scholarly journals First-order kinetics-controlled multiple species reactive transport of dissolved organic compounds in groundwater: Development and application of a numerical model

1990 ◽  
Author(s):  
W.W. Jr. McNab
Keyword(s):  
Numerical Model ◽  
Organic Compounds ◽  
Reactive Transport ◽  
Groundwater Development ◽  
First Order ◽  
First Order Kinetics ◽  
Dissolved Organic Compounds ◽  
Multiple Species

scholarly journals Oxygen consumption during mineralization of organic compounds in water samples from a small sub-tropical reservoir (Brazil)

2003 ◽  
Vol 46 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Marcela Bianchessi da Cunha-Santino ◽  
Irineu Bianchini Júnior
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Tannic Acid ◽  
Theoretical Calculations ◽  
Tropical Reservoir ◽  
First Order ◽  
First Order Kinetics ◽  
Mineralization Processes ◽  
Carbon Concentrations

Assays were carried out to evaluate the oxygen consumption resulting from mineralization of different organic compounds: glucose, sucrose, starch, tannic acid, lysine and glycine. The compounds were added to 1 l of water sample from Monjolinho Reservoir. Dissolved oxygen and dissolved organic carbon were monitored during 20 days and the results were fitted to first order kinetics model. During the 20 days of experiments, the oxygen consumption varied from 4.5 mg.l-1 (tannic acid) to 71.5 mg.l-1 (glucose). The highest deoxygenation rate (kD) was observed for mineralization of tannic acid (0.321 day-1) followed by glycine, starch, lysine, sucrose and glucose (0.1004, 0.0504, 0.0486, 0.0251 and 0.0158 day-1, respectively). From theoretical calculations and oxygen and carbon concentrations we obtained the stoichiometry of the mineralization processes. Stoichiometric values varied from 0.17 (tannic acid) to 2.55 (sucrose).

scholarly journals Radiocatalytic degradation of dissolved organic compounds in wastewater

Nukleonika ◽  
2016 ◽  
Vol 61 (4) ◽  
pp. 473-476 ◽  
Author(s):  
Jaime Jiménez-Becerril ◽  
Anabel Moreno-López ◽  
Melania Jiménez-Reyes
Keyword(s):  
Organic Compounds ◽  
Mineral Content ◽  
Municipal Wastewater ◽  
Order Kinetic ◽  
Organic Substances ◽  
High Concentration ◽  
First Order ◽  
Gamma Radiolysis ◽  
Order Kinetic Model ◽  
Dissolved Organic Compounds

Abstract Wastewater containing a high concentration of organic substances was exposed to gamma radiolysis in the presence and absence of a catalyst (TiO2); radiolysis and radiocatalysis were performed by means of continuous and discontinuous irradiation. Dissolved organic carbon (DOC) was the parameter used to estimate the concentration of organic compounds without interference by the high mineral content. The data was well fitted to the pseudo-first-order kinetic model of Langmuir-Hinshelwood. From a [DOC]0 = 140 ± 7 mg/L, the higher DOC degradation (74%) and apparent rate constant (Kapp = 0.083 h-1) were found using discontinuous radiocatalysis. This process could be an alternative method of treatment of industrial or municipal wastewater

Persistence of Volatile Organic Compounds in Sludge Treated Soils

1997 ◽  
Vol 32 (3) ◽  
pp. 579-598
Author(s):  
M.D. Webber ◽  
J.D. Goodin ◽  
P.J.A. Fowlie ◽  
R.L. Hong-You ◽  
J. Legault
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Room Temperature ◽  
Municipal Sludge ◽  
Laboratory Findings ◽  
First Order ◽  
Boiling Points ◽  
First Order Kinetics ◽  
Volatile Organic

Abstract Laboratory incubation studies were conducted to assess the persistence of ten volatile organic compounds (VOCs) in seven soils treated with 3% dw of anaer-obically digested municipal sludge. The VOCs were probable municipal sludge contaminants and the soils represented wide ranges of constituents likely to sorb organic compounds, e.g., organic carbon (1.3 to 12%) and clay (7 to 50%). The VOCs were spiked into soils at 50 mg kg-1 dw of soil, except for trichloro-ethylene and chloroform which were at 2.5 mg kg-1 dw. Three general patterns of VOC losses from soils were identified: (1) complete volatilization at room temperature within 24 h, (2) complete volatilization/degradation within 144 to 288 h, and (3) incomplete volatilization/degradation within 288 h. All VOC losses were consistent with first-order kinetics and indicated a combination of a rapid initial kinetic (0 to 4 h) followed by a slower kinetic. The slower kinetic was assumed to be more relevant to field VOC losses than the rapid kinetic, and first-order half-lives were calculated using the 4- to 288-h experimental data. The half-lives ranged from 5.5 to 1,926 h with a median value of 70 h, and generally increased with increasing boiling points of the VOCs and with increasing organic carbon contents of the soils. These laboratory findings indicate that VOCs in land-applied sludge are unlikely to represent a hazard to agriculture.

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.

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Modelling waste output from trout farms

1995 ◽  
Vol 31 (10) ◽  
pp. 103-121
Author(s):  
J.-O. Frier ◽  
J. From ◽  
T. Larsen ◽  
G. Rasmussen
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Numerical Model ◽  
Organic Compounds ◽  
Waste Treatment ◽  
Waste Water Treatment ◽  
Nitrogen And Phosphorus ◽  
Waste Discharge ◽  
Scientific Background ◽  
Trout Farms

The aim of waste modelling in aquaculture is to provide tools for simulating input, transformation, output and subsidiary degradation in recipients of organic compounds, nitrogen, and phosphorus. The direct purpose of this modelling is to make it possible for caretakers and water authorities to calculate waste discharge from existing and planned aquaculture activities. A special purpose is simulating outcome of waste water treatment and altered feeding programmes. Different submodels must be applied for P, N, and organics, as well as for the different phases of food and waste treatment. Altogether this calls for an array of co-operating submodels for a sufficient coverage of the options. In all the required fields there is some scientific background for numerical model approaches, and some submodels have been proposed. Because of its multidisciplinary character a synthesized approach is still lacking. Within trout farming this work attempts to establish the different submodels and outlines future possibilities for synthesizing the knowledge to a numerical model.

Biodegradation rates of aromatic contaminants in biofilm reactors

1995 ◽  
Vol 31 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Jean-Pierre Arcangeli ◽  
Erik Arvin
Keyword(s):  
Aromatic Hydrocarbons ◽  
Competitive Inhibition ◽  
Removal Rate ◽  
First Order ◽  
Biofilm Reactors ◽  
First Order Kinetics ◽  
Reducing Conditions ◽  
Low Concentrations ◽  
Degradation Rates ◽  
Order Surface

This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic compounds was typically controlled by first order kinetics. The first-order surface removal rate constants were surprisingly similar, ranging from 2 to 4 m/d. It appears that NSO-compounds inhibit the degradation of aromatic hydrocarbons, even at very low concentrations of NSO-compounds. Under nitrate-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking into account cometabolism and competitive inhibition is proposed.

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