Para-aminobenzoic acid is widely used as an important organic chemical intermediate. However, a large amount of para-aminobenzoic acid sewage is discharged during the production process. Its high toxicity and poor biodegradability have become the focus and difficulty of water pollution control.
Let me introduce to you a new process technology for treating para-aminobenzoic acid wastewater - extraction method. This technology can be said to be a new, efficient, green and safe method.

  1. Extraction agent selection—choose protic ionic liquid as the extraction agent

As a new type of solvent, protic ionic liquids have attracted attention due to their excellent physical and chemical properties, good biological and environmental compatibility. Protic ionic liquids not only have the traditional advantages of ionic liquids, such as good chemical stability, designability, and recyclability, but also have cheap and easily available raw materials, are green and environmentally friendly, and have a simple synthesis process. The synthesis process does not require the introduction of other organic solvents to obtain high-purity products, and the atom economy reaches 100%. Therefore, protic ionic liquids are considered to be as important as traditional ionic liquids as "green solvents" to replace volatile organic solvents.

As the extraction agent for p-aminobenzoic acid, we choose a protic ionic liquid composed of trioctylamine and propionic acid, that is, the extraction agent is N, N, N-tributyl ammonium propionate ionic liquid.

  1. Introduction to the entire extraction process of para-aminobenzoic acid wastewater

① Extraction. The extraction agent is mixed with the sewage containing para-aminobenzoic acid for mass transfer and separation extraction.
② Stripping. The treated extraction phase is added to liquid caustic soda for stripping, and the extraction agent is recycled.

We use an extraction agent (N, N, N-trioctylammonium propionate ionic liquid) that is immiscible with water but has good solubility with para-aminobenzoic acid, so it can well separate para-aminobenzoic acid from sewage.

  1. Para-aminobenzoic acid wastewater extraction equipment - CWL-M series centrifugal extractor can realize continuous extraction operation

At present, there are two main types of extraction equipment to choose from. The first is the traditional reactor and settling tank, and the second is continuous equipment, including centrifugal extractor, extraction tanks and extraction towers. Among them, centrifugal extractor, as new, efficient and continuous liquid-liquid extraction and separation equipment, are increasingly replacing traditional reactor, settling tank and extraction tank. The reason is that the centrifugal extractor has many advantages such as high extraction efficiency, small footprint, continuous operation, and high degree of automation.

The CWL-M series centrifugal extractor launched by Zhengzhou Tiei is a leader in this field. When the CWL-M centrifugal extractor is processing the feed liquid, the organic phase (extraction agent) and the aqueous phase (para-aminobenzyl ester sewage water) enter the centrifugal extractor from their respective feed inlets according to the set ratio. With the rotation of the drum, the two phases are quickly mixed and dispersed through the turbine disk and impeller, and the two-phase solution is fully mass transferred, completing the mixing and mass transfer process. The mixed liquid achieves two-phase separation under the centrifugal force generated by the rotating drum. The loaded extraction agent and wastewater finally enter the collection chamber through their respective weir plates and are led out of the machine through the guide pipes, completing the two-phase separation process.

The specific advantages of the entire CWL-M centrifugal extractor process

①. High extraction efficiency and strong selectivity, the efficient extraction rate of p-aminobenzoic acid can reach more than 93%.

②. The operating conditions are mild and environmentally friendly.

③. The equipment has a high degree of automation and good mixing and separation effects, which can satisfy customers' continuous production.

④. The equipment is selected according to the customer's processing capacity, which can meet different extraction requirements.

Adopt CWL-M centrifugal extraction process is of great significance to the cleaning of chemical organic wastewater.