Decomposition of 2,4,6-trinitrotoluene and other industrial pollutants using pigment derivatives and visible light

Transcription

1 Decomposition of 2,4,6-trinitrotoluene and other industrial pollutants using pigment derivatives and visible light DOI: /RG Benjamin Lukas

2 TNT: Introduction TNT or trinitrotoluene is a yellow colored solid chemical which is made of carbon, hydrogen, oxygen and nitrogen atoms with a formula of C7H5N3O6. It is a highly explosive chemical but with a convenience handling properties with a melting point of C and a boiling point of 240 C with a molecular mass of 227g/mol. The explosive yield of TNT is considered as the standard explosive strength for bombs and other explosives (TNT) C7H5N3O6 (TNT) C7H5N3O6 7CO + 3N2 + 5H2O + 7C 3N2 + 5H2 + 12CO + 2C

3 TNT: Molecular Structure

4 TNT: Production TNT is produced in industry by nitration process of toluene in three steps : - In the first step, toluene is nitrated with a H2SO4 and HNO3 mixture to produce mononitrotoluene ( MNT) - MNT is separated and renitrated in second step to produce dinitrotoluene (DNT) - In the third step, DNT is reacted with anhydrous mixture of fuming nitric acid and oleum to produce crude trinitrotoluene (Crude TNT) Crude TNT is then purified by washing with Na2SO3 in order to remove less stable isomers of TNT and unwanted products from TNT. Pure TNT obtained from sulfitation process is then washed with water, the rinse water is called the red water, a pollutant, which needs to be treated.

5 TNT: Production

6 TNT: Properties There are 2 main properties: 1. TNT is Explosive 2. TNT is toxic which causes: - Skin irritation with the skin turn bright yellow orange colors hence called cannary skin. - Anemia - Abnormality liver functions - Reduced male fertility - Probable carcinogen

7 TNT: Problems-Red Water For every pound of TNT produced, 1.5 gallons of toxic/hazardous waste red water is generated Many countries have not made TNT because of the difficulty and expensive in treating red water. An easy and inexpensive way to treat red water is needed to allow for TNT production.

8 TNT: Problems-Pink Water Some countries have tons of unexploded outdated TNT in storage Demilitarization of these energetic explosives produces millions of gallons of waste water called pink water which must be treated before the water can be released to environment of water treatment facilities. Current demilitarization explosives neutralization procedures are expensive in both their hardware and operating costs.

9 Photocatalyst: Solution to the Problems Treat red and pink water waste streams with pigment derivative which act as photocatalyst to destroy the hazardous compounds with the help of visible light and air. Photocatalyst is a substance which can accelerate the rate of chemical reaction without being involved itself by using light irradiation. A wellknown photocatalyst is chlorophyll which is found in green plants creating chemical reactions when exposed to light As photocatalyst is reuseable the cost of this chemical is very cheap.

10 Photocatalyst Apparatus Photocatalyst molecules used here are pigment derivatives which are fixed or immobilized on the surface of transparent glass panel. The panel can be mounted on a platform so that it can be oriented to the sun for maximum absorption The waste water to be treated is drawn onto panel by means of a pump.

11 Photocatalyst Apparatus Light is absorbed by the material. In our case, blue and red light are absorbed by the catalyst promoting the catalyst from its ground state to excited state. The activated catalyst then reacts with the O2 to produce reactive oxygen species which then reacts with undesired compounds (pollutants) breaking them down into harmless components.

12 Pollutants that can be broken down to gases TRI NITRO TOLUENE (TNT) DI NITRO TOLUENE (DNT) MONO NITRO TOLUENE (MNT) BENZENE TOLUENE DINITROBENZENE NITROBENZENE PHENOL AND ITS DERIVATIVES such as Hydroquinone etc

13 Light Source Other commercial catalyst can only be activated using only Blue light but for our catalysts Blue and Red lights can be used at the same time. The best light source is sunlight but other visible light source such as any headlamp can also be used. The intensity of blue and red lights of sunlight vary with time.

14 Thank you.. For consultation of this project and others previously reported please contact : benjaminlukas@yahoo.com