Effects of initial concentration and irradiation dose to degradation of di butyl phthalate from phosphoric acid (30 % P2O5)

2018 ◽  
Vol 106 (11) ◽  
pp. 909-916
Author(s):  
Louisa Bounemia ◽  
Abdelhamid Mellah
Keyword(s):  
Organic Matter ◽  
Phosphoric Acid ◽  
Optimal Recovery ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Butyl Phthalate

Abstract The pretreatment of the phosphoric acid is a stage of utmost importance leading to an optimal recovery of the uranium present in this acid. To this end, the degradation of the organic matter which obstructs considerably this recovery was tested by γ irradiation. This study lies within the scope of the radiation/matter interaction; concerning the use of the γ irradiator as proceed of phosphoric acid purification by the degradation of di butyl phthalate (DBP). Studies of the interaction of γ radiation with phosphoric acid solutions polluted by an organic matter concern the study of the influence of some parameters such as: dose rate (0.5–35 kGy), initial concentration (50–500 mg/L) of the pollutant, pH and % in P2O5 on the degradation of organic matter by γ irradiation. The reactions followed pseudo first order kinetics for different initial concentrations. The results made it possible to say that the degradation of di butyl phthalate by γ irradiation is dependent on the amount of the concentration of DBP and pH. The G-values decreased with absorbed doses, and increased with higher initial concentrations.Purification of phosphoric acid by γ radiation does not degrade the quality of this acid.

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

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
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.

scholarly journals Oxygen uptake during mineralization of humic substances from Infernão Lagoon (São Paulo, Brazil)

2004 ◽  
Vol 64 (3b) ◽  
pp. 583-590 ◽  
Author(s):  
M. B. Cunha-Santino ◽  
I. Bianchini JR.
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Oxygen Uptake ◽  
Dissolved Oxygen ◽  
Humic Substances ◽  
Aquatic Macrophyte ◽  
Uptake Coefficient ◽  
First Order ◽  
First Order Kinetics ◽  
Different Sources

Assays were carried out to evaluate the dissolved oxygen uptake resulting from mineralization of humic substances (fulvic acid (FA) and humic acid (HA)) from different sources: sediment, dissolved organic matter (DOM) of 120-day decomposed aquatic macrophyte (Scirpus cubensis and Cabomba piauhyensis), and lagoon DOM. The experiments were also aimed at estimating the oxygen uptake coefficient of the mineralization. About 20-30 mg of substrate were added to 1.1 liters of water from Infernão Lagoon (21º33' to 21º37'S; 47º45' to 47º51'W). The solutions were aerated and the dissolved oxygen (DO) was monitored during 40 days. Dissolved organic carbon (DOC) and particulate organic carbon (POC) were estimated after 80 days of the experiment. Anaerobic processes were avoided by aerating the solutions. The results were fitted to a first-order kinetics model, from which the uptake of oxygen parameters was obtained. Oxygen consumption (OC) ranged from 4.24 mg L-1 (HA - S. cubensis) to 33.76 mg L-1 (FA - sediment). The highest deoxygenation coefficient (kD) was observed during mineralization of FA - DOM (0.299 day-1), followed in decreasing order by FA - S. cubensis, HA - sediment, HA - S. cubensis, FA - sediment, and FA - C. piauhyensis (0.282; 0.255; 0.178; 0.130, and 0.123 day-1, respectively). The carbon analyses indicated that the FA and HA samples at the end of the experiment presented a decay that varied from 15.23% to 42.35% and that the FA and HA conversions into POC were relatively low (from 0.76% to 3.94%).

scholarly journals The relative importance of decomposition and transport mechanisms in accounting for soil organic carbon profiles

2013 ◽  
Vol 10 (4) ◽  
pp. 2379-2392 ◽  
Author(s):  
B. Guenet ◽  
T. Eglin ◽  
N. Vasilyeva ◽  
P. Peylin ◽  
P. Ciais ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Carbon ◽  
First Order ◽  
Carbon Decomposition ◽  
First Order Kinetics ◽  
Fresh Organic Matter ◽  
Deep Layers ◽  
Bare Fallow ◽  
Soc Decomposition

