RU2480420C1 - Purification of waste water from heavy metals - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used to treat water in pharmaceutical and food industry. The method of purifying waste water from heavy metals involves passing water in dynamic conditions through a column with a mixture of two modified sorbents in ratio of 2:1. The first sorbent is obtained by immobilisation on anionite AV-17 2-{2-(α-2-oxy-5 sulphophenylazo}-benzylidine hydrazine of benzoic acid, and the second by immobilisation on silica gel which is treated with cetylpyridinium chloride, 2,6,7-trioxyphenylfluorone.

EFFECT: invention enables simultaneous extraction of cadmium, lead, copper, zinc, chromium and manganese, wherein 100 dm³ of water is purified with 20 g of a sorbent mixture in one hour.

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Description

The invention relates to the protection of the environment and can be used to purify water facilities, drinking water; in the pharmaceutical industry in the control of drugs based on medicinal plants with wide opportunities for eco-accumulation of heavy metals (TM) in the food industry. Heavy metals are one of the constituent parts of components of industrial effluents (Avakyan Z.A., 1967; Siegel X., Siegel A., 1993).

Monitoring the degree of water pollution by heavy metals and cleaning water from heavy metals from industrial effluents is an important problem of maintaining their purity and public health (Methods for the study of heavy metals in polluted and diluted wastewater. - M .: Kolos, 1969. p. 68).

The forecasting task is determined by the need to protect natural reservoirs from heavy metal pollution in order to maintain a healthy ecological state of the reservoir and acceptable water standards.

Known chemical, physico-chemical, physical and biological methods of purification of natural, drinking and wastewater, which are based on the following principles [1-3]:

- The chemical process of water purification consists in its chlorination or ozonation. Now the method of water purification by chlorination is outdated; ozonation is a technology, although good, but very expensive and complicated;

- The physical method of purification is boiling. This method, on the one hand, completely purifies water from any pathogens, but on the other hand, this principle of water purification does not allow to get rid of various chemical contaminants. Another physical cleaning technology is ultraviolet irradiation of water. At the same time, all harmful microorganisms are destroyed, and the water is treated with harmful chemicals;

- the biological method of water purification is the use of microorganisms that can feed on heavy toxic metals and thereby destroy them by purifying the water. But this method is expensive.

Membrane water purification consists in the work of activated carbon as a sorbent that traps all possible impurities (organic particles, bacteria, chemicals). Water purification using reverse osmosis makes the liquid very clean, almost distilled. Reverse osmosis through filters for water treatment is quite stable and high quality, however, it also has some disadvantages: this method of water treatment

1) not economical enough, i.e. filters per day can skip no more than 25 liters of water;

2) deprives not only harmful, but also useful elements, which negatively affects the overall quality of water and its consumer properties.

A significant drawback of these methods in water analysis is the complexity of execution and high cost, since they require special equipment. As can be seen from the above, various methods are used for water purification, in general, each of which has its advantages and disadvantages.

The objective of the invention is the development of more affordable, economical, easy-to-use and rapid methods of water treatment, for which there is an excess of MPC for such toxic metals as chromium, manganese, zinc, copper, lead and cadmium in wastewater.

The inventive method is unknown from the prior art, i.e. is new.

The analysis of the prior art by the applicant, 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 an analogue characterized by features identical to all the essential features of the claimed invention.

The novelty of the proposed method is that for the first time in the process of water purification from copper, lead, zinc, cadmium, chromium and manganese in concentrations exceeding the MPC, it is proposed to use a mixture of two sorbents with immobilized organic reagents:

1) AB-17 with immobilized 2- {2- (α-2-hydroxy-5 sulfophenylazo} -benzylidine hydrazine benzoic acid (OSPBGBK);

2) silica gel treated with cetylpyridinium chloride with immobilized 2,6,7-trioxyphenylfluorone (TOF).

The essence of the invention lies in the fact that water is passed dynamically through a column with a mixture of two modified sorbents in a 2: 1 ratio obtained by immobilization of selective organic reagents 2- {2- (α-2-hydroxy-5 sulfophenylazo} -benzylidine hydrazine benzoic acid for anion exchange resin highly basic AB-17 and silica gel treated with cetylpyridinium chloride with immobilized 2,6,7-trioxyphenylfluorone, then the modified sorbents are simultaneously extracted from the aqueous medium to the solid phase copper, zinc, lead, cadmium, chromium and manganese, with 20 dm ^{3 of} water being purified, 20 g of a mixture of sorbents within an hour, after which a mixture of sorbents is regenerated with 20 ml of 4M HCl solution until a negative reaction to ions Cu ²⁺ , Zn ²⁺ , Pb ²⁺ , Cd ²⁺ , Cr ^{3 +} and Mn ²⁺ .

