CN-121974434-A - Method for reducing COD (chemical oxygen demand) of waste water of tetrahydrofuran production process

CN121974434ACN 121974434 ACN121974434 ACN 121974434ACN-121974434-A

Abstract

The invention discloses a method for reducing COD (chemical oxygen demand) of waste water of a tetrahydrofuran production process, which comprises the following steps of S1, introducing the waste water of the tetrahydrofuran production process into a molecular imprinting adsorption unit to selectively adsorb 1, 4-butanediol in the waste water, S2, carrying out in-situ regeneration treatment on a molecular imprinting polymer, simultaneously, sending effluent to a Fenton oxidation unit to carry out oxidation treatment, S3, sending the effluent to an iron removal unit to carry out iron removal operation, S4, introducing the effluent into a photocatalytic membrane separation unit to carry out photocatalytic oxidative degradation operation, and S5, sending the effluent to an active carbon adsorption unit to carry out adsorption treatment, and discharging the effluent after reaching a discharge standard. The wastewater treatment method can not only efficiently and selectively remove the 1, 4-butanediol and greatly reduce the load of the subsequent working section, but also ensure that the COD of the effluent is stably lower than the discharge standard by virtue of the advantages of high-selectivity adsorption, strong-effect oxidation, self-cleaning of a membrane and the like, and the whole process is stable in operation and can meet the long-term treatment requirement of the wastewater.

Inventors

Guo Xuanmeng
LU HENG
TAO CHUNFENG
DU YUXIN
CHENG QIAN
ZENG GUANGJIAN
ZHUANG YAN

Assignees

浙江长鸿生物材料有限公司

Dates

Publication Date: 20260505
Application Date: 20260323

Claims (10)

1. A method for reducing COD in waste water of tetrahydrofuran production process, which is characterized by comprising the following steps: S1, introducing tetrahydrofuran production process wastewater into a molecular imprinting adsorption unit, and selectively adsorbing 1, 4-butanediol in the wastewater by using a molecular imprinting polymer under the condition of pH=6.0-7.0; s2, carrying out in-situ regeneration treatment on the molecularly imprinted polymer after adsorption saturation in the step S1, and simultaneously, sending the effluent treated in the step S1 to a Fenton oxidation unit for oxidation treatment to remove easily degradable organic matters; S3, delivering the effluent treated in the step S2 to an iron removal unit to remove iron ions introduced by Fenton oxidation; s4, introducing the effluent treated in the step S3 into a photocatalytic membrane separation unit, exciting the TiO 2 modified hollow fiber ultrafiltration membrane by using an ultraviolet LED array to perform photocatalytic oxidation degradation on refractory organic matters, and simultaneously realizing self-cleaning of the membrane surface; And S5, delivering the effluent treated in the step S4 to an activated carbon adsorption unit for adsorption treatment, and discharging after reaching the discharge standard.
2. The method for reducing COD in waste water from tetrahydrofuran production process according to claim 1, wherein in the step S1, the molecularly imprinted polymer is prepared by taking TiO 2 microspheres as a carrier, 1, 4-butanediol as a template molecule, acrylamide as a functional monomer, acetonitrile as a pore-forming agent and adding a fluorine-containing cross-linking agent.
3. The method for reducing COD of tetrahydrofuran production process waste water according to claim 2 wherein said fluorine-containing crosslinking agent is obtained by reacting octafluoro-1, 6-hexanediol with acryloyl chloride.
4. The method for reducing COD in waste water of tetrahydrofuran production process according to claim 1, wherein in the step S1, the adsorption operation parameters of the molecular imprinting adsorption unit are that the inflow water flow rate is 2-5 BV/h, the contact time is 15-30 min, and the adsorption temperature is 20-30 ℃.
5. The method for reducing COD of tetrahydrofuran production process wastewater according to claim 1 is characterized in that in step S2, the specific operation steps of in-situ regeneration treatment are that when the concentration of 1, 4-butanediol in effluent of a molecular imprinting adsorption unit reaches 5% of the concentration of water inflow, adsorption saturation is judged, wastewater is stopped being introduced into the adsorption unit, residual wastewater in the unit is emptied, an ultraviolet LED light source in the adsorption unit is started, the wavelength is 360-370 nm, the power density is 50-60 mW/cm 2 , the irradiation time is 30-60 min, a TiO 2 microsphere carrier is excited to generate a photocatalysis effect, 1, 4-butanediol enriched on the adsorption saturated molecular imprinting polymer is subjected to in-situ oxidative degradation, the regeneration of the molecular imprinting polymer is realized, after the photocatalysis regeneration, the adsorption unit is positively washed for 10-20 min by clear water at the flow rate of 2-4 BV/h, degradation residues are removed, and in-situ regeneration of the molecular imprinting polymer is completed, and the next round of adsorption operation can be carried out.
6. The method for reducing COD of tetrahydrofuran production process wastewater according to claim 1, wherein in the step S2, the operating parameters of the Fenton oxidation unit are that the addition amount of H 2 O 2 is 0.5-2.0 g/L, the addition amount of Fe2+ is 0.1-0.5 g/L, the reaction pH is 3.0-4.0, and the reaction time is 30-60 min.
7. The method for reducing COD in waste water from tetrahydrofuran production process according to claim 1, wherein in step S3, the iron removing unit removes iron ions introduced by Fenton oxidation by alkaline precipitation.
8. The method for reducing COD in waste water from tetrahydrofuran production process according to claim 1, wherein in the step S4, the wavelength of the ultraviolet LED array is 360-370 nm, and the power density is 60-80 mW/cm 2 .
9. The method for reducing COD of tetrahydrofuran production process wastewater according to claim 1 is characterized in that in the step S4, a ceramic hollow fiber membrane is selected as a base membrane, the molecular weight cut-off is 5000Da, the base membrane is immersed into TiO 2 sol for loading, and after drying, the base membrane is heated to 350-450 ℃ at a heating rate of 1-5 ℃ per minute for constant temperature calcination for 1-3 hours, so that the TiO 2 crystal form is converted into anatase phase and is firmly loaded on the surface of the membrane, and finally the TiO 2 modified hollow fiber ultrafiltration membrane is obtained.
10. The method for reducing COD in waste water from tetrahydrofuran production process according to claim 1, wherein in step S5, the operation parameters of the activated carbon adsorption unit are that activated carbon is granular or columnar activated carbon, the iodine value is more than or equal to 800mg/g, the adsorption flow rate is 2-5 BV/h, and the contact time is 20-40 min.

