KR20130101278A - Method for separating nmp in industrial waste water - Google Patents

Abstract

The present invention relates to a NMP separation recovery method contained in industrial wastewater.
The present invention separates and recovers NMP organic solvents contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane, so that useful organic solvents contained in industrial wastewater can be separated and recovered and reused as well as treated effluents. Treatment costs can be reduced by reducing the total nitrogen (TN) content. At this time, according to the membrane characteristics of the polyamide reverse osmosis membrane, it is possible to establish the optimum conditions to control the NMP removal rate and total nitrogen (TN) removal rate in the effluent.

Description

Separation and recovery method of NMP in industrial wastewater {METHOD FOR SEPARATING NMP IN INDUSTRIAL WASTE WATER}

The present invention relates to a NMP (N-Methyl-2-pyrrolidone) separation recovery method contained in industrial wastewater, and more particularly, to separate the NMP organic solvent contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane. By recovering, the NMP organic solvent, which is the result of the membrane separation process, is recovered and reused, the permeated treated water is discharged, and the NMP removal rate and total nitrogen (TN) removal rate in the wastewater can be controlled according to the membrane characteristics of the polyamide reverse osmosis membrane. In addition, treatment costs can be reduced by lowering the total nitrogen (TN) in the effluent below the emission allowance.

If the wastewater is discharged to a river or lake without removing nitrogen, it may cause eutrophication and cause green algae, and if it enters the sea, it may cause red tide and destroy ecosystems.

In addition, long-term drinking of groundwater that contains nitrogen by flowing into the groundwater can cause cancer or blue baby syndrome in infants.

As a result, all wastewater discharge facilities have been regulated by tightening the total nitrogen emission standard, but until now, only the biological treatment method has been commercialized, and the technology to remove the nitrogen content in the general wastewater is effective. There is little development of water treatment equipment.

In developed countries, a water treatment method that can remove total nitrogen has been published in the Journal of Korean Society of Environmental Engineers, Vol. 20, No. 2, pp. 161-170, 1998, but it is not practical to apply this technique to the removal of high concentrations of total nitrogen.

Currently, the technology generally used for the decomposition of nitrogen in wastewater requires a lot of operating costs because of the biological decomposition method or additional carbon source for operation, and the reaction time is long, so the large-scale site to equip the facility need.

In addition, the operating conditions (pH control, temperature, wastewater components) are difficult, and if the wastewater contains toxic substances such as heavy metals, it is difficult to apply (killing microorganisms), and high concentrations of chlorine ions are present in the desulfurized wastewater. Therefore, biological treatment methods are difficult to apply.

Recently, some attempts have been made to remove nitrogen using metal powder and sulfamic acid developed in the United States, and to remove nitrogen using waste metal chips. In the former case, sulfamic acid, which is a kind of organic material added to remove nitrogen, has a problem of increasing total nitrogen, and there is a problem of recovering the metal powder. In the case of using the latter waste metal chip, the acid must be used in the pretreatment step. There is a problem in that heavy metals that are dissociated from the waste metal chips with the problem of causing secondary contamination due to the cleaning have to be recovered.

In general, industrial wastewater, more specifically, wastewater generated in semiconductor and battery manufacturing processes, contains a considerable amount of organic solvents. In particular, NMP organic solvents contain a nitrogen source, which restricts them from being discharged as they are. .

Accordingly, the present inventors completed the present invention by confirming that the NMP organic solvent contained in various industrial wastewaters can be recovered by a membrane separation process, and that the total nitrogen (TN) amount in the treated effluent water can be lowered below an allowable discharge standard. It was.

It is an object of the present invention to efficiently recover and reuse NMP organic solvents contained in various industrial wastewaters using polyamide reverse osmosis membranes under optimum conditions, and to discharge the total nitrogen (TN) in the discharged water discharged after treatment. It is to provide a method that can be lowered below.

In order to achieve the above object, the present invention provides a separation and recovery method of the NMP organic solvent contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane.

Separation recovery method of the NMP organic solvent of the present invention is implemented by a membrane module consisting of a polyamide reverse osmosis membrane, wherein the polyamide reverse osmosis membrane is an aromatic multifunctional amine containing two primary amine groups and three or more acyl It is an aromatic polyamide by interfacial polymerization between the aromatic acyl halides which have a halide functional group, and IR analysis of the said polyamide reverse osmosis membrane shows that the amide / benzene absorbance ratio is at least 2.0 or more.

