SU1318536A1 - Method for removing hydrogen sulfide from waste water - Google Patents

Abstract

The invention relates to the electrochemical treatment of wastewater, in particular hydrogen sulfide-containing, balneological complexes discharged by spas and urban spas using artificial hydrogen sulphide mineral waters for treatment, and reduces the energy intensity of the process, reduces the suspended matter content in the treated water, and simplifies the process of maintaining the same degree purification from hydrogen sulfide. The water to be purified is treated in the cathode chamber of a diaphragm electrolyzer at the cathode of hydrophobized carbon while oxygen-containing gas is passed through the water, and a solution of mineral acid is placed in the anode chamber. A cation-exchange matrix is used as the diaphragm, and the mineral acid solution is used in a concentration of 0.5-1.0 M. Table 1. i (L so 00 ate with sr

Description

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The invention relates to the electrochemical treatment of wastewater, in particular hydrogen sulfide-containing wastewater discharged by balneological complexes and the urban hydropathic baths, which use artificial hydrogen sulfide mineral waters for the treatment,

The purpose of the invention is to reduce the energy intensity of the process, reduce the suspended matter content in purified water and simplify the process while maintaining the same degree of purification from hydrogen sulfide.

The method is carried out as follows.

Mineralized wastewater at a water treatment plant containing hydrogen sulfide is fed into the cathode chamber of a laboratory diaphragm electrolyzer with a hydrophobised carbon cathode and a cation-exchange membrane while simultaneously passing oxygen through technical water, and a solution of sulfuric acid is placed into the anode chamber. acids. In the source and purified waters, the hydrogen sulfide content is determined by coulometric titration.

Example 1. Artificial drainage of a bath, containing 20 mg / l of hydrogen sulfide and having a pH of 8.2, salinity of 10 g / l (GHS, 28 g / l; HCO 2.03 g / l and 35 g / l) placed in the cathode chamber of the laboratory diaphragm electrolyzer at,. The cathode is made of carbon black, hydrophobized with fluorine layer F4D at a ratio of 60:40 weight,%, the anode is a platinum-titanium electrode, and an anolyte is 0.5 M solution of sulfuric acid. A membrane is used as the diaphragm. The current density through the membrane is set to 200 A / m and oxygen is blown through the cathode chamber. After 5 min of treatment, the content of hydrogen sulfide in water is 1 mg / p, pH 7.8, the content of suspended substances is 2 mg / l. The specific energy consumption for the oxidation of 1 g of hydrogen sulfide kWh. I

Example2. Artificial drainage of the baths, containing 62 mg / l of hydrogen sulfide, having a pH of 8.7 and a salinity of 10 g / l (; 55 g / l; HCO = 3.25 g / l and C1 0.68 g / l), is subjected to electrical treatment in specified conditions when the concentration of acid in

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anolyte 1.0 M and current density through the membrane 400 A / m. After 8 min, the content of hydrogen sulfide in water is 1 mg / l, the pH after treatment is 8.3, the content

5 suspended substances 5 mg / l. The specific energy consumption for the oxidation of 1 g of hydrogen sulfide is 0.095 kWh.

The indicators obtained by comparing the known and proposed methods are given in the table,

During the process in the cathode chamber, partial reduction of oxygen to hydrogen peroxide HjOj and other active particles occurs.

15 (Oj, BUT), which oxidize the hydrogen sulfide present in water to sulfates. The use of a hydrophobized carbon cathode makes it possible to conduct a process with a current efficiency of not less than 70%, which is explained by the low catalytic activity of this electrode material in relation to the reaction of decomposition of hydrogen peroxide. The use of a cation-exchange membrane avoids the destruction of the peptide formed hydrogen at the anode ,

In the cathode chamber along with the formation of reactive particles

30, hydroxyl ions accumulate, which inevitably can lead to a shift of the catholyte pH to the alkaline side and the formation of insoluble alkaline earth metal compounds,

35 defined in the form of suspended substances. The transfer of protons through the cation-exchange membrane into the cathode chamber makes it possible to avoid a shift of the catholyte pH to the alkaline side. For this

40 centrs as the anolyte is most advisable to use a 0.5-1.0 M aqueous solution of any acid, the anion of which is not destroyed on the anode under these conditions, for example sulfuric or

45 phosphoric acid (for economic reasons, it is preferable to take sulfuric acid). The use of acid at a concentration of less than 0.5 M leads to a noticeable increase in energy costs due to the low electrical conductivity of the anolyte, and concentrations of Bbmie 1, 0 M can cause destruction. anode materials

; 5 We propose a purification method (table) provides a significant reduction in the energy intensity of the electrochemical cleaning process as compared to the known (specific energy consumption for

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Claims (1)

The oxidation of hydrogen sulfide is reduced from 0.15-0.20 kWh / g to 0.06-0.00 kW, h / g), allowing a 40-50-fold reduction in the suspended matter content in purified water (from 100-200 mg / l to 2-5 mg / l) and exclude from the technological scheme of cleaning facilities for the separation of suspended particles and the treatment of the resulting sludge, and therefore greatly simplify and cheapen the cleaning process technology. Invention Formula The method of purification of wastewater from hydrogen sulfide, including their processing in the elective residual content of hydrogen sulfide, mg / l Specific energy consumption for HjS oxidation, kWh / g Content weighted substances in purified water mg / l PH reduction after processing, units pH Chloride content in the purified water, g / l Editor I.Gorn Compiled by T. Barabash Tehred V.Kadar Proofreader V.But ha Order 2473/19 Circulation 851 Subscription VNIIGSh of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Design, 85364 using a cathode made of carbonaceous material, it’s very good, and so that, in order to reduce energy costs and reduce the 5 suspended substances, the treatment is carried out in an electrolyzer with separated electrode chambers using a cation-exchange membrane and a cathode of hydrophobised carbon during the supply of purified water into the cathode chamber with simultaneous supply of oxygen-containing gas to it, and a solution of mineral concentration 0 is fed into the anode chamber, 5-1.0 M, ten 0.06-0.10 2-5 0.2-0.5 0/10