JPS6147134B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adsorbent that has excellent mechanical strength and adsorption performance, and is inexpensive to manufacture. 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 is not necessarily a satisfactory method, and there is a strong need for the development of a new phosphate ion removal technology. On the other hand, titanium oxide, zirconium oxide, and tin oxide hydrates have properties as ion exchangers; for example, in acidic solutions, they fix H ⁺ and become anion exchangers, and phosphate ions , fluorine ion, sulfate ion, chloride ion, arsenate ion,
Adsorbs arsenite ions, chromate ions, molybdate ions, etc. It is also known that in alkaline solutions, it fixes OH ^- and acts as a cation exchanger. The present inventors have conducted research and development of adsorbents focusing on the ion exchange properties of these metal oxide hydrates, but when manufacturing adsorbents using only metal oxide hydrates, the main raw material Both zirconium and titanium are relatively expensive metals, which inevitably increases the cost of the adsorbent. In addition, when producing an adsorbent using the precipitate of these metal oxide hydrates, there are many problems in production, such as the precipitate being gel-like and requiring time for overtreatment;
It has been found that the adsorbent produced in this manner has a fatal drawback of being unable to withstand industrial conditions of use due to its low mechanical strength. As a result of further research, the inventors found that titanium,
The adsorbent obtained by directly mixing zirconium or tin hydrated ferrite with unsaturated polyester resin or polyurethane resin and curing this has excellent mechanical strength and adsorption performance, and is inexpensive to manufacture. I found out that it is cheap,
Based on these findings, we have completed the present invention. That is, the present invention provides an adsorption material obtained by curing a mixture of hydrated ferrite of titanium, zirconium, or tin, or a mixture thereof, and about 1/10 to 3 times the amount (weight) of an unsaturated polyester resin or polyurethane resin. Regarding drugs. The hydrous ferrite of titanium, zirconium or tin used to produce the adsorbent of the present invention is M.Fe _{2.O 4.mH 2} O+XFe ₃ O _{4.nH 2} O
Examples include those expressed by the general formula. Here, M represents titanium, zirconium, or tin. X represents the mixing ratio of Fe ₃ O ₄ · nH ₂ O to M · Fe ₂ O ₄ · mH ₂ O, which is determined by the amount of ferrous ion added during the production of hydrous ferrite, which will be described later. and represents an integer from 0 to 3. m and n represent the water content of the hydrated ferrite, and represent integers from 1 to 4, although they vary depending on the drying conditions. Specifically, for example, as a hydrous ferrite of titanium,
Ti・Fe ₂ O ₄・mH ₂ O＋XFe ₃ O ₄・nH ₂ O (in the formula,
X, m, and n have the same meanings as above), and the hydrated ferrite of zirconium is Zr・Fe ₂ O ₄・mH ₂ O+
XFe ₃ C ₄・nH ₂ O (in the formula,
Fe ₂ O ₄・mH ₂ O＋XFe ₃ O ₄・nH ₂ O (in the formula,
(m and n have the same meanings as above). The moisture content (100°C dry moisture content) of these hydrous ferrites is usually about 6 to 30% by weight. The above-mentioned hydrated ferrite is produced by the following method. In a solution containing metal ions prepared by dissolving metal salts of titanium, zirconium or tin,
For the metal ions contained in this solution, approximately 2
After adding the ferrous salt equivalent to ~11 times the mole, add an alkali to bring the pH of the liquid to about 8 or higher, preferably about 9.
Hold at ~11. After this, if necessary, after bringing the temperature of the solution to about 30-80°C, blowing in an oxidizing gas such as air, oxygen gas or ozone, or adding an oxidizing agent such as hydrogen peroxide, Forms an acid salt precipitate. In this case, the ion adsorption power of the produced hydrous ferrite changes depending on the amount of ferrous salt added. For example, when twice as many moles of ferrous salt as metal ions are added, the ion adsorption power is the highest, and as the amount of ferrous salt added increases, the ion adsorption power tends to decrease. By the way,
Hydrous magnetite such as Fe ₃ O ₄ · nH ₂ O alone has a small ion adsorption power, and the above-mentioned titanium,
By mixing zirconium or tin hydrous ferrite, the ion adsorption power is dramatically improved.
