Adsorption Kinetics of NO2 Gas on Pt/Cr-TiO2/Pt-Based Sensors

Metal oxides are excellent candidates for the detection of various gases; however, the issues such as the limited operating temperature and selectivity are the most important ones requiring the comprehensive understanding of gas adsorption kinetics on the sensing layer surfaces. To this context, the present study focuses mainly on the fabrication of a Pt/Cr-TiO2/Pt type sensor structure that is highly suitable in reducing the operating temperature (from 400 to 200 °C), extending the lower limit NO2 gas concentration (below 10 ppm) with fast response (37 s) and recovery (24 s) times. This illustrates that the sensor performance is not only solely dependent on the nature of sensing material, but also, it is significantly enhanced by using such a new kind of electrode geometry. Moreover, Cr doping into TiO2 culminates in altering the sensor response from n- to p-type and thus contributes to sensor performance enhancement by detecting low NO2 concentrations selectively at reduced operating temperatures. In addition, the NO2 surface adsorption kinetics are studied by fitting the obtained sensor response curves with Elovich, inter-particle diffusion, and pseudo first-order and pseudo second-order adsorption models. It is found that a pseudo first-order reaction model describes the best NO2 adsorption kinetics toward 7–170 ppm NO2 gas at 200 °C. Finally, the sensing mechanism is discussed on the basis of the obtained results.

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The effect of the textile industry dye bath additive EDTMPA on colour removal characteristics by ozone oxidation

Water Science & Technology ◽

10.2166/wst.2007.317 ◽

2007 ◽

Vol 55 (10) ◽

pp. 145-153 ◽

Cited By ~ 12

Author(s):

T. Ölmez ◽

I. Kabdaşlı ◽

O. Tünay

Keyword(s):

Organic Matter ◽

Textile Industry ◽

Reaction Rates ◽

Textile Dye ◽

Pseudo First Order Reaction ◽

Ozone Oxidation ◽

Reactive Dyeing ◽

First Order ◽

Organic Matter Oxidation ◽

Pseudo First Order

In this study, the effects of the phosphonic acid based sequestering agent EDTMPA used in the textile dye baths on colour and organic matter removal by ozone oxidation was experimentally investigated. Procion Navy HEXL dyestuff that has been commonly used for the reactive dyeing of cellulose fibers was selected as the model component. The organic matter oxidation by ozone was determined to obey the pseudo-first order kinetics as they are treated singly or in combination. COD removal rates obtained from pseudo-first order reaction kinetics showed that oxidation of Navy HEXL alone (0.0947 L/min) was faster than that of EDTMPA (0.0171 L/min) and EDTMPA with dye (0.0155 L/min) at pH 3.0. It was also found that reaction rates of single EDTMPA removal and EDTMPA and dye mixture removal increased as the reaction pH was increased from 3.0 to 10.5.

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Multifactorial optimization of the decolorisation parameters of wastewaters resulting from dyeing flowers

Water Science & Technology ◽

10.2166/wst.2009.114 ◽

2009 ◽

Vol 59 (7) ◽

pp. 1361-1369 ◽

Cited By ~ 3

Author(s):

Edison Gil Pavas ◽

Miguel Ángel Gómez-García

Keyword(s):

Hydrogen Peroxide ◽

Organic Matter ◽

Experimental Design ◽

Order Reaction ◽

Pseudo First Order Reaction ◽

First Order ◽

Effluent Standards ◽

Degradation Of Dyes ◽

Pseudo First Order ◽

Dyes Mixture

This work deals with the treatment of the wastewaters resulting from the process of dyeing flowers. In some local cases for growing flowers near to Medellín (Colombia), wastewater color was found to be one of the main problems in meeting local effluent standards. Wastewaters were treated by photodegradation process (which includes photocatalysis) to achieve the degradation of dyes mixture and organic matter in the wastewater. A multifactorial experimental design was proposed, including as experimental factors the following variables: pH, and the concentration of both catalyst (TiO2) and hydrogen peroxide (H2O2). According to the obtained results, at the optimized variables values, it is possible to reach a 99% reduction of dyes, a 76.9% of mineralization (TOC) and a final biodegradability of 0.834. Kinetic analysis allows proposing a pseudo first order reaction for the reduction, the mineralization, and the biodegradation processes.

