JPH06121982A - Method to remove matter which is hardly decomposed by biological method - Google Patents

Abstract

PURPOSE:To provide an efficient removing method of matter which is hardly biologically decomposed. CONSTITUTION:An aq. soln. containing a matter which is hardly biologically decomposed is treated with anion-exchange resin to remove the matter. This matter has at least the following chemical properties (a)-(e). The matter has (a) about 1000-1500 weightaverage mol.wt., (b) phenol type hydroxyl group, carboxyl group, sulfonate group or nitro group in one molecule, and (c) an ester bond in the molecule. The matter is (d) soluble in water and produces precipitate under an acidic condition, and (e) the precipitate is acidic and hygroscopic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating and removing a biologically persistent substance contained in an aqueous solution. More specifically, the present invention relates to a method for separating and removing biologically difficult-to-decompose substances contained in wastewater discharged in the coke manufacturing process, for example.

[0002]

2. Description of the Related Art In the process of producing coke, coke oven gas (COG), tar, and the like that are distilled off during dry distillation of raw coal are cooled with water and used for their respective purposes. At that time, a liquid having a high ammonia content is discharged. This effluent is called ammonium hydroxide and usually contains about 6,000 ppm of ammonia.

In addition to ammonia, the ammonium hydroxide contains a large amount of various substances such as phenol, cresol and other phenols, cyanide, sulfide and the like. Usually, anhydrous water is diluted about 4 to 5 times with industrial water or seawater, and is subjected to biological treatment with activated sludge (fission bacteria, flagellates, ciliates, etc.) The contained substances such as are decomposed and removed.

[0004]

However, since the substances contained in the ammonium hydroxide discharged from the coke manufacturing process are not constant because they differ depending on the conditions such as the carbonization conditions of the raw coal, the load of the activated sludge changes and the activity of the activated sludge is changed. Have a great influence on. In addition, there is a limit to the decomposition and removal rate of the substances contained in the ammonium hydroxide by activated sludge, which is a problem in the wastewater treatment of ammonium hydroxide.

[0005]

[Means for Solving the Problems] The present inventors have conducted various studies to provide a method for separating and removing from biologically difficult-to-decompose substances that cannot be decomposed and removed by activated sludge from ammonic water. That is, the present inventors first specified the components that cannot be decomposed and removed by the activated sludge. As a result, we clarify the physicochemical properties of the substances that occupy most of them, find that the substance is an acidic substance having a carboxyl group or a sulfonic acid group in the molecule, and pay attention to the physicochemical properties, As a result of further studies on the method for removing the biologically difficult-to-decompose substance, it was found that the biologically difficult-to-decompose substance can be efficiently removed by treating the aqueous solution containing the substance with an anion exchange resin. The present invention has been completed.

That is, the gist of the present invention is at least the following physicochemical properties (a) to (e) (a) a weight average molecular weight of about 1,000 to 1,500 (b) a phenolic hydroxyl group in the molecule. , Carboxyl group,
Having a sulfonic acid group or a nitro group (c) Having an ester bond in the molecule (d) Soluble in water to form a precipitate under acidic conditions (e) The precipitate is acidic and exhibits hygroscopicity A method of removing a biologically difficult-to-decompose substance from an aqueous solution containing the biologically difficult-to-decompose substance, the method comprising treating the aqueous solution containing the biologically-hardly-decomposable substance with an anion exchange resin. A method for removing a biologically difficult-to-decompose substance is characterized by removing the substance.

The present invention will be described below. The aqueous solution treated in the present invention contains at least the biologically difficult-to-decompose substance having the physicochemical properties (a) to (e). The biologically difficult-to-decompose substance in the present invention is not decomposed by oxidation with an oxidizing agent such as hydrogen peroxide or oxygen or heating at 200 ° C., and is concentrated in the bottom of the pot by stripping treatment with steam.

Conversion of biologically persistent substances in the present invention
The scientific structure is unknown, but the results of elemental analysis (C
= 21.6%, H = 4.9%, N = 9.8%, ash =
2.7%, other = 61%), X-ray micro analyzer
Results (sulfur is detected), IR spectrum (KBr tablets
Molding method) result (Fig. 1)¹1 H-NMR and
¹³C-NMR [solvent: DMSO (dimethyl sulfoxy
From the results (Fig. 2 and Fig. 3),
It is presumed to be a condensation product of a benzene ring having a functional group.

[0009]

## STR00001 ## --OH --COOH --NO ₂ and / or --SO ₃ H --NOH In addition, GPC (column "Asahipak GS-31"
OH ”, column temperature 40 ° C., eluent; acetonitrile /
Water = 40/60, calibration curve; polyethylene glycol) has a weight average molecular weight of about 1,000 to 1,50.
It is 0.

