Waste water treatment method in preparation of para-aminophenol by electrolytic process

A p-aminophenol and treatment method technology, applied in the field of wastewater treatment, can solve problems such as environmental pollution, PAP loss, rationality of the treatment process, and insufficient economy

Inactive Publication Date: 2003-10-22
EAST CHINA UNIV OF SCI & TECH
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Problems solved by technology

About 13 tons of waste water is produced for every ton of PAP produced. If it is directly discharged, it will not only pollute the environment, but also cause (NH 4 ) 2 SO 4 and loss of PAP
[0003] At present, regarding the treatment method of this type of wa

Method used

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  • Waste water treatment method in preparation of para-aminophenol by electrolytic process

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] 1. Take 65L of waste water, light yellow, PH=7.0, specific gravity 1.12, this batch of waste water is made of 6.25kg of nitrobenzene, 6.8kg of sulfuric acid and appropriate amount of water to participate in the electrolysis reaction, after treatment, purification and separation of PAP.

[0016] 2. After adsorbing PAP through the adsorption column of fruit shell activated carbon (1kg, 3 grades, 1m per grade), the solution is colorless and transparent, with a specific gravity of 1.12 and a pH of 7.0. Liquid PAP outlet concentration is less than 10 -4 g / L, the PAP adsorption rate is greater than 99%.

[0017] 3. Send the above liquid into the double-effect evaporator for evaporation treatment. 53L of steam condensate obtained during evaporation and concentration (collected by a condenser with a distillation device), analyzed by high-pressure liquid chromatography, the content of aniline < 1-2ppm, and the content of nitrobenzene < 1ppm. Sulfuric acid aqueous solution, par...

Embodiment 2

[0023] Repeat the first item of Example 1, 1 kg of fruit shell activated carbon is equally divided into 5 parts, and cross-flow adsorption is performed in a stirred tank. After 5 stages of cross-flow adsorption, the PAP concentration is 0.24g / l. In this case, the adsorption solution is as described in Example 1. Middle 3-5 step method processes, reclaims gained (NH 4 ) 2 SO 4 The quality does not meet the requirements of industrial purity, its organic content> 0.1%, (NH 4 ) 2 SO 4 The color of the skin is white at first, and becomes slightly brownish red after 1 day, and becomes darker and darker after a few days.

Embodiment 3

[0025] Repeat the 1st to the 5th item of embodiment one, but the 6th step gac regeneration, adopt 18%H 2 SO 4 The aqueous solution flows through the activated carbon adsorption column continuously and slowly for desorption, adopts the leaching method for desorption and the leaching time is less than 5 hours, and other conditions are not within the scope of the operating conditions of step 6 in Example 1. Facts have proved that the regeneration rate of activated carbon at this time is <70%, and it cannot be recycled.

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Abstract

The present invention discloses a method for treating waste water produced by p-aminophenol process by electrolysis method. Said method adopts the fruit shell active carbon to make adsorption to remove P-aminophenol, then makes the waste water be evaporated and concentrated to recover industrial-grade ammonium sulfate, the recovery rate of the ammonium sulfate is greater than 98%. The evaporation-obtained water can be used for preparing sulfuric acid aqueous solution whose concentration is 18%, and can be used as electrolyte and fed into electrolytic bath to implement closed circulation of water. The fruit shell active carbon in which the p-aminophenol is adsorbed can be regenerated by using 18 wt% sulfuric acid aqueous solution as desorption agent, and the desorption liquid can be returned into electrolytic bath to participate in electrolysis reaction.

Description

technical field [0001] The invention relates to a method for treating waste water, in particular to a method for treating waste water produced in the process of preparing p-aminophenol by electrolysis. Background technique [0002] The wastewater produced in the process of preparing p-aminophenol by electrolysis mainly contains (NH 4 ) 2 SO 4 , about 13-18 (wt)%; p-aminophenol (PAP), about 1.3g / l; its pH=6.9-7.1, and its specific gravity is 1.12. About 13 tons of waste water is produced for every ton of PAP produced. If it is directly discharged, it will not only pollute the environment, but also cause (NH 4 ) 2 SO 4 and PAP loss. [0003] At present, regarding the treatment method of this type of waste water, only see the method reported in the patent document CN1168865A, although this treatment method has considered to (NH 4 ) 2 SO 4 And PAP recovery treatment, but its whole treatment process is still insufficient in terms of rationality and economy. Therefore, h...

Claims

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Application Information

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IPC IPC(8): C02F1/04C02F1/28
Inventor 张秋香赵培陈敏恒
Owner EAST CHINA UNIV OF SCI & TECH
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