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Adsorption kinetics of 17α-ethinyl estradiol and bisphenol A on carbon nanomaterials. I. Several concerns regarding pseudo-first order and pseudo-second order models

Journal of Soils and Sediments ◽

10.1007/s11368-009-0184-8 ◽

2010 ◽

Vol 10 (5) ◽

pp. 838-844 ◽

Cited By ~ 33

Author(s):

Bo Pan ◽

Baoshan Xing

Keyword(s):

Bisphenol A ◽

Adsorption Kinetics ◽

Carbon Nanomaterials ◽

Ethinyl Estradiol ◽

Second Order ◽

First Order ◽

Pseudo Second Order ◽

Pseudo First Order ◽

Kinetics Of

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Harnessing of Newly Tailored Poly (Acrylonitrile)-Starch Nanoparticle Graft Copolymer for Copper Ion Removal via Oximation Reaction

10.21203/rs.3.rs-412347/v1 ◽

2021 ◽

Author(s):

khaled Mostafa ◽

H. Ameen ◽

A. Ebessy ◽

A. El-Sanabary

Keyword(s):

Experimental Data ◽

Adsorption Capacity ◽

Graft Copolymer ◽

Adsorption Kinetics ◽

Copper Ions ◽

Copper Ion ◽

Second Order ◽

First Order ◽

Pseudo Second Order ◽

Pseudo First Order

Abstract Our recently tailored and fully characterized poly (AN)-starch nanoparticle graft copolymer having 60.1 G.Y. % was used as a starting substrate for copper ions removal from waste water effluent after chemical modification with hydroxyl amine via oximation reaction. This was done to change the abundant nitrile groups in the above copolymer into amidoxime one and the resultant poly (amidoxime) resin was used as adsorbent for copper ions. The resin was characterized qualitatively via rapid vanadium ion test and instrumentally by FT-IR spectra and SEM morphological analysis to confirm the presence of amidoxime groups. The adsorption capacity of the resin was done using the batch technique, whereas the residual copper ions content in the filtrate before and after adsorption was measured using atomic adsorption spectrometry. It was found that the maximum adsorption capacity of poly (amidoxime) resin was 115.2 mg/g at pH 7, 400ppm copper ions concentration and 0.25 g adsorbent at room temperature. The adsorption, kinetics and isothermal study of the process is scrutinized using different variables, such as pH, contact time, copper ion concentration and adsorbent dosage. Different kinetics models comprising the pseudo-first-order and pseudo-second-order have been applied to the experimental data to envisage the adsorption kinetics. It was found from kinetic study that pseudo-second-order rate equation was better than pseudo-first-order supporting the formation of chemisorption process. While, in case of isothermal study, the examination of calculated correlation coefficient (R2) values showed that the Langmuir model provide the best fit to experimental data than Freundlich one.

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Photocatalytic degradation of sulfamethazine in aqueous solution using ZnO with different morphologies

Royal Society Open Science ◽

10.1098/rsos.171457 ◽

2018 ◽

Vol 5 (4) ◽

pp. 171457 ◽

Cited By ~ 12

Author(s):

Zhigang Yi ◽

Juan Wang ◽

Tao Jiang ◽

Qiong Tang ◽

Ying Cheng

Keyword(s):

Aqueous Solution ◽

Photocatalytic Degradation ◽

Reaction System ◽

Degradation Pathway ◽

Order Reaction ◽

Pseudo First Order Reaction ◽

First Order ◽

Different Shapes ◽

Pseudo First Order ◽

Release Ratio

In this study, photocatalytic experiments of 20 mg l −1 sulfamethazine (SMN) in aqueous solution containing ZnO with different morphologies, tetra-needle-like ZnO (T-ZnO), flower-like ZnO (F-ZnO) and nanoparticles ZnO (P-ZnO), were performed. The results indicated that photocatalytic degradation of SMN was effective and followed the pseudo-first-order reaction, but the degree of SMN mineralization showed obvious differences using ZnO with different shapes. After 12 h irradiation, 86%, 71% and 50% of the initial total organic carbon was eliminated in SMN suspension containing T-ZnO, F-ZnO and P-ZnO, respectively. The release ratio of sulfur was close to 100% in the presence of T-ZnO, but reached to 86% and 67% in the presence of F-ZnO and P-ZnO, respectively. The release ratio of nitrogen was about 76%, 63% and 40% using T-ZnO, F-ZnO and P-ZnO as photocatalyst, respectively. The morphology of ZnO played an important role in determining its catalytic activity. Seven intermediates were observed and identified in the UV/T-ZnO reaction system by LC-MS/MS analysis, and a possible degradation pathway was proposed.

