JPS6225415B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to adsorbents using titanium oxide, zirconium oxide or tin oxide hydrates or mixtures thereof. In recent years, the phenomenon of eutrophication in closed water bodies such as the Seto Inland Sea and Lake Biwa has progressed one step further and is now becoming a major social problem. In particular, the removal of phosphate ions, which is one of the causative substances, is an important issue that must be solved immediately. By the way, the current phosphate ion removal technology involves adding chemicals containing metal ions such as calcium and aluminum to wastewater containing phosphate ions, and removing the phosphate ions as poorly soluble phosphates. The coagulation-sedimentation method is considered to be the only method. However, since this method generates a large amount of sludge, there is a risk of secondary pollution, so it cannot necessarily be said to be a satisfactory method, and there is a strong need for the development of a new phosphate ion removal technology. On the other hand, hydrated titanium oxide, zirconium oxide, and tin oxide have good properties as ion exchangers; for example, in acidic solutions, they fix H ⁺ and become anion exchangers, allowing them to form phosphate ions and fluorine ions. Adsorbs oxygen acid ions such as , sulfate ions, chloride ions, and halogen ions. Also, in alkaline solutions, OH ^- is fixed,
It has been known for some time that it acts as a cation exchanger. Although it is known that these hydrates are useful as ion exchangers, it is difficult to make these hydrates mechanically strong enough to be used as ion exchangers, so they are not suitable for industrial use. The reality is that it is not being used. The present inventors focused on the anion exchange ability of the metal oxide hydrate, particularly the ability to selectively adsorb phosphate ions, and as a result of intensive studies on adsorbents using the metal oxide hydrate, The adsorbent obtained by mixing the metal oxide hydrate or a mixture thereof with about 1/10 to 3 times the amount of epoxy resin, unsaturated polyester resin, or polyurethane resin and curing this mixture can be used industrially. It has been found that it has a certain degree of mechanical strength, and has excellent adsorption performance for various anions and cations, especially selective adsorption performance for phosphate ions.Based on these findings, the present invention has been developed. It was completed. That is, the present invention is made by curing a mixture of titanium oxide, zirconium oxide, tin oxide hydrate, or a mixture thereof, and about 1/10 to 3 times the amount of epoxy resin, unsaturated polyester resin, or polyurethane resin. It is an adsorbent. For example, the titanium oxide hydrate used to produce the adsorbent of the present invention has the general formula
Examples include those represented by TiO ₂ .nH ₂ O (in the formula, n is a positive number from 0.5 to 2.0). Specifically, for example, TiO ₂ H ₂ O (TiO(OH) ₂ ),
TiO ₂・2H ₂ O (Ti(OH) ₄ ), TiO ₂・nH ₂ O (n≒
0.5 to 2.0). As a hydrate of zirconium oxide, for example, the general formula ZrO ₂ · nH ₂ O
(In the formula, n is an integer from 0.5 to 2.0). Specifically, for example
ZrO ₂・H ₂ O (ZrO(OH) ₂ ), ZrO ₂・2H ₂ O (Zr
(OH) ₄ ), ZrO ₂ .nH ₂ O (n≒1.5 to 2.0), and the like. Examples of tin oxide hydrates include those represented by the general formula SnO ₂ .nH ₂ O (wherein n is an integer from 0.5 to 2.0). Specifically, for example, SnO ₂ H ₂ O (SnO(OH) ₂ ),
SnO ₂・2H ₂ O (Sn(OH) ₄ ), SnO ₂・nH ₂ O (n≒
1.5 to 2.0). One or more of the above metal oxide hydrates may be used in combination. The metal oxide hydrate may have any shape, but particles with a particle size of about 250 μm or less are particularly preferred from the viewpoint of mixing operation with the resin and adsorption performance, which will be described later. In the present invention, a hydrate of titanium oxide, zirconium oxide or tin oxide or a mixture thereof is used.
