Device and method for recovering and concentrating ortho-toluidine in ortho-toluidine wastewater by membrane extraction

Abstract

The invention relates to a device and a method for recovering and concentrating ortho-toluidine in ortho-toluidine wastewater by membrane extraction. The method comprises: conveying wastewater containing ortho-toluidine to a silicon rubber extraction membrane tube, wherein the silicon rubber extraction membrane tube is put in an acidic extraction solution, ortho-toluidine in the wastewater can penetrate through the tube wall of the silicon rubber extraction membrane tube, enter into the extraction solution and react to generate ortho-toluidine ions, and the rest of the wastewater is discharged from the outlet of the silicon rubber extraction membrane tube with standard level or post-treatment; and taking out the extraction solution when the concentration of the ortho-toluidine ions in the extraction solution exceeds a predetermined value, and adding alkali liquor into the extraction solution to obtain recovered and concentrated ortho-toluidine. According to the device and method provided by the invention, the extraction solution is acidic and is reacted with alkalescent ortho-toluidine to generate the ortho-toluidine ions which cannot penetrate through the silicon rubber extraction membrane tube so as to prevent the ortho-toluidine from returning to the wastewater again. A lot of ortho-toluidine can be separated and concentrated, the mass transfer velocity is relatively rapid, industrial treatment and concentration and recovery of the ortho-toluidine are facilitated, and the use level of the extraction solution is extremely little.

Description

【Technical field】 [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a device and a method for recovering and concentrating o-toluidine in o-toluidine wastewater by membrane extraction. 【Background technique】 [0002] O-toluidine is one of the organic chemical raw materials, widely used in many industries such as pesticides, dyes, medicines, spices, etc. In the dye industry, o-toluidine can be used as a dye intermediate to produce a variety of dyes and organic pigments, and o-toluidine wastewater is a typical refractory organic wastewater, which not only contains a large amount of organic pollutants, but also needs to A large amount of inorganic salts, and the wastewater also contains inorganic salts with a relatively high concentration; at the same time, in the production process of o-toluidine, a large amount of high-concentration o-toluidine wastewater is discharged, and the wastewater is not only large in volume but ...

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Problems solved by technology

Among them, homogeneous non-porous silicone rubber is an important membrane material in membrane extraction technology. Silicon rubber has selective permeability to some organic substances and has a high mass transfer specific surface area. Silicone rubber membranes have been used in some organic wastewater. Treatment, including the separation and recovery of benzoic acid, benzene, toluene, phenol, ethanol, butanol, butanone, acetic acid and ethyl acetate, but the traditional extraction liquid is generally a flow type, not only consumes a large amount, but also cannot concentrate organic matter , and according to the different partition coefficients, repeated extractions are required to completely extract the solute from the solvent; and it can be found that under the same conditions, the removal rate and recovery rate of different organic compounds in the silicone rubber membrane vary greatly, and membrane extraction Technology is not efficient for all organics

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