A method of producing a sorbent for purification of water and aqueous solutions of iron and manganese compounds

 

The invention relates to the preparation of water and aqueous solutions, and in particular to methods of obtaining sorption and filter materials for the purification of natural waters and industrial solutions from iron and manganese compounds. As raw materials used raw calcium carbonate, containing not more than 1% of magnesium carbonate. Carry out chemical processing of the material sequentially in three stages: from 0.01 to 10% solution of salts of divalent manganese, about 0.001 to 5.0% salt solution heptavalent manganese and 0.1-10% solution of potassium or sodium alkali, after the first and second stages of chemical processing is carried out intermediate drying of the material at a temperature of 10-100°C to a residual moisture content of 10-100%, after the third stage carry out the final drying of the material at a temperature ranging from 50 to 300°C to a residual moisture content of not more than 5%. The method provides a reduction process of the sorbent and the improvement of its properties, namely, giving him improved kinetic characteristics and high adsorption capacity in relation to iron and manganese compounds. 2 C.p. f-crystals, 1 Il.

The invention relates to the field of training the native waters and man-made solutions from iron and manganese compounds. The invention can be used in urban municipal services, water treatment systems for settlements, local treatment and purification of water for drinking water of high quality, as well as in industry and agriculture to improve efficiency technologies purification of natural and waste waters of different salinity.

One of the main problems in purification processes of water and aqueous solutions of iron is the difficulty of removal of compounds of divalent iron in the form of simple salts, and also hard to destroy the complex compounds of inorganic and organic nature, which, in contrast to compounds of trivalent iron, greater solubility and reduced susceptibility to hydrolytic decomposition. In this regard, the known sorption and filtration methods of cleaning solutions from iron provide the ability to pre-oxidize the ferrous iron to the ferric state. Such oxidation may be either in solution due to aeration of the water or add in the cleaned water oxidizing chemical reagent in the presence or absence of appropriate catalysts, and on the surface of the criminal code of the t-iron, which is in the processing of quartz sand, gravel, clay or other granular material aerated water or water with any oxidant, in which the granules, such as sand adsorbed and formed a catalyst layer of iron hydroxide, contributing to the further improvement of the water treatment process at its further passage through the layer of sand. When sand is used as the adsorbent and filter material. The main disadvantages of this method are low capacity for iron, leading to restrictions on the maximum concentrations of iron in the treated water and the volume of treated water, and low speed (intensity) of the cleaning process.

A known method of producing adsorbent granular pyrolusite or other natural and artificial minerals manganese oxides [2]. These adsorbents are effective deironing, as they have significant adsorption capacity. The disadvantages of this method are the need to maintain low speeds the transmission of the processed solution through the layer of sorbent material due to the fact that in the process of iron oxidation are formed soluble soedinenie the need for the use of alkalizing agents for regulating the pH of the solution. The latter is due to the fact that the resulting trivalent iron spontaneously undergoes hydrolysis to obtain a solid phase of hydroxides, easily separable by filtration, and the process of hydrolysis is much faster only with the increase of pH of the treated solution.

The closest to the proposed method to the technical essence and the achieved result is a method of obtaining a granulated filter material IWF [3] for the treatment of water and aqueous solutions of iron, consisting in mechanical and thermochemical processing of carbonaceous material (dolomite), its subsequent chemical modification with compounds of divalent manganese and drying at elevated temperature. In data processing produces a granular porous material with a developed specific surface, containing in the pores of the finely dispersed catalytically active manganese dioxide. In one sorption material obtained by this method, combined oxidation (catalytic), alkalizing and filtering functions. The sorbent can be used for cleaning solutions with high content of iron, for additional purification of solutions of manganese in their odnovremenno pH.

The disadvantage of this method [3] is a large value (energy content) of the sorbent, as well as low duration cycle, associated with a limited capacity for iron. Another disadvantage of the sorbent, obtained by the method [3] is a significant drop in filter capacity of the sorbent layer during the sorption cycle.

The objective of the invention is to develop a cheaper method of producing a sorbent having improved properties, namely a high kinetic characteristics, high adsorption ability with respect to compounds of iron, namely a high sorption capacity, and a higher degree of extraction, and increased filtration capacity.

The task is solved by the fact that in the method of producing a sorbent for purification of water and aqueous solutions of iron and manganese compounds, including chemical processing of granular carbonaceous material compounds manganese and subsequent drying of the treated material at elevated temperatures, as a granulated carbonaceous material used raw calcium carbonate, containing not more than 1% of magnesium carbonate, chemical processing mutantnogo manganese and alkali solution, after the first and second stages of chemical processing is carried out intermediate drying of the material at a temperature of 10-100° C to a residual moisture content of not more than 100% and not less than 10%, after the third stage carry out the final drying of the material at a temperature ranging from 50 to 300° C to a residual moisture content of not more than 5%, the chemical processing of granular carbonaceous material is carried out sequentially: 0.01 to 10% solution of chloride of manganese, of 0.001 to 5.0% solution of potassium permanganate, 0.1 to 10% solution of potassium or sodium alkali.

The drawing shows comparative data for water purification from iron various sorbents.

