Activated carbon for textile printing and dyeing wastewater treatment
Discover how activated carbon is revolutionizing the textile printing and dyeing industries. This innovative solution is not only helping minimize environmental impact but also optimizing production processes. Learn more about this powerful tool in our latest article.
Waste gas treatment in the textile industry
I. Main pollutants and characteristics of textile enterprises:
1. Wastewater Mainly includes cotton yarn production wastewater and printing and dyeing processing wastewater;
2. Waste gas Organic solvents mainly include toluene (C8H8), xylene (C7H8), gasoline, etc.;
3. Dust Mainly dust generated when cotton is dropped in cotton mills;
4. Solid waste Mainly waste and waste materials generated during the production or use of various fiber products.
5. Noise Mainly comes from the mechanical operation sound of weaving workshops and printing workshops and the rumble of production equipment, etc.
II. Types of harmful gases produced in textile processing and their sources:
1. Organic solvents:
(1) Formaldehyde Formaldehyde is a colorless, volatile, irritating gas. It has a significant irritating effect on human eyes and upper respiratory tract mucosa. Long-term exposure to low concentrations of formaldehyde can cause chronic respiratory diseases and nasopharyngeal cancer. In clothing production, water-soluble phenol is often added as a mildew preventer to dyeing auxiliaries and finishing agents. Therefore, the residual amount on clothing fabrics will increase with time and its toxicity will increase.
(2) Dichloromethane Dichloromethane is highly corrosive and asphyxiating. It can be absorbed through the skin and cause poisoning.
(3) Chloroform Trichloroethane is a highly toxic substance.
(4) Methanol Methanol is very harmful to the human nervous system.
(5) Carbon tetrachloride Carbon tetrachloride is a carcinogen.
(6) Sulfur hexafluoride Sulfur hexafluoride is a strong mutagen.
(7) Polycyclic aromatic hydrocarbons Polycyclic aromatic hydrocarbons are a class of condensed aromatic compounds containing more than 6 heteroatoms.
2. Inorganic chemical raw materials:
(1) Sulfuric acid Sulfuric acid has a strong pungent odor and is toxic.
(2) Caustic soda Caustic soda generates a large amount of heat when it comes into contact with organic matter.
(3) Soda ash Soda ash has strong hygroscopicity.
(4) Sodium sulfide It can form explosive mixtures in the air.
(5) Sodium carbonate It is a salt with strong alkaline reaction ability.
Activated carbon is widely used in sewage treatment, mainly including the following aspects:
1. Removal of pollutants: Activated carbon can adsorb pollutants such as organic matter, heavy metals, pesticides, etc. in wastewater to reduce the COD value in water. It is especially widely used in oil refineries, mercury-containing wastewater, chromium-containing wastewater, methanol-containing wastewater and other fields.
2. Reduction of chroma and odor: The physical adsorption and chemical adsorption characteristics of activated carbon can remove chroma and odor in water and improve the taste and smell of water. For example, when treating wastewater with complex components and high chroma such as printing and dyeing wastewater, the decolorization ability of activated carbon is very significant.
3. Improve treatment efficiency: Activated carbon can be used in combination with other treatment processes, such as potassium permanganate-activated carbon combined process, biological activated carbon method, powdered activated carbon-activated sludge process, etc., to improve the efficiency and effect of sewage treatment.
4. Reduce treatment costs: Activated carbon has good treatment effect, stable effluent quality, and can save a considerable amount of expenses.
5. Regeneration: Activated carbon has a long service life, is easy to regenerate, and has a high cost-effectiveness. Therefore, it is widely used in chemical, electronic, pharmaceutical, printing and dyeing, food and other fields.
Granular activated carbon: widely used in wastewater treatment, water treatment, air purification and other fields, can remove organic matter, color, odor and other pollutants.
Powder activated carbon: mainly used for decolorization of wastewater, especially suitable for textile, papermaking, food processing, printing and dyeing and other industries.
Palm shell activated carbon: due to its high lipophilicity and adsorption capacity, it is widely used in petrochemical industry and some organic wastewater treatment.
Lignite activated carbon: can be used in gas purification and phenol-containing wastewater treatment and other fields, with good adsorption performance.
Powder activated carbon: Commonly used in wastewater treatment, powdered activated carbon is suspended in wastewater for adsorption reaction. This method is suitable for treating wastewater with high COD value, because the micropores of powdered activated carbon can quickly adsorb organic pollutants and fully contact with wastewater.
Granular activated carbon: Mainly used in the deep treatment stage, purifying wastewater through dual effects of filtration and adsorption. Granular activated carbon is suitable for treating wastewater after preliminary treatment to further remove residual organic pollutants and heavy metals.
Treatment methods for colored wastewater:
Adsorption method: Use adsorbents such as activated carbon and diatomaceous earth to adsorb pigment molecules in wastewater and separate them from water. This method is easy to operate and has good results, but the adsorbent needs to be replaced regularly.
Chemical oxidation method: By adding oxidants, such as hydrogen peroxide and potassium permanganate, the colored substances in the wastewater undergo oxidation reactions and are converted into colorless or low-chromatic substances. This method has a stable treatment effect, but may produce new pollutants.
Biological treatment method: Use the metabolism of microorganisms to degrade colored substances in wastewater into colorless or low-chromatic substances. Biological treatment has the advantages of environmental protection and energy saving, but the treatment time is long and has certain requirements for water quality and temperature.
Membrane separation method: Use membrane technology, such as ultrafiltration and reverse osmosis, to intercept colored substances in wastewater on one side of the membrane, thereby achieving decolorization of wastewater. This method has good treatment effects, but the cost is high.