JP5093292B2 - Method for treating vanadium-containing water - Google Patents

Description

The present invention relates to a method for treating vanadium-containing water by removing vanadium and other impurities from the water to be treated comprising natural water containing vanadium, and in particular to remove vanadium and other impurities with an ion exchange resin to obtain pure water or ultrapure water. The present invention relates to a method for treating vanadium-containing water.

  Vanadium is used as a catalyst, and is contained in ash such as coal and petroleum, as well as in certain natural waters. Vanadium-containing water contains various forms of vanadium depending on its origin. Vanadium forms various compounds depending on the valence of -I to + V, and each compound has one in which vanadium dissociates into a cation and one in which it dissociates into an anion. When vanadium is contained in an ionized or ionizable state like a soluble salt, vanadium can be removed by ion exchange.

  In the above vanadium-containing water, the vanadium compound contained therein dissociates into cations can remove vanadium by cation exchange. In this case, vanadium dissociated into cations can be exchanged and removed by cation exchange resin or zeolite.

  When vanadium-containing water is treated with a cation exchange resin as described above, vanadium is concentrated in the resin by exchange adsorption. However, vanadium compounds are widely used as catalysts, and there are differences in activity depending on the valence of vanadium or the type of compound, but many vanadium compounds have catalytic activity. When vanadium having such catalytic activity is concentrated in the cation exchange resin, the cation exchange resin is oxidized by the catalytic action, and a substance containing an exchange group of the cation exchange resin (for example, polystyrene sulfonic acid) flows out. The cation exchange activity tends to decrease.

An object of the present invention is to produce pure water or ultrapure water by preventing vanadium by cation exchange and preventing anion by anion exchange without preventing deterioration of the cation exchange resin and reducing cation exchange activity. It is to propose a method for treating vanadium-containing water.

The present invention, natural water containing 0.1~313μg / L vanadium capable cation exchange states of oxidation number + II to + IV, removing the vanadium is contacted with mosquito thione exchange resins, cross-linking degree 12 to 16 % Of the cation exchange resin to prevent deterioration of the cation exchange resin by vanadium having an oxidation number of + II to + IV, remove vanadium by cation exchange, and contact with an anion exchange resin to further remove an anion by anion exchange. It is a treatment method for vanadium-containing water, characterized in that it is removed to produce pure water or ultrapure water.

Natural water containing vanadium to be processed in the present invention include vanadium oxidation number + II to + IV are natural water containing a cation exchangeable state, the vanadium as a cation, or releasable state cation Natural water is included, but it may contain vanadium dissociated into anions, vanadium compounds dissociable into anions, vanadium compounds that are not ionized, or other impurities. Natural water containing subject to vanadium treatment of the present invention, Ru natural water der having containing 0.1 ~313 μg / L of vanadium exchangeable state cation.

As described above, vanadium forms a compound having a valence of −I to + V, and among these, + II to + V is common. Oxidation numbers II and III produce salts mainly as cations, but oxidation numbers IV often combine with oxygen to form VO ²⁺ salts. With oxidation number V in ^{VO 3+} and _VO ^{2 +} salts metavanadate ion VO ₃ ^- to form a salt. V ₂ O ₅ widely used as a catalyst is amphoteric and hardly soluble in water. When dissolved in an acid, VO ₂ ⁺ is generated, and metavanadate ions are generated in an alkaline aqueous solution and dissociated into anions.

Vanadium thus forms compounds of various valences. Many natural waters contain vanadium that dissociates into cations. In contrast, wastewater discharged from a system using a vanadium catalyst includes those that dissociate into cations and those that dissociate into anions depending on pH.

In the present invention, natural water containing 0.1~313μg / L vanadium capable cation exchange states of oxidation number + II to + IV, when divided the vanadium is contacted with mosquito thione exchange resins, cross-linking degree 12 By contacting with ˜16% cation exchange resin, deterioration of cation exchange resin by vanadium with oxidation number + II˜ + IV is prevented, vanadium is removed by cation exchange, and contact with anion exchange resin is further conducted by anion exchange. Anion is removed to produce pure water or ultrapure water. In this case, the cation exchange resin and the anion exchange resin may be contacted separately, or may be contacted simultaneously by a mixed bed type or the like. The degree of crosslinking of the anion exchange resin to be used is not limited, and it may be a resin having a standard degree of crosslinking or a resin having a high degree of crosslinking (hereinafter, unless otherwise specified, the term “ion exchange” means “cation exchange and / or anion exchange”). ”).

  As the ion exchange resin used in the present invention, a granular or gel ion exchange resin generally used in water treatment can be used. Such an ion exchange resin uses a copolymer of styrene and divinylbenzene as a base resin, a styrene having a cation exchange group is used as a cation exchange resin, and a styrene exchange resin having an anion exchange group as an anion exchange resin. .

  The cation exchange resin includes a strong acid cation exchange resin having a sulfone group as a cation exchange group and a weak acid cation exchange resin having a carboxylic acid group, and any of them can be used. Anion exchange resins include strong basic anion exchange resins with quaternary ammonium groups as anion exchange groups and weak basic anion exchange resins with primary to tertiary ammonium groups, both of which can be used. is there.

  In the base resin, divinylbenzene serves as a cross-linking agent, and the chain structure is cross-linked to form a network resin. The more divinylbenzene, the more chain branches and the denser the structure, and the smaller the divinylbenzene, the larger the network with less branching. The ratio (% by weight) of the amount of divinylbenzene charged relative to the total amount of monomers charged is indicated as the degree of crosslinking. Resins used for normal water treatment have a degree of crosslinking of about 8% and are called standard crosslinked resins.

