RU2118908C1 - Textile fibrous bulked catalyst - Google Patents

Abstract

FIELD: chemical, oil, light industries, in particular, materials used in catalytic processes, for instance, for cleaning sewage and gas outbursts from sulfides. SUBSTANCE: textile fibrous bulked catalyst is made in the form of fabric (for instance, rib knit fabric) having carrier layer made from single filaments and modified ion-containing complex threads of polyacrylonitrile filaments including one or two ions of metal of variable valence. Weight ratio of carrier layer single filaments and polyacrylonitrile filaments of textile fabric is 60.7-82.3%, linear density of polyacrylonitrile filaments is 32/2-32/4 tex, loop surface module is 3.17-3.35, total linear density of weft and warp threads is 156.3-211.7 tex. EFFECT: increased efficiency by intensified sulfide oxidation rate and wider operational capabilities. 1 tbl, 44 ex

Description

 The invention relates to materials for the implementation of catalytic processes and can be used in the chemical, petrochemical, light industry, in particular for the treatment of wastewater and gas emissions from sulfides.

 Known materials have a number of disadvantages, among them high hydrodynamic drags, high gas phase flow rates, large specific amounts of catalyst, which leads to insufficiently high rates of processes with their participation and some narrowing of the field of applicability.

Closest to the claimed solution is a knitted bulk fibrous catalyst in the form of a fabric, consisting of a carrier of monofilaments and modified complex filaments of PAN fibers containing one of the metal ions of variable valency (Fe ²⁺ , Ni ²⁺ , Cu ²⁺ , Mn ²⁺ , Co ²⁺ , Cr ³⁺ ). The resulting material was used for the catalytic oxidation of sulfides in wastewater. Based on the data given in the description of the prototype: reactor diameter D = 0.01 m, height H = 0.18 m, volumetric air flow rate Q = 2 l / min, catalytically active fiber mass m = 2.8 g, we calculate the cross-sectional area using the formulas from the book [1] reactor S = 3.1416 • D ^2/4 = 3.1416 • 0.01 • 0.01 / 4 = 7.854E-05 ^m2, the volume of the reactor V = S • H = 7.854E-05 • 0.18 = 1.414E-05 m ^3, the reduced traveling speed air W = Q • (1E-3/60) / S = 2 • (1E-3/60) /7.854E-05 = 0.424 m / s, the ratio of the mass of catalytically active fiber to the reactor volume M (module) = (m • 1E-3) / V = 2.8E-3 / 1.414E-05 = 198.1 kg / m ³ . At a sulfide concentration of (0.1-0.2)% by sulfide ion, under certain conditions, 100% sulfide oxidation can be achieved. The maximum oxidation rate was observed on Ni ²⁺ and Cu ²⁺ containing samples [2].

Such catalysts have the following advantages. In contrast to homogeneous ones, they do not pollute wastewater with toxic compounds of variable valence metals (see [3], where it is proposed to oxidize sulfides in tannery wastewater with atmospheric oxygen in the presence of catalysts - Ni ²⁺ and Mn ²⁺ salts in quantities of 0.4 - 0.5 mass fractions from the amount of sulfide in wastewater). The speeds of such processes are not very high. The authors of [3] note that in the case of the presence of a sulfide ion in an amount of more than 6-8 g / l, the oxidation process does not proceed to the end. Fiber catalysts, on the contrary, are easily separated from the reaction solution; they are technologically advanced. The fibers have a developed surface, which greatly facilitates the contact of reagents on their surface, increasing the overall speed of the processes with their participation by reducing the intradiffusion resistance. The fibers are strong and can be processed by traditional textile methods into various forms that are convenient for use (for example, knitted fabrics knitted by the half-method), and it is possible, as was done in the prototype, to bind the catalytically active material and an inert base, giving the fabric strength , crush resistance, the ability to impart optimal hydrodynamic properties, ease of technological manipulation, increased service life.

