RU2150997C1 - Method of adsorption treatment of water - Google Patents

Abstract

FIELD: water treatment. SUBSTANCE: invention relates to treatment of strongly mineralized drinking and industrial water to remove heavy metal ions, petroleum derivatives, phenol, surfactants, and hardness salts. Water is filtered through preliminarily baked, activated naturally occurring adsorbent representing siliceous rock with following mineral composition (from Tatarstan deposits), wt %: opal-crystobalite 51-70, zeolite 9-25, clay constituent (montmorillonite, hydromica) 7-15, calcite 10-25, fragmental silt sandstone - the balance. Adsorbent is activated with 2 N HCl at room temperature for 20 min until content of CaO in adsorbent is no higher than 4%. EFFECT: enhanced water treatment efficiency, prolonged lifetime of adsorbent, and increased its capacity with respect to hardness salts. 3 tbl

Description

 The invention relates to methods for adsorption treatment of water and can be used in the treatment of drinking or industrial water, mineralized sources with a high content of hardness salts from metal ions, oil products, phenol, surfactants.

A known method of purifying water from heavy metal ions by a calcined flask with a size fraction of (1 - 6) • 10 ^-3 m, treated with 4 - 5% aqueous sodium hydroxide / 1 /.

 The disadvantage of this method is the insufficient operating time of the adsorbent to the MPC.

A known method of adsorption purification of water by filtration through siliceous rock of mixed mineral composition, containing, wt.%:
Opal Cristobalite - 30 - 49
Zeolite - 7 - 25
Clay component - 7 - 25
Clastic-sand-silt material - Rest
with a benzene pore diameter of 6.3 - 5.0 nm, the maximum sorption volume of which is 0.025 - 0.045%.

 The disadvantage of this method is the insufficient degree of water purification from both heavy metal ions and hardness salts. As a result, the use of this adsorbent is possible only for the treatment of surface water from household water supplies from metal ions and other harmful substances with a water hardness of not more than 7 mg • equiv / l.

Closest to the claimed invention in technical essence and the achieved result is a method of adsorption purification of water, which consists in filtering water through siliceous rock of mixed mineral composition, containing in wt.%:
Opal Cristobalite - 30 - 50
Zeolite - 7 - 25
Clay component (montmorildonite, mica) - 7 - 25
Calcite - 10 - 28
Clastic-sand-silt material - The rest,
which is calcined before activation at 300 ± 5 ^o C, and after activation is treated with 2n. sodium chloride solution.

The reasons that impede the achievement of the technical result indicated below when using the known method adopted for the prototype include the fact that in the known method there is an insufficient degree of water purification from hardness salts Ca ²⁺ and Mg ²⁺ and a low dynamic capacity for these ions. In addition, the processing of the rock is carried out at the boiling point of the solution, which requires the use of expensive enameled equipment, laborious technological design of the process of activation of the sorbent.

The objective of the invention is to improve the quality of purified water, water purification not only from metal ions, phenol, petroleum products, surfactants, but also from hardness salts (Ca ²⁺ and Mg ²⁺ ) when their content in the source water is up to 15 mg • equiv / l s using activated adsorbents - siliceous zeolite-bearing rocks of mixed mineral composition of deposits of the Republic of Tatarstan.

The technical result of the invention is to increase the degree of water purification from metal ions, including additionally from hardness salts (Ca ²⁺ and Mg ²⁺ ) when their content in the source water is up to 15 mg • equiv / l, increase the duration of the adsorbent and its dynamic capacity , as well as expanding the range of adsorption raw materials.

 The specified technical result in the implementation of the invention is achieved by the fact that in the known method of adsorption purification of water, comprising filtering water through a pre-calcined activated natural adsorbent, according to the invention, silica rock of mixed mineral composition selected from deposits of Tatarstan containing in wt.% Is used as a natural adsorbent : opal-cristobalite 51–70, zeolite 9–25, clay component (montmorillonite, hydromica) 7–15, calcite 10–25, clastic sand-siltstone vy material - the rest, the activation of which is carried out at room temperature with a solution of 2n. hydrochloric acid for 20 minutes until the CaO content in the adsorbent is not more than 4%.

 A comparative analysis of the proposed technical solution with the prototype shows that a better raw material is used as an adsorbent - a siliceous rock of mixed mineral composition, in which the content of opal cristobalite is in the range 51 - 70%, CaO from 5.0 to 16%. In the activated sorbent, the CaO content does not exceed 4% (Table 1), which allows additional purification of water from hardness salts.

