JPS583741B2 - Granular ion exchanger based on titanium bis(phosphate) dihydrogen and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a granular ion exchanger based on titanium bis(phosphate) dihydrogen and a method for producing the same.

Conventionally, titanium bis(phosphate) dihydrogen (hereinafter simply referred to as Tip)
) is known to have excellent performance as an inorganic ion exchanger; for example, its monohydrate crystals adsorb lithium and sodium ions, and its O-
Redihydrate crystals exhibit good adsorption ability for substances with large ionic radii, such as potassium ions and cesium ions.

Incidentally, although such Tip itself exhibits an excellent action as an inorganic ion exchanger, its particle size is
For example, in the case of monohydrate, 0.3-0.6μ and 0-1
In the case of /2 hydrate, it is extremely fine with a diameter of 1 to 2 microns, and various difficulties have arisen in its use.

For example, even if you try to fill a column with such microcrystals and pass water through it, the column will be blocked by the microcrystals and it will be difficult to pass water through the column.Also, solid-liquid separation will be required after ion exchange treatment using a batch method. Sometimes the Tip is so microcrystalline that it is extremely difficult to achieve efficient separation from the liquid.

In order to overcome the above-mentioned difficulties in use due to the fact that Tip is a microcrystal, the present inventors conducted various studies on granulation methods, and found that silicic acid gel, which can be considered as a binder for granulating fine powder, , polyvinyl alcohol,
Even when granulated with gelatin, etc., it was not possible to obtain granulated products with satisfactory properties, but surprisingly, when a carbonaceous material was mixed with the tip and the mixture was fired and carbonized, good properties were obtained. It was discovered that a solid material having mechanical strength, porous interior, and good ion exchange ability can be obtained, and the present invention was completed.

That is, according to the present invention, a granular ion exchanger made of a porous sintered body containing titanium bis(phosphate) dihydrogen and carbon is provided.

The ion exchanger according to the present invention has a structure in which fine titanium bis(phosphate) dihydrogen crystals are strongly bonded to a predetermined particle size via carbon, so it has excellent heat resistance, water resistance, and chemical resistance. In addition, its mechanical strength is high, and since its surface and internal structure are porous, the decrease in ion exchange ability due to the presence of carbon is extremely small.

The granular ion exchanger according to the present invention is manufactured using a tip and a carbonaceous material as raw materials.

Tip is a monohydrate (T i
(HPO,)2・H20) and O-duck hydrate (T i
(HPO4)2.0~”/2 H2 0 ), which have completely different X-ray diffraction patterns and different ion exchange performance, and as mentioned above, monohydrate is Na
+, Li+, etc., and has good adsorption ability for 0 −
The 14-hydrate has a large ionic radius of K+. Shows good adsorption ability for Ce+ etc.

As the carbonaceous material, various organic substances can be used as long as they are easily mixed with the Tip and easily carbonized by firing.
In general, it is preferable to use organic polymers, such as carbohydrates such as sucrose, wheat flour, starch, and carboxymethyl cellulose, proteins such as petroleum proteins, and synthetic polymers such as polyethylene, polyvinyl chloride, and phenolic resins. Resin, sodium lignin sulfonate, pitch, etc. are applicable.

The ratio of Tip to carbonaceous material used is such that the weight ratio of Tip to carbon is 1.0:0.1 to 5, preferably 1.0:
The ratio is in the range of 0.2 to 1.0.

The mixing ratio of the tip and the carbonaceous material affects the mechanical strength and ion exchange capacity of the sintered body, and if the proportion of the carbonaceous material is too large, the ion exchange capacity will be inhibited; If the amount decreases too much, the mechanical strength will be impaired, so it is best to keep it within the above range.

Furthermore, in the present invention, it is advantageous to use non-volatile acids as carbonization accelerators, such as, for example,
Examples include sulfuric acid and phosphoric acid.

These acids significantly accelerate the carbonization of the carbonaceous material due to their dehydration and catalytic effects on thermal decomposition.

This carbonization accelerator is 1% per 100 parts by weight of carbonaceous material.
It is used in a proportion of 5 to 30 parts by weight.

To produce the granular ion exchanger according to the present invention, first,
The Tip described above, a carbonaceous material, and an optional carbonization accelerator are uniformly mixed.

In this case, an appropriate amount of water is preferably present as a mixing medium.