As shown by experiments on the oxidation of sulfides by atmospheric oxygen on fibrous catalysts, the rate of this process is determined by the rate of dissolution of oxygen - the rate of oxidation is highly dependent on the hydrodynamic conditions in the apparatus. With an increase in the reduced air velocity in the apparatus, the catalytic reaction rate increases. Used in the prototype values of the module M = 198 kg / m ³ and the reduced air velocity V = 0.42 m / s are associated with the need to intensify the process of dissolution of air. Such large values of the modulus and gas velocity are associated with non-optimal geometric parameters of the knitted material used. Such a module (packing density) leads to an increase in air consumption, the cost of overcoming high hydraulic resistance. Since the heterogeneous catalytic process proceeds on the surface of the catalyst fiber, the rate of such a process is proportional to the amount of catalyst (modulus), therefore, a high value of the module generally speaking indicates a low specific rate of the catalysis process (the rate of the catalysis process per unit mass of fiber), hereinafter called catalysis process. The same can be said about the reduced speed of air movement - high values of the reduced speed of air movement indicate low values of the speed of the catalytic process and vice versa. Therefore, in the future, the values of the module and the reduced air velocity are used as criteria for the speed of the catalytic process. Thus, the non-optimal geometric parameters of the prototype lead to a non-optimal mode of operation of a unit mass of the catalyst and therefore a decrease in the speed of the process. Another disadvantage of this catalyst is that the fibers contain in their composition only one metal ion. This limits its scope and, in some cases, limits the rate of catalyzed processes. The use of catalysts containing several metals to increase the rate of processes is known in the art for the use of non-fibrous catalysts in gas-phase oxidation reactions of organic compounds with atmospheric oxygen [4]. However, the modification of complex PAN filaments in the prototype in order to create a catalyst containing two metals does not make sense, since the overall process speed in the prototype is limited by the rate of dissolution of oxygen and cannot be increased until the rate of dissolution of oxygen is increased. Another drawback is the lack of stability of the fabric due to the use of loose complex filaments, the structure is subject to creasing during operation, which leads to heterogeneous hydrodynamic parameters, slip of the liquid and the oxidizing gas, and the formation of stagnant zones.

 The technical result of this invention is to increase the rate of the catalysis process and expand the scope of applicability.

 The technical result is achieved by the fact that the textile bulk fibrous catalyst in the form of a web (for example, bonded by the semifang method) consists of a carrier of monofilaments and modified ion-containing multifilament yarns of polyacrylonitrile fibers, including one or two metal ions of variable valency, and the ratio of the mass of monofilaments in the textile web of the carrier to the mass of PAN of complex filaments 60.7 - 82.3%, linear density of PAN filaments 32/2 - 32/4 tex, surface loop module 3.17 - 3.35, total linear density of filaments warp and weft 156.3-211.7 tex.

 The experimental studies of the process of dissolving air on contact elements in the form of volumetric textile fibrous structures showed that the essential features are: the ratio of the mass of monofilament of the carrier to the mass of PAN of complex yarns (mass of the base to PAN) 60.7 - 82.3%, linear density of PAN threads 32/2 - 32/4 tex, surface loop module 3.17 - 3.35, total linear density of warp and weft 156.3 - 211.7 tex.

 These distinguishing features make it possible to ensure a hydrodynamic regime that provides the best in terms of the dissolution rate of both the oxidizing gas and the possible impurities contained in the oxidizing gas, which leads to an increase in the rate of catalysis in the processes of wastewater treatment and gas emissions. An increase in the rate of catalysis can reduce the packing density (module) and the gas feed rate, which leads to material savings, lower hydrodynamic drags and energy consumption for passing gas through the apparatus. This will expand the scope of applicability and, in particular, use the proposed catalyst for the purification of gases from hydrogen sulfide.

 The fibrous catalyst in the form of a three-dimensional textile knitted fabric was made, for example, from polypropylene monofilaments according to TU-6-06-537-86 with a diameter of 0.3 mm, as a carrier, multifilament yarns made of polyacrylonitrile (OST-6-06-2-80) were used. The fibrous catalyst was manufactured by the semifang method. The manufacture of paintings was carried out on standard equipment.

Further, in order to impart catalytic properties to the textile bulk material, chemical modification of the fibers contained in its composition is carried out. Since such a modification reduces the strength of the fiber, it is produced in a ready-made textile material. Modification is carried out in two stages. At the first - by hot alkaline-hydrazine treatment according to the procedure corresponding to the mode of production of fiber "copan" [5], the ion-exchange properties are imparted to the fiber. The treatment consists in the action of an alkaline solution of hydrazine hydrochloride, solution parameters: NaOH concentrations of 100-150 g / l, N ₂ H ₆ Cl ₂ 100-150 g / l, temperature 90-100 ^o C, processing time 60-150 min. In this case, hydrazine and carboxyl groups are formed on the fiber, which are capable of forming complexes with transition metal ions. After washing with demineralized water, the web is sent to the second stage. The second stage consists in fixing the transition metal ions on the fiber by immersing (30-60) min in an aqueous solution of salts of one or two metals of variable valency (for example, sulfates, chlorides, nitrates) in an amount of 1-5% for each of the metal ions. In this case, metal ions form complex bonds with the main nitrogen-containing and acidic carboxyl groups, forming a catalytically active material. The final stages are washing and drying.