A distinctive feature of the proposed method is optimal set of techniques and operations, including the selection of granulated carbonaceous material, the choice of reactants, their concentration, as well as a certain sequence of their application, conditions and sequence additional processing, including drying and heat treatment. The mentioned combination and only she can solve the problems of the invention.

In has been changed the way previously studied and taken into account all the mistakes that were admitted during the development of previously proposed methods.

For processes obeszal Timo hammered deposited iron oxide during water treatment. Repeatedly in cycles of filtration (adsorption, coagulation and deposition) and backwash (regeneration) involves only the outer surface of the granules. It makes no sense to use or tailor to get a mechano-chemical, thermal and other methods materials with internal porosity.

- Try to get the active catalytic film of a mixture of oxides of manganese, using only the connection of double-manganese and subsequent chemical treatment, or the connection heptavalent manganese and subsequent heat treatment, or only a mixture of these compounds leads to the fact that only a fraction of the reagents becomes active product, which should consist of the catalytic film. Getting the film is most expedient to regulate chemical method, using as reagents and salts of divalent manganese and hexavalent manganese and alkali.

In the proposed method, based on the chemical precipitation of active manganese oxides on the surface of the granular material, in contrast to thermal methods do not form a continuous “skin” inactive source reagent on the surface of the granules, preventing simultaneous COI is required for rapid coagulation of colloids, formed by iron and manganese compounds.

Thus, the proposed method allows to obtain the most stable and the most active sorbents (filter materials) for the treatment of water and aqueous solutions of iron and manganese compounds possessing simultaneously the following functions: (a) catalytic oxidative function for translation of divalent iron in the trivalent state; b) alkalizing the function to adjust the pH of the treated water or aqueous solution to pH>7) the ability to contact coagulation hydrolyzed iron compounds; g) the ability to filter sediment.

Other distinctive features of the proposed method can be described as follows: obtaining and securing on the surface of the filter material of the active layer is not achieved at the expense of its internal porosity or ion-exchange properties of this material, but due to the special procedures of application active substances, including alkaline or weakly basic material; this in turn allows arbitrarily adjust the amount applied to the surface compounds manganese and get the sorption material, not blocked solid Catalonia or alkaline material in conditions of almost unlimited buffer capacity in the zone of oxidation (compared to the amount of hydrolysis acid), hydrolysis, contact coagulation and chemical regeneration (the opposite of oxidation) catalyst layer due to dissolved in the recycled water of oxygen in accordance with the following reactions:

MnO2+Fe2+MnO+MP2O3+Fe3+

About2+Fe2++H2OFe(OH)3

Fe3++H2AboutFe(OH)3+H+

H++Caso3CA2++HCO-3

nF(OH)3[Fe(OH)3]n

O2+MP+MP2O3MnO2

For the proposed method it is advisable to use granulated calcium carbonate, containing not more than 1% of magnesium carbonate, as the latter has a much greater solubility than calcium carbonate, which can lead to contamination of the treated water.

To avoid deterioration of the sorbent due to the deposition of the active compounds of manganese are not on the surface of the sorbent, and in solution it is advisable after the first and second stages chem is over 100%. Thus to prevent loss of chemicals and preventing the reduction of the reactivity of the reagents, it is advisable to carry out the drying at these stages at a temperature of 10-100° C to a residual moisture content was not less than 10%.

To stabilize the properties of the obtained sorbent is advisable to carry out the final stage of drying to a residual moisture content of not more than 5% at a temperature ranging from 50 to 300° C. At temperatures below 50°C drying processes up to 5% moisture and less inefficient and time consuming at temperatures above 300° C partly lost reactivity formed on the granules of the adsorbent film of manganese dioxide.

It is advisable to carry out chemical processing of granular carbonaceous material sequentially with solutions of manganese chloride with a concentration of not less than 0.01%, the potassium permanganate is not less than 0.001%, potassium or sodium alkali concentration not less than 0.1%. At lower concentrations decreases the reactivity of the reactants and increases the amount of wastewater.

It is advisable to carry out chemical processing of granular carbonaceous material sequentially with solutions of manganese chloride with a concentration of not more than 10%, the permanganate is intratech increased consumption of reagents without improving the sorption properties of the obtained sorbent.

Examples of the method.

Example 1.

In the capacity of chemically resistant material containing 10 kg of granulated calcite (caso3) with grain size 0,8-1,2 mm, add 1.5 liters of 1% aqueous solution of manganese chloride. The mixture is stirred for 5 min, and then, continuing to mix, dried with hot air at a temperature of 65° C to a residual moisture content of 100%, i.e., until the free liquid between the granules will not disappear, making sure that yourself granules remained wet. In the resulting product added to 1.2 l of 1% aqueous potassium permanganate solution, the resulting mixture was stirred for 5 min, and then, continuing to mix, dried with hot air at a temperature of 65° C to until free liquid between the granules will not disappear, making sure that yourself granules remained wet. In the resulting product add 0.7 liters of 1% aqueous sodium hydroxide solution, the resulting mixture was stirred for 5 min, and then, continuing to mix, dried with hot air at a temperature of 120° up until pink granules will not change to dark brown and until the granules will not be dry with residual moisture not more than 5%.