The homogeneous mixture thus obtained is then dried and solidified.

In this case, if you add a carbonization accelerator such as sulfuric acid or phosphoric acid,
The mixture gives a dark brown solid when dried at 105° C. for 3 hours.

The drying temperature is 100°C or higher, usually 100 to 200°C.

Next, the obtained solid material is sintered and carbonized at high temperature, and the obtained sintered body is pulverized to an appropriate particle size and sieved.

In the present invention, the calcination carbonization conditions must be set within an appropriate range since they affect the performance of the resulting product.

In the present invention, the temperature is 185 to 400°C, preferably 20°C.
Temperatures between 0 and 250°C are employed.

If this firing temperature is too high, the carbon content in the product will decrease,
As the mechanical strength decreases, the structural change of the tip becomes significant, and the ion exchange capacity of the product decreases.

On the other hand, if the firing temperature is too low, foaming will not occur during firing and carbonization, and the ion exchange capacity of the product will decrease.

Therefore, it is advantageous to employ a temperature in this range.

When obtaining a granular ion exchanger according to the present invention, the raw material mixture may be formed into granules in advance, and the granular particles may be calcined and carbonized as they are.

The granular ion exchanger according to the present invention has good mechanical strength and ion exchange capacity, and its structure is carbon-containing porous (allows ions of about 1 Å to freely pass through). It also has the ability to adsorb organic substances such as.

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

Example I A: Production of granular ion exchanger A predetermined amount of Tip,
The carbonaceous material was added, 9M sulfuric acid and 7M phosphoric acid as carbonization accelerators, and an appropriate amount of water were added and stirred uniformly, followed by drying at 105° C. for about 3 hours until the mixture became a blackish brown solid.

Next, this crucible was covered with a lid and heated in an electric furnace heated to a predetermined temperature to sinter the contents.

After cooling, the yield of the fired product was determined, and then the fired product was crushed, sieved, thoroughly washed with water until acid content disappeared, and then dried at 50 to 60°C for 24 hours.

Table 1 shows the component composition of the product thus obtained in relation to the manufacturing conditions.

B: Ion adsorption test (batch method) Using the sample prepared as described above (particle size 60 to 100 mesh), the equilibrium ion exchange capacity between the granulated material and an aqueous chloride (NaCt, KCt) solution was determined in the batch method. (QAmeq/S') and the saturated ion exchange capacity (Qmeq/y) at pH 4.5, and from these ion exchange capacities, ion exchange characteristics such as selection coefficient (KH) and distribution coefficient (KD) can be determined. I asked for it.

The results are shown in Table 2.

The sample numbers shown in the table correspond to the samples in Table 1.

Note that the selection coefficient, adsorption amount, and distribution coefficient in Table 2 have the following meanings.

(However, in the above formula, C is the initial amount of chloride MCA used (2
．． 5 meq), S indicates the capacity of MCt (251 ILl), and ■ indicates the amount of ion exchanger used (0.5 Si'). No. 10) equilibrium ion exchange capacity (
QA) is 0.86 to 1.10 meq/g, 1.46 for Na+ and K+, excluding the 350°C sintered body.
~1.98 meq/g, and the QA of those containing TiP-H20 (No. 1 to No. 5) is 0.4 3 to 0.
9 5 meq/g, 0.1 4 ~0.24 meq/g
It can be seen that the product according to the present invention has a large adsorption capacity even though it contains carbonaceous matter.

In those containing TiP-H20 (A1-16.5), the saturated ion exchange capacity QO for Na+ at pH 4.5 shows a fairly large value, which can be seen from the selection coefficient (KH), distribution coefficient (KD), etc. like,
It is not possible to separate Na+ and K+.

On the other hand, granules containing /dihydrate (No. 6 to No.
．． 10) Saturated ion exchange capacity Q for Na'', K+
O is 1.2 and 8, respectively, except for products fired at 350°C.
~1.78meq/g, 1. 5 6 ~2. 3
4 meq/g, KH and KD for K show significantly larger values than those for Na+, and %
It was confirmed that the granulated material containing the hydrate has an excellent selective adsorption property for K+.

QA and Q0 have maximum values at a sintering temperature of 200° C., and these values decrease as the temperature increases.

In particular, the ion exchange capacity of the product fired at 350°C is reduced to about % of that of the product fired at 200°C.

