KR102574977B1 - Manufacturing method of bead-type adsorbent for arsenic removal using mine drainage sludge - Google Patents

Abstract

The present invention relates to a method for manufacturing a bead-type adsorbent for removing arsenic using acid mine drainage, which is capable of adsorbing arsenic by drying acid acid drainage sludge, mixing it with an inorganic binder, and molding it into a bead-type adsorbent.
The present invention includes a mine drainage storage step (S10) in which solid foreign substances are precipitated while receiving and storing the mine drainage; a sludge dry powder step (S20) of dehydrating and drying the precipitated mine drainage sludge to produce sludge dry powder and homogenizing the sludge dry powder into a 25 to 35 mesh; a sludge powder homogenization step (S30) of sifting the produced mine drainage sludge dry powder through a sieve of a predetermined size and homogenizing the mine drainage sludge powder to have a standard size or less; An inorganic binder mixing step (S40) of mixing inorganic binder, CaO, and water with mine drainage sludge powder and evenly stirring; A bead-type adsorbent manufacturing step (S50) of preparing a bead-shaped adsorbent from a mixture of acid mine drainage sludge powder, inorganic binder, CaO, and water; but, the inorganic binder mixing step (S40) is based on 100 weight of the mine drainage sludge powder 5 to 10 parts by weight of inorganic binder, 10 to 20 parts by weight of CaO, and 30 to 40 parts by weight of water are mixed. to be characterized

Description

Manufacturing method of bead-type adsorbent for arsenic removal using mine drainage sludge}

The present invention relates to a method for manufacturing a bead-type adsorbent for removing arsenic using acid mine drainage, which is capable of adsorbing arsenic by drying acid acid drainage sludge, mixing it with an inorganic binder, and molding it into a bead-type adsorbent.

As one of the recent serious environmental problems, the problem of handling heavy metals including arsenic (As) in aqueous solutions has emerged as an issue. Soil contamination is becoming serious due to the spread of heavy metals, including arsenic (As), generated by mining activities, and crops grown in contaminated soil also accumulate heavy metals that are harmful to the human body. There is a risk of causing disease.

A typical product that has been used as an adsorbent for arsenic removal in water quality is hydroxyl granules called GFH (granula feric hydroxide) (hereafter referred to as GFH). GFH is a granular adsorbent used as a material for removing arsenic and phosphorus in most water treatment facilities. Currently, the related market relies entirely on imported materials, and the cost of treatment is very high, so it is very important to find an adsorbent that can replace GFH.

On the other hand, acid mine drainage sludge (AMD) is an inorganic sludge containing a large amount of iron and has high recycling value as an iron hydroxide-based adsorbent material. sludge), and about 6,000 tons of sludge per year (based on the annual sludge treatment amount of water purification facilities in 2018) is disposed of as waste (landfill or cement supplementary material).

Although the sludge treated in this way has variability in components depending on the treatment process and seasonal pollutant load (influent water quality, flow rate, etc.), it is possible to standardize and commercialize for the purpose business by utilizing the overall main components, structure, and physical properties in common. Research results are coming out.

Korean Patent Publication No. 10-2019-0048515 (2019.05.09.)

An object to be solved by the present invention is to provide a method for manufacturing a bead-type adsorbent for removing arsenic using acid mine drainage, which can adsorb arsenic by drying acid mine drainage sludge, mixing it with an inorganic binder, and molding it into a bead-type adsorbent. .

A method for manufacturing a bead-type adsorbent for removing arsenic using acid mine drainage sludge according to the present invention includes a mine drainage storage step (S10) of precipitating solid foreign substances while receiving and storing mine drainage; a sludge dry powder step (S20) of dehydrating and drying the precipitated mine drainage sludge to produce sludge dry powder and homogenizing the sludge dry powder into a 25 to 35 mesh; a sludge powder homogenization step (S30) of sifting the produced mine drainage sludge dry powder through a sieve of a predetermined size and homogenizing the mine drainage sludge powder to have a standard size or smaller; An inorganic binder mixing step (S40) of mixing inorganic binder, CaO, and water with mine drainage sludge powder and evenly stirring; A bead-type adsorbent manufacturing step (S50) of preparing a bead-shaped adsorbent from a mixture of acid mine drainage sludge powder, inorganic binder, CaO, and water; but, the inorganic binder mixing step (S40) is based on 100 weight of the mine drainage sludge powder 5 to 10 parts by weight of inorganic binder, 10 to 20 parts by weight of CaO, and 30 to 40 parts by weight of water are mixed. to be characterized

Preferably, the sludge drying powder process (S20) is characterized by using hot air drying or natural drying.

