Benzoic acid extraction into benzoic acid wastewater treatment process
benzoic acid and benzoic acid, in medicine, food, chemical industry, etc, they are widely used to the preparation of a variety of drugs, plastic plasticizer, etc. Because of benzoic acid of low cost, and its downstream products sodium benzoate is still the first choice of varieties of preservatives. As in mosquito-repellent incense, herbal syrup used as antiseptic fungicide, used as a corrosion inhibitor in automotive antifreeze, used as a catalytic agent in dyeing and printing industry agent, etc.
2, benzoic acid, industrial production method and the wastewater discharge
in the industrial production of benzoic acid method is given priority to with toluene liquid phase air oxidation method. Due to the process on cobalt salt or manganese salt as catalyst, acetic acid as solvent, with mature technology, the advantages of mild reaction conditions, less 'three wastes', now is still the most main production line of benzoic acid.
toluene liquid phase air oxidation process of waste water is light yellow transparent liquid, main ingredients of benzoic acid and acetic acid, the pH value in 1. 8 - 2. 1, chemical oxygen demand ( CODcr) More than about 20000 mg/L.
3, benzoic acid wastewater treatment case on
toluene liquid phase oxidation process for an enterprise in benzoic acid production process by wastewater benzoic acid content is 0. 314 mol/L, acetic acid content is 0. 25 mol/L, pH value of 2. 03, chemical oxygen demand ( CODcr) Is 23270 mg/L. We take the extraction of benzoic acid and acetic acid recovery step by step, after a three-stage countercurrent extraction, acid recovery rate is above 99%, two levels of countercurrent extraction of acetic acid, acetic acid recovery rate is about 95%.