SU1286601A1 - Method of producing nitrogen-containing derivative of hydrolyzed lignin - Google Patents

Abstract

The invention relates to the chemical processing of plant materials, in particular the production of nitrogen-containing derived hydrolytic lignin (AHL), used to sorb heavy metal anions from wastewater. In order to provide better sorption capacity for heavy metal anions, the method provides for treatment in a pH-determined environment. The preparation of AHL is carried out by treating the starting technical lignin with an aqueous solution of Cd-alkyltrimethyl ammonium chloride with a concentration of 5-10 g / l in the presence of alkali at a pH of 10-12. The resulting product is separated and dried. AHL sorbent testing of anions, for example, MoO or WO, indicates that the statistical capacity of MoO is 78.67 mg / g or 0.82 mmol / g, the dynamic capacity is 51.08 mg / g or 0.53 mmol / g , and for a static capacity of 84.21 mg / g or 1.65 mmol / l, dynamic 55.82 mg / g or 1.095 mmol / l, versus 22-26 mg / g and 14-18 mg / g, respectively, for the known lignin (without alkali). The degree of extraction of anions from acidic solutions is 42.8-48 at a pH of 2.1-2.4. 3 tab. c (L 00 05 O5

Description

one

The invention relates to the chemical processing of plant materials, in particular, to an improved method for the preparation of a nitrogen-containing derivative-hydrolysis linin, used as a sorbent for heavy metal anions and wastewater.

The purpose of the invention is to increase the sorption capacity of a nitrogen-containing hydrolyzed lignin derivative in relation to heavy metal anions. This is achieved using a pH-determined medium for treating the starting lignin.

Example 1. In a 250 ml glass flask, 2 g of air-dry technical 1 and lysis of lignin and 100 ml of an aqueous alkaline solution of alkyltrimethylammonium chloride (ATM) with a concentration of 10 g / l, having a pH of 10.0 ( adding a 0.1N solution of NaOH or a 20-25% solution of NH OH). The flask is closed tightly fitted with a rubber stopper of the Substance; it is periodically mixed and kept in contact for 70 hours at 20 + at atmospheric pressure. The solid is then separated from the solution, washed with distilled water, and air dried at room temperature.

Using the obtained sorbent, the isotherm of the sorption molybdate ion is removed from acidic aqueous solutions (pH 2–4) in the range of initial concentrations of i MoO / 50–200 mg / g. The static capacity of the sorbent calculated by the Langmuir equation is 78.67 mg / g or 0.82 mmol / g. The dynamic capacity of the sorbent is 51.08 mg / or 0.53 mmol / g.

Example 2. A 2 g air-dry technical1 hydrolytic lignin is placed in a 250 ml flask. Then, 100 ml of an aqueous alkaline solution of ATM with a concentration of 10 g / l, having a pH of 12 (add 0.1N NaOH solution or

20-25% solution of NH.OH). The flask

 t

Close tightly fitted rubber stopper. Substances, periodically stirring, kept in contact for 70 hours at t. 20 + + 2 C and atmospheric pressure. The obtained solid product is separated from the solution, washed with distilled

five

0

air at room 5

NOI with water and dried at natal temperature.

- The static capacity of the resulting sorben according to the WO anion, determined by the method of Example 1, is equal to 84.21 mg / g or 1.65 mmol / g, and the dynamic sorption capacity for the same anion is 55.82 mg / g or 1.095 mmol / g .

In the proposed method of sorbent activation, the hydrolysis lignin is treated with an aqueous solution of alkyl trimethylammonium chloride with a concentration of 5-10 g / l in the presence of an alkaline reagent. Reducing the concentration of ATM (5 g / l) leads to a decrease in the sorption capacity of the final product (2 times). This is due to the fact that the ATM sorbent is not fully saturated with ATM. A further increase in the concentration of ATM (10 g / l) is impractical because of the high consumption of modifying reagent, which leads to a significant reduction in the efficiency of the proposed method of modification.

The sorption properties of the activated nitrogen-containing sorbent with respect to the anions of heavy non-ferrous metals (in particular, molybdenum, tungsten, vanadium) are carried out under static (1-method) and dynamic (2-method) conditions.

