JPH08196804A - Adsorption treatment of selenium-containing solution - Google Patents

Abstract

PURPOSE: To efficiently adsorb and separate Se from an Se-contg. soln. and to reduce the concn. of Se in treated water. CONSTITUTION: An Se-contg. soln. is brought into contact with an adsorbent obtd. by carrying a compd. of at least one kind of metal selected from among Ti, Zr, Hf, La, Ce, Pr, Nd, Sm, Eu and Gd on a carrier to adsorb and separate the Se in the Se-contg. soln.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the production of selenium and its compounds which are widely used in rectifiers, solar cells, red pigments, insecticides, etc., as well as the use and disposal of these selenium-containing products. The present invention relates to an adsorption treatment method for a selenium-containing solution, which can separate selenium in the selenium-containing solution.

[0002]

2. Description of the Related Art Conventionally, as a method for separating selenium from a selenium-containing solution, for example, a method has been known in which sodium sulfide is added to a selenium-containing solution under acidic conditions to separate a precipitate that forms a sparingly soluble selenium sulfide. ing.

[0003]

However, it is difficult to control the addition amount of sodium sulfide by the method of adding sodium sulfide to the selenium-containing solution under acidic conditions and separating the precipitate that has produced selenium sulfide, as described above. However, when excessive sodium sulfide is added, there is a problem that selenium sulfide is redissolved, processing accuracy is poor, and selenium cannot be efficiently separated. The present invention is capable of efficiently adsorbing and separating selenium from a selenium-containing solution,
Moreover, it aims at providing the processing method of the selenium containing solution which can make the selenium concentration in treated water low.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that elements of titanium, zirconium, hafnium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium. Based on this finding, it is possible to solve the above problems by bringing an adsorbent having at least one metal compound selected from the group supported on a carrier into contact with a selenium-containing solution. Reached That is, the present invention relates to titanium, zirconium, hafnium,
Selenium in a selenium-containing solution by contacting an adsorbent in which at least one metal compound selected from the element group of lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium is supported on a carrier with a selenium-containing solution The gist is a method for adsorption treatment of a selenium-containing solution, which is characterized by adsorbing and separating.

The present invention will be described in detail below. As the adsorbent used in the present invention, at least one metal compound selected from the element group of titanium, zirconium, hafnium, lanthanum, cerium, praseodymium, neodymium, samarium, europium and gadolinium is supported on a carrier. Yes, especially at least 1 selected from the group of elements titanium, zirconium, hafnium, cerium
It is preferable to support a metal compound of a kind on a carrier. The carrier used in the present invention is preferably granular, and its particle size is suitably 0.2 to 2 mm.
Organic polymer materials such as phenol resin and polystyrene are preferable as such materials, and natural zeolite, synthetic zeolite, acid clay, silica gel,
Examples thereof include silica-alumina gel, granular activated carbon, molecular adsorbent resin, synthetic granular activated carbon, ion exchange resin and chelate resin.

The metal compound may be supported on the carrier in the form of a metal chloride or oxide. The amount of the metal compound supported on the carrier at that time is preferably 50 to 500 g, and more preferably 100 to 300 g, per liter of the carrier. Further, as a method for supporting the metal compound on the carrier used in the present invention, the solution or slurry of the metal compound and the carrier are put into a container and stirred or mixed, or the solution of the metal compound is added to the carrier. It is preferable that the metal compound is supported on the carrier by passing the solution through a column packed with and contacting it. The adsorbent used in the present invention may be a commercially available product, and a preferred specific example thereof is zirconium oxychloride (ZrO 2).
A granular adsorbent "Uniselec UR-3700S" (manufactured by Unitika Ltd.) in which Cl ₂ .8H ₂ O) is supported on polystyrene is exemplified.

The selenium-containing solution to be used in the present invention includes, for example, the production of selenium and its compounds widely used in rectifiers, solar cells, red pigments, insecticides, etc., and the use of these selenium-containing products. And the selenium-containing solution discharged at the time of disposal. Also,
In the present invention, the selenium-containing solution to be brought into contact with the above adsorbent has a pH of 1 to 3, more preferably,
It is preferable to adjust with hydrochloric acid or caustic soda so as to be 1 to 2. When the pH of the selenium-containing solution exceeds 3, it becomes difficult for selenium to dissolve, and the selenium-containing solution is not adsorbed by the adsorbent packed in the column and is easily blocked. Further, when the pH of the selenium-containing solution is less than 1, it becomes difficult for selenium to adsorb only a trace amount.