Abstract. Soil is the major terrestrial reservoir of carbon and a substantial part of this carbon is stored in deep layers, typically deeper than 50 cm below the surface. Several studies underlined the quantitative importance of this deep soil organic carbon (SOC) pool and models are needed to better understand this stock and its evolution under climate and land-uses changes. In this study, we tested and compared three simple theoretical models of vertical transport for SOC against SOC profiles measurements from a long-term bare fallow experiment carried out by the Central-Chernozem State Natural Biosphere Reserve in the Kursk Region of Russia. The transport schemes tested are diffusion, advection and both diffusion and advection. They are coupled to three different formulations of soil carbon decomposition kinetics. The first formulation is a first order kinetics widely used in global SOC decomposition models; the second one, so-called "priming" model, links SOC decomposition rate to the amount of fresh organic matter, representing the substrate interactions. The last one is also a first order kinetics, but SOC is split into two pools. Field data are from a set of three bare fallow plots where soil received no input during the past 20, 26 and 58 yr, respectively. Parameters of the models were optimised using a Bayesian method. The best results are obtained when SOC decomposition is assumed to be controlled by fresh organic matter (i.e., the priming model). In comparison to the first-order kinetic model, the priming model reduces the overestimation in the deep layers. We also observed that the transport scheme that improved the fit with the data depended on the soil carbon mineralisation formulation chosen. When soil carbon decomposition was modelled to depend on the fresh organic matter amount, the transport mechanism which improved best the fit to the SOC profile data was the model representing both advection and diffusion. Interestingly, the older the bare fallow is, the lesser the need for diffusion is, suggesting that stabilised carbon may not be transported within the profile by the same mechanisms than more labile carbon.

Photochemical combustion of organic matter in sea water, for nitrogen, phosphorus and carbon determination

1968 ◽  
Vol 48 (1) ◽  
pp. 143-152 ◽  
Author(s):  
F. A. J. Armstrong ◽  
Susan Tibbitts
Keyword(s):  
Organic Matter ◽  
Sea Water ◽  
Phosphorus Compounds ◽  
Nitrogen Compounds ◽  
English Channel ◽  
First Order ◽  
First Order Kinetics ◽  
Channel Water ◽  
Carbon Determination ◽  
Nitrogen Phosphorus

A photochemical reactor, using a medium power mercury arc lamp for oxidation of organic matter in sea water, is described. The decomposition of some known compounds in distilled water and in sea water, using a 380 W lamp, was followed. First order kinetics with rate constants in the range 0·2–4·0 h−1 were observed. All the nitrogen compounds tested, including urea and some of its derivatives, were oxidized quantitatively. Breakdown of phosphorus compounds was rapid, but polyphosphate esters yielded polyphosphate ion which was only slowly hydrolysed to reactive orthophosphate. If polyphosphate is to be determined, hydrolysis by heating with acid should follow the irradiation. Some samples of English Channel water contained 0·02-0–05 fig-axom P/1. as organic polyphosphate.

scholarly journals Modelling organic matter dynamics in different soils.

1990 ◽  
Vol 38 (3A) ◽  
pp. 221-238 ◽  
Author(s):  
E.L.J. Verberne ◽  
J. Hassink ◽  
P. de Willigen ◽  
J.J.R. Groot ◽  
J.A. van Veen
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
State Level ◽  
N Cycling ◽  
First Order ◽  
Soil Microbial ◽  
First Order Kinetics ◽  
Different Soils