In addition, in the separation system configuration of the present invention, a plurality of vessels incorporating a plurality of polyamide reverse osmosis membrane modules are arranged in parallel to form a stage, and two or more stages are arranged in series. . At this time, the production water obtained in the first stage is applied as raw water in the next stage. The polyamide reverse osmosis membrane is preferably a spiral wound module.

The membrane module composed of the polyamide reverse osmosis membrane of the present invention is carried out under operating pressure conditions within 80 kgf / cm 2.

The present invention provides a method for separating and recovering NMP organic solvents contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane, thereby enabling the economical recovery and reuse of expensive NMP organic solvents.

In addition, the total amount of nitrogen (TN) in the effluent discharged after NMP organic solvent treatment can be lowered. At this time, the total amount of nitrogen (TN) by reprocessing the production water more than once using a multi-stage separation system to improve the quality of discharged water. Can be lowered to the emission tolerance. Accordingly, it is possible to prevent environmental pollution by the discharged water and to reduce the cost of wastewater treatment.

In addition, the NMP separation recovery method of the present invention is carried out by a membrane module composed of a polyamide reverse osmosis membrane, and at this time, it is possible to establish the optimum conditions for controlling the NMP removal rate and the total nitrogen removal rate in the wastewater according to the characteristics of the membrane. .

1 is an IR analysis result of the polyamide reverse osmosis membrane of the present invention,
Figure 2 is a schematic diagram of a multi-stage separation system consisting of a multi-stage in the separation recovery method of the present invention.

The present invention provides a method for separating and recovering an NMP organic solvent contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane.

Separation and recovery of the NMP organic solvent contained in the industrial wastewater of the present invention is characterized in that it is carried out by a membrane module consisting of a polyamide reverse osmosis membrane, wherein, depending on the membrane characteristics, NMP removal rate and total nitrogen removal rate in the wastewater Can be controlled.

The reverse osmosis membrane made of the aromatic polyamide of the present invention is formed by interfacial polymerization between an aromatic polyfunctional amine containing two primary amine groups on an porous support and an aromatic acyl halide having three or more acyl halide functional groups. An aromatic polyamide consists of a repeating unit structure represented by following formula (1).

Formula 1

As a result of the IR analysis shown in FIG. 1 , an amide / benzene absorbance ratio in the aromatic polyamide molecule is used.

At this time, it is used as an index for estimating the thickness of the polyamide layer formed on the membrane according to the amide / benzene absorbance ratio in the aromatic polyamide molecule. As the ratio of amide / benzene absorbance in the aromatic polyamide molecule increases, the polyamide layer thickness also increases. It will increase. As a result of IR analysis, the amide / benzene absorbance ratio in the aromatic polyamide molecule can be set to the membrane thickness, and the NMP organic solvent contained in the industrial wastewater by using a polyamide reverse osmosis membrane whose value satisfies at least 2.0 or more. Optimize the removal rate or total nitrogen removal rate.

In addition, the system configuration of the present invention is a plurality of vessels, preferably three to eight polyamide reverse osmosis membrane module is a plurality of vessels are arranged in parallel to form a single stage (stage), the two stages The above is arranged in series. In this case, by reducing the total nitrogen (T-N) in the effluent to below the discharge limit by treating the production water obtained in the first stage in the next stage in the multi-stage separation system connected in series to improve the discharge water quality.

Figure 2 shows a schematic diagram of the multi-stage membrane module of the present invention, the total nitrogen in the effluent by treating the production water obtained in the first stage to the next stage in the multi-stage separation system connected in series to improve the discharge water quality (TN) ) Can be lowered below the emission limit.

The polyamide reverse osmosis membrane used in the present invention is a form in which a large membrane area is integrated on a compact scale, and uses a spiral wound module.

In the separation recovery method of the present invention, the operating pressure of the membrane module is preferably performed within 80kgf / ㎠.

Hereinafter, the present invention will be described in more detail with reference to Examples.

This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

≪ Example 1 >

Wastewater at pH 13.1 containing 1.5 to 2.0 wt% NMP, 1.5 to 2.5 wt% KOH, less than 0.1 wt% surfactant, and 95 wt% or more of other Si components was prepared as test raw water.