In the present invention, it is necessary to bring the adsorbent into contact with the selenium-containing solution. Usually, the adsorbent is packed in a column and the selenium-containing solution is subjected to space velocity (SV) = 2 to 20 hr. It is preferable to pass the solution in a downward flow of ^-1 to bring it into contact with the adsorbent. At this time, in the case where the selenium-containing solution contains a suspended substance, it is preferable to remove the suspended substance by solid-liquid separation by filtration, precipitation or the like, and then contact the adsorbent.

Next, in the present invention, in order to elute the selenium adsorbed on the adsorbent, for example, sodium hydroxide (NaOH) having a concentration of 40 g / liter or more is used, and the capacity is 2
L / l-adsorbent Using the above, selenium can be eluted by passing the adsorbent adsorbing selenium at a space velocity (SV) of 5 hr ^-1 or less in a downward flow.

[0010]

In the present invention, although the detailed adsorption mechanism is unknown, for example, the granular adsorbent "Uniselec UR-370" is used.
When a selenium-containing solution adjusted to pH 1 to 3 is brought into contact with "0S" (manufactured by Unitika Ltd.), Cl and Se are expressed by the following formula.
Is replaced and Se is adsorbed, resulting in a strong "-
It is considered that a bond of “Zr—Se” is formed and selenium can be adsorbed and separated.

[0011]

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[0012]

EXAMPLES Next, the present invention will be described in detail with reference to examples. Example 1 First, 2.32 g of selenous acid (H ₂ SeO ₃ ), 12.8 g of sodium sulfate (Na ₂ SO ₄ ) and 180 g of 35% by weight hydrochloric acid (HCl) were dissolved in water to have a pH of 1.4. , Suspended substance (SS) less than 1 mg / l, Selenium (Se)
79 mg / liter, sodium sulfate (Na ₂ S0 ₄ )
18 liters of a selenium-containing solution containing 710 mg / liter was prepared.

Next, a commercially available granular adsorbent "Uniselec U" is used.
60 ml of "R-3700S" (manufactured by Unitika Ltd.) was packed in a glass column having a diameter of 9 mm.

The above selenium-containing solution was passed through a glass column in a downward flow at a space velocity (SV) = 5 hr ⁻¹ (0.3 liter / hr) for adsorption treatment, and a passing amount of 25 liters. / L-The treated water was sampled for each adsorbent (1.5 L), and the selenium concentration was measured by the atomic absorption photometry.

Further, a granular adsorbent "Uniselec UR-3700S" having adsorbed selenium was added to 80 g / liter of sodium hydroxide (NaOH) 3 liter / liter-adsorbent (0.18 liter) and water 1 liter / liter-. The adsorbent (0.06 liter) was passed through at a space velocity (SV) = 2 hr ⁻¹ (0.12 liter / hr) in a downward flow to elute selenium to obtain an eluent. The selenium concentration in the eluent was measured.

As a result, the selenium concentration of the treated water was as low as 0.001 mg / liter up to the flow rate of 175 liters / liter-the adsorbent (10.5 liters). UR-3700S "
13.8 g of selenium could be adsorbed and separated per liter. The selenium concentration in the eluent is 345
At 0 mg / liter, the elution rate was 99.8%.

[0017]

According to the present invention, selenium can be efficiently adsorbed and separated from a selenium-containing solution, and the selenium concentration in treated water can be reduced.

Claims (1)

[Claims] 1. An adsorbent in which at least one metal compound selected from the group of elements of titanium, zirconium, hafnium, lanthanum, cerium, praseodymium, neodymium, samarium, europium and gadolinium is supported on a carrier, and a selenium-containing solution. An adsorption treatment method for a selenium-containing solution, which comprises adsorbing and separating selenium in the selenium-containing solution by contacting with.