 In all experiments on oxidation in the liquid phase, the reduced air velocity was chosen W = 0.01 m / s, since with a further decrease in this value, the oxidation rate begins to decrease, and when the gas is removed from hydrogen sulfide, the reduced velocity is determined by the volumetric gas flow rate. In all further examples, the following textile parameters of the catalyst are given: the ratio of the mass of monofilament of the carrier to the mass of PAN of complex yarns (mass of the warp to PAN),%; linear density of PAN filaments, tex; loop surface module; total linear density of warp and weft threads, tex. The remaining parameters (the height of the loop row, the loop step, etc.) are calculated in accordance with GOST 8847-87.

Example 1. Textile volumetric fibrous catalyst in the form of a web, made by the method of "semifang" with the parameters: the ratio of the mass of the monofilament of the carrier to the mass of PAN complex yarns (warp mass to PAN) 66.9%, linear density of PAN threads 32/3 tex, surface loop module 3.19 , the total linear density of warp and weft 184 tex. Its modifying treatment consisted in the action of a hot alkaline solution of hydrazine hydrochloride with parameters: NaOH concentration of 120 g / l, N ₂ H ₆ Cl ₂ concentration of 120 g / l, solution temperature of 93 ^o C, PAN fiber module of 50 kg / m ³ , processing time 90 min. After washing with distilled water, the material was soaked in a 5% solution of nickel sulfate (Ni ^{2+ ion} ) for 40 minutes, followed by washing with distilled water again. The nickel content on the fiber is 0.7 mmol / g.

The catalyst in the form of a roll 0.1 m high was charged into the reactor, shown in the drawing, where 1 is the reactor vessel, 2 is the water thermostatic jacket, 3 is the reaction solution, 4 is the catalyst roll, 5 is the gas distribution grid, 6 is the air supply, 7 - rubber seal rings. The diameter of the reactor is D = 0.05 m, the volume of liquid in the reactor is 300 ml, the reduced air velocity is W = 0.01 m / s, the ratio of the mass of the catalytically active fiber to the volume of the solution (module) M = 8.88 kg / m ³ , the solution used was the tannery’s wastewater after an ashing operation, containing sulfides in the amount of 800 mg / l (0.08%), COD (chemical oxygen consumption) - (18 000 - 20 000) mg O / l, pH - 12.7, temperature 25 ^o C, and previously water was purified from suspended particles. At the moment of air supply, wastewater sulfides begin to oxidize by the reaction 2S ^2- + 2O ₂ + H ₂ O ====> S ₂ O $\genfrac{}{}{0ex}{}{\text{2-}}{\text{3}}$ + 2OH ^- . In 53 minutes, the sulfide content dropped to zero. Compared with the prototype, the reduced air velocity decreases by 40 (0.42 / 0.01) times, and the module by 22 (198 / 8.88) times. This indicates in accordance with the above about the increase in the reaction rate in comparison with the prototype.

Example 2. Textile volumetric fibrous catalyst in the form of a web, made by the method of "semifang" with the parameters: the ratio of the mass of the monofilament of the carrier to the mass of PAN of complex yarns (mass of the base to PAN) 66.9%, linear density of PAN threads 32/3 tex, surface loop module 3.19 , the total linear density of warp and weft 184 tex. Chemical modification mode: NaOH concentration of 120 g / l, N ₂ H ₆ Cl ₂ concentration of 120 g / l, solution temperature of 93 ^o C, PAN fiber module of the bath 50 kg / m ³ , processing time 90 min. But instead of a nickel-containing catalyst, Fe ²⁺ was taken - containing a catalyst, for which a 5% iron solution of FeSO ₄ was used at the stage of preparation of the catalyst. The iron content on the fiber was 0.89 mmol / g. The reactor is the same as in example 1. The oxidation parameters: the height of the catalyst coil 0.1 m, the reduced air velocity W = 0.01 m / s, the module M = 18.54 kg / m ³ , the volume of wastewater in the reactor V = 300 ml. The wastewater is the same as in Example 1. After 53 minutes of oxidation, the sulfide content in the wastewater dropped to zero. Compared with the prototype, the reduced air velocity decreases by 40 times, and the module by 10.6 times. This indicates an increase in the reaction rate compared to the prototype.