This is considered to be due to a structural change in the % hydrate during high temperature firing.

No. 1 1, No. In No. 12, the influence of additives during firing on the ion exchange properties was investigated.

As a result, the ion exchange capacity of A12 with the additive added was slightly increased.

This is probably because carbonization is slightly promoted by the addition of inorganic acid.

No. 1 2, No. l 3 , No. In 14, the influence of carbon quality on ion exchange properties was investigated.

As a result, QA and QO decreased in the order of sucrose, wheat flour, and sodium ligninsulfonate.

This tendency also appeared in the ion exchange properties of KMKD and the like.

That is, among the carbonaceous materials used, sucrose gave the best results.

Example 2 Hard glass column (inner diameter 9 mm, height 200 m
m), dried granulated ion exchanger (60-100 mesh)5. The Og was pre-wetted with water and then packed.

A predetermined amount of the sample solution is passed through this at a rate of 0.4 to 0. 5m
1/min, and the effluent from the column was collected in 10 ml portions using a fraction collector, and the Na+ and K+ contained in each fraction were measured using a flame photometer, Mg2+, and C.
A2+ was quantified using an atomic absorption spectrophotometer, and the process by which each ion was adsorbed to the granules was investigated.

Furthermore, 6M of cations adsorbed on the granulated ion exchanger
The sample was completely eluted with 30 ml of hydrochloric acid and an appropriate amount of water, and each ion in the eluate was quantified to determine the ion exchange capacity, KD, separation coefficient (αHa), and other ion exchange properties of the granulated ion exchanger.

These results are shown in Table 3.

In addition, in Experiment Boil 7, artificial seawater was used, and Ca2+, Mg2
The adsorption trends of K'' and Na+ in the presence of + were investigated.

The distribution coefficients KD, KD and separation coefficient KM in the table have the following meanings.

(mNa and mK in the formula are N adsorbed per 1 g of exchanger.
(in the formula, M represents an element such as Na, Mg, Ca, etc.) No. I
, No. In No. 2, the concentration of the sample NaCl-KCl mixed aqueous solution is approximately twice the concentration of both salts contained in seawater, and the Na/K atomic ratio is 50.8.

The granulated product (A1) containing monohydrate packed in the column has K
Since it adsorbed only a small amount of K+, it was unsuitable as an ion exchanger for K+.

The ion exchange capacity for K+ of the granulated material (A2) containing 0 to % hydrate is 0. 5 7 7 meq /g, but the atomic ratio of adsorbed Na and K is 1.83, αN8
showed 27.9.

A3, 116. 4 and A5 use solutions with approximately the same concentrations of Na Cl and KCl contained in seawater.

When this solution was passed through the column, the amount of Na+ and K'' (7) adsorption and the value of αba gradually increased as the amount of the solution increased.

In A6, the sum of the concentrations of NaCl and KCl is No. Exactly the same solution as used in step 2 was used, but the concentration of NaCl was reduced and the concentration of KCl was increased tenfold.

As a result, the exchange amount of Na+ was 1.05 meq/g to 0.
．． The amount of K+ exchanged decreased to 8 5 6 meq/g, but the exchange amount of K+ was 0. 5 7 7 meq/g 1. 0 5
meq/g.

In this case, the value of αHa was approximately 5 since the K+ concentration in the solution was relatively high.

No. In 7, artificial seawater was used as the sample liquid.

As a result, the exchange capacity of Na+ and K+ is
The atomic ratio of Na and K was 2.13, which was exactly the same value, although both were slightly decreased compared to that of A4 using the l-KCl mixed solution.

Compared to K+, there is a considerable amount of Mg in artificial seawater.
Contains Ca2+.

Nevertheless, these ions were only slightly adsorbed on the granules containing 0 to 1/2 hydrates, and α%a both showed large values.

Claims (1)

[Claims] 1. A granular ion exchanger made of a porous sintered body containing titanium bis(phosphate) dihydrogen and carbon. 2. A method for producing a granular ion exchanger comprising the step of firing and carbonizing a mixture of titanium bis(phosphate) dihydrogen and a carbonaceous material to obtain a porous sintered body. 3. The method according to claim 2, wherein calcination carbonization is performed using an inorganic acid as a carbonization accelerator. 4. The method according to claim 2 or 3, wherein the firing carbonization is performed using a temperature of 180 to 400°C.