Concrete example

6 ml of diluted (1: 1) sulfuric acid and 1.0 g of ammonium persulfate were added to 1 liter of analyzed water to destroy complexes of copper, lead, cadmium, zinc, chromium, and manganese with organic impurities contained in wastewater. The sample was boiled for 10-15 minutes and left for one hour. If necessary, water after cooling was filtered off from mechanical impurities. Excess acid was neutralized by adding 10% ammonia solution to a neutral medium. Then water was passed through a column filled with a mixture of modified sorbents in a dynamic mode. As sorbents used:

1) highly basic anion exchange resin AB-17 with immobilized OSBBGBK for group extraction of cadmium, lead, copper and zinc;

2) silica gel treated with cetylpyridinium chloride with immobilized TOF for group extraction of chromium and manganese.

The sample is passed through a column with a diameter of 2 cm and a height of 10 cm filled with a mixture of modified sorbents (AV-17-OSFBGBK and SG-CPU-TOF) in a 2: 1 ratio. After purification, the water is checked for the content of residual amounts of HM by the atomic absorption method.

The degree of purification from heavy metals was carried out in the effluents of the Aviaagregat plant and the water of the Oktyabrskaya Revolution canal to the treatment facilities in Makhachkala.

The results of the determination are presented in the table.

Element The content of heavy metals, mg / l MPC Before cleaning After cleaning The drains of the plant "Aircraft Unit" Water channel "October Revolution" The drains of the plant "Aircraft Unit" Water channel "October Revolution" Cr 0.62 ± 0.02 0.35 ± 0.02 0.0033 0.0017 0.20 Mn 0.28 ± 0.03 0.16 ± 0.03 0.0015 0,0009 0.10 Cu 0.69 ± 0.02 0.32 ± 0.02 0.0021 0.0012 1,0 Zn 0.75 ± 0.02 0.43 ± 0.02 0.0025 0.0022 0.60 Pb 0.36 ± 0.03 0.22 ± 0.02 0.0000 0.0000 0,03 Cd 0.020 ± 0.004 0.014 ± 0.005 0.0000 0.0000 0.001

MPC - for waters of cultural and domestic water use.

As can be seen from the table, the content of chromium and manganese is almost three times higher than the maximum permissible concentration; for lead and cadmium dozens and more times an excess of MPC is observed, and for zinc a slight excess in the effluents of the Aviaagregat plant.

Exceeding the MPC for Cr, Mn, Pb, and Cd is also observed in the waters of the channel named after "October revolution".

Thus, the data presented indicate a high degree of contamination of industrial effluents of the Aviaagregat plant and the Canal named after "October Revolution", which indicates the need for treatment before entering open water.

The content of heavy metals in purified water is below the MPC.

The novelty of the proposed method is that for the first time in the process of purification from chromium, zinc, copper, manganese, lead and cadmium in concentrations exceeding the maximum permissible norms, it is proposed to use a mixture of two modified sorbents in a 2: 1 ratio obtained by selective (selective) immobilization organic reagents for anion exchangers: AB-17 and silica gel-cetylpyridinium chloride, then, creating optimal conditions, extract them from a large volume of the aqueous medium to the solid phase and purify the water from these metals.

The claimed method is intended for use in laboratories of treatment facilities that monitor the degree of wastewater treatment.

The advantage of the claimed method are:

1. Ease of execution.

2. Profitability (for the concentration and determination of six elements using modified reusable sorbents in a ratio of 2: 1).

3. High selectivity (anion exchange resin AB-17-OSFBGBK) extracts copper, zinc, lead and cadmium from water at the same time, and SG-CP-TOF - chromium, manganese. All macro components and some micro components do not interfere with the determination.

4. Expressivity (within an hour you can clean 100 dm ^{3 of} water 20 g with a mixture of sorbents from six heavy metals in concentrations exceeding the MPC in various waters).

5. The detection limit is 1-3 μg / L.

Literature

1. Smirnov A.D. Sorption water purification. L .: Chemistry. 1982. 168 p.

2. Smirnov D.N., Genkin V.E. Wastewater treatment in metal processing. 1989.28 p.

3. Ashirov A. Ion-exchange wastewater treatment, solutions and gases. L .: Chemistry. 1983. 295 p.

Claims (1)

A method of treating wastewater from heavy metals, which consists in the fact that the water is passed dynamically through a column with a mixture of two modified sorbents in a 2: 1 ratio obtained by immobilization of 2- {2- (α-2-hydroxy) anion exchange resin AB-17 -5-sulfophenylazo)} - benzylidine hydrazine of benzoic acid and silica gel treated with cetylpyridinium chloride, 2,6,7-trioxyphenylfluorone, then cadmium, lead, copper, zinc, chromium and manganese are simultaneously extracted with a new solid phase, with 100 dm ³ 20 g of a mixture of sorbents are purified within an hour.