A mathematical model was developed to describe carbon (C) and nitrogen (N) cycling in different soil types, e.g. clay and sandy soils. Transformation rates were described by first-order kinetics. Soil organic matter is divided into four fractions (including microbial biomass pool) and three fractions of residues. The fraction of active soil organic matter was assumed to be affected by the extent of physical protection within the soil, as was the soil microbial biomass. The extent of protection influenced the steady state level of the model, and, hence, the mineralization rates. The mineralization rate in fine-textured soils is lower than in coarse-textured soils; in fine-textured soils a larger proportion of the soil organic matter may be physically protected. The availability of organic materials as a substrate for microorganisms is not only determined by their chemical composition, but also by their spatial distribution in the soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

2013 ◽  
Vol 69 (6) ◽  
pp. 1219-1226
Author(s):  
C. Chen ◽  
Q. Xie ◽  
B. Q. Hu ◽  
X. L. Zhao
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Degradation Rate ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Solution Ph ◽  
First Order ◽  
First Order Kinetics ◽  
Catalyst Dosage ◽  
H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

scholarly journals Hydrolysis and Photolysis Kinetics, and Identification of Degradation Products of the Novel Bactericide 2-(4-Fluorobenzyl)-5-(Methylsulfonyl)-1,3,4-Oxadiazole in Water

2018 ◽  
Vol 15 (12) ◽  
pp. 2741 ◽  
Author(s):  
Xingang Meng ◽  
Lingzhu Chen ◽  
Yuping Zhang ◽  
Deyu Hu ◽  
Baoan Song
Keyword(s):  
Degradation Product ◽  
High Performance ◽  
Degradation Products ◽  
Degradation Mechanism ◽  
The Novel ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
High Resolution Mass Spectrometer

Hydrolysis and photolysis kinetics of Fubianezuofeng (FBEZF) in water were investigated in detail. The hydrolysis half-lives of FBEZF depending on pH, initial concentration, and temperature were (14.44 d at pH = 5; 1.60 d at pH = 7), (36.48 h at 1.0 mg L−1; 38.51 h at 5.0 mg L−1; and 31.51 h at 10.0 mg L−1), and (77.02 h at 15 °C; 38.51 h at 25 °C; 19.80 h at 35 °C; and 3.00 h at 45 °C), respectively. The photolysis half-life of FBEZF in different initial concentrations were 8.77 h at 1.0 mg L−1, 8.35 h at 5.0 mg L−1, and 8.66 h at 10.0 mg L−1, respectively. Results indicated that the degradation of FBEZF followed first-order kinetics, as the initial concentration of FBEZF only had a slight effect on the UV irradiation effects, and the increase in pH and temperature can substantially accelerate the degradation. The hydrolysis Ea of FBEZF was 49.90 kJ mol−1, which indicates that FBEZF belongs to medium hydrolysis. In addition, the degradation products were identified using ultra-high-performance liquid chromatography coupled with an Orbitrap high-resolution mass spectrometer. One degradation product was extracted and further analyzed by 1H-NMR, 13C-NMR, 19F-NMR, and MS. The degradation product was identified as 2-(4-fluorobenazyl)-5-methoxy-1,3,4-oxadiazole, therefore a degradation mechanism of FBEZF in water was proposed. The research on FBEZF can be helpful for its safety assessment and increase the understanding of FBEZF in water environments.

Sorbate destruction and non-enzymatic browning in model aqueous systems Destruccion de sorbatos y pardeamiento no enzimático en sistemas modelo acuosos

1997 ◽  
Vol 3 (6) ◽  
pp. 405-411 ◽  
Author(s):  
C.A. Campos ◽  
S.M. Alzamora ◽  
L.N. Gerschenson
Keyword(s):  
Citric Acid ◽  
Phosphoric Acid ◽  
Sorbic Acid ◽  
Zero Order ◽  
Model Systems ◽  
Enzymatic Browning ◽  
First Order ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
System Composition

