APPLICATION OF NATURAL SORBENTS OF KOSTANAY REGION FOR WATER QUALITY CORRECTION.

Makhmutova Zh.S., Iskeyeva G.A.

KSU named after A. Baytursynov, Kostanay, Kazakhstan, mahmutova76@inbox.ru

Natural sorbents of natural and artificial origin (clay rocks, zeolites and some other materials) are increasingly used for water purification. The main directions of using natural sorbents are related to the technological processes of adsorption purification. The use of such sorbents is due to their rather high capacity, selectivity, cation-exchange properties. Some of them are of relatively low cost and available for application.

The adsorption capacity of natural sorbents of theKostanay region with respect to iron ions (III), manganese ions (II), acetic acid molecules was studied.

  The adsorption properties of the analyzed natural sorbents were determined from the change in the concentration of water-polluting compounds before and after adsorption.

The concentration of iron ions, manganese ions was determined by the photometric method. In the case of studying the adsorption properties of sorbents with respect to iron, the method essence involves adding ammonium thiocyanate or potassium solution to a water sample with iron ions and photometric measurement of the optical density of the solution of blood-red iron complex:

Fe ³⁺ + SCN^- = [Fe (SCN )]²⁺

If the manganese ion (II) was the adsorbent, the detected ion was oxidized with ammonium persulfate to permanganate of a crimson ion in thepresenceofsilvernitratecatalyst:

2 MnSO₄+5(NH₄)₂S₂O₈+8H₂O=2HMnO₄+5(NH₄)₂SO₄+7H₂SO₄

The photometric measurements were performed on KFK-3-01-"30M3" instrument,at the wavelength of 530.1 nanometers for manganese and 470.0 nm for iron, at which the absorption is maximized. When measuring the optical density of the colored adsorbentsolutions in the range of maximum light absorption, the determination sensitivity increases.

Under the condition of obtaining a linear calibration graph, the iron or manganese concentration in the water samples after adsorption was calculated by comparison using the formula:

С_х= С₀*А_х/А₀, where

С₀,С_{х –} Ion concentration in the water sample before and after adsorption, g / ml;

А_0, А_х- Optical densities of the adsorbent solution before and after adsorption;

In the course of the experiment, 150 ml of a contaminated water sample with the given concentration of iron, manganese and acetic acid ions were added to the sample of the natural sorbent 15 g. The contents of the test tube were thoroughly mixed with a shaking machine for 2 hours. Thenthemixture was filtered. The filtrate was transferred to a colored solution and its optical density was measured photometrically.

The concentration of acetic acid in the water sample before and after adsorption was determined by titration with a standardized solution of potassium hydroxide. The acid concentration was calculated from the titration results:

N_K= N_al*V_al/ V_к

The adsorption capacity of the sorbents was calculated from the equation:

А.С. = (С₀-С_х)*V*100 /С_0, where

А.С – Adsorption capacity of the sorbent, %;

С₀ - Concentration of the pollutant in the water sample before adsorption, g / ml;

С_{х –} Impurity concentration after adsorption, g / ml;

V- Solution volume from which adsorption took place, ml.

The obtained experimental data on the adsorption capacity of natural sorbents in the Kostanay region are given in Table 1.

Table 1 - Adsorption capacity of natural sorbents.

№	Natural sorbents	Adsorption capacity in relation to:
		iron ions (III)	manganese ions (II)	Acetic acid
1	Ore	43,35 %	35,56 %	89,99 %
2	Sand	49,98 %	14,14 %	62,73%
3	Asbestos	93,08 %	95,41 %	-
4	Yellow clay	92,31 %	69,85 %	92,02 %
5	Red clay	91,80 %	92,06 %	95,15 %
6	Soil	90,27 %	74,07 %	-

As follows from Table 1, asbestos, yellow and red clays have the greatest adsorption capacity with respect to iron ions, while ore has the smallest one. According to adsorption capacity to manganese ions, sorbents can be arranged in increasing order in a row: sand (14.14%) - ore (35.5%) - yellow clay (69.85%) - soil (74.07%) - red clay (92.06%) - asbestos (95.41%).The adsorption capacity of ore, yellow and red clay with respect to acetic acid is in 1.43; 1.47; 1.52 times greater than the sand adsorption capacity.

As follows from Table 1, adsorption properties of sorbents depend on their chemical structure, contact area with adsorbent.

Figure 1 presents the data on the application of various natural sorbents to improve water quality.

Figure 1 - Natural sorbents’effect on the degree of water purification.

On the basis of Figure 1 experimental data, it can be concluded that for the adsorption water purification from iron ions (III), manganese ions (II) and acetic acid the use of such natural sorbents as yellow clay, red clay and asbestos is efficient. However, in view ofasbestos carcinogenic properties, its use should be limited.

References:

1. Vezentsev, A.I. Adsorption properties of the beneficiaries of natural montmorillonite-containing clays // А.I. Vezentsev. - Belgorod: Belgorod State National Research University, 2011. - P. 103-108.

2. Tsitovich I.K. Course of Analytical Chemistry. - M.: Higher Education, 1994.- P.352-353.

3. Fomin G.S. Water. Publisher "Protector", 2010. - P.314-319.