Carrying out activation under mild conditions, treating HCl at room temperature allows one to obtain a higher quality adsorbent compared to the prototype in terms of physicomechanical and structural properties (Table 2). The increase of physical and mechanical properties - water resistance from 96.3% to 98.2 - 99.3% and mechanical crushing strength from 125 to 206 • 10 ⁴ kg / m ² allows to increase the service life of the adsorbent.

Increasing the average pore diameter of benzene from 7.1 to 8.6 nm and the maximum volume of the adsorption space from 0,053 to 0,083 • 10 ^-3 m ^3/1 leads to improved structural properties, which can extract water from large molecules of harmful substances, namely Ca ²⁺ and Mg ^{2+ ions} .

 As a result, we have a new sequence of signs of a solution, namely, a new adsorbent is processed by known methods, but using different conditions for their implementation, which leads to the achievement of the specified technical result.

 The analysis of the prior art by the applicants, including a search by patent and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype, as the closest in the totality of the features of the analogue, allowed us to establish a set of essential distinguishing features in relation to the technical result perceived by the applicant in the claimed method set forth in the claims.

 Therefore, the claimed invention meets the condition of "novelty."

 To verify the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions in order to identify features that match the distinctive features of the claimed method from the prototype. The search results showed that the claimed invention does not follow explicitly from the prior art for the specialist, since the influence of the transformations provided for by the essential features of the claimed invention is not revealed from the prior art determined by the applicant to achieve a technical result.

 Therefore, the claimed invention meets the condition of "inventive step".

 The implementation of the proposed method is illustrated by the following example.

Example 1 (prototype). As an adsorbent, siliceous rock of mixed mineral composition is used, containing in wt.%: Opal-cristobalite 30–50, zeolite 7–25, clay component 7–25, calcite 10–28, clastic-silt material — the rest taken from Tatarstan deposits . Before activation, the rock is calcined at 300 ± 5 ^° C, 1N HCl is activated while the solution is boiling for 2 hours, and then further treated with 2N. sodium chloride solution. The chemical composition of the starting and activated sorbent is given in table 1. The main physical and mechanical characteristics of the obtained adsorbent are given in table. 2. The indicators of water purification obtained by the prototype adsorbent are given in table. 3.

 Example 2. As an adsorbent, siliceous rock of mixed mineral composition is used, containing in wt.%: Opal-cristobalite 51–70, zeolite 9–25, clay component (montmorillonite, hydromica) 7–15, calcite 10–25, sandstone -aleurite material - the rest, selected from the deposits of Tatarstan.

The adsorbent in the air-dry state is crushed, crushed and dispersed on sieves, a fraction (1.0 - 4.0) • 10 ^-3 m is isolated. The sample is calcined (the rate of temperature rise is 50 ^o C per hour) in an electric furnace at 300 ^o C within 2 hours. In a porcelain glass load pre-prepared sample and 2N. a solution of hydrochloric acid (HCl) at a ratio of T: W = 1: 2. Processing is carried out at room temperature for 20 minutes, periodically stirring with a glass rod. Then the hydrochloric acid solution is drained and the adsorbent is neutralized with a 0.05 N NaOH solution to pH = 7.0.

 The chemical composition of the source and activated rocks under various activation conditions is given in table. 1 (examples 3 to 5 with a CaO content in the feed rock of 9.98%; examples 6 to 8 with a CaO content in the feed rock of 5.40%). In the table. 2 shows the main physical and mechanical characteristics of the natural adsorbent obtained under various activation conditions (examples 3 to 5). In the table. 3 shows the indicators of water purification with the inventive adsorbent (example 2).

As the test water, industrial water is used, or a model mixture (distilled water + impurities). The concentration of metals in the model mixture corresponds to their possible content in industrial waters: the total initial hardness (Ca ²⁺ + Mg ²⁺ ) in the range up to 15 mg • equiv / l. The following metal concentrations according to GOST 2874-82 are taken as breakdown: total hardness not more than 7 mg • equiv / l, iron - not more than 0.3 mg / l, copper - not more than 1.0 mg / l, nickel - not more than 0 , 02 mg / l, manganese - not more than 0.1 mg / l, zinc - not more than 0.5 mg / l, phenols - not more than 0.001 mg / l.

 A portion of the adsorbent 0.080 - 0.150 kg is poured into the adsorption column at 2/3 in height.

The adsorption process is carried out at a temperature of 20 ± 5 ^o C. From the tank, the investigated water of constant initial concentration is fed through the rotameter from the bottom up with a speed of 0.5 l / h to the adsorption column.

Water analysis is carried out on an atomic absorption spectrophotometer using metal cations Ca ²⁺ , Mg ²⁺ , Fe ^{2+, 3 +} Cu ²⁺ , Ni ²⁺ , etc., by phenols, surfactants, petroleum products using a KFK-3 photometer.

