JPS58219940A - Adsorbing material for organic substance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porous adsorbent that adsorbs organic compounds dissolved or suspended in water using van der Waals forces.

Conventionally, hydrophobic fiber moldings and the like have been used to treat oil spilled into water.

This material is suitable for adsorbing oil that has surfaced on the water, but the hydrophobic nature of the material is detrimental to the adsorption of dissolved or suspended oil and hydrophilic organic matter, which reduces the contact area with water. This has the disadvantage that a high adsorption effect cannot be obtained due to the decrease in the amount of adsorption.

There are also activated carbon and porous resins with a three-dimensional cross-linked structure, but they have the drawback of being easily pulverized when handling activated carbon mines and difficult to recover after being put into water. Introducing hydrophilic groups and ion exchange groups into the three-dimensionally crosslinked porous resin mineral resin.In order to prevent the introduction of these groups from increasing the water solubility of the resin, complicated methods are required for the preparation, such as introducing three-dimensional crosslinks, which makes the resin expensive. It has the disadvantage of becoming a thing.

The present inventors have worked diligently to eliminate the drawbacks of these adsorbents and develop an easy-to-handle adsorbent, and have discovered that polyolefin porous hollow fibers made hydrophilic have excellent adsorption performance for organic matter in water. In other words, although it was conventionally thought that making an adsorbent hydrophilic would reduce its ability to adsorb lipophilic substances, polyolefin adsorption in the adsorption of nine organic substances dissolved and suspended in water. When a porous adsorbent is used, its adsorption capacity does not decrease significantly even if it becomes hydrophilic due to adsorption by van der Waals rock, and by making it hydrophilic, it becomes easier for water molecules to penetrate into the fine pores of the porous adsorbent. It has been discovered that the adsorption capacity is increased by significantly increasing the opportunity to contact suspended organic substances, that is, the effective surface area. That is, the present invention provides a hydrophobic organic substance in water, which is characterized in that the surface of an adsorbent made of porous hollow short fibers of polyolefin in which micropores are interconnected on the inner wall surface and the outer wall surface of the hollow fibers is made hydrophilic. and adsorbents for hydrophilic organic substances.

As polyolefins, polyethylene, polypropylene, polytetrafluoroethylene, and copolymers containing these as main components are preferably used. The fill can be torn to yield hollow fibers with fine pores in the sidewalls. By this method, a hollow fiber is formed by a large number of strip-shaped pores formed from microfibrils in which micropores are arranged in the fiber length direction and knots in which the microfibrils are connected at right angles to the microfibrils. It is possible to obtain a hollow fiber having a laminated structure in which the inner wall surface and the outer wall surface of the hollow fiber are interconnected.

The average pore diameter, porosity, etc. of the obtained hollow fibers can vary, but the average pore diameter is 0.06 to 10μ.
Preferably. If it is less than 0.06μ, there is a high possibility of clogging and a decrease in effective surface area. In order for water to freely pass through the hydrophilized micropores, 10
It is not necessary that the pore diameter be 10 μm or more, and pores with a pore size of 10 μm or more can be used satisfactorily for the purpose of the present invention, but the surface area will be reduced accordingly.

In fact, the microporous structure is formed from a large number of clofibrils and knots that connect them, and the above-mentioned structure has a laminated structure in which a large number of pores communicate with each other and are interconnected from the inner wall of the hollow fiber to the outer wall. The membrane has a large surface area inside the micropores, and even if one becomes clogged, water can penetrate into the inner pores through the surrounding pores, so there is no performance deterioration due to clogging. There is.

The shape of the hollow fiber is arbitrary, but the inner diameter is 100 to 500A.
1 wall thickness 10~100μ, porosity 20~90cm, surface area 1
It is preferable that it is 0 to 100 di/f.

The fiber length of the hollow short fibers is arbitrary, but when used suspended in water to be treated, the fiber length is preferably 1 to 500 m. An adsorbent made of longer short fibers shaped into a blind or streamer shape, a web made of hollow short fibers glued together, or a woven fabric of any shape can also be used.

The method of the present invention uses a porous hollow fiber in which micropores are interconnected on the inner wall surface and the outer wall surface of the hollow fiber, but since f overseparation is not performed, pinholes still exist no matter how wide the pore size distribution is. There is no problem in doing so. Furthermore, since they are short fibers, the water to be treated enters and contacts the inner surface of the membrane from the inside of the hollow fibers via the fiber openings, resulting in more effective tying.

Hydrophilization can be carried out by immersing the core short fibers in a liquid that has an affinity for the polyolefin and is miscible with water or an aqueous solution thereof, and allowing the liquid to enter the micropores.

