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.

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.

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.

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

1996 ◽  
Vol 34 (9) ◽  
pp. 41-48 ◽  
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.

Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

2007 ◽  
Vol 275 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Shih-Chin Tsai ◽  
Tsing-Hai Wang ◽  
Yuan-Yaw Wei ◽  
Wen-Chun Yeh ◽  
Yi-Lin Jan ◽  
...  
Keyword(s):  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Adsorption Desorption ◽  
Kinetics Of

Study on the Thermodynamic Properties of Two Anti-Cancer Drugs

2013 ◽  
Vol 634-638 ◽  
pp. 1086-1089
Author(s):  
W. W. Zhao ◽  
J. Q. Gao ◽  
D. H. Liu ◽  
Z. X. Li
Keyword(s):  
Atmospheric Pressure ◽  
Order Reaction ◽  
Dissolution Enthalpy ◽  
Differential Heat ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Knowing That ◽  
Anti Cancer ◽  
Pseudo First Order ◽  
The Relationship

The dissolution enthalpy of Cisplatin and Etoposide in the appropriate solvent were measured by RD496-2000 microcalorimeter under the conditions of atmospheric pressure and 309.65 K. The differential heat and the integral heat of the process are obtained, thereby establishing the relationship between the heat and the amount of solute, knowing that the dissolution process is the pseudo-first order reaction. In turn, the half-life, △solHm, △solGm, △solSm are also can obtained.

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