The way the sorption of tungsten (vi) from aqueous solutions

 

The method of extracting tungsten (VI) from aqueous solution relates to the field of extraction of substances with the use of sorbents and can be used in ferrous and nonferrous metallurgy, as well as for the treatment of industrial and domestic wastewater. The objective of the invention is to find the optimum conditions for rapid and efficient way to extract ions of tungsten (VI) from aqueous solution. This is achieved by the fact that the sorption is carried out by ion-exchange resin brand AM-2B containing exchange group-CH₂-N(CH₃)₂, -CH₂-N(CH₃)₃when pH7 and alkaline pre-treatment sorbent at pH4 and pH > 5 and acid pre-treatment sorbent at pH5 and water pre-treatment sorbent. Sorption on ion-exchange resin brand AM-2B under optimal conditions is a quick and effective method of extraction of ions of tungsten (VI) from aqueous solutions. 3 C.p. f-crystals, 4 Il.

The method of extracting tungsten (VI) from aqueous solution relates to the field of extraction of substances with the use of sorbents and can be used in ferrous and nonferrous metallurgy, as well as for cleaning industrial is (Zelikman A. N., Kites B., metallurgy of rare metals. - M.: metallurgy, 1991, S. 38-39). To this end, apply slightly basic anion exchange resin containing amine groups, or ampholytes containing carboxyl and amine groups.

The disadvantage of the methods is the length of the sorption process.

The closest technical solution is the way sorption of tungsten ions from aqueous solutions, including contact solution and the anion brand S-2B (VI all-Union conference on the chemistry and technology of molybdenum and tungsten. The abstracts. Academy of Sciences of the USSR. Nalchik, 1988, s 170).

The disadvantage of this method is that the sorption was studied depending on the pH of the initial solution and does not take into account the change of the pH value in the sorption process that affects the final results of the extraction of tungsten ions from solution.

Task to be solved by the claimed invention is directed, is to find the optimum conditions for rapid and efficient way to extract ions of tungsten (VI) from aqueous solution.

The technical result that can be achieved with the implementation of the invention is the efficiency of the process of sorption of tungsten (VI) from aqueous solution.

This technical result is achieved in that in the method of conducting a preliminary alkaline, acid or water processing anion-exchange and sorption of lead while maintaining the setpoint of pH on ion-exchange resin containing exchange group-CH₂-N(CH₃)₂, -CH₂-N(CH₃)₃after alkaline pre-treatment of the anion sorption of lead at pH7, after acid pre-treatment of the anion sorption of lead at pH4 and pH>5, water after pre-treatment of the anion sorption of lead at pH5.

The essence of the method is illustrated by drawings, where Fig.1-4 are given the dependence of sorption exchange capacity (SOY) sorbent, mg, W(VI) per 1 g of sorbent, the pH of the solution, time of adsorption (day) and method of pre-treatment sorbent.

Examples of specific implementation method.

Sorption of W(VI) was obtained from 200 cm³the original solution of Na₂WO₄·H₂O, lot of 2 sorbent, the Sorbent previously in the day was kept at 0.1 N. solutions of NaOH, H₂SO₄or in distilled water.

The concentration of tungsten ions was determined on the photocolorimeter brand KFK-3, and acid-base characteristics of the solution was controlled by a pH-meter pH-121.

Mixing and key system has changed slightly. However, for greater assurance of achieving equilibrium contact of the sorbent and solution carried out not less than one day. To maintain a given pH value of the solution in the process of sorption as neutralizers used a solution of NaOH and Hcl. Set the pH value was maintained for 5 h from the start of the sorption neutralization solution, in the future, the pH did not change significantly, therefore, the adjustment of pH was carried out once a day.

Sorption was carried out at room temperature.

Using the values of the concentrations of tungsten ions in aqueous solution source and after sorption, the expected SOYBEAN, mg/,

Example 1 (Fig.1).

Sorbent previously in the day was kept at 0.1 N. NaOH solution.

In Fig.1 are given the results of sorption from aqueous solution with a concentration of 3000 mg W(VII)/DM³during 3 days. Sorption is carried out at pH<7. The best results were obtained at pH 1-2 during 3 days, SOY=262 mg/,

Example 2 (Fig.2).

Sorbent previously in the day was kept at 0.1 N. the solution of Hcl.

In Fig.2 shows the results of sorption from aqueous solution with a concentration of 3000 mg W(VII)/DM³during 5 days. Sorption is realized at pH4 and pH>5. At pH 4-5 sorption DOS 6,5-8 for a time less than 2 days SOY=281 mg/g, for a time less than 3 days, SOY=291 mg/,

Example 3 (Fig.3-4).

Sorbent pre 9 day kept in distilled water.

In Fig.3 are given the results of sorption from aqueous solution with a concentration of 3000 mg W(VII)/DM³during 3 days. Sorption is realized at pH5. The best results were obtained at pH 8-9 at the time of 0.04 days (1 hour), SOY=280 mg/g at pH 8 during the day SOY=296 mg/,

In Fig.4 shows the results of sorption of W(VI) at pH of 6.2 to 6.8, depending on the initial solution concentration (2,5-9,1 g/DM³W(VI)) and the time of sorption. Best results are obtained during more than two days;

SOY=470 mg/g at C_Ref=9,1 g/DM³W(VI) and time of sorption of 2 days.

From the data of Fig.1-4, it follows that at room temperature the results of sorption depends on pre-treatment sorbent, the concentration of the initial solution, the pH of the solution in the process of sorption and sorption time.

Polymerized processes in weakly acidic solutions, increase the sorption capacity macroporous sorbent, but reduce the speed of sorption as a polymerization conversion is carried out in time.

Compared with the prototype sorption on ion-exchange resin brand S-2B in the ditch.

Claims

1. The way the sorption of tungsten ions from aqueous solutions, including contact solution and the anion brand S-2B, characterized in that before sorption conduct a preliminary alkaline, acid or water treatment resin, and the sorption of lead while maintaining the setpoint of pH on ion-exchange resin containing exchange group

-CH₂-N(CH₃)₂;

-CH₂-N(CH₃)₃.

2. The method according to p. 1, characterized in that after alkaline pre-treatment of the anion sorption of lead at pH7.

3. The method according to p. 1, characterized in that after acid pre-treatment of the anion sorption of lead at pH4 and pH > 5.

4. The method according to p. 1, characterized in that water after pre-treatment of the anion sorption of lead at pH5.