SU1328300A1 - Method of removing organic admixtures from waste water - Google Patents

Abstract

The invention relates to methods for treating wastewater from organic impurities and allows an increase of 7-15% in the degree of wastewater treatment in a multi-cycle mode. Adsorption absorption of organic impurities is carried out on a new adsorbent containing porous silica as a base, and as a promoting additive a mixture of polyvalent metal oxides — cobalt, nickel, and copper in the amount of 4.3–6.1 wt.% With the following proportions. in a mixture, wt.%: Nickel oxide 50-60} copper oxide 25-35; cobalt oxide 10-20. Then the impurities are oxidized with hydrogen peroxide in an amount of 4 to 5 mg / mg of adsorbed impurities. 1 hp f-ly 4 tab. i

Description

The invention relates to methods for treating wastewater from organic impurities, specifically from ore-acid organic dyes and synthetic surface-active substances (SAL), as well as to the preparation of adsorbents for their purification and can be used for deep purification of wastewater finishing industries of textile, leather and knitting industry, household chemical goods.

The aim of the invention is to improve the degree of purification of wastewater from organic impurities in a multi-cycle mode,

Example 1: Preparation of the adsorbent catalyst for the process,

In the Ka4ectBe adsorbent-catalytic carrier), granulated silica gel with a grain size of 1-3 mm is used. The adsorbent catalyst is prepared according to a known procedure. The silica gel is dried for 2 hours at 150 ° C, then impregnated with a solution of salts of a, active components. The impregnating solution contains 120 g / l of a mixture of nitrate salts Ni, Cu, Co.

The carrier is impregnated by immersing it in a solution of Ni, Cu, and Co salts at the rate of one volume of solution per one volume of carrier and keeping it for 70 minutes with occasional stirring. During this time, all air is practically expelled, which prevents destruction of the carrier during the subsequent heat treatment. To evenly distribute the active components on the surface of the carriers, the latter is kept in the solution for 3-4 hours at 80-90 ° C, then the solution is evaporated. After that, the carrier with active components is calcined at ZOO-ZZO C for 2.5-5 hours until the complete cessation of the release of nitrogen oxides. The total content of oxides 4-6 wt.% / Optimal adsorbent-catalyst is obtained from a solution concentration, g / l: N (N0 ,,), 60; Cu (NOj) 3 &; Co (NO) j 24.

To determine the required concentration of the amount of oxides on silica gel, experiments on sewage purification from dyes and spawning were carried out. The experiments were carried out in a laboratory setting. Into the reactor. With a coaxially arranged filter filled

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with a sorbent-catalyst, pour the drain to be cleaned so that the water level is 1-2 cm above the level of the catalyst. In order to aerate the runoff and circulate the water being purified, water is pumped through the stationary adsorbent-catalyst into the reactor through the nozzle and the compressor. To achieve the desired effect of wastewater treatment, organic dyes and synthetic surfactants, with a total concentration of organic pollutants by COD 140 mg / l and surfactant 20 mg / l, this process is carried out (bringing organic pollutants to the surface adsorbent-catalyst) for 6 minutes In this case, the volume of the adsorbent-catalyst in the reactor is 9.5 liters, the volume of treatment of wastewater is 4.8 liters. This volume of catalyst adsorbent allows, without degrading the quality of the sorbate, to carry out ten 6-minute cycles, i.e. clean 48 liters of wastewater. After the end of the tenth cycle, a solution of 30% hydrogen peroxide at the rate of 5 mg per 1 mg of adsorbed organic pollutants is added to the treated wastewater and, in a similar manner, the chemisorbed organic compounds are oxidized for a period of time necessary for the complete decomposition of hydrogen peroxide. Contamination. The process is then repeated with a regenerated adsorbent catalyst. The concentration of the amount of oxides upon receipt of the adsorbent varies in the range of 2–9% by mass, the concentration of the impregnating solution varies from 50 to 200 g / l of a mixture of nitrate salts with the ratio NiCNOj): Cu (N03) 2:: CoCNO) 2.5: 1, 5: i. The resulting adsorbent-catalyst contains 1-10 wt.% Active components with oxides,%: Ni 55; C.30; From 15

The results of the experiment are presented in table.1.

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As can be seen from Table 1, the required concentration of the sum of the oxide of the silica gel is 4-6 wt.%. An increase in the concentration of active components (more than 6 wt.%) Leads to a decrease in the sorption capacity of the adsorbent-catalyst and, consequently, to a decrease in the effect of wastewater treatment. In addition, with an increase in the number of active components, the degree of regeneration of the adsorbent-catalyst decreases due to a decrease in the specific surface of the catalyst and a change in structure due to clogging of the pores.

When the concentration of the active components is less than 4-6 wt.%, The degree of regeneration of the adsorbent-catalyst decreases significantly, which leads to a decrease in the total cleaning cycles and, ultimately, to premature poisoning of the adsorbent-catalyst.

