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Electrochemical decomposition of formaldehyde

Number of pages: 79 File Format: word File Code: 31749
Year: Not Specified University Degree: Master's degree Category: Biology - Environment
Tags/Keywords: Electrochemical analysis - Electrochemical oxidation - Environment - Formaldehyde - Formaldehyde resins - formalin - Isolation of formaldehyde - Purification of formaldehyde - Taguchi method
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  • Summary of Electrochemical decomposition of formaldehyde

    Master thesis in chemical engineering

    Abstract

    Electrochemical analysis of formaldehyde

    Formaldehyde is one of the substances It is an organic chemical that is widely used as a raw material in many industries. Industrial effluents that contain high concentrations of formaldehyde must be treated before entering the environment due to its possible carcinogenic and mutagenic risks. The purpose of this study is the effect of effective factors in separating formaldehyde by electrochemical oxidation method. In this study, experiments were designed and conducted using the Taguchi method according to the 4 main influencing factors, and according to the results of the experiments, it was observed that time has the most effect and electrolyte has the least effect on formaldehyde separation. The effect of electrolyte on energy consumption was also investigated and it was observed that hydrochloric acid has the lowest energy consumption in the solution to separate formaldehyde. Also, the optimal mode for removing formaldehyde is obtained at pH = 3, amperage 0.4, sodium hydroxide (NaOH) electrolyte and in 2 hours, in which 30% of formaldehyde was removed. style="direction: rtl;">

    Introduction

    One ??of the consequences of the industrial world and the modernization of current life is environmental pollution, which shows its destructive effects in all aspects of human life, including water, soil and air. Industrial wastewater, which is a product of technological progress in the industry, imposes its harmful effects on the water and soil environment day by day. It is obvious that with the existence of various industries and the wide spread of environmental pollution, scientific and research steps to control pollution should be accompanied by proper planning and practical measures. In our country, wastewater enters the surface and underground water sources without any restrictions, and industrial wastewater also travels the same route. The need to know wastewaters and their pollution and their treatment methods is a problem that requires the great efforts of researchers and environmental health engineers of this country. Obviously, due to the variety of processes and variety of chemical substances that are sometimes dangerous and pollute the environment, each of them creates special problems for the environment, and therefore, each wastewater related to a specific industry requires a separate study and investigation and special research on the type of pollution and its control methods. The industries that produce formaldehyde or deal with this substance in some way are among the industries that play an important role in polluting water and creating environmental problems, and they have been obliged to solve their industrial wastewater problems under the pressure of the Environmental Protection Agency. What makes this fact card important is that without the separate removal of formaldehyde, the overall treatment of the wastewater of such industries will be disrupted, and if, due to economic issues, it is not possible to create a treatment plant for the entire wastewater, without pre-treatment of formaldehyde, the urban wastewater treatment plant will face problems.

     

     

    1-1-formaldehyde and its uses

     

    Common names and synonyms of formaldehyde: formaldehyde, methanol, methylene oxide, oxymethylene, methylaldehyde, oxomethane common names for formaldehyde solutions: formalin and formalin.

    1-1-1- Formaldehyde applications

    Formaldehyde is a building block of chemicals, an intermediary in various organic compounds from amino and phenolic resins to chemical fertilizers. The most consumption of formaldehyde is in the production of amino and phenolic resins. Which provides a good reason for 55% of the total demand capacity. Other important uses include wood industry products, molding compounds, casting resins, and adhesives for coating. Wood products account for about 36% of the total formaldehyde demand for plywood applications. Under some conditions, urea-formaldehyde resins release formaldehyde, which creates environmental and health problems. Both amino and phenolic resins are used as molding compounds. A large number of amino resins are melamine resins used in tableware. Phenolic molding resins are used in electrical control devices, telephones. Formaldehyde is used to produce a fixed finish for cellulosic fabrics. Finishing of fabrics based on formaldehyde includes melamine, urea, formaldehyde, glyoxal, triazim, triazones. Aldehydes are used in the manufacture and synthesis of alcohols, acids and other chemicals. They are also used in rubber industry, paper industry, tannery and agriculture. Among the general uses of formaldehyde, it is used to store anatomical parts in medical schools and medical institutions, it is a deodorizing agent and a bactericidal agent, as well as a protein hardening agent. In addition, the products obtained from formaldehyde are widely used in a wide range of industries such as automobile manufacturing and construction, papermaking and textile weaving. Formaldehyde is also present in the body's natural metabolism, but its amount is small[1-5]. Formaldehyde exists in the environment as a result of natural processes and man-made sources. Formaldehyde is produced industrially in large quantities and has many uses. Two other man-made sources are: automatic exit from engines without catalytic converters. Residues, emissions or wastes resulting from the manufacture of formaldehyde by substances derived from it or reacted with it. Formaldehyde has medicinal uses as a sterilizer in various industries. It is also used as a preservative in consumer goods, such as food, cosmetics and household cleaners. One of its main uses is in the production of urea-formaldehyde and melamine-formaldehyde resins. Urea-formaldehyde resin used for building insulation ([1]UFFI) can continue to emit formaldehyde after installation or form a permanent source of formaldehyde emission. Many indoor environmental sources that can expose humans to formaldehyde include cigarettes and tobacco products, furniture or upholstery containing formaldehyde-based resins, building materials containing urea-formaldehyde resins, formaldehyde-containing adhesives used for plastic surfaces and parquets, carpets, disinfectants (deodorizers), gas heaters, and open fireplaces. It can be, they are. Formaldehyde is formed naturally during the oxidation of hydrocarbons. These hydrocarbons react with OH and ozone radicals and form formaldehyde and other aldehydes as intermediates in a series of reactions that ultimately lead to the formation of carbon monoxide, carbon dioxide, hydrogen and water. Formaldehyde production factories and industries that somehow deal with formaldehyde are among the most important sources of formaldehyde and major environmental pollutants.

