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Original title: Treatment of high concentration phenol-containing wastewater Abstract: According to the current production level of polycarbonate in China, 6-8 tons of high-salt organic phenol-containing wastewater will be produced when 1 ton of product is produced. The wastewater has high pH value, complex components, high salt content, excessive phenol content and high cod value, which can not meet the national sewage discharge standards. In order to improve the overall environmental and economic benefits, this paper focuses on the treatment of high concentration phenolic wastewater. Phenolic pollutants are a kind of organic pollutants with strong toxicity, which can not only directly endanger human health, but also cause great damage to the ecological environment. When acting on the human body, phenolic compounds will react with proteins in the cytoplasm to form insoluble proteins, which will affect cell vitality, cause spinal cord stimulation and lead to systemic poisoning. When phenolic pollutants are directly discharged into the soil or water environment without treatment, the soil can adsorb some pollutants and form soluble substances, which remain in the soil and water environment for a long time. Phenolic pollutants can cause changes in the structure, composition and pH of soil or water, cause eutrophication of water,cbd crystallization equipment, inhibit the life activities of animals, plants and microorganisms in water and soil, and make plants and animals fall into ecological crisis and lead to ecological disaster. Therefore, the development of effective phenolic wastewater treatment technology is particularly important. Chemical method and physicochemical method are the main treatment methods of high concentration phenol wastewater. With the development of environmental science, the technology of treating high concentration phenol-containing wastewater (phenol > 1 000 mg/L) is becoming more and more mature. At present, the main treatment technologies are chemical method and physicochemical method. When the phenol-containing wastewater is chemically treated,wiped film distillation, the usual method is the polycondensation method. The condensation polymerization method is that under certain pressure and temperature conditions, formaldehyde and phenol react through a catalyst to form a phenolic resin. After solid-liquid separation of the product, the secondary wastewater whose phenol content has dropped to a certain concentration can be treated by fixed bed and dynamic countercurrent activated carbon adsorption, so that the phenol content in the wastewater can meet the discharge standard (the phenol content in industrial wastewater in China should not be higher than 5mg/L). When physical and chemical methods are used to treat phenol-containing wastewater, the commonly used methods include extraction, adsorption, liquid membrane and steam dephenolization. Extractants commonly used in the extraction method include butanol, benzene, etc. In order to effectively extract phenolic compounds, the most widely used extractants are tributyl phosphate (TBP), trioctylphosphine oxide (TOPO) and N, decarboxylation after extraction ,rotovap distillation, N-di (1-methylheptyl) acetamide (N-503), etc. Among them, N-503 is a commonly used extractant with high efficiency of dephenolization, the extraction distribution coefficient is large, and the extraction rate is more than 95%. However, the content of phenol in the wastewater after extraction is still higher than the discharge standard, and the extractant in the wastewater will also cause secondary pollution to the environment. Therefore, the N-503 extraction method is only used for the first stage recovery treatment of high concentration phenol-containing wastewater. In order to meet the discharge standard of phenols in wastewater, secondary biochemical treatment is still needed. Based on the method of wastewater treatment by extraction, a synergistic complexation extraction method was proposed by related scholars, and four new HC extractants were developed. The extraction effect of HC-3 and HC-4 extractants is remarkable, and the content of phenol in wastewater can be reduced to less than 10 mg/L. The solid adsorbents commonly used in the adsorption method are sulfonated coal, activated carbon, etc., and the resin adsorbents are mainly macroporous resins. The results show that the porous polymeric adsorbent has good adsorption effect on phenol and high phenol removal efficiency, and the macroporous resin adsorption is a common and efficient method for the treatment of phenol-containing wastewater. At present, GDX series, H series and NKA series resins have been developed in China, and their performances are close to or exceed those of foreign products. DA-201, H-103 and NKA-2 resins are widely used as adsorbents. H-103 macroporous resin was prepared by two-step crosslinking method, with large specific surface area and average pore diameter of 90. The adsorbent has strong adsorption capacity and good treatment effect on phenol-containing wastewater. When DA-201 macroporous resin is used to treat the pretreated wastewater with phenol content as high as 8000 mg/L ~ 40000 mg/L, the phenol content can be reduced to less than 0.5 mg/L, which meets the national discharge standard.
Expand the full text In addition, polyvinyl alcohol fiber (PVAF), activated carbon fiber (ACF) and the like can also be used as adsorbents for the treatment of high-concentration phenol-containing wastewater. It has a unique microporous structure, with a variety of functional groups and a huge specific surface area, which promotes the adsorption and exchange capacity of this kind of large, fast regeneration. The adsorption capacity of phenol on PVAF can be as high as 95%, and the removal rate of phenol by secondary adsorption can reach 99.99%. Liquid membrane method originated earlier, and there are many studies on its separation technology at home and abroad. After the treatment, the amount of phenol in the water can be reduced to less than 0.5 mg/L, and no secondary pollution occurs. At present, this method is mainly used to treat bisphenol A and coking wastewater. The essence of the steam dephenolization method is that phenol and steam form an azeotropic mixture, the phenol in the water is transferred into the steam to purify the wastewater, and then the phenol-containing steam is washed with alkali liquor to recover phenol, with a dephenolization rate of about 80%. Table 1 Comparison of advantages and disadvantages of treatment technologies for high concentration phenol-containing wastewater (Source: CNKI) Conclusion There are many kinds of treatment technologies for high concentration phenol-containing wastewater,wiped film evaporator, and they are becoming more and more mature. It is often difficult to achieve expectations with only one method, so several technologies should be used in combination to achieve both economical and efficient results. Copyright notice: This article is an original article, and it is forbidden to reprint. Please go to the public name of Jinzhi Innovation for reprinting authorization. Return to Sohu to see more Responsible Editor:. toptiontech.com

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