This will bring out the features of the present invention. To explain the above in more detail, in the general formula MFe ₂ O ₄ · mH ₂ O + XFe ₃ O ₄ · nH ₂ O, the value of X changes depending on the amount of ferrous salt added. For example, if ferrous salt is added twice the mole of metal ions, X=0,
Adding 11 times the mole makes X=3. Generally X
As the value of increases, the ion adsorption power of the produced hydrous ferrite tends to decrease. The resulting hydrated ferrite precipitate is separated, washed with water, and then dried. Drying is done by air drying, or at a temperature below about 100°C, preferably below about 50°C, for about 1 to 20 hours.
dry. As mentioned above, the moisture content after drying is preferably within the range of about 6 to 30% by weight. In this way, hydrous ferrites of titanium, zirconium or tin are obtained. Examples of titanium, zirconium, or tin metal salts used in the production of hydrous ferrite include titanium tetrachloride (TiCl ₄ ), titanium sulfate (Ti
(SO ₄ ) ₂ ), zirconium oxychloride (ZrOCl ₂
8H ₂ O), zirconium tetrachloride (ZrCl ₄ ), zirconium nitrate (Zr(NO ₃ ) ₄・4H ₂ O), zirconium sulfate (Zr(SO ₄ ) ₂・4H ₂ O), zirconium acetate (Zr
(CH ₃ COO) ₄ ), tin tetrachloride (SnCl ₄ ), tin nitrate (Sn(NO ₃ ) ₄ ), and tin sulfate (Sn(SO ₄ ) ₂ ). These metal salts are typically about 0.05 to
It is used in the form of a 2.0 mol% solution. Examples of ferrous salts include ferrous sulfate ( _FeSO4.7H2O ) and ferrous nitrate (Fe( _{NO3 ) 2} .
6H ₂ O), ferrous chloride (FeCl ₂ ), etc. These ferrous irons are usually added in form, but may also be added in solution. Examples of the alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, and sodium carbonate. These are usually used in an aqueous solution of about 5 to 20% by weight. When blowing oxidizing gas, the time varies depending on the type of oxidizing gas, but usually about 1~
It takes about 3 hours. As the oxidizing agent, for example, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, etc. are used. The hydrated ferrite may have any shape, but those with a particle size of about 250 μm or less are particularly preferred in terms of mixing operation with the resin and adsorption performance, which will be described later. Hydrous ferrite may be used alone or in combination of two or more. In the present invention, the hydrated ferrite thus obtained is mixed with an unsaturated polyester resin or polyurethane resin in an amount of about 1/10 to 3 times, preferably about 1/5 to 1 time (by weight). 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, if the proportion of resin is small and is less than about 1/10 times the above amount, the adsorption performance is excellent, but the mechanical strength is reduced and it is not suitable for industrial use. There is. The unsaturated polyester resin used to produce the adsorbent of the present invention may be any known unsaturated polyester resin, but specifically,
For example, a compound obtained by condensing 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. Saturated linear polyesters, such as styrene, chlorostyrene,
Examples include those dissolved in vinyl monomers such as methyl methacrylate and diallyl phthalate. The dicarboxylic acids mentioned above may be modified with unsaturated dicarboxylic acids or saturated dicarboxylic acids, such as fumaric acid, itaconic acid, phthalic anhydride, adipylic acid, hettic acid, sebacic acid, isophthalic acid, terephthalic acid. The dihydric alcohol may also be modified with glycols such as bisphenol A, hydrogenated bisphenol A, butanediol diethylene glycol, dipropylene glycol, triethylene glycol, trimethylene glycol, hexanediol, pentanediol, and the like. Any known polyurethane resin can be used as the polyurethane resin, but specifically, polyurethane resins having two or more hydroxyl groups in the molecule, such as polyether polyols, polyester polyols,
Polymer polyols, butadiene polyols,
Polyols such as polycarbonate diol and castor oil and two or more isocyanate groups in the molecule, such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (Piure MDI), naphthalene diisocyanate (NDI), and dimethyl diphenyl diisocyanate (TODI). , polymethylene polyphenyl polyisocyanate (crude MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and other polyisocyanates are reacted by a known method. can give. 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 aforementioned unsaturated polyester resin or polyurethane resin is liquid at room temperature, it can be used as is, but if it is solid,