It is mixed with 1/10 to 3 times the amount, preferably about 1/5 to 1 times the amount (by weight) of epoxy resin, unsaturated polyester resin or polyurethane resin. When the amount of the resin exceeds about three times the amount, the mechanical strength of the adsorbent increases, but the adsorption performance decreases. On the other hand, the proportion of resin is small, about 1/10 of the above
If the amount is less than double, the adsorption performance is excellent, but the mechanical strength is reduced and cannot be used industrially. Examples of the epoxy resin used to produce the adsorbent of the present invention include 2,2'-bis(4-
Diglycidyl ether produced by the reaction of hydroxyphenyl)propane with epichlorohydrin or methylepichlorohydrin, diglycidyl ether produced by the reaction of glycols with epichlorohydrin or methylepichlorohydrin, and the reaction of phenol with formaldehyde. Examples include polyglycidyl ether produced by the reaction of the novolac thus obtained with epichlorohydrin or methylepichlorohydrin, tetraglycidyl ether of tetraphenylene ethane, and epoxy resin derived from polybutadiene. Unsaturated polyester resin is produced by mixing a dicarboxylic acid having a double bond in the molecule, such as maleic acid or its anhydride, or fumaric acid, with a dihydric alcohol, such as ethylene glycol or propylene glycol, by a known method. An unsaturated linear polyester obtained by condensation is dissolved in a vinyl monomer such as styrene, chlorostyrene, methyl methacrylate, diallyl phthalate, etc. The dicarboxylic acids mentioned above may be modified with unsaturated dicarboxylic acids or saturated dicarboxylic acids, such as phthalic acid, itaconic acid, phthalic anhydride, adipic acid, hettic acid, sebacic acid, isophthalic acid, terephthalic acid. Also,
Dihydric alcohols include bisphenol A, hydrogenated bisphenol A, butanediol, diethylene glycol, dipropylene glycol,
It may be modified with glycols such as triethylene glycol, trimethylene glycol, hexanediol, and pentanediol. Polyurethane resins are polyols that have two or more hydroxyl groups in the molecule, such as polyether polyols, polyester polyols, polymer polyols, butadiene polyols, polycarbonate diols, and castor oil, and two or more isocyanate groups in the molecule. , such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (Piure MDI), naphthalene diisocyanate (NDI), dimethyl diphenyl diisocyanate (TODI), polymethylene polyphenyl polyisocyanate (crude)
It is obtained by reacting polyisocyanates such as MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone diisocyanate (IPDI) by a known method. This polyurethane resin is usually produced by reacting isocyanate groups contained in the resin with each other by heat or a crosslinking agent, or by reacting with isocyanate groups such as ethylene glycol, propylene glycol, butanediol, glycerin, hexanetriol, and trimethylolpropane. , reacts with water etc. to become a thermosetting resin. If the above-mentioned epoxy resin, unsaturated polyester resin or polyurethane resin is liquid at room temperature, it can be used as is, but if it is solid, it can be used for example by carbonizing butane, hexane, cyclohexane, benzene, toluene, etc. Hydrogen, halogenated hydrocarbons such as methylene chloride, chloroform, trichloroethane, and chlorobenzene, alcohols such as methanol, ethanol, and propanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, ethyl ether, dioxane, etc. Organic solvents such as ether or mixtures thereof or
Make it into a liquid by heating below 90℃. Specific methods for mixing the metal oxide hydrate with the resin include, for example, mixing the metal oxide hydrate and the resin in a container equipped with a stirrer at high speed, a batch method using a kneader, or Examples include a method of continuous mixing, and a method of batchwise or continuous mixing using a device used for mixing solids and liquids. When mixing the metal oxide hydrate and the resin, if not necessary, use an amine curing agent such as diethylenetriamine, triethylenetetramine, metaphenylenediamine, phthalic anhydride, maleic anhydride, etc. for the epoxy resin. , an acid anhydride curing agent such as methylnadic anhydride, etc. may be added in an appropriate amount. In addition, for unsaturated polyester resins, for example, benzoyl peroxide (BPO), lauroyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide,
