PHOTOCATALYTIC ACTIVITY OF HIGH-CONCENTRATION TITANIUM DIOXIDESLURRIES AT NEUTRAL PH

The properties of high-concentration titanium dioxide slurries under UV irradiation were (Evonik Aeroxide® P25) at concentrations of 0.5, 1, 1.5, 2 and 2.5 g L-1 were irradiated by a mercury lamp (254 nm). At neutral pH, within the studied concentration range, nanoparticles form agglomerates of tens of micrometers. Their size, measured by optical microscopy, increases linearly with catalyst concentration. The attenuation length of the UV radiation was measured by a spectrophotometer with an integrating sphere. The concentration of the model contaminant (Orange II) was determined by spectrophotometry at intervals of 20 minutes, during the irradiation time (6 hours). The measured values fit satisfactorily to a pseudo first order kinetics. At catalyst concentrations of 1 g L-1 and higher, the kinetic constant is (8.1 ± 0.5) x 10-3 min-1. This is explained by the diminution of the attenuation length and the simultaneous increase of the total exposed surface at higher catalyst concentrations.

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Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment

Water Science & Technology ◽

10.2166/wst.2009.066 ◽

2009 ◽

Vol 59 (4) ◽

pp. 823-832 ◽

Cited By ~ 3

Author(s):

Ye Changqing ◽

Wang Dongsheng ◽

Wu Xiaohong ◽

Qu Jiuhui ◽

John Gregory

Keyword(s):

Kinetic Constant ◽

Nonlinear Least Squares ◽

Precise Determination ◽

K Value ◽

First Order ◽

First Order Kinetics ◽

Parallel Reactions

The speciation of Al-OH complexes in terms of Ala, Alb and Alc could be achieved by traditional ferron assay and Alb is generally considered as Al13, however, the inherent correlation between them remains an enigma. This paper presents a modified ferron assay to get precise determination of Al13 using nonlinear least squares analysis, and to clarify the correlation between Alb and Al13. Two parallel reactions conforming to pseudo-first-order kinetics can simulate the complicate reactions between polynuclear complexes and ferron successfully. Four types of experimental kinetic constant (k value) of Al-OH complexes can be observed by this method when investigating three typical aluminium solutions. Comparing with the results of 27Al NMR, the species with moderate kinetics around 0.001 s−1 can be confirmed to resemble to Al13 polycation. The other types of kinetics are also well-regulated in partially neutralized aluminium solutions with various OH/Al ratios (b values) in the range 0 ∼ 2.5. It would provide potential means to trace the in-situ formation of Al13 in dilute solutions such as coagulation with Al-based coagulants

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Kinetics of dechlorination of atrazine using tin (SnII) at neutral pH conditions

Applied Chemical Engineering ◽

10.24294/ace.v3i1.575 ◽

2020 ◽

Vol 3 (1) ◽

pp. 49

Author(s):

Vijay Kumar ◽

Simranjeet Singh

Keyword(s):

Aqueous Media ◽

Spectrometric Analysis ◽

First Order ◽

Neutral Ph ◽

First Order Kinetics ◽

Condi Tions ◽

Ph Conditions ◽

Pseudo First Order ◽

Reaction Constants ◽

Kinetics Of

Atrazine is a broad spectrum herbicide of triazine family. It is a chlorine-containing molecule and it can persist in environment. Chemical and biochemical techniques are the main techniques used to decompose the chemicals. In pre-sent study, the dechlorination of atrazine (Atr) via reaction with Sn(II) ion under aqueous media at neutral pH condi-tions was studied. The observed dechlorinated metabolite was 4-Ethylamino-6-isopropylamino-[1,3,5]triazin-2-ol. Identification of dechlorinated product of Atr was performed by using spectroscopic (FTIR) and mass (ESI-MS) spectrometric analysis. The kinetics of the dechlorination of Atr was measured by using pseudo-first order kinetics. The observed reaction constants was, kobs = 6.11x10-2 (at 430 mg/ L of Atr), and kobs = 6.14 x10-2 (at 215 mg/ L of Atr). The calculated half-life (t1/2) period was, t1/2 = 0.204 d (at 430 mg/ L of Atr), and t1/2 = 0.205 d (at 215 mg/ L of Atr).

