CN101456617A - Method for removing bromate ion in drinking water - Google Patents

Abstract

The invention relates to a method for removing bromate ions in drinking water, which belongs to the technical field of drinking water purification treatment. The invention utilizes the ion exchange principle of inorganic layered compounds to remove bromate ions in drinking water. The main points of the method of the present invention are: adopt a certain amount of divalent metal oxide, trivalent metal oxide or trivalent metal hydroxide, the two are mixed according to the molar mass ratio of 3:1 or 3:2, and the mixed solid The powder is pressed into flakes or columns, and then sintered at 1300-1600°C for 8-12 hours; the sintered product is ground into fine particles and put into saturated divalent metal chloride or nitrate solution, and stirred with a magnetic stirrer 48 hours to make it fully react; then filter, dry and grind to obtain the inorganic layered compound. The layered compound is filled in a packing column of a traditional commonly used filter device as a filter adsorption material. The removal rate of drinking water containing bromate can reach 87-97% after being treated by packed column.

Description

A method for removing bromate ions in drinking water

technical field

The invention relates to a method for removing bromate ions in drinking water, which belongs to the technical field of drinking water purification treatment.

Background technique

Natural river water is generally used as the source of drinking water in my country. Natural fresh water generally contains bromide ions, which can be converted into bromate ions after treatment with ozone-biological activated carbon technology. Especially when seawater intrudes into natural river water, the concentration of bromide ions can increase significantly, leading to an increase in the concentration of bromate in the treated drinking water, which may affect the health of residents. The World Health Organization lists bromate as a substance that may pose a carcinogenic risk to humans. Both my country and the U.S. Environmental Protection Agency limit the content of bromate in drinking water to less than 10 μg/L.

At present, the technologies for removing bromate in drinking water mainly include chemical reduction, activated carbon adsorption, light and photocatalytic degradation, and biological methods. But these methods have their own problems. The method of adding Fe(II) will increase the chroma of the effluent, and at the same time it is difficult to determine the dosage; UV photodegradation requires a large light source power and consumes a lot of energy; although photocatalysis can improve the degradation efficiency, it is economical. Poor performance and engineering operability; the removal effect of biological method is greatly limited by conditions such as water temperature, microbial culture and competing anions, and the effect is unstable; the adsorption and reduction of bromate by activated carbon is relatively affected by organic matter and anions in the water. Many, and there are problems with regeneration.

Layered compounds with a hydrotalcite-like structure have been proven to be able to use interlayer anion substitution to treat many common pollutants, such as the removal of chromate and phosphate in water. Studies have shown that the pollutants entering the interlayer can exist stably in the layered compounds, so that the layered compounds with a hydrotalcite-like structure can effectively remove large anion groups in drinking water, and can achieve the purpose of purifying drinking water.

Contents of the invention

The purpose of the present invention is to utilize the original commonly used filtering device, and adopt the metal compound to synthesize the inorganic layered compound with anion exchange function as the filtering material, to remove the bromate ion in the drinking water.

A kind of method of removing bromate ion in drinking water of the present invention is characterized in that it has following process and step:

a. preparation removes and purifies the inorganic stratified compound of bromate ion: first prepares the special compound of removing bromate ion, and it has following structural formula: ${\left[m_{1-x}^{\mathrm{II}}{m}_x^{\mathrm{III}}{\left(\mathrm{Oh}\right)}_{2x}\right]}^{x+}{\left(A^{\mathrm{no}-}\right)}_{x/\mathrm{no}}\·m{h}_{2}o,$ Wherein M ^II is a divalent metal ion, M ^III is a trivalent metal ion, A is an interlayer anion, and the A anion is any one of OH ^- , Cl ^- or NO ₃ ^- ; preparing the inorganic layered compound The steps are: weigh a certain amount of divalent metal oxygen compound, trivalent metal oxide or trivalent sodium hydroxide, mix the two in a molar mass ratio of 3:1 or 3:2, and make the mixture fully uniform ; Press the mixed solid powder into a sheet or column; then sinter at 1300-1600°C for 8-12 hours; grind the sintered product into fine particles and put it into a nearly saturated second-order metal chloride or nitrate solution Stir vigorously with magnetic stirring for 48 hours to make it fully react; then filter to obtain a precipitate, dry the precipitate at 105°C, and then grind to obtain an inorganic layered compound powder, which is sealed and stored for later use;

The reaction formula that this layered compound generates is:

3M ^II O M ^III 2O ₃ +M ^II A ₂ +10H ₂ O→[M ^II ₂ M ^III (OH) ₆ ] ₂ A ₂ 4H ₂ O

Above-mentioned divalent metal oxide is any one in calcium chloride, magnesium oxide, zinc oxide; Trivalent metal oxide is iron oxide, aluminum oxide, and trivalent hydroxide is iron hydroxide, aluminum hydroxide, in Any one of trivalent metal oxide or trivalent metal hydroxide;

b. the above-mentioned prepared inorganic layered compound filling is placed in the packing column in the existing filter column reactor device commonly used in the tradition; Then the drinking water containing bromate ion is passed from the bottom of the column, and with The flow rate of 60-100ml/h passes through the packed column and flows out from the top of the packed column; the results show that after the drinking water containing bromate ions is treated, the removal rate of bromate ions reaches 87-95%.