Example 3. Statistical study (1-procedure). In a 250-ml glass flask with rubber tightly fitted stoppers, 100 ml of an aqueous solution of salts of heavy non-ferrous metals (pH 2-3) are sequentially introduced in the range of initial concentrations of metals 50-200 mg / l and O, 1 g of air-dry technical hydrolytic lignin (fraction

5 1,000-0,630 mm). Sorption systems are incubated for 2 hours with constant stirring of the solution using a mechanical platform (oscillations per minute). Then

0 the filtrate is analyzed for residual, the metal content in the solution. The value of the static capacity of the sorbent is determined by the graphic-analytical method from sorption isotherms

5 Langmuir.

Example 4: Dynamic study (2-procedure) 1 Aqueous solutions of heavy non-ferrous metal salts with initial concentration of metal

five

0

3 to 190–200 mg / l and a pH of 2-3 are filtered through a layer of activated sorbent (2 g of modified g of lidine lignin, fractions of 1,000–0.630 mm) loaded into a glass column. The cross-sectional area is 0.79 cm. Filtering rate 0, 3-0.5 ml / min. Temperature . The magnitudes of the sorbent dynamic capacities are determined from the output sorption dynamics curves.

When conducting repeated experiments, they do not get sharply deviating results, which indicates the subordination of random measurement errors to the normal law of probability distribution. The value of the standard deviation (-S 0.194 mg / g for molybdenum) falls within the allowable range (for molybdenum 3.5 mg / g), which indicates the reliability of the experimental data.

Comparison of the sorption capacity of non-activated hydrolytic lignin, activated by the known and proposed methods for anions of molybdenum and tungsten is given in Table. one.

The optimum pH of the sorbent-activating solution is 10-12.

In tab. Figure 2 shows the experimental data on the sorption of heavy non-ferrous metal anions by hydrolysis lignin modified with an aqueous solution of alkyltrimethylammonium chloride at various pH values of the solution.

With a lower alkalinity value (pH 8.0), the effect of complete saturation of the ATM sorbent is not achieved, since the pH value of the solution is insufficient to transfer the ATM to a fully undissociated state. This leads to a significant decrease in the sorption capacity of the final product with respect to the anions of heavy non-ferrous metals. In a more alkaline medium (pH 12), the process of partial dissolution of the sorbent takes place, which makes its use in the processes of industrial wastewater treatment ineffective.

Activated sorbent obtained by the proposed method, RE86601 .4

It is recommended for sorption of heavy non-ferrous metal anions capable of forming polyacids in acidic solutions. These metals include

5 molybdenum, tungsten, vanadium. The range of pH values 2-3 is optimal for the sorption process, corresponds to the highest degree of polymerization of polyacids, and in these conditions

fO, there is a maximum degree of extraction of heavy non-ferrous metal anions from solutions by modified hydrolysis lignin (see Table 3).

15

The dependence of the degree of extraction of molybdenum anions by the modified hydrolytic lignin on the pH of the solution, 1.06 mmol / l (initial concentration of Mo), (. T gl 1 g / l; (amount of lignin), t 20 ± 2 ° C are presented in Table 3 .

The spent sorbent can be subjected to heat treatment, as a result of which easily recyclable ash containing up to 60% of metals is obtained, or the spent hydrolysis lignin can be used 30 as a precoat in the process of mechanical dewatering of sewage.

Thus, the activated 35 nitrogen-containing sorbent obtained by the proposed method can be used for sorption of heavy non-ferrous metal anions capable of forming polyacids in acidic solutions (in particular, for sorption of molybdenum, tungsten, vanadium).

Claims (1)

Invention Formula 45 A method of producing a nitrogen-containing hydrolytic lignin derivative by treating a starting technical hydrolyzing lignin with an aqueous solution of C d-C alkyl alkyl trimethyl 50 with monium chloride with a concentration of 5 to 10 g / l, in order to increase the sorption capacity of the target product with respect to heavy metal anions, 55 process is carried out in the presence of alkali at pH 10-12. 12866016 Table 1 Hydrolytic lignin (GL) 4-82-4 GL + alkali 7-103-5 GL + ATM22-2614-18 GL + alkali + + ATM80-8552-58 note GL - technical hydrolytic lignin; ATM is a technical alkyltrimethylammonium chloride of the general formula K (CH3) where R is C-C alkyl, g with a concentration of 5-10 g / l. table 2 GL + alkali + + ATM 10-1278.67 Note. WITH ttcx pH 1.0 1.95 2,12,43,04,055,15,95 Recovery rate S,% 1.6 15.2 42.8 48.0 42.6 34.0 1.7 1.7 84.21. 1.94 mmol / L (initial concentration W) Table