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Design of Impinging Stream-Cavitations and Micro-Electrolysis Reactor and Treatment of High Concentration Wastewater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.781-784.1994 ◽

2013 ◽

Vol 781-784 ◽

pp. 1994-1997 ◽

Cited By ~ 1

Author(s):

Hao Wu ◽

Fu Bao Li ◽

Qin Li ◽

Wei Sha

Keyword(s):

Reaction Time ◽

Reaction Rate ◽

Cod Removal ◽

High Concentration ◽

Air Compressor ◽

First Order ◽

First Order Kinetics

A micro-electrolysis reactor combined with the technology of impinging stream-cavitations drum was designed. Then it was used in the treatment of high concentration wastewater. Under the conditions of reaction time is 60 min, ratio of iron to carbon is 1 and the pressure of the air compressor is 8Mpa, the COD and chromaticity could remove 95.7% and 85.9% respectively. The biodegradability was improved obviously with 0.55 of BOD5/COD. The determinations of kinetics under the best conditions show that, the mode of COD removal basically conforms to the rule of first order kinetics. The reaction rate in our reactor was faster than only micro-electrolysis or only cavitations obviously. The conjunction of impinging stream-cavitations and micro-electrolysis has good synergism and facilitation.

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Photocatalytic Degradation of Bismarck Brown G Using Irradiated ZnO in Aqueous Solutions

E-Journal of Chemistry ◽

10.1155/2010/719674 ◽

2010 ◽

Vol 7 (2) ◽

pp. 540-544 ◽

Cited By ~ 8

Author(s):

Falah H. Hussein ◽

Ahmed F. Halbus ◽

Hussein A. K. Hassan ◽

Wisam A. K. Hussein

Keyword(s):

Zinc Oxide ◽

Aqueous Solutions ◽

Photocatalytic Degradation ◽

Irradiation Time ◽

Degradation Process ◽

First Order ◽

Photocatalytic Decolorization ◽

First Order Kinetics ◽

Decolorization Efficiency ◽

Increasing Temperature

In this study, a homemade photoreactor equipped with 125w/542 high pressure mercury lamp as a source for near-UV radiation, was used for photocatalytic degradation of aqueous solutions of Bismarck brown G, (C18H20N8Cl2),4-[5-(2,4-Diamino-5-methylphenyl)diazenyl-2-methylphenyl] diazenyl -6-methylbenzol-1,3-diamin using zinc oxide. The disappearance of the original colored reactant concentrations with irradiation time was monitored spectrophotometrically by comparison with unexposed controls. It is noticed that the photocatalytic degradation process was high at the beginning and then decreased with time following pseudo first-order kinetics according to the Langmuir–Hinshelwood model. The effects of zinc oxide mass, dye concentration and temperature on photocatalytic decolorization efficiency (P.D.E.) were studied. P.D.E. reached 95.76% for Bismarck brown G after 50 minutes of irradiation at 293.15 K P.D.E. was found to increase with increasing temperature and the activation energy of photocatalytic degradation was calculated and found to be equal to 32±1 kJ mol-1.

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Dissipation and Residues of Thiram in Potato and Soil

Journal of Chemistry ◽

10.1155/2015/623847 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Shaowen Liu ◽

Aijuan Bai ◽

Li Zhou ◽

Chuanshan Yu ◽

Yanjie Li ◽

...

Keyword(s):

High Performance ◽

Residue Field ◽

High Concentration ◽

Recommended Dosage ◽

Potato Leave ◽

First Order ◽

First Order Kinetics ◽

Wettable Powder ◽

Residue Levels ◽

Derivation Method

The residue levels of thiram during potato cultivation in open field were evaluated. Thiram residues were determined by methylation derivation method with high performance liquid chromatography (HPLC). Wettable powder (WP) formulation containing 25% thiram was applied at 2320 g active gradient hm−2(a.i. hm−2) dosage for the dissipation study. The decline rate in potato leave and soil followed first-order kinetics equation, and the half-life ranged from 2.8 to 5.4 days and 2.6 to 9.9 days, respectively. In terminal residue, the thiram was sprayed at 580 g a.i. hm−2(low concentration, recommended dosage) and 1160 g a.i. hm−2(high concentration, double of recommended dosage). The residues of thiram in potato and soil samples collected in the field at preharvest interval of 21 days and 30 days were all below 0.02 mg kg−1. The results show that thiram possesses low dietary risk in potato at harvest according to supervised residue field trial. It may be safe when used at recommended rate of application.