As the cation exchange resin used in the present invention, a highly crosslinked resin having a crosslinking degree of 12 to 16% is used. By using such a highly crosslinked cation exchange resin and contacting with vanadium-containing water, deterioration of the resin is prevented even when vanadium is concentrated in the resin, and the cation exchange capacity is not lowered.

The method for contacting the vanadium-containing natural water with the ion-exchange resin is not particularly limited, and a method of immersing the ion-exchange resin in the vanadium-containing natural water and stirring may be used, but the vanadium-containing natural water is passed through the packed bed of the ion-exchange resin. A method of contacting with water is preferred. In this case, when ion exchange is performed using a cation exchange resin and an anion exchange resin, each resin may be used alone to form a packed bed. However, both resins may be mixed to form a mixed bed. Can also be watered.

The conditions for water flow can be the same as those for treatment by ordinary ion exchange. The water flow rate varies depending on the vanadium concentration of the water to be treated, the target value of water quality treatment, etc., but generally 5 to 100
L / L-Resin / hr, preferably 10-30 L / L-Resin / hr. The end of water flow can be determined by detecting the leakage of ions or the like in the treated water. In this case, when the vanadium-containing natural water contains other cations such as sodium in addition to vanadium, it ends when the first leaking cations start leaking. When the vanadium-containing natural water contains only vanadium, it ends when the vanadium leaks or when a substance containing an exchange group of the ion exchange resin (for example, polystyrene sulfonic acid) leaks a predetermined amount (for example, 0.1 mg / L). can do.

  By continuing the water flow, vanadium is exchanged and adsorbed in the ion exchange resin and concentrated in the resin. Therefore, the water flow is stopped and the regeneration is started when the above-mentioned ions start to leak. For regeneration, as in the case of normal ion exchange, in the case of a cation exchange resin, an acid such as hydrochloric acid or sulfuric acid, and in the case of an anion exchange resin, an alkali such as sodium hydroxide is passed as a regenerant, followed by extrusion, washing, etc. To finish playback. Vanadium and other cations adsorbed on the cation exchange resin by regeneration elute, the resin is regenerated to H form, and the anion exchange resin is also regenerated to OH form. Is done.

In the present invention, natural water containing 0.1 to 313 μg / L of vanadium having an oxidation number of + II to + IV in a cation-exchangeable state is brought into contact with a cation exchange resin having a crosslinking degree of 12 to 16%, whereby the oxidation number + II Prevents deterioration of cation exchange resin by ~ + IV vanadium, removes vanadium by cation exchange , and further removes anions by anion exchange by contacting with anion exchange resin to produce pure water or ultrapure water Is to do.

According to the present invention, natural water containing 0.1~313μg / L vanadium capable cation exchange states of oxidation number + II to + IV, removing the vanadium is contacted with mosquito thione exchange resins, cross-linking degree 12 By contacting with ˜16% cation exchange resin, deterioration of cation exchange resin by vanadium with oxidation number + II˜ + IV is prevented, vanadium is removed by cation exchange, and contact with anion exchange resin is further conducted by anion exchange. Since the anion was removed to produce pure water or ultrapure water, the cation exchange resin was prevented from being deteriorated, and vanadium was removed by cation exchange without lowering the cation exchange activity. It is possible to remove pure water from natural water containing vanadium Others can be carried out ultra-pure water production.

  Hereinafter, the present invention will be described with reference to examples and comparative examples.

[Example 1]:
A column packed with 7.5 mL of a highly crosslinked cation exchange resin (Diaion SK112, trademark, manufactured by Mitsubishi Chemical Corporation, with a crosslinking degree of 12%) was charged with vanadium-containing water (VOSO ₄ 1 mg / L aqueous solution) as water to be treated. Vanadium was removed by passing water at a flow rate of 1 mL / min. Vanadium concentration in the treated water at the time when 500 mL of treated water was passed and at the time when 1000 mL was passed was not detected, and vanadium could be removed. Further, the polystyrenesulfonic acid concentration in the treated water was 0.05 mg / L, respectively, and the resin hardly deteriorated.

[Comparative Example 1]
In Example 1, when tested in the same manner except that a standard crosslinking degree cation exchange resin (Diaion SK1B, trademark, manufactured by Mitsubishi Chemical Co., Ltd., crosslinking degree 8%) was used as the ion exchange resin, 500 mL of water to be treated was used. The vanadium concentration in the treated water at the time of passing water and 1000 ml of water was not detected, and vanadium could be removed. However, the polystyrenesulfonic acid concentrations in the treated water were 2.1 mg / L and 4.2 mg / L, respectively, and the resin deteriorated.

[Comparative Example 2]
In Example 1, a test was conducted in the same manner except that the water to be treated containing no vanadium was used. As a result, the polystyrenesulfonic acid concentration in the treated water at the time when 1000 mL was passed was 0.05 mg / L. It became the equivalent value.

From the above results, it can be seen that when vanadium-containing water is treated with a cation exchange resin having a standard degree of crosslinking, the cation exchange resin deteriorates, but the treatment can be prevented by treating with a highly crosslinked cation exchange resin.

Claims (1)

0.1~313μg / L of natural water containing, removing the vanadium is contacted with mosquito thione exchange resins, cross-linking degree from 12 to 16% of the cation exchange vanadium capable cation exchange states of oxidation number + II to + IV By contacting with the resin, the deterioration of the cation exchange resin by vanadium having an oxidation number of + II to + IV is prevented, vanadium is removed by cation exchange , and further, the anion is removed by anion exchange by contacting with the anion exchange resin. A method for treating vanadium-containing water, which comprises producing water or ultrapure water.