For example, hydrocarbons such as butane, hexane, cyclohexane, benzene, toluene, halogenated hydrocarbons such as methylene chloride, chloroform, trichloroethane, chlorobenzene, methanol,
Alcohols such as ethanol and propanol; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; Boil until liquid. A specific method for mixing a hydrous ferrite of titanium, zirconium, or tin with an unsaturated polyester resin or a polyurethane resin includes, for example, stirring the hydrous ferrite and the resin at high speed in a container equipped with a stirrer. Examples include a method of mixing in a batchwise or continuous manner using a kneading machine, a method of batchwise or continuous mixing using a device used for mixing solids and liquids, and the like. When mixing the hydrous ferrite and the resin, 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 mixing the hydrated ferrite and the resin, it is 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 to 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, hydrated ferrite and liquid resin are simultaneously supplied and coated and granulated to create a spherical adsorbent. You may. The adsorbent of the present invention obtained in this manner can be used as an adsorbent for various anions and cations, but in particular, with regard to anion adsorption, it selectively adsorbs phosphate ions from acidic solutions. Therefore, it can be used as an adsorbent for phosphate ions. Further, the adsorbent of the present invention has the characteristic that it selectively adsorbs a large amount of phosphate ions in a pH range of about 1 to 5, but hardly adsorbs alkaline ions. Therefore, after performing an adsorption operation in an acidic solution with a pH of about 1 to 5, it can be desorbed with an alkaline solution, and it can be used repeatedly. In addition, the adsorbent of the present invention has excellent mechanical strength, so it can withstand industrial usage conditions, and can be applied not only to fixed bed adsorption equipment, but also to moving bed and fluidized bed adsorption equipment, especially when performing adsorption operations. I can't help it. Furthermore,
It also has excellent resistance to chemicals such as acids and alkalis, so it does not deteriorate even after repeated desorption and adsorption, and can be used repeatedly for a long time. In particular, hydrated ferrite forms a crystal lattice of a safe compound, with titanium and titanium in the positions occupied by iron atoms in the lattice composed of added ferrous salt
Since it is presumed that zirconium or tin atoms are incorporated and form a solid solution, these metals have the advantage of being stable and difficult to elute. Furthermore, the adsorbent of the present invention can be magnetically separated, and solid-liquid separation of the adsorbent is easy. In addition, the adsorbent of the present invention can be manufactured by a simple operation of simply mixing a hydrous ferrite of titanium, zirconium, or tin with an unsaturated polyester resin or a polyurethane resin and curing the mixture, so the manufacturing cost is low. It has the advantage of being cheap. EXAMPLES The present invention will be described in more detail with reference to Examples below. Example 1 A 0.15 mol aqueous solution of titanium tetrachloride was prepared. This solution contains 7gr of metal ions as Ti. 84g of ferrous sulfate crystals (FeSO ₄ .7H ₂ O) are also added to this aqueous solution and dissolved while stirring. This amount corresponds to 0.3 mol as ferrous ion. Next, a 15% by weight sodium hydroxide solution is added dropwise to this aqueous solution while stirring, producing a blue-green precipitate. Continue dropping until the pH of the aqueous solution reaches 10. Next, air is blown into the aqueous solution at a flow rate of 10/hour while heating it to 60 to 70°C. Continuing to blow air will lower the pH of the aqueous solution, so in this case, add 15% by weight sodium hydroxide solution to maintain the pH at 10. Air is blown for about 2 hours to form a black titanium hydrated ferrite precipitate. Next, this black precipitate was suctioned off, washed with deionized water until the solution became neutral, and then washed for 70 minutes.