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On the Chemical Reactivity of the Phytochrome Chromophore in the Pr and Pfr Form

Zeitschrift für Naturforschung C ◽

10.1515/znc-1985-3-413 ◽

1985 ◽

Vol 40 (3-4) ◽

pp. 215-218 ◽

Cited By ~ 27

Author(s):

Fritz Thümmler ◽

Peter Eilfeld ◽

Wolfhart Rüdiger ◽

Doo-Khil Moon ◽

Pill-Soon Song

Keyword(s):

Reaction Kinetics ◽

Rate Constants ◽

Chemical Reactivity ◽

Order Reaction ◽

First Order Reaction ◽

Limiting Factor ◽

Pseudo First Order Reaction ◽

First Order ◽

Pseudo First Order ◽

The Difference

The reactivity of the phytochrome chromophore and related tetrapyrroles towards ozone and tetranitromethane was investigated. Both oxidizing reagents cause bleaching of the main absorption band of the pigment. The rate constants for this bleaching were determined under conditions of pseudo first order reaction kinetics. The rate constants for the reaction with ozone are similar for native phytochrome and for freely accessible tetrapyrroles (biliverdin, small chromopeptides from phytochrome) indicating that accessibility is not the limiting factor for the reaction with ozone. Under a variety of conditions, the Pfr chromophore reacts by about 10% faster than the Pr chromophore. This may reflect the true difference in reactivity. The rate constants for the reaction with tetranitromethane are much larger for biliverdin, bilirubin and small chromopeptides from phytochrome than for native phytochrome. The limiting factor for this reaction in native phytochrome therefore is the accessibility of the chromophore by the reagent. Previous conclusions on the difference in exposure of the tetrapyrrole chromophore in Pr and Pfr are confirmed.

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FIBRINOPEPTIDE B RELEASE FROM NORMAL FIBRINOGEN AND FIBRINOGEN LONDON I IN THE PRESENCE OF INHIBITORS OF FIBRIN POLYMERIZATION

10.1055/s-0038-1643341 ◽

1987 ◽

Author(s):

W Ruf ◽

A Bender ◽

K T Preissner ◽

D A Lane ◽

G Müller-Berghaus

Keyword(s):

Initial Phase ◽

Slow Rate ◽

Order Reaction ◽

Pseudo First Order Reaction ◽

Reaction Conditions ◽

Fibrin Polymerization ◽

First Order ◽

Molar Excess ◽

Pseudo First Order ◽

Fibrinogen Molecule

The fibrinopeptides A and B (FPA and FPB) are cleaved from the fibrinogen molecule with different rates. In the initial phase of the thrombin-fibrinogen reaction, FPB is released with a slow rate, which is enhanced upon polymerization of desA-fi-brin monomers. The aim of the present study was to further characterize the mechanism leading to the enhanced rate of FPB release during polymerization. For this purpose, the release of FPB from normal fibrinogen and from fibrinogen London I, which exhibits a polymerization defect located in the D-domain, was studied in the presence and absence of the fibrinolytic fragment D1 (D1) and of the synthetic tetrapeptide Gly-Pro-Arg-Pro (GPRP). Steady state parameters for fibrinopeptide release were determined under pseudo-first order reaction conditions. In the initial phase of the thrombin-fibrinogen reaction, the release of FPA was unchanged in the presence of D1. Furthermore, the release of FPA from fibrinogen London I did not reveal any difference in comparison to normal fibrinogen. GPRP prevented not only fibrin polymerization, but also the enhanced rate of FPB release. On the contrary, the rate of FPB release in the presence of a 16- and 32-fold molar excess of over fibrinogen did not differ from a reaction mixture with no added D1. Si-miliar to the inhibited rate of FPB release in the presence of GPRP, the release of FPB from fibrinogen London I occurred with a slow rate, which was not enhanced by the addition of a 16-fold molar excess of D1. Since the release neither from normal fibrinogen nor from ribrinogen London I was affected by D1, it was concluded that the D-E contact formed by D1 with an E-domain of a desA-fibrin molecule does not enhance the release of FPB. While GPRP keeps fibrin in monomeric form by inhibiting the polymerization sites in the D-domains, D1 does not prevent the formation of fibrin oligomers. Therefore, acceleration of FPB release is caused by a conformational change, which is induced by binding of reciprocal polymerization sites to an E-as well as a D-domain of the same desA-fibrin molecule.