Example2. Under the conditions of Example 1, the required composition of the sum of nickel, cobalt and copper oxides on silica gel is determined.

The results of these experiments are presented in table 2.

As can be seen from table 2, the best results are obtained with the following composition of oxides,%: Ni 50-60; From 10-20; C 25-35. This is due to the fact that with a decrease in the content of a particular impurity, the Fermi level is always pulled to the middle of the exclusion zone. An increase in the concentration of impurities leads to a monotonic shift of the Fermi level. Consequently, as the concentration of impurities increases, they act either as g or as a promoter with respect to the same reaction.

Froze In order to determine the optimal dose of hydrogen peroxide required for the oxidation of adsorbed organic impurities, the experiments of example 1 are carried out. A triple mixture of oxides on silica gel of the following composition is used as the adsorbent-catalyst,%: Ni 55; From 15; C 30.

The effect of the dose of hydrogen peroxide on the efficiency of wastewater treatment and the degree of regeneration of the adsorbent-catalyst are shown in Table 3.

As can be seen from Table 3, the best results are obtained when the dose ratio of hydrogen peroxide per unit of adsorbed organic impurities is 4.5–5 mg / mg of adsorbed contaminants. When the dose ratio of hydrogen peroxide is more than 5 mg / mg, the degree of regeneration increases slightly and costly reagent overruns. In addition, the efficiency of wastewater treatment is somewhat reduced.

water, which is due to the disproportionality of the rates of decomposition of hydrogen peroxide and the catalytic oxidation of organic pollutants.

Thus, due to the preliminary concentration of organic dyes and surfactants on the complex adsorbent-catalyst with the proposed percentage ratio of components and their subsequent decomposition with hydrogen peroxide, a 95-96% reduction in bichromate oxidation is achieved while simultaneously regenerating the adsorbent-catalyst.

Example 4: For a comparative check of the proposed method with a known wastewater containing dyes and synthetic surfactants, it is processed

in the following modes.

By a known method, waste water containing dyes and surfactants and having a COD of 140 mg / l is treated with ozone (concentration 40 g / m) and then filtered through AG-3 activated carbon with a particle size of 3-5 mm and a loading height of 1.0 m with speed of 10 m / h.

The proposed method is the same

the initial waste water is treated as in example 1 in a catalytic reactor with an adsorbent-catalyst, which is silica gel modified with oxides of Co, Cu, Ni of the following composition,%: Ni 55; C 30; Co 15, as well as using a known adsorbent when carrying out the purification process in the proposed mode as in Example 1. The known adsorbent catalyst contains 24 wt.% Copper chromite on a snickel; it is obtained by impregnating KSK silica gel with an excess of copper dichromate solution and then drying and calcining until spinel.

The averaged data of this experiment are summarized in table 4.

As can be seen from Table 4, the proposed adsorbent-catalyst and the mode of sewage treatment are superior to those known by all technological indicators. The degree of purification increases by an average of 35-40%, and the degree of regeneration by 20%, which ultimately makes it possible to carry out about 200 cycles of wastewater treatment, as compared with the known method.

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Claims (2)

The formula of the invention is their quantitative ratio in mixture, wt.%: 1, Wastewater treatment method lp „„ Nickel oxide 50-60 organic impurities, including their wasps  i- V copper oxide 25-35 adsorption absorption and oxidation, 5 cobalt 10-20 characterized in that, in order to increase the degree of purification your oxidation is carried out with hydrogen peroxide multicyclic mode, adsorption after absorption of impurities, absorption is carried out on the composite 2. Method pop.1, distinguishing adsorbent on the basis of silica gel, with fOc and with the fact that hydrogen peroxide of 4.3-6.1 wt.% Of the mixture of oxides is taken in the amount of 4-5 mg / mg of adsorneyl, copper and cobalt, with next impurities. Table 1 Concentration 2.2 3.1 4.3 5.4 6.1. 7.4 8.6 9.3 active ingredient; ow, wt.% .. Efficiency. cleaning up. COD% 81.4 85.6 95.3 96.0 95.8 90.1 83.4 74.2 The degree of regeneration of the adsorbent-catalyst mash,% 51.2 68.9 94.2 94.7 94.7 86.2 86.3 86.4 The number of full cycles without change cleaning effect of 18 36 196 198 196 183 156 140 and the degree of regeneration of the adsorbent-catalyst Efficiency cleaning up COD% 94.1 96.2 94.6 87.9 96.1 95.2 93.8 95.2 89.2 The degree of regeneration of the adsorbent-catalyst,. d. i 74, 89 71 90 95 92 94 93 64 89.3 94,194,694,7 94.3 94,796,295,8 COD 140 Intensity Editor N. Gunko Compiled by L.Ananyeva Tehred M.Hodanich Order 3446/25 Circulation 850 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Table 3 94,894,9 94,691.2 Table4 78 81.2 96.0 Proofreader A. T sko