 Tests to determine the dynamic capacity of the adsorbent for recoverable substances are carried out according to TU 2164-001-44947114-97 "Sorption-filtering material", Kazan, 1997, 17 S. OKP code. 216491. Group L91.

 Determination of surface-active substances (SAS) is carried out according to ISO 7875 / 1-84. Water quality. Determination of surfactants. M., 1987.11 p. UDC 543.3: 661.185.1. Group T58.

 Phenol is determined according to ISO 6439-84. Water quality. Determination of phenolic index-4-aminoantipyrino. M., 1987.11 p. UDC 543.38.547.56. Group T58.

 Petroleum products are determined by the method described in Lurie, Yu.Yu. Analytical chemistry of industrial wastewater. M., Chemistry, 1984, p. 269.

In the table. 2 in example 5 shows that the optimal concentration of a solution of hydrochloric acid for subsequent processing of the rock is 2N. the solution at an activation time of 20 minutes, which ensures a CaO content of 3.73 (a decrease from 9.98% in the original rock), an increase in water resistance to 98.2%, and mechanical strength up to 206 • 10 ⁴ kg / m ² , the average pore diameter for benzene is up to 8.6 nm, the maximum adsorption space is up to 0.083 • 10 ³ m ³ / kg (Tables 1, 2).

 A decrease in the concentration of hydrochloric acid to 1 N at an activation time of 40 min leads to a slight increase in all indicators and an insufficient decrease in the CaO content in the sorbent to 6.25% (Table 1, Example 3, Table 2, Example 3).

Increased activation from 20 to 40 minutes at 2n. HCl concentrates leads to a decrease in water resistance to 97.1%, mechanical strength to 179 • 10 ⁴ kg / m ² , average pore diameter up to 8 nm and the maximum adsorption space to 0.070 • 10 ³ m ³ / kg when the CaO content in the sorbent in the required limits are 3.07% (tab. 1, 2, examples 4, 5).

In the table. 3 shows comparative data on the purification of water from harmful impurities when they are combined with the original and activated sorbent in comparison with the analogue and prototype. As can be seen from the above table. 3 data, activation of siliceous rock of mixed mineral composition 2n. HCl for 20 min at room temperature allows water to be additionally purified from hardness salts (Ca ²⁺ and Mg ²⁺ ). In this case, the operating time of the adsorbent to the MPC for hardness salts increases by 14 times compared with the prototype, and the dynamic capacity by 10 times without deterioration of the same characteristics for other water-polluting impurities (heavy metal ions, surfactants, petroleum products, phenol) with their simultaneous presence in water.

Thus, the above information indicates that when using the claimed method the following set of conditions:
- a tool embodying the claimed method in its implementation, is intended for use in industry, namely in housing and communal services, energy and food industry;
- for the claimed method in the form as described in the claims, the possibility of its implementation using the examples described in the application is confirmed.

 Therefore, the claimed invention meets the condition of "industrial applicability".

Using the claimed invention will allow:
1. To purify water not only from the surface sources of domestic household water supply, but also from the mineralized water of underground sources with hardness salts of up to 15 mg • eq / l of metal ions, phenol, surfactants, oil products and hardness salts, as well as after-treatment of drinking water in home fontanels.

 2. To increase the physical and mechanical properties of the adsorbent, which increases the quality and service life of the adsorbent.

 3. To expand the scope of natural adsorption raw materials.

 The use of activated adsorbent is planned at drinking water treatment plants of the central artesian water supply for the treatment of mineralized water from underground sources of central domestic water supply (in quick filters as filter material instead of the quartz sand used), as well as from settlements and in fontanelles for water purification.

Sources of information
1. A.S. 1823393, class C 02 F 1/28, 1/62, 5/00, BI, N 31, 1996

 2. RF patent N 2111171, cl. C 02 F 1/28, 1998

 3. RF patent N 2111172, cl. C 02 F 1/28, 1998 (prototype).

Claims (1)

A method of adsorption purification of water, comprising filtering water through a pre-calcined, activated natural adsorbent, characterized in that silica rock of mixed mineral composition containing in wt.% Is used as a natural adsorbent:
Opal Cristobalite - 51 - 70
Zeolite - 9 - 25
Clay component (montmorillonite, hydromica) - 7 - 15
Calcite - 10 - 25
Clastic-sand-silt material - Rest
the activation of which is carried out with a solution of 2N hydrochloric acid at room temperature for 20 minutes until the CaO content in the adsorbent is not more than 4%.

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