  • Contents & References of Electrochemical decomposition of formaldehyde

    List:

    Chapter One: Introduction

    1-1- Formaldehyde and its uses. 3

    1-1-1- Applications of formaldehyde. 3

    1-2- The sources of formaldehyde release in the environment. 4

    1-3- Formaldehyde production processes. 5

    1-4- Health effects of formaldehyde. 6

    1-5- Physical and chemical properties, analytical methods. 7

    1-5-1- physical and chemical properties of formaldehyde. 7

    1-5-2- Analytical methods. 8

    1-6- Formaldehyde purification methods. 9

    1-6-1- Chemical method. 9

    1-6-1-1- reaction with lime water. 9

    1-6-1-2- reaction with ammonia. 9

    1-6-1-3- reaction with potassium. 10

    1-6-1-4- reaction with hydrogen peroxide H2O2. 10

    1-6-1-5- reaction with sodium cyanide NaCN. 10

    1-6-1-6- surface adsorption reaction on the surface of active carbon. 10

    1-6-2- biological method. 11

    1-6-2-1- Principles and laws of biological oxidation. 11

    1-6-2-2-types of biological treatment. 11

    1-6-2-2-1- aerobic purification. 12

    1-6-2-2-2- Anaerobic treatment. 12

     

    Title                                                                                                                                                                                                                  . 14

     

    Chapter Three: Designing experiments by Taguchi method

    3-1- Introduction.. 23

    3-2- Definitions of basic concepts. 25

    3-2-1- Answer.. 25

    3-2-1-1- Bigger (more) type answers - better. 25

    3-2-1-2- Less-better answers. 25

    3-2-1-3- Closer-better answers. 25

    3-2-2- factor... 25

    3-2-2-1- quantitative and qualitative factors. 25

    3-2-2-2- Controlling and disturbing factors. 26

    3-2-3- level.. 26

    3-2-4- main effect. 26

    3-2-5- mutual effects. 26

    3-3- Types of test design methods. 27

    3-3-1- Single factor method. 27

    3-3-2- multi-factor method. 28

    3-3-3- factorial method. 28

    3-3-4- Answer procedure method. 29

    3-3-5- Taguchi method. 30

    3-4- Experiment design process. 31

    3-4-1- Planning phase and important concepts in it. 31

    3-4-1-1- Determining the number of interactions. 32

    3-4-1-2- Selecting the appropriate orthogonal array. 32

    3-4-1-3- degrees of freedom factor. 32

    3-4-1-4 degrees of freedom of mutual effects. 32

    3-4-1-5- degrees of freedom of the whole experiment. 32

    3-4-1-6- Properties of orthogonal arrays. 32

     

    Title                                                                                                                                                                                                                                                                                       Page 35

    3-4-1-7-1- Using triangular tables. 35

    3-4-1-7-2- Using linear graphs. 35

    3-4-2- Executive phase. 35

    3-4-3- Analysis phase. 35

    Chapter Four: Tools, Materials and Methods

    4-1- Tools.. 37

    4-2- Materials.. 37

    4-3- Methods.. 38

    Chapter Five: Results and Analysis

    5-1- Analysis phase. 44

    5-1-1- Experiment and preliminary analysis. 44

    5-1-1-1- Calculation of the main effect of factors. 44

    5-1-1-2- Estimation of the answer in optimal conditions. 45

    5-1-1-3- Checking the accuracy index. 46

    5-1-2- Analysis of variance (ANOVA). 46

    5-1-2-1- Definition of important concepts in variance analysis. 47

    5-1-2-2- standard analysis method. 49

    5-1-2-3- Analysis method. 49

    5-1-2-3-1- Application of ratio. 49

    5-1-3- Different types of loss function. 50

    5-1-3-1- The closer the type characteristic to the nominal value, the better. 50

    5-1-3-2- type characteristic, the smaller the better. 50

    5-1-3-3- The larger the type, the better. 50

    List of sources and sources. 60

     

     

    Source:

     

     

    1- Hosseini, Hassan (1375).Treatment of wastewater containing formaldehyde in chemical industries, master's thesis, Tehran: Sharif University of Technology.

