RU2394776C1 - Method of extracting iron (iii) ions from aqueous solution - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to extraction of metals using sorption materials and can be used in ferrous and non-ferrous metallurgy, during purification of industrial and household effluent from iron (III) ions, as well as in agriculture and medicine. In order to realise the method of extracting iron (III) ions from an aqueous solution, the solution to be purified is brought into contact with sorption materials in form of bean husks, first held for one day in a 0.1 n solution of HCl or H2SO4, and sorption is carried out at pH 1-2. The bean husks selectively sorb Fe (III) ions from the solution of a mixture of salts which contain Fe (III) and Fe (II) ions. ^ EFFECT: method provides optimum conditions for fast and efficient extraction of Fe (III) ions from industrial and household effluent using agricultural products. ^ 2 cl, 3 dwg, 6 tbl, 4 ex

Description

The method of extraction of iron (III) ions from an aqueous solution relates to the field of extraction of substances by ion-exchange materials and can be used in non-ferrous and ferrous metallurgy, in the treatment of industrial and domestic wastes, as well as in agriculture and medicine.

Known methods for the extraction of iron (III) ions by adsorption on cation exchange resins [R. Ripan, I. Chetyanu. Inorganic chemistry, v.2. Chemistry of metals. Because of the "World", M., 1972. S. 687].

The disadvantage of this method is the high cost of sorbents.

The closest technical solution is a method for extracting iron (III) ions from an aqueous solution [Ru 2046102 C1, 10.20.1995 (D2)] with a sorbent material (carbon mineral sorbent), comprising contacting the solution with a sorbent material.

The disadvantage of this method is that the optimal conditions for the sorption of iron ions by bean seeds and their constituents are unknown.

The problem to which the claimed invention is directed is to find optimal conditions for a quick and effective method for extracting iron (III) ions from industrial and domestic wastes using agricultural products.

The technical result that can be achieved by carrying out the invention is to improve the kinetic characteristics of the process of extracting iron ions from an aqueous solution with a simultaneous high degree of their extraction, reducing the consumption of reagents, and the efficiency of the process through the use of agricultural waste.

This technical result is achieved by the fact that in the known method for extracting iron (III) ions from an aqueous solution, comprising contacting the solution with a sorbent material, the bean skin is used as a sorbent, previously aged for 0.1 day in a day. a solution of HCl or H ₂ SO ₄ , and sorption is carried out at pH = 1-2, and the bean skin selectively sorb Fe (III) ions also from a mixture of salts containing Fe (III) and Fe (II) ions.

The essence of the method is illustrated by the results of sorption of iron (III) ions from an aqueous solution, the data in tables 1-6 and figure 1-3.

Examples of specific performance of the method.

For the study, we used bean seeds of the 2008 harvest. Previously, the sorbent was kept at 0.1 N for a day. solutions of HCl or H ₂ SO ₄ in 0.1 N. NaOH solution or in distilled water.

Sorption of iron ions was carried out from 100 cm ^{3 the} initial solution of FeCl ₃ or FeSO ₄ . Sorbent masses in g were: beans 15, peel 1, cotyledons 14.

Sorption was carried out under static conditions with continuous stirring; during the sorption process, the set pH of the solutions was maintained by continuously neutralizing the solution with NaOH alkali or HCl acid (H ₂ SO ₄ ). The correction of the pH to a predetermined value was carried out within three hours and every day from the start of sorption.

Sorption indicators are given in the form of the residual concentration of iron ions at a given time from the start of sorption, C / mg / dm ³ , pH — constant pH during sorption, SOE, mg / g — sorption exchange capacity of the sorbent in mg sorbate per 1 g of sorbent when the system reaches equilibrium and OE, mg / g, is the capacity of the sorbent, in mg of sorbate per 1 g of sorbent, at a given point in time, min.

Example 1 (table 1).

Table 1 shows the results of sorption of Fe (III) at pH = 2 by beans and its constituent parts from a solution of FeCl ₃ .

Table 1 Sorbent pretreatment Sorption time, min The concentration of Fe (III), g / DM SOYE, mg / g source residual Peel, weight 1 g sour 60 1,303 1,171 24.0 alkaline 60 1,303 1,126 4.1 water 60 1,303 1,262 4.1 Cotyledons, weight 14 g sour 60 1,160 0.923 1.7 alkaline 60 1,160 0,992 1,2 water 60 1,160 1,022 1,0

The best sorption results were obtained when using bean peel as a sorbent, especially during acid treatment of the sorbent.