Examples of such liquids include alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and ethylene glycol, and various surfactants; however, considering the possibility of remaining in the membrane and re-elution, lower alcohols are recommended. It is preferable to use

The adsorption mechanism of the hollow fibers is based on van der Waals vacuoles that act between the organic substance and the polyolefin polymer substance, and is different from the so-called separation method using one separation. Therefore, the types of organic substances targeted are:
It is not limited by the size of the molecule, and the adsorption effect is even greater for substances having a hydrophobic chemical structure (for example, an alkyl group, an ester group, an aromatic ring, etc.).

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Polyethylene hollow fiber 0.7F having an inner diameter of 260μ, a wall thickness of 55μ, a porosity of 60cm (by mercury intrusion method), a surface area of 40tn''/f, and a group of micropores with a pore diameter of 0.06 to 2μ. was cut into approximately 5 to 5111 IK, made hydrophilic with ethanol 50- and then washed with pure water.
pm methyl orange aqueous solution 50mj! 100 with
When added to a 1 nt beaker and stirred with a glass rod,
In a few minutes, the pale orange color of the methyl orange aqueous solution disappeared, and the polyethylene hollow fibers were dyed pale yellow. When this hollow fiber was transferred to a 1()4 glass filter and washed with 50 methanol, the pale yellow color of the hollow fiber disappeared and methyl orange was easily desorbed.

For comparison, the same operation as above was performed on a commercially available synthetic pulp made of polyethylene (Mitsui Zerapack), but the methyl orange aqueous solution was not decolorized. According to a scanning electron micrograph, the shape of this synthetic pulp is an aggregate of fibrils with a width of 5 μm and a length of a few centimeters, and micropore groups like the polyethylene hollow fibers are observed. It did not fit.

From this, it is clear that the hollow filamentous body having micropores created by tearing microfibrils in the side wall as in the present invention is excellent in adsorbing organic substances.

Example 2 It has an inner diameter of 200μ, a wall thickness of 25μ, a porosity of 50cm, a surface area of 50'tn''/f, and a hole/diameter of 0.06 in the side wall.
Polypropylene hollow fiber with ~2μ micropores 0.5
When conducting the same experiment as in Example 1 regarding f,
The polypropylene hollow fiber was dyed pale yellow, and the methyl orange aqueous solution was decolored. In addition, this colored hollow fiber is
When the mixture was transferred to a 4-glass filter and washed with 50 methanol, its original white color returned. From this, it was confirmed that the polypropylene and pyrene hollow fibers also have the ability to adsorb and desorb organic compounds.

Example 5 In order to quantitatively understand the adsorption performance, the same polyethylene hollow fiber used in Example 1 was soaked with methanol.
After time Soxhlet extraction, removing oligomers and additives and making it hydrophilic at the same time, washing with pure water, the length is 1~Strm.
A glass chromato tube with an inner diameter of 15 trm was filled with the cut fiber 2f.

To prevent the cut fibers from flowing out or floating up, a small amount of silica wool was packed above and below the cut fibers. Prepare dilute aqueous solutions of the adsorbed substances listed in Table 1, pass through the column at a constant flow rate (0.5 d/min), collect the effluent with a fraction collector, and measure its absorbance using a self-recording spectrometer. did. A typical example of the obtained results is shown in FIG. From the obtained adsorption curve, we can determine the breakthrough capacity (the amount of organic matter adsorbed per 1f of adsorbent until it leaks out, 1111/f adsorbent) and the saturated adsorption amount (1f of adsorbent).
The maximum amount of I-substance adsorbed (wg/f adsorbent) was calculated and is shown in Table 1. From this, it was confirmed that the hollow fibers adsorb various organic substances. Furthermore, the same operation was performed for benzene, toluene, and xylene, and it was confirmed that the adsorption amount could be reduced, but since these are volatile, it was not possible to quantify the saturated adsorption amount and breakthrough capacity.

Table 1: Adsorption performance of polyethylene hollow fibers

[Brief explanation of the drawing]

FIG. 1 shows the adsorption curve of organic substances by polyethylene hollow fibers. The vertical axis indicates the ratio (D/Do) of the absorbance (D) of the treatment solution to the absorbance (DO) of the stock solution.

Claims (1)

[Claims] 1) A hydrophobic organic substance in water and a hydrophilic material, characterized in that the surface of an adsorbent made of polyolefin porous hollow short fibers in which micropores are interconnected on the inner wall surface and the outer wall surface of the hollow fibers is made hydrophilic. adsorbent for organic substances