Raw water was passed through a separate module composed of a polyamide reverse osmosis membrane, and the measured pressure was performed at 50 ° C. and pH 13 at 50 ° C. under a pressure of 13 ° C. in a constant pressure operation. In this case, the IR analysis of the polyamide reverse osmosis membrane, the amide / benzene absorbance ratio was 2.107. The polyamide reverse osmosis membrane coated with m-phenylenediamine on a polyporous support made of polysulfone, and after removing the excess metaphenylenediamine solution from the microporous support, a freon TF solvent (Trichloro) The organic solution of trimesoyl chloride (TMC) dissolved in loctrifluoroethane) was brought into contact with the coated support to induce an interfacial polymerization reaction, wherein the contact time between the aqueous solution and the organic solution was 10 seconds, reaction. Was substantially completed in 1 second. Thus, the wastewater was designed to pass through the reverse osmosis membrane system, and at this time, the production water and the concentrated water were designed to be circulated to the raw water tank. Thus, the test items of T-N removal rate were observed.

≪ Comparative Example 1 &

As a result of IR analysis, it was carried out in the same manner as in Example 1 except that it was applied to a membrane module composed of a polyamide reverse osmosis membrane having an amide / benzene ratio of 1.271 in a polyamide molecule.

Experimental Example 1 Properties of Membrane

The properties of the polyamide reverse osmosis membranes used in Example 1 and Comparative Example 1 were measured and described in Table 1 below.

As shown in Table 1 and Figure 1, the reverse osmosis membrane used in the present invention utilized a membrane having an amide / benzene absorbance ratio of 2.107 through IR analysis in the embodiment, the amide / benzene absorbance ratio through the IR analysis Is used as an index of thickness of the polyamide separator, wherein the higher the amide / benzene absorbance ratio, the thicker the polyamide layer is formed.

Experimental Example 1 Evaluation of Total Nitrogen (T-N) Removal Rate

Total nitrogen (T-N) removal rates were observed for the polyamide reverse osmosis membranes used in Example 1 and Comparative Examples 1 and 2.

Figure 2 shows the total nitrogen (T-N) removal rate of the membrane according to the polyamide reverse osmosis membrane, the polyamide reverse osmosis membrane used in Example 1 showed the best removal rate.

From the above results, for the polyamide reverse osmosis membranes of Example 1 and Comparative Example 1, after fixing the operating pressure of 50 kgf / cm 2 condition, the total nitrogen removal rate results for each polyamide reverse osmosis membrane used are shown in Table 2 below . .

At this time, the total nitrogen (T-N) removal rate is calculated by the following equation (1).

Equation 1

The result is that the production water obtained in the first stage (stage 1) is reprocessed to the next stage (stage 2) in a multi-stage separation system connected in series to improve the quality of the production water. At this time, the IR analysis of the membrane showed that the absorbance ratio of amide / benzene was 2.0 or higher, that is, in Example 1, where the thickness of the polyamide membrane was relatively thick, the total nitrogen (TN) removal rate was found to be 90% or higher. The total nitrogen (TN) removal rate was superior to that of the film of Comparative Example 1 under the conditions. Finally, it was possible to lower the total nitrogen (T-N) to below the emission limit.

As described above, the present invention provides a method for separating and recovering NMP organic solvent contained in industrial wastewater by a membrane module composed of a polyamide reverse osmosis membrane.

According to the NMP separation recovery method of the present invention, the expensive NNP organic solvent discharged while contained in industrial wastewater is recovered and reused, and a process for reducing the total amount of nitrogen (TN) in the effluent is performed. Industrial wastewater treatment costs can be reduced.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

10: high pressure pump 11: influent (wastewater)
12: First stage 13: Number of first stage production
14: Second stage 15: Final production water (effluent)
16: concentrated water (recovery)

Claims (6)

A plurality of vessels in which a plurality of polyamide reverse osmosis membrane modules are embedded are arranged in parallel to form a unit stage,
NMP organic solvent separation recovery method contained in industrial wastewater by the polyamide reverse osmosis membrane module mounted to each unit stage through a multi-stage separation system composed of two or more unit stages in series. The method of claim 1, wherein the multi-stage separation system is characterized in that the production water obtained in the first unit stage is applied as raw water of the next unit stage. The polyamide reverse osmosis membrane of claim 1, wherein the polyamide reverse osmosis membrane is an aromatic polyamide by interfacial polymerization between an aromatic polyfunctional amine containing two primary amine groups and an aromatic acyl halide having three or more acyl halide functional groups. The separation recovery method. 4. The method of claim 3 wherein said aromatic polyamide has an amide / benzene absorbance ratio in the molecule of at least 2.0 or greater. The method of claim 1, wherein the polyamide reverse osmosis membrane is a spiral wound module. The separation and recovery method according to claim 1, wherein an operating pressure of the membrane module composed of the polyamide reverse osmosis membrane is within 80 kgf / cm 2.

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