Description

Method for reducing COD (chemical oxygen demand) of waste water of tetrahydrofuran production process Technical Field The invention relates to the technical field of chemical industrial wastewater treatment, in particular to a method for reducing COD (chemical oxygen demand) of industrial wastewater of tetrahydrofuran. Background Tetrahydrofuran (THF) is an important organic solvent and chemical raw material, and is widely applied to the synthesis fields of high polymer materials, medical intermediates and fine chemical products. In industrial production, tetrahydrofuran is mainly prepared by a dehydration cyclization method of 1, 4-Butanediol (BDO), and wastewater generated by the process contains high-concentration organic pollutants such as 1, 4-butanediol, tetrahydrofuran and derivatives thereof, and the Chemical Oxygen Demand (COD) is generally up to thousands to tens of thousands of milligrams per liter, which belongs to typical high-concentration organic wastewater difficult to degrade. Currently, treatment technologies for such wastewater mainly include a physical adsorption method, a higher oxidation method, a membrane separation method, and the like. The physical adsorption method generally uses activated carbon, resin and other materials to adsorb organic matters, but has the problems of poor adsorption selectivity, limited adsorption capacity, difficult regeneration and the like. Although advanced oxidation methods such as Fenton oxidation, ozone oxidation and the like can effectively degrade organic matters, the method has the advantages of large medicament consumption, high operation cost and easiness in generating secondary pollution such as iron mud and the like. The membrane separation technology can realize the interception of pollutants, but the membrane has serious pollution and fast flux attenuation, and restricts the long-term stable operation. In addition, the single treatment process is difficult to cope with the characteristics of complex components and poor biodegradability of the tetrahydrofuran production wastewater, and a plurality of technical combinations are often required in practical engineering, but the existing combination process generally has the defects of long flow, high energy consumption, large occupied area and the like, and is difficult to meet the increasingly strict environmental protection emission requirements and the enterprise cost reduction and synergy requirements. Therefore, developing an efficient, economical and stable tetrahydrofuran production wastewater treatment technology is still a technical problem to be solved in industry. Disclosure of Invention In view of the shortcomings of the prior art, the invention provides a method for reducing COD of waste water of a tetrahydrofuran production process, which aims to solve the technical problems that high-concentration 1, 4-butanediol and complex organic matters in the waste water of the tetrahydrofuran production process are difficult to effectively remove by a traditional single water treatment process, the treatment process is long, secondary pollution is easy to generate, the adsorbent material is difficult to regenerate, the membrane pollution is serious and the like. In order to achieve the above purpose, the invention adopts the following technical scheme: A method for reducing COD of waste water from tetrahydrofuran production process, said method comprising the steps of: S1, introducing tetrahydrofuran production process wastewater into a molecular imprinting adsorption unit, and selectively adsorbing 1, 4-butanediol in the wastewater by using a molecular imprinting polymer under the condition of pH=6.0-7.0; s2, carrying out in-situ regeneration treatment on the molecularly imprinted polymer after adsorption saturation in the step S1, and simultaneously, sending the effluent treated in the step S1 to a Fenton oxidation unit for oxidation treatment to remove easily degradable organic matters; S3, delivering the effluent treated in the step S2 to an iron removal unit to remove iron ions introduced by Fenton oxidation; s4, introducing the effluent treated in the step S3 into a photocatalytic membrane separation unit, exciting the TiO 2 modified hollow fiber ultrafiltration membrane by using an ultraviolet LED array to perform photocatalytic oxidation degradation on refractory organic matters, and simultaneously realizing self-cleaning of the membrane surface; And S5, delivering the effluent treated in the step S4 to an activated carbon adsorption unit for adsorption treatment, and discharging after reaching the discharge standard. In the step S1, the molecularly imprinted polymer is prepared by taking TiO 2 microspheres as a carrier, 1, 4-butanediol as a template molecule, acrylamide as a functional monomer and acetonitrile as a pore-forming agent and adding a fluorine-containing cross-linking agent. As a preferable technical scheme, the fluorine-containing cross-linking agent is obtained by reacti