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The bead-type adsorbent for arsenic removal produced according to the present invention has the advantage of being able to manufacture an adsorbent for arsenic removal efficiently and at a reasonable price because it uses mine drainage, which is discarded as waste, as an adsorbent for arsenic removal.

In addition, since the adsorbent is molded into a bead shape, there is an advantage in that input and recovery can be easily used.

1 is a flow chart of a manufacturing process of a bead-type adsorbent for arsenic removal using acid mine drainage sludge according to the present invention.
Figure 2a is an analysis graph of FT-IR before and after adsorption of As (III) by the adsorbent for removing arsenic according to the present invention.
Figure 2b is an analysis graph of FT-IR before and after adsorption of As (V) by the adsorbent for removing arsenic according to the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the method for manufacturing a bead-type adsorbent for removing arsenic using acid mine drainage sludge according to the present invention includes a mine drainage storage step (S10), a sludge drying powder step (S20), a sludge powder homogenization step (S30), It includes an inorganic binder mixing step (S40) and a bead-type adsorbent manufacturing step (S50).

In the mine drainage storage step (S10), the mine drainage is supplied and stored using a storage tank. In the storage tank, the solid foreign matter contained in the mine drainage is separated and precipitated.

In the sludge dry powder step (S20), the precipitated mine drainage sludge is dehydrated and dried to produce sludge dry powder. At this time, the mine drainage sludge may be dried in a hot air dryer or naturally dried at room temperature.

In the sludge powder homogenization step (S30), the resulting dry acid drainage sludge powder is sieved through a sieve of a predetermined size and homogenized to have a size smaller than a standard size. At this time, when the sludge powder is homogenized to have about 25 to 35 mesh, it can be molded while being evenly mixed with an inorganic binder described later.

In the inorganic binder mixing step (S40), the inorganic binder, CaO, and water are mixed with the mine drainage sludge powder and stirred evenly. At this time, 5 to 10 parts by weight of an inorganic binder, 10 to 20 parts by weight of CaO, and 30 to 40 parts by weight of water are mixed based on 100 parts by weight of the mine drainage sludge powder. In this case, as the inorganic binder, a liquid inorganic binder containing water may be used. Inorganic binders can induce Portland cementation reaction by components such as Ca, Si, Mg, Mn, Al, etc., which are the main components of mine drainage sludge, and prevent loosening when molding in a bead shape. will do In addition, CaO forms the skeleton of the mixture to form strength when manufactured in a bead shape.

In the bead-type adsorbent manufacturing process (S50), a bead-shaped adsorbent is manufactured by introducing a mixture of acid mine drainage sludge powder, inorganic binder, CaO, and water into a granulator. Accordingly, the fluidized bed structure and agitation inside the granulator, and the rotational structure inside repeat kneading and crushing, and the adsorbent, which is a bead-shaped granular body with a diameter of 2 to 3 mm, can be produced. These bead-type adsorbents have the advantage of being easy to input and recover during arsenic removal.

<Example 1>

Mine drainage sludge discharged from coal mines in the Najeon area was dehydrated and dried with hot air to prepare sludge dry powder. In addition, 100 g of an inorganic binder, 150 g of CaO, and 300 g of water were added to 1000 g of dry sludge powder passed through a 24 mesh sieve and mixed evenly while stirring. Then, the mixture was put into a granulator to prepare an adsorbent for removing arsenic (CMDS-NJ) of Example 1 as granular particles having a diameter of 2 to 3 mm.

<Example 2>

An adsorbent for removing arsenic (CMDS-HB) of Example 2 was prepared in the same manner as in Example 1 using mine drainage discharged from a coal mine in the Hambaek area with granular particles having a diameter of 2 to 3 mm.

<Example 3>

An adsorbent for removing arsenic (CMDS-YD) of Example 3 was prepared in the same manner as in Example 1 using mine drainage discharged from coal mines in the Yeongdong area, with granular particles having a diameter of 2 to 3 mm.

<Example 4>

An adsorbent for removing arsenic (CMDS-DW) of Example 4 was prepared in the same manner as in Example 1 using mine drainage discharged from coal mines in the Dongdong area with granular particles having a diameter of 2 to 3 mm.

<Example 5>

An adsorbent for removing arsenic (CMDS-HT) of Example 5 was prepared in the same manner as in Example 1 using mine drainage discharged from coal mines in the Hamtae area with granular particles having a diameter of 2 to 3 mm.