The effect of system composition on sorbate destruction and sensory damage due to non-enzy matic browning was studied in aqueous model systems with a water activity ( aw) of 0.91 and a pH of 5.0-6.0. The rate constants of sorbate destruction could be described by first order kinetics and those from non-enzymatic browning by zero order kinetics. Both reactions were found to be related not only to temperature and pH but also to the humectants (NaCl, glycerol) used to depress aw. A higher preservative retention and a smaller amount of browning was produced by the use of a mixture of 35.0 g/kg of NaCl and 220.0 g/kg of glycerol as a humectant instead of one of them alone, citric acid instead of phosphoric acid as the acidifying agent, and glass flasks instead of polyethylene containers. The non-enzymatic browning reactions were greatly influenced by sorbic acid destruction. The inclusion of glycine was responsible for the enhanced sorbate destruc tion and browning development.

scholarly journals Photocatalytic removal of cefazolin from aqueous solution by AC prepared from mango seed+ZnO under UV irradiation

2018 ◽  
Vol 20 (2) ◽  
pp. 399-407 ◽  
Keyword(s):  
Activated Carbon ◽  
Kinetic Model ◽  
Uv Irradiation ◽  
Advanced Oxidation ◽  
Beam Radiation ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Mango Seed

Presence of antibiotics in the environment specially in aqueous environments is considered a major warning about health and environment. Thus, this study aims the efficiency of coupled process of Activated Carbon (AC) prepared from mango seed+ZnO under UV irradiation as an advanced oxidation process in removing cefazolin antibiotic from aqueous solutions. This experimental study was carried out in a discontinuous reaction chamber with volume of one liter. In this process, the effect of initial pH parameters of the environment (3– 9), initial concentration of cefazolin (20 – 200 mg/L), concentration of modified, photocatalyzer (20 – 100 mg/L) and reaction time (10 – 60 min) were studied. The pilot used consisted of a low pressure mercury lamp with a 55-watt beam radiation power inside the steel chamber. The kinetic of the process was studied based on pseudo first order kinetics. Results showed that the highest removal efficiency of cefazolin antibiotics in the reaction of UV/AC + ZnO, at optimal conditions of pH= 3, contact time of 60 min, initial concentration of 100 mg/L and modified photocatalyzer of 0.1 g/L was equal to 96%. The kinetic model determined for the process followed kinetic model of pseudo- first order kinetics with high correlation of (R2 = 0.99). Results of present study revealed that photocatalyzer process of nanoparticles oxidation on synthetic activated carbon can be effectively used as an advanced oxidation reaction to remove cefazolin and similar pollutants.

scholarly journals Gamma Radiolysis Studies of Aqueous Solution of Brilliant Green Dye

2011 ◽  
Vol 8 (2) ◽  
pp. 680-684
Author(s):  
D. V. Parwate ◽  
S. S. Mankar
Keyword(s):  
Aqueous Solution ◽  
Brilliant Green ◽  
Parent Compound ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
First Order Kinetics ◽  
Gamma Radiolysis ◽  
Rate Of Reaction ◽  
Before And After ◽  
Degradation Reaction

The effect of γ–radiation on colour intensity of aqueous solution of Brilliant Green has been investigated at two different concentrations. The degradation of Brilliant Green (BG) has also been investigated in presence of suspended ZnO, by adding different amounts of ZnO. Simultaneously the conductance and pH of each solution system were measured before and after γ-irradiation. All the γ–irradiations were performed at a dose rate of 0.60 kGyhr-1in GC-900. The maximum dose required for the complete degradation of the dye was found to be 0.39 kGy. G(-dye) values were found to decrease with increase in gamma dose and were in the range 4.26 - 12.81. The conductance (7.6 - 25.3 μS) and pH values increased marginally with dose for both the concentrations. The rate of decolouration was found to be high at lower doses and the efficiency of dye removal was higher at low concentration of the dye. This may be attributed to the presence of reaction by-products from the destruction of parent compound build up and compete for reaction intermediate species. The rate of reaction and rate constants were calculated and it was found that the degradation reaction follows first order kinetics. It was found that the decolouration percentage was more in dye systems in absence of ZnO.

Sign in / Sign up

Export Citation Format

Share Document