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Effect of Cyclodextrins on Photodegradation of 4,4-Bis(4-Hydroxyphenyl)Pentanoic Acid under UV Irradiation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.665.455 ◽

2014 ◽

Vol 665 ◽

pp. 455-458

Author(s):

Li Guo ◽

Jin Huang ◽

Jun Wu ◽

Lei Lei Luo

Keyword(s):

Aqueous Solutions ◽

Fluorescence Spectra ◽

High Efficiency ◽

Uv Light ◽

Order Reaction ◽

Pentanoic Acid ◽

Pseudo First Order Reaction ◽

First Order ◽

Inclusion Interaction ◽

Pseudo First Order

The photodegradation of 4,4-bis (4-hydroxyphenyl) pentanoic acid (DPA) with two cyclodextrins (α-CD and β-CD ) in aqueous solutions induced by UV-light was studied in this paper by means of fluorescence spectra and high efficiency liquid chromatography. The result suggested that DPA with α-CD or β-CD formed inclusion compound in aqueous solutions. The photodegradation of DPA with two cyclodextrins or without cyclodextrin was pseudo-first order reaction. The photodegradation of DPA was accelerated by the addition of β-CD in aqueous solutions, but the that of DPA was inhibited in case of adding α-CD. These differences were due to the differences in inclusion interaction of DPA with α-CD or β-CD.

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Enhancement of decomposition of 2-chlorophenol with ultrasound/H2O2 process

Water Science & Technology ◽

10.2166/wst.1996.0173 ◽

1996 ◽

Vol 34 (9) ◽

pp. 41-48 ◽

Cited By ~ 17

Author(s):

Jih-Gaw Lin ◽

Cheng-Nan Chang ◽

Jer-Ren Wu ◽

Ying-Shih Ma

Keyword(s):

Ionic Strength ◽

Reaction Rate ◽

Order Reaction ◽

Pseudo First Order Reaction ◽

Initial Concentration ◽

First Order ◽

Toc Removal ◽

Cp Decomposition ◽

Effects Of Ph ◽

Pseudo First Order

We investigated the effects of pH, ionic strength, catalyst, and initial concentration on both decomposition of 2-chlorophenol (2-cp) and removal of total organic carbon (TOC) in aqueous solution with ultrasonic amplitude 120 μm and H2O2 (200 mg/l). When the initial concentrations of 2-cp was 100 mg/l and the pH was controlled at 3, the rate of 2-cp decomposition was enhanced up to 6.6-fold and TOC removal up to 9.8-fold over pH controlled at 11. At pH 3, the efficiency of decomposition of 2-cp was 99% but the removal of TOC was only 63%; a similar situation applied at pH 7 and 11. Hence intermediate compounds were produced and 2-cp was not completely mineralized. When the concentration of ionic strength was increased from 0.001 to 0.1 M, the rate of 2-cp decomposition was enhanced only 0.3-fold, whereas the TOC removal was not enhanced. In comparison of the effects of pH and ionic strength, pH had greater influence on both 2-cp decomposition and TOC removal than ionic strength. The effect of a catalyst (FeSO4) on decomposition of 2-cp was insignificant comparing with direct addition of H2O2. The reaction rate at a smaller initial concentration of 2-cp (10 mg/l) was more rapid than at a greater one (100 mg/l). The rate of 2-cp decomposition and TOC removal appeared to follow pseudo-first-order reaction kinetics.

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