KR950013320B1 - Waste water treatment method - Google Patents

Abstract

The method for treating a waste water generated in the manufacture of a para-nitroaniline from the raw material of para-nitro chlorobenzene and ammonia is characterized by adding 65ml of 98% sulfuric acid to 600ml of a waste liquor having pH 9.8 and 6250ppm COD to obtain the waste liquor having pH 5, adding 120ml of a toluene to the waste liquor, shaking the mixture to extract an organic material of the waste water and to separate the toluene and the solution in the separating funnel, and fractionally distilling the impurity-contg. toluene to recover the toluene.

Description

Organic Compound Synthesis Process Using Toluene

1 is a process chart for preparing paranitroaniline.

2 is a schematic representation of a wastewater treatment process.

The present invention relates to a method for treating wastewater in an organic compound synthesis process using toluene.

For example, the present invention relates to a method for treating wastewater generated in a paranitroaniline manufacturing process using toluene.

Paranitroaniline is a substance widely used as an intermediate of azo dyes or azoic dyes. As a commercial method for preparing paranitroaniline, paranitro acetanilide obtained by nitriding acetanilide and paranitrochlorobenzene are reacted at high temperature with ammonia. The present invention relates to a method for treating wastewater generated when paranitrochlorochloro (hereinafter referred to as PNCB) is reacted with ammonia to produce paranitroaniline (hereinafter referred to as PNA). PNA is prepared according to the process diagram shown in FIG. 1 via the following chemical scheme.

At this time, the waste liquid having recovered PNA in the form of powder (solid) generates wastewater having approximately the following composition due to unreacted PNCB, ammonia water and by-product ammonium chloride.

When producing PNA 700kg

。 Emission: about 12.5㎥

。 PH: 9 ~ 11

。 COD: 3,000 ~ 4,000PPM

。 BOD: 85PPM

SS: 85 ~ 76PPM

NH _X : 12 ~ 10PPM

In order to adjust this to the current wastewater discharge limit of pH: 6.8 to 8.0 and below the COD 360PPM, the treatment of drastically lowering the pH and COD values has to be performed. The present invention relates to a method of treating wastewater that satisfies environmental standards.

Such wastewater purification using toluene can be applied to the purification of wastewater generated in similar organic compound synthesis processes.

Wastewater treatment method of the present invention is a pH, COD, BOD, suspended matter (Suspended Solid: SS) and the like by adjusting the pH, solvent extraction, chemical treatment such as oxidation and physical treatment such as adsorption. The wastewater treatment method using toluene is minimized, and the treatment process is described in a table as shown in Table 1.

TABLE 1

The solvent extraction process using toluene in the above-described process will be described with reference to Examples.

TABLE 2

Toluene Extraction Process

When 600 ml of 98% sulfuric acid is added to 600 ml of dark brown wastewater with a pH of 9.8 and a COD of 6250PPM, the pH of the waste liquid is maintained at about 5. 120 ml of toluene is added thereto and shaken. The organic matter in the wastewater is extracted to the toluene, and the toluene and the aqueous solution are separated using a separating funnel. Fractional distillation of the toluene containing the separated impurities allows the toluene to be recovered and reused. When the solvent extraction method is performed three times, almost all organic substances are extracted and removed.

The COD removal test results by toluene extraction are shown in Table 3 and Table 4.

TABLE 3

In an abnormal test

① Sample Toluene is 5: 3

② If the extraction is carried out up to the third extraction, it is possible to treat wastewater of less than 350 ppm COD.

(3) Subsequent treatment with activated carbon results in less than 50 ppm of treated wastewater.

TABLE 4

By treating the wastewater treated with activated carbon as described above, residual impurities in the waste liquid can be adsorbed and removed, and thus, purified wastewater that is harmless to the environment when discharged at COD 200 ± 50 and pH 6.8 to 7.0 can be obtained.

Claims (1)

In the method for treating wastewater generated in the production of paranitroaniline using paranitrochlorochlorobenzene and ammonia as raw materials, the process for producing paranitroaniline using toluene which combines toluene extraction process, oxidation process and activated carbon treatment process after pH adjustment Treatment method.