<Experimental example>

<Confirmation of adsorption efficiency of As(III) and As(V)>

Arsenic removal adsorbents of Examples 1 to 5 were installed in an adsorption tower, and arsenic-containing solutions of As(III) and As(V) were continuously passed under pH 5.0, 6.5, 9.3 and 10.2, and arsenic discharged from the adsorption tower. By measuring the concentration of arsenic, the arsenic adsorption efficiency of the arsenic removal adsorbent was confirmed, and the adsorption efficiency of As (III) is shown in Table 1, and the adsorption efficiency of As (V) is shown in Table 2.

pH 5.0 6.5 9.3 10.2 Example 1 49.75mg/g 39.53mg/g 63.12mg/g 58.89 mg/g Example 2 46.73mg/g 35.71mg/g 66.12mg/g 57.56mg/g Example 3 47.39mg/g 41.32mg/g 70.82mg/g 57.56mg/g Example 4 43.10mg/g 33.11mg/g 68.98mg/g 50.36mg/g Example 5 42.40mg/g 40.2mg/g 69.58mg/g 64.35mg/g

pH 5.0 6.5 9.3 10.2 Example 1 119.05mg/g 64.52mg/g 57.58 mg/g 50.3mg/g Example 2 123.0mg/g 65.36mg/g 60.32mg/g 53.25mg/g Example 3 65.36mg/g 50.12mg/g 43.25mg/g 40.25mg/g Example 4 135 mg/g 58.82mg/g 50.28mg/g 45.68mg/g Example 5 66.23mg/g 62.32mg/g 50.11mg/g 40.12mg/g

As shown in Tables 1 and 2, it was confirmed that the bead-type adsorbent for removing arsenic using the acid mine drainage sludge prepared according to the present invention can adsorb As(III) and As(V). In particular, it was confirmed that the adsorbed amount of As(V) increased under the condition, and the adsorbed amount of As(III) increased under the basic condition. This is considered to be because the pKa of As(III) and As(V) are different.

<Arsenic adsorption FT-IR confirmation>

FT-IR analysis before and after adsorption of As(III) and As(V) using the arsenic removal adsorbents of Examples 1 and 3 is shown in FIGS. 2a and 2b, respectively.

As can be seen in FIGS. 2A and 2B , it was found that the arsenic removal adsorbents of Examples 1 and 3 adsorbed arsenic.

<Checking the arsenic adsorption Dubinin-Radushkevich (D-R) adsorption isothermal model>

The D-R adsorption isotherm is most widely used to understand the adsorption mechanism or to determine the adsorption energy because it can be determined from the adsorption energy (Ali et al. 2016). The Dubinin-Radüschkebig (D-R) adsorption isothermal model indicates that the adsorption process is either physical adsorption or ion exchange (He et al. 2014; Xu et al. 2017).

As a result of calculating the adsorption energy values of the adsorbents for removing arsenic of Example 1 and Example 3 of the present invention, both adsorbents were 8 kJ/mol or less. Therefore, it was found that it was physical adsorption. This is called physical adsorption when the energy value is E<8 kJ/mol, chemical adsorption when E>16 kJ/mol, and ion exchange when the energy value is 8 kJ/mol <E<16 kJ/mol (Redl et al., 1996). according to the report.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited thereto, and the technical spirit of the present invention and the following Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described in.

S10: Mine drainage storage process
S20: Sludge dry powder process
S30: Sludge powder homogenization process
S40: Inorganic binder mixing process
S50: Bead-type adsorbent manufacturing process

Claims (5)

A mine drainage storage step (S10) of precipitating solid foreign substances while receiving and storing mine drainage;
a sludge dry powder step (S20) of dehydrating and drying the precipitated mine drainage sludge to produce sludge dry powder and homogenizing the sludge dry powder into a 25 to 35 mesh;
a sludge powder homogenization step (S30) of sifting the produced mine drainage sludge dry powder through a sieve of a predetermined size and homogenizing the mine drainage sludge powder to have a standard size or smaller;
An inorganic binder mixing step (S40) of mixing inorganic binder, CaO, and water with mine drainage sludge powder and evenly stirring;
A bead-type adsorbent manufacturing step (S50) of preparing a bead-shaped adsorbent from a mixture of acid mine drainage sludge powder, inorganic binder, CaO, and water;
In the inorganic binder mixing step (S40), 5 to 10 parts by weight of inorganic binder, 10 to 20 parts by weight of CaO, and 30 to 40 parts by weight of water are mixed based on 100 parts by weight of mine drainage sludge powder,
The bead-type adsorbent manufacturing process (S50) is a method for manufacturing a bead-type adsorbent for arsenic removal using acid mine drainage sludge, characterized in that it is produced in a granulator in a bead-shaped granular material with a diameter of 2 to 3 mm.
The method of manufacturing a bead-type adsorbent for arsenic removal using acid mine drainage sludge according to claim 1, wherein the sludge drying powder process (S20) uses hot air drying or natural drying.
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