sciences ◽

10.3390/ijms22157879 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7879

Author(s):

Yingxia Gao ◽

Yi Zheng ◽

Léon Sanche

Keyword(s):

Condensed Phase ◽

Genetic Material ◽

High Energy ◽

Dna Lesions ◽

Low Energy ◽

Experimental Investigations ◽

Experimental Conditions ◽

Strand Breaks ◽

Sequence Of Events ◽

Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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Review of the Upright Balance Assessment Based on the Force Plate

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052696 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2696

Author(s):

Baoliang Chen ◽

Peng Liu ◽

Feiyun Xiao ◽

Zhengshi Liu ◽

Yong Wang

Keyword(s):

Postural Balance ◽

Force Plate ◽

Assessment Method ◽

Balance Assessment ◽

Experimental Conditions ◽

Methodological Research ◽

Assessment Tests ◽

Wide Range ◽

Foot Posture ◽

Plate System

Quantitative assessment is crucial for the evaluation of human postural balance. The force plate system is the key quantitative balance assessment method. The purpose of this study is to review the important concepts in balance assessment and analyze the experimental conditions, parameter variables, and application scope based on force plate technology. As there is a wide range of balance assessment tests and a variety of commercial force plate systems to choose from, there is room for further improvement of the test details and evaluation variables of the balance assessment. The recommendations presented in this article are the foundation and key part of the postural balance assessment; these recommendations focus on the type of force plate, the subject’s foot posture, and the choice of assessment variables, which further enriches the content of posturography. In order to promote a more reasonable balance assessment method based on force plates, further methodological research and a stronger consensus are still needed.

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Towards Reduced CNNs for De-Noising Phase Images Corrupted with Speckle Noise

Photonics ◽

10.3390/photonics8070255 ◽

2021 ◽

Vol 8 (7) ◽

pp. 255

Author(s):

Marie Tahon ◽

Silvio Montresor ◽

Pascal Picart

Keyword(s):

Phase Error ◽

Speckle Noise ◽

Experimental Conditions ◽

Benchmark Data ◽

Wide Range ◽

Phase Images ◽

Different Depths ◽

Phase Data ◽

Do So

Digital holography is a very efficient technique for 3D imaging and the characterization of changes at the surfaces of objects. However, during the process of holographic interferometry, the reconstructed phase images suffer from speckle noise. In this paper, de-noising is addressed with phase images corrupted with speckle noise. To do so, DnCNN residual networks with different depths were built and trained with various holographic noisy phase data. The possibility of using a network pre-trained on natural images with Gaussian noise is also investigated. All models are evaluated in terms of phase error with HOLODEEP benchmark data and with three unseen images corresponding to different experimental conditions. The best results are obtained using a network with only four convolutional blocks and trained with a wide range of noisy phase patterns.

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Kinetics and Equilibrium of Radioactive Metal Adsorption onto Sugarcane Bagasse Waste: Comparison of Batch and Column Adsorption Modes

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2019-1418 ◽

2021 ◽

Vol 235 (3) ◽

pp. 281-294

Author(s):

Abida Kausar ◽

Haq Nawaz Bhatti ◽

Munawar Iqbal

Keyword(s):

Sugarcane Bagasse ◽

Flow Rate ◽

Breakthrough Curves ◽

Quadratic Model ◽

Waste Biomass ◽

Initial Concentration ◽

Bed Height ◽

Column Adsorption ◽

Central Composite ◽

Bagasse Waste

Abstract Sugarcane bagasse waste biomass (SBWB) efficacy for the adsorption of Zr(IV) was investigated in batch and column modes. The process variables i.e. pH 1–4 (A), adsorbent dosage 0.0–0.3 g (B), and Zr(IV) ions initial concentration 25–200 mg/L (C) were studied. The experiments were run under central composite design (CCD) and data was analysed by response surface methodology (RSM) methodology. The factor A, B, C, AB interaction and square factor A2, C2 affected the Zr(IV) ions adsorption onto SBWB. The quadratic model fitted well to the adsorption data with high R2 values. The effect of bed height, flow rate and Zr(IV) ions initial concentration was also studied for column mode adsorption and efficiency was evaluated by breakthrough curves as well as Bed Depth Service and Thomas models. Bed height and Zr(IV) ions initial concentration enhanced the adsorption of capacity of Zr(IV) ions, whereas flow rate reduced the column efficiency.

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Experimental Investigation and Modeling of Inertance Tubes

Journal of Fluids Engineering ◽

10.1115/1.1989369 ◽

2005 ◽

Vol 127 (5) ◽

pp. 1029-1037 ◽

Cited By ~ 6

Author(s):

L. O. Schunk ◽

G. F. Nellis ◽

J. M. Pfotenhauer

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Acoustic Power ◽

Operating Conditions ◽

Thermodynamic Efficiency ◽

Pulse Tube ◽

Design Charts ◽

Wide Range ◽

Pulse Tube Refrigerators

Growing interest in larger scale pulse tubes has focused attention on optimizing their thermodynamic efficiency. For Stirling-type pulse tubes, the performance is governed by the phase difference between the pressure and mass flow, a characteristic that can be conveniently adjusted through the use of inertance tubes. In this paper we present a model in which the inertance tube is divided into a large number of increments; each increment is represented by a resistance, compliance, and inertance. This model can include local variations along the inertance tube and is capable of predicting pressure, mass flow rate, and the phase between these quantities at any location in the inertance tube as well as in the attached reservoir. The model is verified through careful comparison with those quantities that can be easily and reliably measured; these include the pressure variations along the length of the inertance tube and the mass flow rate into the reservoir. These experimental quantities are shown to be in good agreement with the model’s predictions over a wide range of operating conditions. Design charts are subsequently generated using the model and are presented for various operating conditions in order to facilitate the design of inertance tubes for pulse tube refrigerators. These design charts enable the pulse tube designer to select an inertance tube geometry that achieves a desired phase shift for a given level of acoustic power.

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