[0010] Specifically, there is an example of cold water such as COG or tar discharged in the coke manufacturing process, which is cold water. For cheap water, it is usually 6,000 to 6,50
0ppm ammonia, COD conversion approximately 4,000-
Phenols such as 5,000 ppm and cresol are contained as main components, and in addition, about 500 to 700 ppm of cyanide compound in COD conversion, about 300 to 4
The biologically degradable substance of the present invention of 00 ppm and the biologically easily degradable substance of unknown structure of about 700 to 1,000 ppm are contained as minor components.

In the case of treating ammonium hydroxide, the main components such as phenol and cresol may be decomposed and removed in advance by an activated sludge treatment according to a conventional method. As the activated sludge at this time, the above-mentioned bacteria that decompose phenol, cresol and the like are used, and usually diluted with industrial water or seawater to about 4 to 5 times and reacted at a temperature of 30 to 40 ° C. Then, sedimentation separation is performed to obtain a supernatant.

The pH of the aqueous solution containing the biologically difficult-to-decompose substance is usually about 8.0 to 8.5. In the present invention, the aqueous solution is treated with an anion exchange resin. The anion exchange resin used is not particularly limited as long as it is a resin having a quaternary ammonium group or a primary to tertiary amine bonded as an exchange group, but a strong base having a quaternary ammonium group as an exchange group. The most suitable is anionic anion exchange resin.

The exchange capacity should be as high as possible. Specifically, the weakly basic anion exchange resins include "Diaion" WA10, WA11, WA2.
0, WA21, WA30 (all manufactured by Mitsubishi Kasei Co., Ltd.), and as a strongly basic anion exchange resin, "Diaion" SA10A, SA10B, SA11A, S
Examples include A11B, SA20A, SA21B (all manufactured by Mitsubishi Kasei Co., Ltd.).

The ion exchange treatment is carried out by precipitating the biologically difficult-to-decompose substance by adjusting the pH to 6 or less,
Alternatively, the substance can be further separated and removed by applying it to a product obtained by centrifugation or filtration with a super decanter or the like.

[0015]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Example 1. The low water discharged from the coke manufacturing process was diluted four times with seawater. The diluted solution was subjected to high performance liquid chromatography (HPLC: column “Nucleosil 10
0 ”, column temperature 40 ° C., eluent; acetonitrile / water = 40/60), and as a result, biologically persistent substances, phenol, cresol, and xylenols were present ((a) in FIG. 4). ).

10 ml of the diluted solution was treated with anion exchange resin ("Diaion" SA10A) which had been conditioned (de-Cl treatment) (SV:
10 to 30 hr ^-1 ). The treated liquid was analyzed by HPLC. A similar treatment was performed on activated carbon. The HPLC results are shown in FIGS. 4 (c) and 4 (b).

2 and 3, DMSO represents dimethyl sulfoxide, and TMS represents trimethylsilane. As is clear from FIG. 4, it is understood that the biologically difficult-to-decompose substance which could not be removed by the anion exchange treatment can be favorably adsorbed and removed. Further, it is understood that the ion exchange treatment is more effective than the activated carbon treatment.

[0018]

According to the method of the present invention, most of the components which could not be decomposed and removed by a biological method such as the treatment of activated sludge in the past, accounted for most of the above-mentioned biological and biodegradable substances having the physicochemical properties. The substance can be removed and its content reduced.

[Brief description of drawings]

FIG. 1 is an IR spectrum of a biologically persistent substance according to the present invention.

FIG. 2 shows ¹ H-NMR and ¹³ C-NMR analysis results of the same substance.

FIG. 3 shows ¹ H-NMR and ¹³ C-NMR analysis results of the same substance.

FIG. 4 is a HPLC analysis result of a diluted solution of ammonium hydroxide (a), a HPLC analysis result of an activated carbon treatment solution of the diluted solution (b), and an HPLC analysis result of an anion exchange solution of the diluted solution (c).
Indicates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidenori Harauchi, No. 1 Kyushu Town, Sakaide City, Kagawa Prefecture, Sakaide Factory, Mitsubishi Chemical Co., Ltd. (72) Inventor Hideki, No. 1, Kyushu Town, Sakaide City, Kagawa Prefecture Mitsubishi Kasei Stock company Sakaide factory

Claims (2)

[Claims] 1. At least the following physicochemical properties (a) to (e): (a) a weight average molecular weight of about 1,000 to 1,500 (b) a phenolic hydroxyl group or a carboxyl group in the molecule;
Having a sulfonic acid group or a nitro group (c) Having an ester bond in the molecule (d) Soluble in water to form a precipitate under acidic conditions (e) The precipitate is acidic and exhibits hygroscopicity A method for removing a biologically difficult-to-decompose substance from an aqueous solution containing the biologically difficult-to-decompose substance, the method comprising treating the aqueous solution containing the biologically difficult-to-degrade substance with an anion exchange resin. A method for removing a biologically difficult-to-decompose substance, which comprises removing the substance. 2. The method for removing a biologically difficult-to-decompose substance according to claim 1, wherein the aqueous solution containing the biologically-hardly-decomposable substance is ammonium hydroxide discharged from the coke manufacturing process.