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Photocatalytic, Sonolytic and Sonophotocatalytic Degradation of 4-Chloro-2-Nitro Phenol

Archives of Environmental Protection ◽

10.2478/aep-2013-0015 ◽

2013 ◽

Vol 39 (2) ◽

pp. 17-28 ◽

Cited By ~ 21

Author(s):

Anoop Verma ◽

Harmanpreet Kaur ◽

Divya Dixit

Keyword(s):

Synergistic Effect ◽

Organic Pollutants ◽

Catalyst Concentration ◽

Environmentally Friendly ◽

Mercury Lamp ◽

First Order ◽

Complete Degradation ◽

First Order Kinetics ◽

Oxidant Concentration ◽

Artificial Uv

Abstract The photocatalytic, sonolytic and sonophotocatalytic degradation of 4-chloro-2-nitrophenol (4C2NP) using heterogeneous (TiO2) was investigated in this study. Experiments were performed in slurry mode with artificial UV 125 watt medium pressure mercury lamp coupled with ultrasound (100 W, 33+3 KHz) for sonication of the slurry. The degradation of compound was studied in terms of first order kinetics. The catalyst concentration was optimized at 1.5 gL-1, pH at 7 and oxidant concentration at 1.5 gL-1. The results obtained were quite appreciable as 80% degradation was obtained for photocatalytic treatment in 120 minutes whereas, ultrasound imparting synergistic effect as degradation achieved 96% increase in 90 minutes during sonophotocatalysis. The degradation follows the trend sonophotocatalysis > photocatalysis > sonocatalytic > sonolysis. The results of sonophotocatalytic degradation of pharmaceutical compound showed that it could be used as efficient and environmentally friendly technique for the complete degradation of recalcitrant organic pollutants which will increase the chances for the reuse of wastewater.

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Surface-Related Kinetic Models for Anaerobic Digestion of Microcrystalline Cellulose: The Role of Particle Size

Materials ◽

10.3390/ma14030487 ◽

2021 ◽

Vol 14 (3) ◽

pp. 487

Author(s):

Michał Piątek ◽

Aleksander Lisowski ◽

Magdalena Dąbrowska

Keyword(s):

Particle Size ◽

Anaerobic Digestion ◽

Microcrystalline Cellulose ◽

Kinetic Constant ◽

Spherical Particles ◽

Kinetics Model ◽

Hydrolysis Rate ◽

Crystalline Cellulose ◽

First Order ◽

First Order Kinetics

In this work, for modelling the anaerobic digestion of microcrystalline cellulose, two surface-related models based on cylindrical and spherical particles were developed and compared with the first-order kinetics model. A unique dataset consisting of particles with different sizes, the same crystallinity and polymerisation degree was used to validate the models. Both newly developed models outperformed the first-order kinetics model. Analysis of the kinetic constant data revealed that particle size is a key factor determining the anaerobic digestion kinetics of crystalline cellulose. Hence, crystalline cellulose particle size should be considered in the development and optimization of lignocellulose pre-treatment methods. Further research is necessary for the assessment of impact of the crystalline cellulose particle size and surface properties on the microbial cellulose hydrolysis rate.

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Electro-photocatalytic degradation of amoxicillin using calcium titanate

Open Chemistry ◽

10.1515/chem-2018-0108 ◽

2018 ◽

Vol 16 (1) ◽

pp. 949-955 ◽

Cited By ~ 3

Author(s):

Lvshan Zhou ◽

Xiaogang Guo ◽

Chuan Lai ◽

Wei Wang

Keyword(s):

Photocatalytic Degradation ◽

Reaction Rate ◽

Irradiation Time ◽

Oxygen Demand ◽

Reaction Rate Constant ◽

Calcium Titanate ◽

Experimental Conditions ◽

Exponential Factor ◽

First Order ◽

First Order Kinetics

AbstractThe electro-photocatalytic degradation of amoxicillin in aqueous solution was investigated using single factor test by the potassium permanganate method for measuring the values of chemical oxygen demand (CODMn). Batch experiments were carried out successfully under different conditions, including initial amoxicillin concentration, calcium titanate dosage, pH, UV irradiation time, electrolyte and temperature. The experimental results show that there is a great difference between electro-photocatalytic and photocatalitic degradation. The maximum electro-photocatalytic degradation efficiency can increase to 79% under the experimental conditions of 200 mL amoxicillin solution (100 mg L-1) with 0.5 g calcium titanate by pH=3 for 120 min irradiation and 0.058 g sodium chloride as electrolyte at 318.5K. In addition, the reaction rate constant of 0.00848~0.01349 min-1, activation energy of 9.8934 kJ mol-1 and the pre-exponential factor of 0.5728 were obtained based on kinetics studies, indicating that the electro-photocatalytic reaction approximately followed the first-order kinetics model.

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Heat-induced denaturation and aggregation of ovalbumin at neutral pH described by irreversible first-order kinetics

Protein Science ◽

10.1110/ps.03242803 ◽

2003 ◽

Vol 12 (12) ◽

pp. 2693-2703 ◽

Cited By ~ 82

Author(s):

Mireille Weijers ◽

Peter A. Barneveld ◽

Martien A. Cohen Stuart ◽

Ronald W. Visschers

Keyword(s):

First Order ◽

Neutral Ph ◽

First Order Kinetics

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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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