Method for preparing sodium persulfate through direct electrooxidation

Abstract

The invention discloses a method for preparing sodium persulfate by direct electrooxidation. The method is characterized in that an anode is a titanium-plated platinum electrode prepared by a roasting method, a cathode is an alloy electrode prepared by a casting method, a bath pressure is greatly reduced, a two-electrode system is adopted, an anode electrolytic solution is a mixed solution of 220-300g / L of sodium sulfate and 200-400g / L of sulfuric acid, a cathode electrolytic solutionis a 20% wt dilute sulfuric acid solution, an anode additive is 0-2g / L sodium thiocyanate, the main product sodium persulfate is obtained after the electrolytic reaction is carried out in a plate frame type electrolytic cell under the constant current conditions that the temperature is 15-40 DEG C and the current density is 0.5-1.5 A / m<2>, the current efficiency can be up to 90.23%, and the concentration of the sodium persulfate can be up to 198.95 g / L. According to the method, by changing electrode materials and optimizing process conditions, the purposes of low energy consumption, low cost, low raw material consumption and relatively high current efficiency and yield are achieved.

Description

[0001] (1) Technical field [0002] The invention relates to a method for preparing sodium persulfate by direct electrooxidation. [0003] (2) Background technology [0004] Sodium persulfate is a strong oxidizing agent and can be used as an oxidizing agent to convert Cr 3+ , Mn 2+ and so on are oxidized to the corresponding high oxidation state compounds, when there is Ag + When it exists, it can promote the above oxidation reaction; it can be used as bleaching agent, metal surface treatment agent, chemical reagent, pharmaceutical raw material; battery, accelerator and initiator of emulsion polymerization. Activated sodium persulfate can be used in in-situ remediation of oil-contaminated soil. The traditional preparation of sodium persulfate generally uses electrolytic oxidation of ammonium sulfate aqueous solution to generate ammonium persulfate, and then undergoes metathesis reaction with sodium hydroxide to drive out the by-product ammonia, then concentrate under reduced...

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Problems solved by technology

The traditional preparation of sodium persulfate generally uses electrolytic oxidation of ammonium sulfate aqueous solution to generate ammonium persulfate, and then undergoes metathesis reaction with sodium hydroxide to drive out the by-product ammonia, then concentrate under reduced pressure, crystallize, and dry to obtain sodium persulfate. The equation is: (NH4) 2 +2NaOH→Na 2 S 2 o 8 +2NH 3 +2H 2 O, or use electrolytic cold sulfuric acid to obtain peroxodisulfuric acid, and then react with alkali to obtain sodium persulfate. The reaction principle is 2HS0 4 - -2e - →H 2 S 2 o 8 , H 2 S 2 o 8 +2NaOH→Na 2 S 2 o 8 +2H 2 O, but the above methods all have disadvantages such as high power consumption, low current efficiency, low yield, high cost, and large consumption of raw materials

[0005] Japanese patent publication 31190 / 1980 (shown 55) discloses a kind of preparation method of sodium persulfate, is in the presence of ammonium ion, carries out electrolysis by using neutral raw material as anode, but this method is because of having lower electric current efficiency so considered uneconomical

Japanese patent application delay publication 56395 (shown 50) discloses a kind of preparation method of sodium persulfate, and the raw material of use is sodium bicarbonate, but although this method has used specific electrolytic cell and expensive titanium negative electrode, current in electrolysis extremely inefficient

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