The invention utilizes the principle of ion exchange without layered compounds to remove bromate ions in drinking water. The advantage of the invention is that the prepared inorganic layered compound filter material has extremely small solubility and will not cause secondary pollution to drinking water during use. In addition, bromate ions entering the interlayer have good stability and are not easily released again under the influence of chloride ions or nitrate ions in water.

The invention utilizes the original filter column device and combines the new inorganic layered compound as filter material or adsorption material, and can effectively remove bromate ions in drinking water, and the removal rate can reach 87-95%.

Description of drawings

Fig. 1 is a simple schematic diagram of a conventional conventional filter column reactor device utilized in the present invention.

Detailed ways

Specific embodiments of the present invention are described below.

In the embodiment, the present invention utilizes the traditional and commonly used original filter column reactor device (see Figure 1). In the packing column in the filter column reactor device, the prepared inorganic layered compound is filled and placed in the middle part as a filter adsorption material, and filter sand is installed at the upper and lower ends to support and evenly distribute water. function, while the inorganic layered compound is placed on the bottom sand to play the role of filtration and adsorption.

Example 1

Weigh 168g of calcium oxide and 102g of alumina, press the mixed solid into a sheet or column, and sinter at 1500°C for 12 hours. The sintered product was ground and put into a nearly saturated calcium chloride solution, stirred by magnetic force for 48 hours and then filtered. The solid material was dried at 105° C. and then ground. Take 20g of the prepared solid material and fill it into a cylindrical packed column, pass drinking water containing bromate 37.678μg/L from the bottom of the column, and pass through the packed column at a flow rate of 60 ~ 100ml/h and then from the packed column top out. The results showed that after 100L of bromate-containing drinking water was treated, the removal rate of bromate reached 91%-95%, and its concentration dropped below 10μg/L.

Example 2

Weigh 84g of calcium oxide and 107g of iron hydroxide, press the mixed solid into a sheet or column, and sinter at 1500°C for 12 hours. The sintered product was ground and then put into a nearly saturated calcium chloride solution, stirred by magnetic force for 48 hours and then filtered. The solid material was dried at 105° C. and then ground. Get the prepared solid material 10g and drop into 100L drinking water containing bromate 34.532μg/L. The mixture was stirred for 1 hour and then filtered. The results showed that after 100L of bromate-containing drinking water was treated, the removal rate of bromate reached 87%, and its concentration dropped below 10μg/L.

The solid material referred to in Example 1 is the inorganic layered compound Ca-Al-LDH (LDH means an interlayer compound containing ^OH- , and the original text of LDH is Layered Double Hydroxides).

The solid material referred to in Example 2 is the inorganic layered compound Ca-Fe-LDH (LDH means an interlayer compound containing ^OH- , and the original text of LDH is Layered Double Hydroxides).

Claims (1)

1. method of removing bromate ions in drinking water is characterized in that it has following process and step:

A. the inorganic layered compounds that purifies bromate ion is removed in preparation: at first the extraordinary compound of bromate ion is removed in preparation, and it has following structural formula: M wherein ^IIBe divalent-metal ion, M ^IIIBe trivalent metal ion, A is the interlayer intercalant anion, and the A negatively charged ion is OH ^-, Cl ^-Or NO ₃ ^-In any; The step for preparing described inorganic layered compounds is: take by weighing a certain amount of divalent metal oxygenate, trivalent metal oxide or trivalent sodium hydroxide, both are the mixed of 3:1 or 3:2 by the mole mass ratio, and make mixing full and uniform; With blended solid powder compression slabbing or column; Then 1300～1600 ℃ of sintering temperatures 8～12 hours; Product behind the sintering ground to form drop into behind the particulate in nearly saturated the divalent metal muriate or nitrate solution; Stirred 48 hours with magnetic agitation is powerful, it is fully reacted; Filter then, obtain throw out, this throw out 105 ℃ of oven dry down, is ground then, obtain the inorganic layered compounds powder, sealing is preserved standby; The reaction formula that this lamellar compound generates is:

3M ^IIO·M ^III ₂O ₃+M ^IIA ₂+10H ₂O→[M ^II ₂M ^III(OH) ₆] ₂A ₂·4H ₂O

Above-mentioned bivalent metal oxide is any in calcium chloride, magnesium oxide, the zinc oxide; Trivalent metal oxide is ferric oxide, aluminum oxide, and trivalent oxyhydroxide is ironic hydroxide, aluminium hydroxide, chooses any one kind of them in trivalent metal oxide or trivalent metal hydroxides;

B. the above-mentioned inorganic layered compounds for preparing is filled in the filled column that is positioned in the tradition existing filter column type reactor device commonly used; To contain of the bottom feeding of the tap water of bromate ion then, and pass through packed column, and flow out from the top of packed column with 60～100ml/ hour flow from post; The result show contain bromate ion tap water after treatment, the clearance of bromate ion reaches 87～95%.

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