    2.U.S. Centers for Disease Control Agency for Toxic Substances and Disease Registry (ATSDR). "Toxicological Profile for Formaldehyde." (1997). http://www.atsdr.cdc.gov/toxprofiles/tp111.html.

    3. World Health Organization. "IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Volume 88, (2006), Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxy-2-propanol." http://monographs.iarc.fr/ENG/Monographs/vol88/volume88.pdf.

    4. World Health Organization. "International Program on Chemical Safety, Environmental Health Criteria 89: Formaldehyde." (1999) http://www.inchem.org/documents/ehc/ehc/ehc89.htm.

    5. U.S. Environmental Protection Agency. "Formaldehyde: Hazard Summary." (2003). http://www.epa.gov/ttn/atw/hlthef/formalde.html.

    6Nhproctor, Jp Hughes. Chemical Hazards of the Workplace, Fifth Edition, (1978), P 273.

    7. Goodman, L. Gilman, A. (1975). , The Pharmacological Basis of Therapeutics, 5th Edition. New York, Macmillan Publishing Co, P-578.

    8. Hendrick, DJ. Rando, RJ. and Lane, DJ. (1982). "Formaldehyde asthma: Challenge exposure levels and fate after 5 years". Journal of Occupational and Environmental Medicine, vol.24, 893–7.

    9.Toxity&Hazard Indus Chsus Safety Mamual, (1982)

    10.Plunkett,Er. Barbela, T. (1977). American Industrial Hygiene Association Journal, vol. 38, 61-62.

    11. Health & Safety Executive Monograph Formaldehyde, (1981), P.8

    12- Salehi, Hossein (1379).

    13. Wang, H. Yu, X. Wu, L. Wang, Q. and Sun, D. (2005). "A Comparative Study on Electrochemical Oxidation of Phenolin Two Types of Cells". Russian Journal of Electrochemistry, Vol.41, 719-724.

    14. Habibi, B. Delnavaz, N. (2010) "Electrocatalytic oxidation of formic acid and formaldehyde on platinum nanoparticles decorated carbon-ceramic substrate". International Journal Of Hydrogen Energy, vol. 35, 8831-8840.

    15. Enyo, M. (1985). "Anodic Formaldehyde oxidation on Pt, Pd, Au and Pd-Au alloy electrodes in NaoH and Na2CO3 solutions". Journal of Applied Electrochemistry, vol.15907-911.

    16. Selvaraj, V. Nirmala Graceb, and Alagar, A. M. (2009). "Electrocatalytic oxidation of formic acid and formaldehyde on nanoparticle decorated single walled carbon nanotubes". Journal of Colloid and Interface Science, vol.333, 254–262.

    17. Yang, H. Lu, T. H. (1997). "Preparation of highly dispersed gold microparticles and their electrocatalytic activity for the oxidation of formaldehyde". Journal of Applied Electrochemistry, vol. 27, 428-433.

    18. Zhang, C. He, H. Tanaka, K. (2006). "Catalytic performance and mechanism of a Pt/TiO2 catalyst for the oxidation of formaldehyde at room temperature". Applied Catalysis B: Environmental, vol. 65, 37–43.

    19. Liu, H. Ye, X. Lian, Z. Wen, Y. and Shangguan, W. (2006). "Experimental study of photocatalytic oxidation of formaldehyde and its by-products". Research Chemical Intermed., Vol.26, 329-16.

    20- Tolli, Amir Sarafi, Amir Mohbi, Ali Ghahrani, Pasha (1387). Madras.

    21. Motheo, A. J. Ernesto, R. Olivi, P(2000). "The Oxidation of Formaldehyde on High Overvoltage DSA Type Electrodes". Journal of Brazilian Chemical Society, Vol. 11, 16-21.

    22. Fukunaga, M. Guimaraes, J. Bertazzoli, R. (2008). "Kinetics of the oxidation of formaldehyde in a flow electrochemical reactor with TiO2/RuO2 anode". Chemical Engineering Journal, vol. 136, 236–241.

    23. Wang, L. Sakurai, M. and Kameyama, H. (2009). "Study of catalytic decomposition of formaldehyde on Pt/TiO2 alumite catalyst at ambient temperature". Journal of Hazardous Materials, vol. 167,399–405.

Electrochemical decomposition of formaldehyde
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