Method for recovering p-aminobenzoic acid in p-aminobenzoic acid process wastewater

A technology for the recovery and treatment of p-aminobenzoic acid, which is applied in natural water treatment, extraction water/sewage treatment, water/sludge/sewage treatment, etc. It can solve problems such as difficult recycling, poor biodegradability, and high toxicity, and achieve good results. Extraction effect, effect of good industrialization prospect

Pending Publication Date: 2019-06-07
江苏尚莱特医药化工材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] P-aminobenzoic acid is an important organic chemical intermediate and is widely used, and its output is increasing year by year. At the same time, the amount of sewage discharge in the production process is also increasing year by year. It has high toxicity and poor biodegradability, which has become the focus and difficulty of water pollution control. , the general coagulation, biochemical or chemical oxidation treatment methods are difficult to recover from the water body, and this type of wastewater needs to be pretreated to achieve further biochemical or photochemical treatment to meet the discharge requirements

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0019] The recovery treatment method of the p-aminobenzoic acid in the p-aminobenzoic acid process wastewater of the present embodiment has the following steps:

[0020] ① Add 50mL of extractant to 100mL of p-aminobenzoic acid process wastewater [tested, COD value is 10000mg / L, p-aminobenzoic acid concentration is 4600mg / L] [volume percentage is 40% tributyl phosphate + 10 Composed of % n-octanol + 50% kerosene], stir at room temperature (15-25°C, the same below) for 15 minutes, and let stand to separate layers (about 30 minutes).

[0021] The lower layer is the raffinate, that is, the raffinate water phase or the treated wastewater. After testing:

[0022] The COD value of the raffinate aqueous phase is 1100mg / L, and the COD removal rate is 89.0%.

[0023] The concentration of p-aminobenzoic acid in the raffinate aqueous phase was 279mg / L, and the extraction rate was 93.9%.

[0024] The upper layer is the extract, that is, the p-aminobenzoic acid layer loaded with the extra...

Embodiment 2～ Embodiment 5）

[0030] The method of each embodiment is basically the same as that of Example 1, and the differences are shown in Table 1.

[0031] Table 1

[0032]

[0033] As can be seen from Table 1, the larger the ratio of tributyl phosphate in the extractant, the lower the concentration of p-aminobenzoic acid in the raffinate aqueous phase, the higher the extraction rate of p-aminobenzoic acid, and the COD removal rate is 40%. Tributyl phosphate is the highest.

Embodiment 6～ Embodiment 9）

[0035] The method of each embodiment is basically the same as that of Example 1, and the differences are shown in Table 2.

[0036] Table 2

[0037]

[0038] As can be seen from Table 2, the greater the amount of extractant, the lower the concentration of p-aminobenzoic acid in the raffinate aqueous phase, and the higher the extraction rate of p-aminobenzoic acid. In combination with the economic point of view, the extraction agent with half the amount of waste water is the most good.

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Abstract

The invention discloses a method for recovering p-aminobenzoic acid in p-aminobenzoic acid process wastewater. The method comprises the following steps: 1, adding an extractant to the p-aminobenzoic acid process wastewater, and performing extraction to obtain an extract and a raffinate; 2, adding a back-extractant to the extract obtained in step 1, and performing back-extraction to obtain a back-extract and a back-raffinate; and 3, acidifying the back-raffinate obtained in step 2 to recover the p-aminobenzoic acid. Tributyl phosphate, n-octanol and kerosene are mixed according to a certain volume ratio to form the extractant, so the recovery method can achieve a good extraction effect, allows the COD removal rate to exceed 80% and reach up to about 90%, and makes the extraction rate also exceed 90%; and a certain amount of an aqueous sodium hydroxide solution is used to perform the back-extraction, so the method allows the back-extraction rate to be almost 100%, allows the recovery rate of p-aminobenzoic acid in the wastewater to exceed 90%, and has a good industrialization prospect.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, and in particular relates to a recovery and treatment method for p-aminobenzoic acid in p-aminobenzoic acid process wastewater. Background technique [0002] P-aminobenzoic acid is an important raw material for organic synthesis. Its synthesis methods mainly include iron filings reduction, electrolytic synthesis, catalytic hydrogenation and Raney nickel reduction. Most industrial production uses catalytic hydrogenation. The synthesis method Use p-nitrobenzoic acid as the starting material, adjust the pH value with sodium hydroxide solution to dissolve the raw material, after catalytic hydrogenation, then acidify with concentrated hydrochloric acid, p-aminobenzoic acid is precipitated from the solution, and after cooling and separation, p-nitrobenzoic acid is obtained. Aminobenzoic acid products, while centrifuge mother liquor is p-aminobenzoic acid process wastewater, its ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/26C07C227/40C07C229/60C02F101/38C02F103/36
Inventor 胡国宜胡锦平王仁冬李艳芬
Owner 江苏尚莱特医药化工材料有限公司
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