Example 3. Textile volumetric fibrous catalyst in the form of a web, made by the method of "semifang" with the parameters: the ratio of the mass of the monofilament of the carrier to the mass of PAN complex threads (mass of the base to PAN) 66.9%, the linear density of PAN threads 32/3 tex, the surface loop module 3.19 , the total linear density of warp and weft 184 tex. Chemical modification mode: NaOH concentration of 120 g / l, N ₂ H ₆ Cl ₂ concentration of 120 g / l, solution temperature of 93 ^o C, PAN fiber module of the bath 50 kg / m ³ , processing time 90 min. But in this example, we took a catalyst containing two metals - Fe ²⁺ and Ni ²⁺ , for which, at the stage of preparation of the catalyst, a solution of FeSO ₄ and NiSO ₄ salts containing 5% iron and 5% nickel was used. The nickel content on the catalyst is 0.38 mmol / L, and iron 0.41 mmol / L. The reactor is the same as in Example 1. Oxidation parameters: catalyst roll height 0.1 m, reduced air velocity W = 0.01 m / s, module M = 3.94 kg / m ³ , waste water volume in the reactor V = 300 ml. The wastewater is the same as in Example 1. After 53 minutes of oxidation, the sulfide content in the wastewater became zero. Compared with the prototype, the reduced air velocity decreases by 40 times, and the module - by 50.17 times. This indicates an increase in the reaction rate compared to the prototype. The nickel-iron-containing catalyst in Example 3 is more efficient in purification than the nickel and iron-containing forms of the catalyst separately, which confirms a higher rate for the two-metal form of the catalyst (the module required for the complete oxidation of sulfides for a given time is lower in Example 3 than in examples 1 and 2). Thus, the use of the inventive catalyst in one-metal form with iron or nickel already allows you to achieve the specified technical result, but the use of a two-metal nickel-iron form allows you to further increase the speed of the oxidation of sulfides in comparison with the prototype.

Known [6] are methods for purifying gases from sulfides by purging them through an absorption solution containing an alkaline agent and a regenerated oxidizing agent, for example, Fe ³⁺ , hydroquinone, organic cobalt compounds, and others. In this case, hydrogen sulfide is oxidized to sulfur, and the absorption solution is regenerated by air purging. The disadvantage of such catalysts is the complexity of the hardware design, insufficiently high speeds and degrees of purification, especially at low levels of hydrogen sulfide in the gas. Compared to the prior art, volumetric textile fibrous catalysts have characteristics that accelerate the dissolution of hydrogen sulfide and oxidizing gas, thereby increasing the speed of the process and the degree of purification. In addition, they allow combining the processes of dissolution of hydrogen sulfide, its oxidation and regeneration of the absorption solution, which facilitates the structural design of processes with their participation. But the catalytic purification of gases from sulfides using the prototype is difficult due to the need for high densities of the packing (module), so that the process speeds are sufficiently high, this leads to high hydrodynamic drags and makes it difficult to pass large volumes of gases through the apparatus. The advantages of the inventive catalyst for gas purification from sulfides are confirmed by examples 4-6, 9, 21-28, and examples 4-6 are given in detail.