The resulting product is cooled and feel its sorption and F. the key water from the iron.

At the same speed (60 cm3/h) transmission of the source water with a pH of 6 and an iron content of 2.5 mg/l through the column, one of which is 10 cm3commercial BIRM, and the other 10 cm3sorbent KAM-based calcite obtained by the proposed method, the length of filter runs before the breakthrough of iron at a concentration of 0.3 mg/l is as follows:

KAM - 460 h; BIRM - 380 hours

Example 2. Carry out the process of sorbent CAM, as described in example 1. The resulting product is cooled and feel its sorption and filtration properties to remove manganese from water in comparison with the properties of BIRM. At the same speed (60 cm3/h) transmission of the source water with a pH of 6 and with a manganese content of 0.5 mg/l through the column, one of which is 10 cm3commercial BIRM, and the other 10 cm3sorbent KAM-based calcite obtained by the proposed method, the length of filter runs before the breakthrough of manganese in a concentration of 0.1 mg/l is as follows:

KAM - 220 h; BIRM - 140 hours

Example 3. Carry out the process as described in example 1, except that instead of calcite take crumbs with a grain size of 0.8-2 mm, the resulting product - sorbent KAM - cooled and experience it serushago material IWF. For the detection of objective differences in the investigated properties within a short period of time tests are conducted with highly contaminated solutions at high speed bandwidth solutions through the column. For this column load 5 cm3sorbent CAM, the other 5 cm3IWF. Cook slightly acidic solution (pH 3) iron (II) concentration in water of 10 mg/l, stabilize the solution by the addition of ascorbic acid to concentrations of 20 mg/l, hold partial neutralization with dilute caustic soda solution to pH 5 and passed through a column loaded by different sorbents with initial velocity 10 cm3/min (120 column volumes per hour). In the process, the speed of transmission through the IWF spontaneously and significantly decreases, therefore, the processing bandwidth of 10 l of solution through the CAM 18 h, through the IWF 25 PM Volumes skipped solutions to the breakthrough of iron at a concentration of 0.3 mg/l the following:

Through the KAM - 4600 ml; Through IWF - 3750 ml

Example 4. Carry out the process of the sorbent as described in example 1, except that instead of calcite take crumbs with a grain size of 0.8-2 mm, the resulting product is cooled and feel its sorption and filtration of NWO is for. For the detection of objective differences in the investigated properties within a short period of time tests are conducted with highly contaminated solutions in terms of the maximum possible velocity through the column. For this purpose, in each column load 5 cm3the sorbent is prepared slightly acidic solution (pH 4) iron (II) concentration in water of 4.5 mg/l, stabilize the solution by adding ascorbic acid to a concentration of 10 mg/l, are neutralized with dilute caustic soda solution to pH 6 and passed through a column loaded by different sorbents with a speed of 50 cm/min (600 column volumes per hour).

The drawing shows the results of comparative tests of the functional properties of sorbents: KAM obtained by the proposed method, well-known industrial sorbent-BIRM iron removal, as well as the prototype of the sorbent CM with well-developed porosity - natural zeolite-clinoptilolite modified with compounds of manganese. It is seen that the sorbent CAM continues to operate in conditions where the BIRM is no longer clear water.

Sources of information

1. RF patent №2187462.

2. Kul L. A., Strokach PP Technology for purification of natural waters. Vyscha SHKOLA, Kiev, 1986.

2. The method according to p. 1, wherein after the first and second stages of chemical processing is carried out intermediate drying of the material at a temperature of 10-100°C to a residual moisture content of not more than 100% and not less than 10%, after the third stage carry out the final drying of the material at a temperature ranging from 50 to 300°C to a residual moisture content of not more than 5%.

3. The method according to p. 1, characterized in that the chemical treatment of granular carbonaceous material is carried out sequentially: 0.01 to 10% solution of chloride of manganese, of 0.001 to 5.0% potassium permanganate solution; 0.1 to 10% solution of potassium or sodium alkali.



 

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FIELD: sorbents.

SUBSTANCE: invention relates to preparation of compounds based on poorly soluble polyvalent metal salts of polybasic acids, in particular titanium phosphate, which can be used as sorbents for various cations from aqueous solutions. Synthesis of titanium phosphate-based sorbent is accomplished by interaction of phosphate solution with titanium-containing solution preheated to 70-100°C at P/Ti ratio (1.0-2.6):1. Resulting hydrogel is separated from mother liquor, washed with water, and subjected to heat treatment for 20-36 h at 35 to 100°C, after which dried at higher temperature (100-120°C). Titanium-containing solution may be 0.6-2.8 M solution of titanium in sulfuric or hydrochloric acid and phosphate solution may be 0.5-3.6 M orthophosphoric acid solution. According to invention, before heat treatment or after drying, hydrogel is, respectively, molded or ground to granule or particle size 0.6 to 10.0 mm.

EFFECT: enabled preparation of granulated amorphous sorbent resistant to spontaneous destruction in aqueous media, having improved sorption characteristics and low hydrodynamic resistance.

4 cl, 1 tbl, 10 ex

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