Example 2 (table 2, figures 1-3)

Table 2 shows the results of sorption of iron (III) ions by the skin of a bean depending on the pH value, preliminary treatment of the sorbent, sorption time, and initial solution concentration. The mass of the skin is 1 g.

Figure 1 shows the dependence of the extraction in% wt. from the initial concentration With _ref , g / DM ³ .

Figure 2 shows the dependence of the equilibrium concentration C _equal , g / dm ³ from the initial concentration C _ref , g / dm ³ .

Figure 3 shows the dependence of SOE, mg / g, from the equilibrium concentration of C _{equal to} , g / DM ³ .

The dependency graphs in figures 1-3 are constructed according to table.2.

From the data of Table 2 it follows that the best sorption results were obtained by acid treatment of the sorbent and pH = 2.

table 2 sorption pH Sorption time, h The concentration of Fe (III), g / DM ³ OE, mg / g Recovery,% wt. source residual Acid treatment of the sorbent (0.1 n HCl solution) 2 one 1,189 0.949 24.0 twenty one one 1,303 1,290 1,0 one 2 one 1,303 1,171 13.0 10 2 24 1,303 1,081 22.0 17 2 one 2,953 2,732 22.1 7 2 3 2,953 2,550 40.3 fourteen 2 48 2,953 2,292 66.1 22 one one 3,644 3,115 52.9 fifteen one 24 3,644 3,080 56.4 fifteen 2 one 3,644 2,806 83.8 23 2 3 3,644 2,730 91.4 25 2 24 3,644 2,652 99,2 27 2 48 3,644 2,630 101,4 28 one one 5,762 4,713 29.9 thirty one 24 5,762 4,529 104.9 eighteen 2 one 5,762 4,529 123.3 21 2 3 5,762 4,100 166.2 29th 2 24 5,762 4,060 170,2 thirty 2 48 5,762 4,008 175.4 thirty 2 one 6,766 4,695 207.0 31 2 3 6,766 4,220 255.0 38 2 24 6,766 4,120 216.0 32 2 48 6,766 3,939 283.0 42 2 72 6,766 3,919 285.0 42 2 one 8,106 4,848 325.8 40 2 3 8,106 4,279 382.7 47 2 24 8,106 3,750 436.6 54 2 48 8,106 3,555 455.1 56 2 72 8,106 3,360 474.6 59 2 one 9,918 5,302 461.6 47 2 3 9,918 4,442 547.6 55 2 24 9,918 3,476 644.2 65 2 48 9,918 3,126 679.2 68 2 72 9,918 2,775 714.3 72 Water treatment of the sorbent (distilled water) one one 1,303 1,303 - - 2 one 1,303 1,262 4.1 3 2 24 1,303 1,072 23.1 eighteen Alkaline treatment of the sorbent (0.1 N NaOH solution) one one 1,303 1,303 1,0 - 2 one 1,303 1,126 4.1 fourteen 2 24 1,303 1,303 1,0 -

From the data of Fig. 1, it follows that in the range C _out = 1.189-5.762 g / dm ^{3 the} extraction of Fe (III) is caused by sorption of Fe (III) ions by the skin of the bean, and in the range C _out = 5.762-9.918 g / dm ^{3 the} extraction of ions iron is probably caused by sorption on the bean skin with iron ions of a different composition.

From the data of figure 2 it follows that the maximum in the graph is caused by the same reasons as when considering figure 1.

According to figure 3, lines a and b can be represented by the equations:

SOE = 38.261С _equal (R ² = 0.9023) - line a

SOE = -375.26C _equal +1749 (R ² = 0.9972) - line b

The intersection of the lines determines the value of C _equal , at which the SOE by ion Fe (III) under these conditions has a maximum value:

C _equal = 4.2295 g / dm ³ ; SOY _max = 161.8261 mg / g.

Hence, the extraction of the ions Fe (III) is carried out before sorption equilibrium concentration C _eq = 4.2295 g / dm ^3, which corresponds to C _ref = 5.9693 g / ^dm3. From a solution with a higher concentration of bean skin, iron ions of a different composition are sorbed.

Example 3 (table 3)

Table 3 shows the results of sorption of Fe (II) from a solution of FeSO _{4 with} bean skin. The mass of the skin is 1 g.