Example 4. The experiments on the purification of air from hydrogen sulfide were carried out in the same reactor as in examples 1 to 3, with 1% H ₂ S in the air supplied to the reactor, air supplied in an amount of 2 l / min (which corresponds to the above air velocity 0.017 m / s). A nickel-containing catalyst in the form of a web with textile weaving parameters was used: the ratio of the mass of the monofilament of the carrier to the mass of PAN of complex yarns (warp to PAN) 66.9%, the linear density of PAN threads 32/3 tex, the surface loop module 3.19, the total linear density of the warp and duck 184 tex. The chemical modification process was carried out with the following parameters: concentration of modifying NaOH solution 120 g / l, N ₂ H ₆ Cl ₂ 120 g / l, temperature 93 ^o C, processing time 90 min. The nickel salt solution was treated with 5% nickel ion of an aqueous solution of NiSO ₄ for 40 minutes. The nickel content on the catalyst was 0.7 mmol / g. The catalyst was again used in the form of a roll 0.1 m high, module M = 8.88 kg / m ³ . An aqueous solution of NaHCO ₃ with a concentration of 10% was used as an alkaline absorber, the temperature at which the reaction was carried out was 25 ^o C. Under these conditions, hydrogen sulfide is oxidized by atmospheric oxygen to elemental sulfur by the reaction S ^2- + H ₂ O + 1/2 O ₂ ---> S ⁰ + 2 OH ^- . Moreover, the content of hydrogen sulfide in the air leaving the reactor is 0.12%. The degree of purification from hydrogen sulfide can be calculated by the formula (C _ref - C _con ) / C _ref • 100%, where C _ref is the initial concentration, C _end is the final concentration. In this case, obtaining the degree of purification (1 - 0.12) / 1 • 100 = 88%. An example proves the possibility of using the proposed catalyst for the purification of gases from hydrogen sulfide, in accordance with the foregoing, the use of a prototype for gas purification is impossible.

Example 5. Experiments on the purification of air from hydrogen sulfide on an iron-containing catalyst were carried out in the same reactor as in examples 1 to 3, with 1% H ₂ S in the air supplied to the reactor and air supplied in an amount of 2 l / min ( which corresponds to a reduced air velocity of 0.017 m / s). In this case, the parameters of the experiment on air purification from hydrogen sulfide were as follows. Iron-containing catalyst in the form of a web with textile weaving parameters: ratio of the mass of monofilament of the carrier to the mass of PAN of complex yarns (warp to PAN) 66.9%, linear density of PAN threads 32/3 tex, surface loop module 3.19, total linear density of warp and weft 184 tex. Parameters of chemical modification: concentration of modifying NaOH solution 120 g / l, N ₂ H ₆ Cl ₂ 120 g / l, temperature 93 ^o C, processing time 90 minutes Treatment with a solution of iron salt was carried out from 5% Fe ²⁺ ion of an aqueous FeSO ₄ solution for 40 minutes. The iron content of the catalyst was 0.89 mmol / L. The catalyst was again used in the form of a roll 0.1 m high, module M = 8.88 kg / m ³ . An aqueous solution of NaHCO ₃ with a concentration of 10% was used as an alkaline absorber, the temperature at which the reaction was carried out was 25 ^o C. Moreover, the content of hydrogen sulfide in the air leaving the reactor was 0.54%. The degree of purification from hydrogen sulfide can be calculated by the formula (C _ref - C _con ) / C _ref • 100%, where C _ref is the initial concentration, C _end is the final concentration. In this case, we obtain the degree of purification (1 - 0.54) / 1 • 100% = 0.46%. An example proves the possibility of using the proposed catalyst for the purification of gases from hydrogen sulfide, in accordance with the foregoing, the use of a prototype for gas purification is impossible.

Example 6. The experiments on the purification of air from hydrogen sulfide were carried out in the same reactor as in examples 1 to 3, with 1% H ₂ S in the air supplied to the reactor, air supplied in an amount of 2 l / min (which corresponds to the above air velocity 0.017 m / s). In this case, the parameters of the experiment on air purification from hydrogen sulfide were as follows. Nickel-iron-containing catalyst in the form of a web with textile weaving parameters: ratio of the mass of monofilament of the carrier to the mass of PAN of complex yarns (warp mass to PAN) 66.9%, linear density of PAN threads 32/3 tex, surface loop module 3.19, total linear density of threads warp and weft 184 tex. Parameters of chemical modification: concentration of modifying NaOH solution 120 g / l, N ₂ H ₆ Cl ₂ 120 g / l, temperature 93 ^o C, processing time 90 minutes Absorption of iron and nickel produced from 5% for each of Ni ²⁺ and Fe ²⁺ ions aqueous solution of NiSO ₄ and FeSO ₄ for 40 minutes. The nickel content on the catalyst was 0.38 mmol / L, and iron 0.41 mmol / L. The catalyst was again used in the form of a roll 0.1 m high, module M = 8.88 kg / m ³ . An aqueous solution of NaHCO ₃ with a concentration of 10% was used as an alkaline absorber, the temperature at which the reaction was carried out was 25 ^° C. Moreover, the content of hydrogen sulfide in the air leaving the reactor was zero. In this case, we obtain the degree of purification (1 - 0.0) / 1 • 100% = 100%. An example proves the possibility of using the proposed catalyst for the purification of gases from hydrogen sulfide, in accordance with the foregoing, the use of a prototype for gas purification is impossible. The nickel-iron containing catalyst in Example 6, as in the case of sulfide wastewater treatment (see Examples 1-3), is more effective in terms of purification than the individual nickel and iron containing forms of the catalyst, which confirms a higher rate for the two-metal form of the catalyst. Thus, in comparison with the prototype, where a catalyst containing only one metal is used, the proposed two-metal form allows to increase the speed of the oxidation process.