Dry below ℃. This is ground in a mortar to a particle size of 120 microns or less to obtain a titanium hydrated ferrite powder. Place 20g of hydrated titanium ferrite powder in a beaker and add isophthalic acid-based unsaturated polyester resin (manufactured by Takeda Pharmaceutical Company Limited; Polymer
6709) Add 20gr and mix thoroughly with a stirring rod.
Next, add 0.1gr of cobalt naphthenate and 0.2gr methyl ethyl ketone peroxide, mix well, and harden. Curing time is approximately 30-60 minutes. Next, the solidified material 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 1 0.05 mol aqueous solution of zirconium oxychloride
adjust. This solution contains 4.55gr of metal ions as Zr. 27.8 gr of ferrous sulfate crystals (FeSO ₄ .7H ₂ O) are added to this aqueous solution and dissolved with stirring. This amount is as iron ion
Equivalent to 0.1mol. Next, add 15% by weight to this aqueous solution.
While stirring the sodium hydroxide solution of
If the solution is dropped until the concentration reaches 11, a bluish-green precipitate will form.
Next, while heating this aqueous solution to 50 to 80℃,
Blow air at a flow rate of /hour. Continuing to blow air will lower the pH of the aqueous solution, so in this case, add a 15% by weight sodium hydroxide solution dropwise.
Keep PH at 10. If air is continued to be blown until the pH no longer decreases, a black zirconium hydrated ferrite precipitate will form. Next, this black precipitate is suctioned off, washed with deionized water until the liquid becomes neutral, and then dried at below 50°C.
This is ground in a mortar to a size of 120 microns or less to obtain zirconium hydrated ferrite powder. Next, 10g of this zirconium hydrated ferrite powder was placed in a beaker, and then, in the same manner as in Example 1, it was mixed with 10g of isophthalic acid-based unsaturated polyester resin and cured to obtain an adsorbent. Example 3 14g of the zirconium hydrated ferrite powder prepared in Example 2 was placed in a beaker, and the same procedure as in Example 1 was carried out to prepare an isophthalic acid-based unsaturated polyester resin.
6gr, cobalt naphthenate 0.03gr, methyl ethyl ketone peroxide. After adding 06gr and stirring thoroughly, leave it to harden in about 60 minutes. After crushing this into an appropriate size, it was refined into particles of 8 to 23 mesh to obtain an adsorbent. Example 4 1 0.05 mol aqueous solution of zirconium oxychloride
adjust. This solution contains 4.55gr of metal ions as Zr. Add 153 gr of ferrous sulfate crystals (FeSO ₄ .7H ₂ O) to this aqueous solution and dissolve while stirring. This amount is as iron ion
Equivalent to 0.55mol. Next, add 15 to this aqueous solution.
While stirring the wt% sodium hydroxide solution,
If the solution is added dropwise until the pH of the solution reaches 9.5, a blue-green precipitate will form. Next, air is blown into the aqueous solution at a flow rate of 10/hour while heating it to 40 to 70°C. Continuing to blow in air will lower the pH of the aqueous solution, so at this time, drop a 15% by weight sodium hydroxide solution to maintain the pH at 10. If air is continued to be blown until the pH no longer decreases, a black zirconium hydrated ferrite precipitate will form. Thereafter, an adsorbent was obtained by processing in the same manner as in Example 1. Example 5 In the same manner as in Example 2, 16 gr of zirconium hydrated ferrite powder was obtained. Next, 7gr of bisphenolic unsaturated polyester resin (Prominate P-350 manufactured by Takeda Pharmaceutical Company Limited) was added to this powder, and after stirring and mixing thoroughly, 0.035gr of 1% by weight cobalt naphthenate solution, 0.07gr of methyl ethyl ketone peroxide, Further, 0.007g of dimethylaniline is added, thoroughly mixed under a nitrogen gas stream, and cured. 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 2, 16 gr of zirconium hydrated ferrite powder was obtained. While suspending this powder in 10ml of water, add 10ml (approximately 10gr) of a hydrophilic urethane polymer (a hydrophilic polyether polyol made by copolymerizing ethylene oxide and propylene oxide with tolylene diisocyanate added to both ends). Add dropwise while mixing. The reaction between the hydrophilic urethane prepolymer and water immediately begins, and a foamable gel of polyurethane resin is formed while generating carbon dioxide gas. In this gel, zirconium hydrated ferrite powder is dispersed and held.
