Method for treating highly saline atrazine production waste water

Abstract

A method for treating highly saline atrazine production waste water is mainly applied to treating wastewater generated in an atrazine production process and mainly comprises the steps of reaction, precipitation, filtering, nanofiltration, active carbon absorption and the like, wherein one or more of compounds A, B and C are added to the waste water to remove most organic matters in the waste water through reaction and precipitation at first; secondly, TOC (total organic carbon) in the waste water is reduced to about 500 mg / L through nanofiltration; and then the TOC in the waste water is absorbed through active carbon absorption so as to be reduced below 10 mg / L; therefore, COD (chemical oxygen demand) is 30-40 mg / L; as a result, the waste water can be emitted as reaching the standard or used as chemical saline for the chlor-alkali industry. The active carbon saturated in absorption can be recycled by using acids, bases or organic solvents; and the recycled active carbon can be reused.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and relates to a treatment process for atrazine wastewater, in particular to a treatment method for high-salt wastewater produced in the production process of atrazine. Background technique [0002] Atrazine, also known as atrazine, atrazine, is a herbicide used in sweet sorghum, sugarcane, sorghum, and corn cultivation. The production process of atrazine is to react cyanuric chloride with isopropylamine and ethylamine. After the reaction is completed, steam distillation is used to obtain the product atrazine. Every ton of atrazine produces about 2.5 tons of wastewater. The wastewater contains unreacted raw materials, intermediate products, atrazine and its hydrolyzate, NaCl and NaOH, etc., and the COD reaches about 6000mg / L. If the wastewater is discharged directly, It will cause great harm to the environment and must be disposed of. [0003] Atrazine production wastewater contains 10-15% NaCl, w...

AI Technical Summary

Problems solved by technology

[0004] Zhao Chun et al. (CN101734821B) proposed neutralization, aluminum trichloride and polyacrylamide coagulation, sand filtration, decompression evaporation, activated carbon adsorption process, but the amount of waste residue produced by this process is a lot, including waste residue of coagulation and salt precipitation The sodium chloride is hazardous waste, and the treatment cost is still very high; Zheng Zheng et al. (CN100465100C) proposed to use high-frequency voltage to treat atrazine wastewater. Wastewater, this method consumes a lot of energy and is not suitable for industrialized production; Cheng Di et al. (CN102107999B) proposed the technology of air blowing off ethylamine and isopropylamine, acid precipitation and recovery of atrazine, but the actual atrazine production wastewater not only contains atrazine Degassin mainly contains by-products of atrazine production and hydrolysis products. The content of atrazine is not high, so the COD of water treated by this process is 2000-3000mg / L, which still does not meet the emission standard; activated carbon powder and activated carbon It has been proved by many documents that fibers can absorb trace amounts of atrazine in water, such as Tang Dengyong et al.

[0005] (CN101698665B) proposes the technology of dilute alkali neutralization, active carbon fiber adsorption, methanol regeneration, and the example that gives is the experimental result of the aqueous solution containing atrazine and sodium chloride prepared in proportion, which is very different from actual production, and atrazine The solubility of atrazine in water is only 33mg / L, while the COD of the actual production wastewater is 6000mg / L, and the TOC is about 2000-3000mg / L. Obviously, the main part of organic carbon (TOC) is not atrazine, so the practical value of this process is not great. ; Shen Rongming (Master Thesis of Zhejiang University, 2007) studied ozone oxidation and Mn 2+ 、Cu 2+ , Fe 2+ The degradation process of the simulated wastewater in the catalytic ozonation laboratory and the actual production wastewater showed that the oxidative degradation effect on the simulated wastewater in the laboratory was obvious, but it was basically ineffective on the actual production wastewater. The literature did not give the reason; Wei Hong et al. (China Environmental Science, 2005, 25 (1): 92-95) studied the process of foam nickel / iron powder dechlorination and degradation of atrazine, which is only applicable to waste water containing trace amounts of atrazine; Cao Lianqiu et al. (Journal of Harbin University of Commerce (Nature Science Edition) 2008, 24 (6): 667-671) reported the research on the degradation of trace atrazine in water by activated carbon-supported titanium dioxide catalyst; Application in pollution remediation and atrazine production wastewater treatment, but the experiment is limited to water samples prepared in the laboratory, only the content of atrazine in the water is analyzed, other organic matter is not considered, and there is no report on industrial application

[0006] Foreign research mostly focuses on the removal and degradation of trace amounts of atrazine in water, such as Kearney; Philip C. et al. (USP5,011,599) disclosed a process for treating atrazine-containing wastewater by first ozone oxidation and then microbial degradation; Sadowsky et al. (USP6,369,299) disclosed a transgenic plant capable of degrading triazine rings; Hrsak et al. (USP7,658,850) disclosed a hybrid bacterium capable of degrading atrazine and other triazine ring compounds; Achintya N.Bezbaruah (Journal of Environmental Science and Health Part B, 2009, 44:518-524) and others have studied the process of nano-iron catalytic degradation of low-concentration atrazine; Selma Mededovic et al. -2709) studied the process of electric pulse degradation of atrazine; Jasbir Singh et al. (Weed Science, 1998, 46: 381-388) studied the enhancement of iron ions on the degradation of atrazine in aqueous bodies and soils, Charles M.Sharpless et al. (Aquatic Sciences, 2003, 65: 359-366) studied the law of atrazine degradation by ultraviolet light, and so on. These studies used various technologies to degrade trace amounts of atrazine in water, but the COD in water did not decrease. Treatment After the water still can not be discharged directly

Rajendra Kumar Sharma et al. (Bull Environ Contam Toxicol, 2008, 80:461-464) studied the adsorption of low concentrations of atrazine (COD) by charcoal, fly ash, coconut charcoal, sawdust, coconut fiber and bagasse charcoal. If the technology is directly used for high-concentration wastewater, the treatment cost will be high due to the large amount of adsorbent used

[0007] From the published papers or patents, atrazine wastewater treatment methods mainly include activated carbon adsorption, electrochemical oxidation, ozone oxidation, catalytic oxidation, biodegradation, etc., but these technologies are not suitable for industrial production due to various reasons, so the existing The production equipment adopts the method of multi-effect evaporation for preliminary treatment, which is very costly, and the generated waste residue still needs to be treated as hazardous waste, and the treatment cost is very high

Images