 The following examples (examples 7, 8) show the possibility of oxidation on the inventive catalyst for organic cysteine sulfide, phenol. They confirm the possibility of expanding the scope of the proposed catalyst in comparison with the prototype, where only the sulfide oxidation reaction is catalyzed.

Example 7. Oxidation of cysteine. The textile bulk fibrous catalyst in the form of a web was carried out by the "semifang" method, and the web had the following parameters: the ratio of the mass of monofilament of the carrier to the mass of PAN of complex yarns (warp mass to PAN) 66.9%, linear density of PAN threads 32/3 tex, loop surface module 3.19, total linear density of warp and weft 184 tex. Its modifying treatment consisted in the action of a hot alkaline solution of hydrazine hydrochloride with parameters: NaOH concentration of 120 g / l, N ₂ H ₆ Cl ₂ concentration of 120 g / l, solution temperature of 93 ^o C, PAN fiber module of 50 kg / m ³ , processing time 90 min. After washing with distilled water, the material was soaked in a 5% solution of nickel sulfate (Ni ^{2+ ion} ) for 40 minutes, followed by washing with distilled water again. In order to increase the nickel fastening strength on the catalyst fiber, it was additionally treated with a 4% NaOH solution, its temperature was 25 ^° C, and the treatment time was 5 min. In this case, additional "crosslinking" with oxygen groups is formed between nickel ions: -O-. This was necessary because, unlike sulfides, cysteine is unable to “crosslink” nickel on the fiber, but it is able to form strong complexes with nickel, which would lead to leaching of the metal from the fiber into the solution and rapid deterioration of the catalyst (in the case of sulfide oxidation in such a treatment it was not necessary, since the action of the sulfides themselves leads to "crosslinking" by groups -S-). The nickel content on the fiber is 0.7 mmol / g. The catalyst in the form of a coil 0.1 m high was charged into the reactor shown in the drawing, the reactor diameter D = 0.05 m, the volume of liquid in the reactor 300 ml, the reduced air velocity W = 0.01 m / s, the ratio of the mass of the catalytically active fiber to the volume of the solution (module ) M = 8.88 kg / m ³ , a solution of cysteine in water with an organic sulfur content of 800 mg / L was used as the test solution. The reaction temperature is 25 ^o C. Under these conditions, cysteine is oxidized to cystine. After 50 minutes of oxidation, the cysteine content in the solution became zero.

Example 8. Oxidation of phenol. The bulk textile fibrous catalyst was performed in the form of a semifang in the form of a web, and the web had the following parameters: the ratio of the mass of the monofilament of the carrier to the mass of PAN of complex yarns (mass of the base to PAN) 66.9%, linear density of PAN threads 32/3 tex, loop surface module 3.19, total linear density of warp and weft threads 184 tex modifying treatment it was in action hot alkaline solution of hydrochloric hydrazine with the following parameters: concentration of NaOH 120 g / l, the concentration of n ₂ H ₆ Cl ₂ 120 g / l, solution temperature is 93 ^o C, modulator bath of PAN fiber 50 kg / m ^3, the treatment time 90 min. After washing with distilled water, the material was soaked in a 5% solution of copper and iron sulfate (for Cu ²⁺ and Fe ^{2+ ions} ) for 40 minutes, followed by washing with distilled water again. In order to increase the strength of metal fixing on the fiber, the catalyst was additionally treated with a 4% NaOH solution, its temperature was 25 ^o C, the processing time was 5 minutes. In this case, additional "cross-linking" with oxygen groups is formed between metal ions: -O-. The copper content on the fiber is 0.3 mmol / g, the iron content is 0.45 mmol / l. The catalyst in the form of a coil 0.1 m high was charged into the reactor shown in the drawing, the diameter of the reactor D = 0.05 m, the volume of liquid in the reactor 300 ml, the reduced air velocity W = 0.01 m / s, the ratio of the weight of the catalytically active fiber to the volume of the solution (module ) M = 8.88 kg / m ³ , a phenol solution in water with a phenol oxygen content of 500 mg / l was used as the test solution. The reaction temperature is 25 ^° C. Under these conditions, phenol is oxidized to phenyl phenolate. After 62 minutes of oxidation, the phenol content in the solution became zero.

