The influence of solution matrix on the photocatalytic removal of color from natural waters

1998 ◽  
Vol 38 (6) ◽  
pp. 155-162 ◽  
Author(s):  
M. Bekbölet ◽  
Z. Boyacioglu ◽  
B. özkaraova
Keyword(s):  
Reaction Kinetics ◽  
Natural Waters ◽  
Removal Rate ◽  
Color Removal ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Phosphate Ions ◽  
Photocatalytic Removal ◽  
Adsorption Data ◽  
Pseudo First Order

Photocatalytic color removal of humic acid was studied in the presence of common inorganic anions; namely, chloride, nitrate, sulfate and phosphate ions at pH 6.8. Color removal rates were explained in terms of pseudo-first order and Langmuir-Hinshelwood kinetics. The Freundlich adsorption data were also evaluated to assess a relationship between the adsorption data and the reaction kinetics. The presence of chloride, nitrate and sulfate ions exhibited different trends when the rate is expressed as pseudo-first order reaction kinetics. In case of Langmuir-Hinshelwood kinetics, the decolorization rates were decreased in the order of the anions as, chloride, nitrate and sulfate. The presence of phosphate ions strongly inhibited the color removal rate.

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

1985 ◽  
Vol 40 (3-4) ◽  
pp. 215-218 ◽  
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.

Pseudo-first order reaction kinetics and thermodynamic properties study of neem oil esterification using MgO grafted natural hydroxyapatite

RSC Advances ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 8892-8901 ◽  
Author(s):  
Himadri Sahu ◽  
Kaustubha Mohanty
Keyword(s):  
Thermodynamic Properties ◽  
Reaction Kinetics ◽  
Fish Bone ◽  
Order Reaction ◽  
Neem Oil ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Natural Hydroxyapatite ◽  
Kinetics And Thermodynamic

In this work, waste fish bone was used as a source of natural hydroxyapatite which was later used for the preparation of a metal grafted catalyst.

scholarly journals Comparative studies on the removal of copper (II) by Ulva fasciata activated carbon and commercially activated carbon

2012 ◽  
Vol 14 (4) ◽  
pp. 88-94 ◽  
Author(s):  
R.P. Suresh Jeyakumar ◽  
V. Chandrasekaran
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Synthetic Wastewater ◽  
Batch Adsorption ◽  
First Order ◽  
Ulva Fasciata ◽  
Adsorption Data ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Adsorbent Dose

Abstract In this work, the efficiency of Ulva fasciata sp. activated carbons (CCUC, SCUC and SSUC) and commercially activated carbon (CAC) were studied for the removal of Cu (II) ions from synthetic wastewater. Batch adsorption experiments were carried out as a function of pH, contact time, initial copper concentration and adsorbent dose. The percentage adsorption of copper by CCUC, SSUC, SCUC and CAC are 88.47%, 97.53%, 95.78% and 77.42% respectively. Adsorption data were fitted with the Langmuir, Freundlich and Temkin models. Two kinetic models pseudo first order and the pseudo second order were selected to interpret the adsorption data.

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

2007 ◽  
Vol 55 (10) ◽  
pp. 145-153 ◽  
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.

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

2009 ◽  
Vol 59 (7) ◽  
pp. 1361-1369 ◽  
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.

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

2018 ◽  
Vol 5 (4) ◽  
pp. 171457 ◽  
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.

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

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.

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

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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