Chemical sulfide oxidation of wastewater - effects of pH and temperature

2004 ◽  
Vol 50 (4) ◽  
pp. 185-192 ◽  
Author(s):  
A. Haaning Nielsen ◽  
J. Vollertsen ◽  
T. Hvitved-Jacobsen
Keyword(s):  
Rate Equation ◽  
Oxidation Rate ◽  
Sulfide Oxidation ◽  
Chemical Oxidation ◽  
Process Models ◽  
Temperature Dependency ◽  
Stoichiometric Coefficient ◽  
Effects Of Ph ◽  
Temperature Ranges ◽  
Sewer Networks

In this study, the kinetics and stoichiometry of chemical sulfide oxidation of wastewater from sewer networks were investigated. Based on experiments, it was shown that the stoichiometry could be considered identical for wastewater from two sampling sites. However, the kinetics differed significantly among the wastewaters from the two sites. Effects of pH and temperature were investigated in the pH and temperature ranges 5-9 and 5-25°C, respectively. The rate of chemical sulfide oxidation could be related to the dissociation of H2S to HS-, with HS- being oxidized at a higher rate than H2S. The temperature dependency of the chemical sulfide oxidation rate was described using an Arrhenius relationship. The oxidation rate was found to double with a temperature increase of 12¡C. The stoichiometry of the chemical oxidation was not significantly affected by varying pH and temperature. Based on the experiments, a general rate equation, including a stoichiometric coefficient describing chemical sulfide oxidation in wastewater was proposed, enabling the process to be incorporated into sewer process models that can predict odor and corrosion problems.

Determination of Kinetics and Stoichiometry of Chemical Sulfide Oxidation in Wastewater of Sewer Networks

2003 ◽  
Vol 37 (17) ◽  
pp. 3853-3858 ◽  
Author(s):  
Asbjørn H. Nielsen ◽  
Jes Vollertsen ◽  
Thorkild Hvitved-Jacobsen
Keyword(s):  
Sulfide Oxidation ◽  
Sewer Networks

Final products and kinetics of biochemical and chemical sulfide oxidation under microaerobic conditions

2018 ◽  
Vol 78 (9) ◽  
pp. 1916-1924 ◽  
Author(s):  
Lucie Pokorna-Krayzelova ◽  
Dana Vejmelková ◽  
Lara Selan ◽  
Pavel Jenicek ◽  
Eveline I. P. Volcke ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Oxidation Rate ◽  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Cost Effective ◽  
Anaerobic Treatment ◽  
Batch Experiments ◽  
Cost Effective Method ◽  
Microaerobic Conditions ◽  
Kinetics Of

Abstract Hydrogen sulfide is a toxic and usually undesirable by-product of the anaerobic treatment of sulfate-containing wastewater. It can be removed through microaeration, a simple and cost-effective method involving the application of oxygen-limiting conditions (i.e., dissolved oxygen below 0.1 mg L−1). However, the exact transformation pathways of sulfide under microaerobic conditions are still unclear. In this paper, batch experiments were performed to study biochemical and chemical sulfide oxidation under microaerobic conditions. The biochemical experiments were conducted using a strain of Sulfuricurvum kujiense. Under microaerobic conditions, the biochemical sulfide oxidation rate (in mg S L−1 d−1) was approximately 2.5 times faster than the chemical sulfide oxidation rate. Elemental sulfur was the major end-product of both biochemical and chemical sulfide oxidation. During biochemical sulfide oxidation elemental sulfur was in the form of white flakes, while during chemical sulfide oxidation elemental sulfur created a white suspension. Moreover, a mathematical model describing biochemical and chemical sulfide oxidation was developed and calibrated by the experimental results.