 Other examples see in the table. Example 9 demonstrates the possibility of oxidizing hydrogen sulfide in air at a concentration of eight times less, and the reduced air velocity is eight times greater than in examples 4-6, and again, the absence of hydrogen sulfide in the output stream can be achieved, i.e. 100% degree of purification. Examples 10 to 12 show the possibility of oxidation of sulfides in wastewater, the same as in example 1, but with a sulfide concentration of 1000 - 8000 mg / l (0.1 - 0.8)%, which is wider than the limits specified in the prototype (0.1 - 0.2%). Examples 13 to 44 show the influence of the geometric characteristics of the weaving of the catalyst - the ratio of the mass of the monofilament of the carrier to the mass of PAN of complex yarns, linear density of PAN yarns, surface loop module, total linear density of warp and weft threads. The deviation of the textile parameters from the claimed (the ratio of the mass of the monofilament of the carrier to the mass of PAN of complex yarns (mass of the warp to PAN) 60.7 - 82.3%, linear density of PAN threads 32/2 - 32/4 tex, surface loop module 3.17 - 3.35, total linear density of threads warp and weft 156.3 - 211.7 tex) is impractical, since in this case the dissolution rate of air is deteriorated, and in order to maintain sufficiently high speeds of catalytic processes, it is necessary to sharply increase the module and the reduced air velocity in the apparatus.

Note. In all experiments, the same reactor was used, shown in the drawing, with parameters: height of the catalyst roll 0.1 m, diameter of the reactor D = 0.05 m, and the volume of liquid in the reactor 300 ml. In experiments with wastewater oxidation, wastewater was taken from an ashes of skins with parameters: COD (chemical oxygen consumption) - (18,000 - 20,000) mg O ₂ / L, pH - 12.7, temperature 25 ^o C, and previously the water was cleared of suspended particles.

 In contrast to the prototype, the stiffness of the woven structure of the catalyst allows it to be used not only in the form of a roll, but also in others, for example, wave-like, cylinders stacked in a different order, inclined plates stacked in different directions. The tests carried out on these forms of catalysts gave identical results with a roll form.

 List of references.

 1. K.F. Pavlov, P.G. Romankov, A.A. Noskov. Examples and tasks on the course of processes and apparatuses of chemical technology. L. Chemistry. 1976, p. 267.

 2. (prototype). L. Ya. Tereshchenko, R.F. Vitkovskaya, S.V. Petrov. Oxidation of sulfides by atmospheric oxygen on a fibrous catalyst. On Sat Environmental protection and resource saving (Interuniversity collection of scientific papers.). S-P. 1995.S. 157.

 3. Yu. M. Laskov, T.G. Fedorovskaya, G.N. Zhmakov. Wastewater treatment of leather and light industry enterprises. M. Light and food industry. 1984, p. 72.

 4. J. Germain. Catalytic conversion of hydrocarbons. C. World. 1972, p. 247.

 5. Mubarakshin G. M. Production and study of modified PAN fiber with ion and electron exchange properties. Diss. for a job. student Art. ct n 1979. C 84.

 6. E.F. Shkapov, I.S. Antsypovich. Purification of ventilation air and gases from hydrogen sulfide. M. 1970.

Claims (1)

 Textile volumetric fibrous catalyst in the form of a web consisting of a carrier of monofilaments and modified ion-containing complex filaments of polyacrylonitrile fibers, characterized in that the ratio of the mass of the monofilament of the carrier to the mass of PAN of the complex fibers is 60.7 - 82.3%, the linear density of PAN threads 32/2 - 32/4 tex, surface loop module 3.17 - 3.35, total linear density of warp and weft 156.3 - 211.7 tex, and multifilament yarns of polyacrylonitrile fibers contain one or two metal ions of variable valence STI.

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