This gel was cut into an appropriate size to obtain an adsorbent. Example 7 The adsorbent obtained in Example 2 was crushed to 120mesh.
A sieved product was obtained. Next, the above adsorbent powder was added 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 after shaking all day and night (24 hours),
Table 1 shows the results of measuring the phosphate ion concentration in the simulated wastewater and measuring the amount of phosphate ion adsorbed by the adsorbent. Note that this table also includes the amount of adsorption of activated alumina powder, which has been known as an adsorbent for phosphate ions.

[Table] Adsorbents
4 Commercial activity 0.8 500 50 56
Alumina Example 8 The adsorbent obtained in the same manner as in Example 3 was finely granulated into 32-0 mesh, and was placed in a column of 10 gr (approximately 14
ml) filled. Here, simulated wastewater containing 300 ppm of phosphate ions (adjusted to PH = 4 with dilute sulfuric acid) prepared using monosodium hephosphate was SV3 (1/
The liquid was passed through at a flow rate of (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 2.5 liquid passages was approximately 65 mgPO ₄ /g adsorbent. When 30 ml of 15 wt% NaOH solution was passed through this at SV=1 (1/hr), it was found that about 95% of the adsorbed phosphate ions were desorbed. Example 9 The adsorbent obtained in the same manner as in Example 3 was granulated into 8 to 32 meshes, and 20gr (approx.
30ml) filled. Add 380ppm phosphate ion here
SV = activated sludge treated water 5 adjusted to contain
The solution was passed at a flow rate of (1/Hr). The amount of phosphate ion adsorbed by the adsorbent after 5 passes was approximately 52 mg PO ₄ /g adsorbent. Add 40ml of 15wt% NaOH solution to this.
It was found that approximately 94% of the adsorbed phosphate ions were desorbed when the solution was passed at a rate of 1 (1/Hr). Next, 2% by weight of H ₂ SO ₄ was added to the adsorbent after desorption.
After regenerating by passing 40 ml of the solution at SV=10 (1/Hr), the activated sludge treated water of No. 5 was passed under the same conditions as above, and repeated use was continued. The results are shown in Table 3.

[Table] As is clear from this table, the adsorbent of the present invention has a
It was found that the adsorption capacity hardly decreased even after repeated use. Example 10 2% by weight H ₂ SO ₄ was added to a test solution containing 500 ppm of phosphate ions prepared using monosodium phosphate.
100 ml each of simulated wastewater was prepared by adding the solution or 2% by weight NaOH solution to adjust the pH to 1, 2, 3, 5, 8, 10, and 12. Next, the adsorbent obtained in Example 2 was pulverized into 120-mesh sieved products, and 300 mg of each was added to the above simulated wastewater. After shaking for a day and a night (24 hours), the phosphate ion concentration in the simulated wastewater was measured, and the phosphate ion and adsorption amount of the adsorbent were measured. The results are shown in Table 4 and FIG.

[Table] As is clear from Table 4 and Figure 1,
It can be seen that the adsorbent of the present invention adsorbs a large amount of phosphate ions especially in the pH range of 2 to 5, but hardly adsorbs on the alkaline side of pH 10 or higher.

[Brief explanation of the drawing]

In Figure 1, the horizontal axis shows the concentration of phosphate ion-containing aqueous solution.
The PH is shown on the vertical axis, and the amount of phosphate ion adsorbed by the adsorbent of Example 2 of the present invention is shown.

Claims (1)

[Claims] 1. Made by curing a mixture of titanium, zirconium, or tin hydrated ferrite, or a mixture thereof, and about 1/10 to 3 times the amount (weight) of unsaturated polyester resin or polyurethane resin. adsorbent.