Appropriate amounts of catalysts such as t-butyl peroxide isobutyrate and curing accelerators such as cobalt naphthenate, manganese naphthenate, dimethylaniline, phenylmorpholine, diethanolaniline, vanadyl acetylacetonate, and phenylphosphinic acid are added. It's okay. After the metal oxide hydrate and resin are mixed, they are cured. The curing operation is usually carried out at room temperature, but if the curing time is long, it may be heated to about 30-90°C. If necessary, the cured product may be crushed using a hammer mill, a roll crusher, etc., and then granulated. In that case, the particle size is approximately 3-60
Preferably mesh. Alternatively, the mixture can be continuously extruded into a cylinder onto a device such as a steel belt conveyor, the residence time of the mixture can be maintained on the steel belt conveyor until the mixture has hardened, and then the hardened cylinder can be extruded for a suitable length of time. You can also cut it at the right angle. In addition, using a dish-type rolling granulator or centrifugal flow coating granulator using small particles of the mixture as cores, metal oxide hydrate powder and liquid resin are simultaneously supplied and coated and granulated to produce spherical adsorbents. You may create one. The adsorbent of the present invention obtained in this manner can be used as an adsorbent for various anions and cations, but in particular, for anion adsorption, it selectively adsorbs phosphate ions from acidic solutions. Therefore, it can be used as an adsorbent for phosphate ions. Furthermore, since it has excellent mechanical strength, when used industrially, it can be applied not only to fixed bed adsorption equipment but also to moving bed and fluidized bed adsorption equipment. Furthermore, it has excellent resistance to chemicals such as acids and alkalis, so it does not deteriorate even after repeated desorption and regeneration, and can be used repeatedly for a long time. EXAMPLES The present invention will be specifically explained below with reference to Examples. Example 1 Prepare 100 c.c. of a 1 mol aqueous solution of zirconium oxychloride. This solution contains 9.1gr of metal ions as Zr. When 6N ammonia water is added dropwise to this aqueous solution, a white precipitate of zirconium hydroxide is generated. Add 6N ammonia water until no precipitate forms. The pH of the liquid at this time was 6.0. Next, this white precipitate is separated by suction, washed three times with deionized water, and then dried at below 50°C. Yield approximately 16.0gr. This is ground to 120 microns or less in a mortar to obtain a hydrated zirconium oxide powder. Take 16g of zirconium oxide hydrate powder in a beaker,
This is an isophthalic acid-based unsaturated polyester resin (Polymer 6709, manufactured by Takeda Pharmaceutical Company Limited).
Add 16gr and mix thoroughly with a stirring rod. Next, 0.08gr of cobalt naphthenate and 0.16gr of methyl ethyl ketone peroxide are added, thoroughly mixed, and hardened. Curing time is approximately 30-60 minutes. Next, the solidified resin was taken out from the beaker, crushed into an appropriate size, and then refined into particles of 8 to 32 mesh to obtain an adsorbent. Example 2 In the same manner as in Example 1, 16 gr of zirconium oxide hydrate powder was obtained. Next, 4gr of the same isophthalic acid-based unsaturated polyester resin as in Example 1, 0.02gr of cobalt naphthenate, and 0.04gr of methyl ethyl ketone peroxide were added to this hydrate powder, stirred and mixed thoroughly, and left to harden in about 60 minutes to solidify. become After crushing this solidified resin into a suitable size, an adsorbent finely granulated to 8 to 32 mesh was obtained. Example 3 16g of commercially available titanium oxide hydrate powder was taken, and an adsorbent solidified with an isophthalic acid-based unsaturated polyester resin was obtained in the same manner as in Example 1. Example 4 An equal volume mixture of 100 c.c. of a 1 mol titanium tetrachloride aqueous solution and 100 cc. of a 1 mol zirconium oxychloride aqueous solution is prepared. This liquid contains 4.8gr as Ti and as Zr.