Removal of hexavalent chromium from aqueous solution using exfoliated polyaniline/montmorillonite composite

2014 ◽  
Vol 70 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Jun Chen ◽  
Xiaoqin Hong ◽  
Yongteng Zhao ◽  
Qianfeng Zhang
Keyword(s):  
Adsorption Capacity ◽  
Chemical Oxidation ◽  
Maximum Adsorption Capacity ◽  
Isothermal Model ◽  
Adsorption Characteristic ◽  
In Situ Chemical Oxidation ◽  
Acid Copolymer ◽  
Chemical Oxidation Polymerization ◽  
Effects Of Ph ◽  
Pseudo Second Order

Exfoliated polyaniline/montmorillonite (PANI/MMT) composites with nanosheet structure were successfully prepared by in situ chemical oxidation polymerization with MMT platelets as the scaffold. Amphoteric polymer, (2-methacryloyloxyethyl)trimethyl ammonium chloride and methacrylate acid copolymer, was used to modify montmorillonite and a large number of carboxylic acids were introduced on the surface of the clay platelets, which can be used as a dopant of PANI and play a ‘bridge’ role to combine PANI with clay. Adsorption experiments were carried out to study the effects of pH, contact time, Cr(VI) concentration, adsorbent dose and temperature. The adsorption of Cr(VI) on the PANI/MMT was highly pH dependent and the adsorption kinetics followed a pseudo-second-order model. The Langmuir isothermal model described the adsorption isotherm data well and the maximum adsorption capacity increased with the increase in temperature. Thermodynamic investigation indicated that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the adsorbent – liquid interface. The maximum adsorption capacity of the PANI/MMT composites for Cr(VI) was 308.6 mg/g at 25 °C. The excellent adsorption characteristic of exfoliated PANI/MMT composites will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.

Features of Stress Changes in the Alloy Ti50Ni48,7Mo0,3V1 under Loading in a Wide Temperature Range

2015 ◽  
Vol 1085 ◽  
pp. 299-302 ◽  
Author(s):  
Viktor Gyunter ◽  
Gulsharat Baigonakova ◽  
Еkaterina Marchenko ◽  
Аnatoly Klopotov
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Yield Point ◽  
Memory Effect ◽  
Wide Temperature Range ◽  
Temperature Dependency ◽  
Maximum Value ◽  
Stress Changes ◽  
Temperature Ranges

The results of the study on properties of shape memory effect alloys, obtained on the basis of the experimentally determined temperature dependency of the shear martensitic stress in the alloyTi50Ni48.7Mo0.3V1, are described. It has been established that the total strain of the sample and the yield point reach a maximum value (ε = 25.5 %, σВ= 1280 МPа) at a test temperature of 300 K. It has been methodically shown how using this experiment in NiTi-based alloys it is possible to estimate temperature ranges of shape memory effect occurrence and to determine parameters of mechanical properties.

Effects of Iron on Chemical Sulfide Oxidation in Wastewater from Sewer Networks

2007 ◽  
Vol 133 (6) ◽  
pp. 655-658 ◽  
Author(s):  
Asbjørn Haaning Nielsen ◽  
Thorkild Hvitved-Jacobsen ◽  
Jes Vollertsen
Keyword(s):  
Sulfide Oxidation ◽  
Sewer Networks

Biological sulfide removal under alkaline and aerobic conditions in a packed recycling reactor

2009 ◽  
Vol 59 (7) ◽  
pp. 1415-1421 ◽  
Author(s):  
A. González-Sánchez ◽  
S. Revah
Keyword(s):  
Oxidation Rate ◽  
Sulfide Oxidation ◽  
Specific Area ◽  
Alkaline Condition ◽  
Lower Growth ◽  
Oxidation Rates ◽  
Sulfide Removal ◽  
Nylon Fiber ◽  
Biofilm Development ◽  
Recycling Reactor

