Adsorption oxidation method for treating high-concentration acrylonitrile wastewater

Abstract

The invention relates to an adsorption oxidation method for treating high-concentration acrylonitrile wastewater, which comprises the following steps of: adding aqueous solution of a flocculating agent into the acrylonitrile wastewater, stirring, and standing until flocs are settled at the bottom of a container for later use; making the wastewater pass through a microfiltration membrane or an ultrafiltration membrane to remove suspended particles, the flocs and acrylonitrile oligomer from the wastewater, regulating the pH value of the wastewater, adding activated carbon and a Fenton reagent, and stirring for adsorption oxidation; filtering the wastewater by using activated carbon filter cloth, adding the activated carbon and hydrogen peroxide into the wastewater, and stirring for secondary adsorption oxidation; and filtering the wastewater by using the activated carbon filter cloth, and neutralizing filtrate by using sodium hydroxide until the filtrate is neutral. The method improves treatment efficiency, is not limited by the chemical oxygen demand (COD) of the wastewater, avoids secondary pollution, is low in energy consumption, easy and convenient to operate and small in occupied area, and has the characteristics that the method is high-efficiency, economic and environment-friendly.

Description

technical field [0001] The invention relates to a method for treating acrylonitrile wastewater, in particular to an adsorption oxidation method for treating high-concentration acrylonitrile wastewater. Background technique [0002] Acrylonitrile (AN) is mainly used in the production of acrylic fiber, nitrile rubber, adiponitrile, acrylamide, ABS resin, etc. Other uses such as caprolactam, polyol polymer, acrylonitrile in synthetic fiber, synthetic rubber, plastics and other fields It also has broad application prospects. In the production process of acrylonitrile, every 1 ton of acrylonitrile produced is accompanied by about 1 ton of waste water, and the quenching, absorption, and recovery systems need a large amount of water as quenching water, absorption water and solvent water. There are 10 sets of acrylonitrile plants in my country, with an annual output of more than 1 million tons of acrylonitrile. Under such circumstances, the treatment of high-concentration, highly t...

AI Technical Summary

Problems solved by technology

At the end of the 20th century, foreign countries used electrolysis to treat this wastewater and had industrial applications, but due to its high cost, the application was very limited.

At present, the main methods of my country's treatment of this wastewater are: (1) incineration. Many high-concentration acrylonitrile wastewaters in my country are treated with this method. The advantage is that the treatment is thorough, but the energy consumption of wastewater treatment is high. It is around 230-250 yuan, and in the actual operation process, due to the harmful gas generated by combustion, it will cause secondary pollution and air pollution, and its own equipment is also prone to scaling

(2) Evaporation and rectification method, the principle is to use the different boiling points of the substances in the waste water, acrylonitrile is 77.3°C, acetonitrile is 81.6°C, water is 100°C, and the heavy component is higher than 120°C. Heating and controlling the temperature in the still , to obtain components with different boiling points from different parts of the top of the fractionation tower to achieve the purpose of separation, but its disadvantages are high energy consumption, incomplete treatment, and high treatment cost

(3) Fenton (Fenton) reagent method, hydrogen peroxide and catalyst Fe 2+ The oxidation system formed is called Fenton's reagent, in Fe 2+ Under the action of catalysis, hydrogen peroxide can generate active hydroxyl radicals, thereby triggering free radical chain reactions, accelerating the oxidation of organic matter and reducing substances, thereby effectively reducing COD in acrylonitrile wastewater, and the removal rate can reach about 80%. As acrylonitrile Wastewater pretreatment is a relatively effective method, but hydrogen peroxide is easy to decompose ineffectively during the operation of this treatment method, resulting in a decrease in treatment efficiency and an increase in treatment cost, and it is difficult to achieve efficient treatment of acrylonitrile wastewater by Fenton reagent