Table 3 sorption pH Sorption time, h The concentration of Fe (II), g / DM ³ SOYE, mg / g Recovery,% wt. source residual Acid treatment of the sorbent (0.1 N H ₂ SO ₄ solution) 2 one 1,491 1,409 8.2 5.5 3 one 1,491 1,443 4.8 4.8 Water treatment of the sorbent (distilled water) 2 one 1,491 1,412 7.9 5.3 3 one 1,491 1,392 9.9 6.6 Alkaline treatment of the sorbent (0.1 N NaOH solution) 2 one 1,491 1,377 11,4 7.6 3 one 1,491 1,403 8.8 5.9

From the data in Table 3 it follows that Fe (II) ions are weakly sorbed by the skin of beans.

A slight sorption of iron ions from a solution of FeSO ₄ is probably due to the presence of a small amount of oxidized Fe (III) ions in the solution.

Example 4 (Tables 4 and 5)

Table 4 shows the results of sorption of iron ions by the skin of a bean from a mixture of FeCl ₃ and FeSO ₄ salts during acid treatment of the sorbent (0.1 N H ₂ SO ₄ solution) and pH = 2. The mass of the skin is 1 g.

Table 4 Sorption time, h The concentration of Fe, g / DM ³ SOYE, mg / g Recovery,% wt. Fe _commonly Fe (III) Fe (II) source residual source residual source residual one 3,268 2,935 1,656 1,213 1,612 1,723 44,4 33.3 3 3,268 2,677 1,656 0.885 1,612 1,793 77.1 18.1 24 3,268 2,759 1,656 0.939 1,612 1,820 71.7 15.6

From the data of table 4 it follows that the bean skin from a mixture of salts of FeCl ₃ and FeSO ₄ sorb only Fe (III) ions.

Due to the redox reaction between Fe (III) ions and the bean skin, the concentration of Fe (II) ions increases over time. Therefore CDE sorbent for ion Fe (III) increases, and extraction of total iron Fe solution _commonly drops due to transition of Fe (III) → Fe (II ).

Table 5 shows the results of sorption of iron ions by the skin of beans from a solution of FeCl ₃ salt during acid treatment of the sorbent (0.1 N solution of H ₂ SO ₄ ) and pH = 2. Sorption time 96 hours. Skin weight 1 g.

Table 5 Experience number The concentration of Fe, g / DM ³ SOYE, mg / g Recovery,% wt. Fe _commonly Fe (III) Fe (II) source residual source residual source residual one 8,169 2,107 8,169 0.688 traces 1,419 748.1 74,2 2 10,595 2,197 10,595 0.778 traces 1,419 981.7 79.3

From the data in Table 5 it follows that, similarly to the data in Table 4, as the Fe (III) ions sorb from the FeCl ₃ salt solution, the concentration of Fe (II) ions in the solution increases.

Table 6 shows the results of sorption of Fe (II) from a solution of FeSO ₄ cotyledons, the mass of cotyledons is 14 g.

Table 6 sorption pH Sorption time, h The concentration of Fe (II), g / DM ³ SOYE, mg / g Recovery,% wt. source residual Acid treatment of the sorbent (0.1 N H ₂ SO ₄ solution) one one 1,160 1,040 0.86 10.3 2 one 1,160 0.923 1,69 20,4 Water treatment of the sorbent (distilled water) one one 1,160 1,040 0.86 10.3 2 one 1,160 1,022 0.99 11.9 Alkaline treatment of the sorbent (0.1 N NaOH solution) one one 1,160 1.003 1.12 13.5 2 one 1,160 0,992 1.20 14.5

From the data in Table 6 it follows that Fe (II) ions are weakly sorbed by bean cotyledons.

Compared to the prototype, according to the data of Tables 1-6 and Figs. 1-3, the possibilities of fast and efficient extraction of iron (III) from industrial and domestic wastes using agricultural products are shown.

From a mixture of salts containing Fe (III) and Fe (II) ions, Fe (III) ions can be selectively removed by sorption on the bean skin.

Claims (2)

1. The method of extraction of iron (III) ions from an aqueous solution, comprising contacting the solution with a sorbent material, characterized in that the bean skin is used as a sorbent material, previously aged for 0.1 days in a day. a solution of Hcl or H ₂ SO ₄ , and sorption is carried out at pH 1-2. 2. The method according to claim 1, characterized in that the bean skin selectively sorb Fe (III) ions from a mixture of salts containing Fe (III) and Fe (II) ions.

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