The biological sulfide removal from wastewater caustic streams can be achieved without significant dilution by alkaliphilic microorganisms which usually show lower growth and oxidation rates as compared with acidic and neutral bacteria. To improve volumetric removal rates under alkaline condition (pH 10), an Alkaliphilic Sulfide-oxidizing Bacteria Consortium (ASBC) was studied in a Packed Recycling Reactor (PRR). A commercial Nylon fiber resulted to be a convenient packing support for biofilm development as it has high specific area and similar hydrophobic propertie. The PRR reached a maximum sulfide oxidation rate of 100 mmol L−1 d−1 with efficiency close to 100%, representing an enhancement of 56% from the maximum sulfide oxidation rate reached for a free cell continuous culture. Higher sulfide loading rates induced oxygen limiting conditions reducing the biological activity despite the considerable biofilm attached on the nylon fiber.

THE EFFECTS OF pH ON THE OXIDATION RATE OF EPINEPHRINE

1987 ◽  
Vol 67 (3) ◽  
pp. A280-A280 ◽  
Author(s):  
S. M. Parnass ◽  
V. L. Baughman ◽  
D. J. Miletich ◽  
R. F. Albrecht
Keyword(s):  
Oxidation Rate ◽  
Effects Of Ph

Recent findings on sinks for sulfide in gravity sewer networks

2006 ◽  
Vol 54 (6-7) ◽  
pp. 127-134 ◽  
Author(s):  
A.H. Nielsen ◽  
T. Hvitved-Jacobsen ◽  
J. Vollertsen
Keyword(s):  
Large Diameter ◽  
Sulfide Oxidation ◽  
Sulfur Cycle ◽  
Metal Sulfides ◽  
Sulfide Concentration ◽  
Dissolved Sulfide ◽  
Gravity Sewer ◽  
Large Diameter Pipes ◽  
Steep Slopes ◽  
Sewer Networks

Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However, sulfide emission and thereby potential hydrogen sulfide buildup in the sewer atmosphere is of particular importance in sewers constructed with large diameter pipes, in sewers constructed with steep slopes and in sewers conveying low pH wastewater. Precipitation of metal sulfides is only important when the sulfide concentration in the wastewater is low; i.e. less than 1 g S m−3.

Decolourization of Simulated Dye Wastewater Containing Reactive Blue 19 (RB19) by the Electro-Fenton Reaction in the Presence of Metal Oxide-Coated Electrodes

2013 ◽  
Vol 858 ◽  
pp. 40-45
Author(s):  
Moe Thazin Shwe ◽  
Marites M. Dimaculangan ◽  
Mark Daniel G. De Luna
Keyword(s):  
Fenton Reaction ◽  
Advanced Oxidation Process ◽  
Textile Wastewater ◽  
Electrochemical Reactor ◽  
Chemical Oxidation ◽  
Reactive Blue 19 ◽  
Decolorization Efficiency ◽  
Effects Of Ph ◽  
Simulated Wastewater ◽  
Viable Treatment

Reactive Blue (RB 19), also known as Remazol brilliant blue, is a widely-used colorant in various textile applications. RB 19 is very resistant to chemical oxidation due to its aromatic anthraquinone structure highly stabilized by resonance. Its relatively low fixation efficiency (75-80%) attributed to the competition between the formation of the reactive form (vinyl sulfone) and the hydrolysis reaction, results in its prevalence in textile wastewater discharges. In this study, electro-Fenton (EF) process, a popular advanced oxidation process (AOP) was used to treat RB 19 dye-containing simulated wastewater. The electrochemical reactor (0.5 L) used in all experiments had parallel plate/mesh electrodes coated with metal oxides. Synthetic textile wastewater was prepared by dissolving RB 19 dye (300 ppm) in distilled water. The effects of pH, initial [Fe2+], initial [H2O2] and current on RB 19 decolorization efficiency were investigated. Removal of 100 percent RB 19 was achieved at pH 2, 0.71 mM initial [Fe2+], 5 mM initial [H2O2] and 1.86 A in 20 minutes. High decolorization efficiencies and absence of sludge during the treatment process render the electro-Fenton process a viable treatment option for dye wastewaters.

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