Contains 9.1gr of metal ions. A 3N NaOH solution is added dropwise to this mixed aqueous solution to adjust the pH to 7.
It is thought that titanium oxide hydrate and zirconium oxide hydrate are coprecipitated in the solution. Next, this precipitate is washed and separated, dried at a temperature of 50° C. or less, and pulverized to a size of 120 mesh or less. (yield approx.
26gr) Next, 16gr of the pulverized product was taken, and an adsorbent solidified with an isophthalic acid-based unsaturated polyester resin was obtained in the same manner as in Example 1. Example 5 A 16 gr zirconium oxide hydrate powder was obtained in the same manner as in Example 1. Next, 7gr of bisphenol-based unsaturated polyester resin (manufactured by Takeda Pharmaceutical Company Limited, Prominate P-350) was added to this hydrate powder.
After stirring and mixing thoroughly, 0.035gr of 1% cobalt naphthenate, 0.07gr methyl ethyl ketone peroxide, and further 0.007gr dimethylaniline were added and thoroughly mixed under a N ₂ atmosphere to harden. Curing time is 35-45 minutes. The solid thus obtained was crushed and refined to obtain an adsorbent of 8 to 32 mesh. Example 6 In the same manner as in Example 1, 16 gr of zirconium oxide hydrate powder was obtained. While suspending this powder in 10 ml of water, 10 ml of hydrophilic urethane prepolymer (hydrophilic polyether polyol made by copolymerizing ethylene oxide and propylene oxide with tolylene diisocyanate added to both ends) is mixed therein. Add dropwise while stirring. A reaction between the hydrophilic urethane prepolymer and water immediately begins, and a foamable gel of polyurethane is formed while generating carbon dioxide gas. Zirconium oxide hydrate powder is dispersed and held in this gel. This gel was cut into an appropriate size to obtain an adsorbent. Example 7 The adsorbent prototyped in Example 2 was pulverized to obtain a 120 mesh sieved product. Next, add the above adsorbent powder in the amount shown in the table below to 100 ml of simulated wastewater (PH = 3) containing 500 ppm of phosphate ions prepared using monosodium phosphate, and leave it for one day and night (24 hours).
After shaking, the phosphate ion concentration in the simulated wastewater was measured, and the amount of phosphate ion adsorbed by the adsorbent was measured. The results are shown in Table 1. Note that this table also shows the amount of adsorption of activated alumina powder, which has been conventionally known as a phosphate ion adsorbent.

[Table] Alumina Example 8 20 ml (approximately 20 gr) of the adsorbent prepared in Example 2 (8 to 32 meshes) was packed into a column with an inner diameter of 16 mmφ, and adjusted using monosodium phosphate. Simulated wastewater containing 200 ppm of phosphate ions (PH= with dilute sulfuric acid)
3) was passed at a flow rate of SV=2 1/hr. Then, the column effluent was sampled at regular intervals and the phosphate ion concentration was measured. The results are shown in Table 2.

[Table] The amount of phosphate ion adsorbed by the adsorbent after 5 passes is:
Approximately 47 mg PO ₄ /g adsorbent. 15% on this
It was found that about 93% of the adsorbed phosphate ions were desorbed when 40 c.c. of NaOH solution was passed through it at SV = 2 1/hr. Furthermore, after desorption and regeneration, the sample was repeatedly used under the same conditions as above, passing through the simulated waste water of No. 5, and it was found that the adsorption capacity did not decrease at all even after 30 uses.

Claims (1)

[Claims] 1. An adsorbent obtained by curing a mixture of a hydrate of titanium oxide, zirconium oxide, or tin oxide, or a mixture thereof, and about 1/10 to 3 times the amount of epoxy resin, unsaturated polyester resin, or polyurethane resin.