METHOD FOR SUPPRESSING DECREASE IN CONCENTRATION OF OXIDIZING AGENT IN SULFURIC ACID SOLUTION CONTAINING PERSULFURIC ACID COMPONENT

WIPO Patent Application WO/2021/090582

A1

According to the present invention, a sulfuric acid solution which contains, as an oxidizing agent, a persulfuric acid component such as peroxomonosulfuric acid, a peroxomonosulfuric acid salt, peroxodisulfuric acid or a peroxodisulfuric acid salt, and in which nitrogen oxide ions are present as impurities that promote a decrease in the concentration of the oxidizing agent, is exposed to a gas that is inert to the sulfuric acid solution containing a persulfuric acid component. While the inert gas is not restricted as long as the gas is not reactive with a sulfuric acid solution that contains a persulfuric acid component, air or a nitrogen gas (N2) is preferable as the inert gas from the viewpoint of safety or the production cost. Consequently, by suppressing a decrease in the concentration of an oxidizing agent in a sulfuric acid solution containing a persulfuric acid component, a decrease in the concentration of an effective oxidizing agent is able to be minimized even if nitrogen oxide ions, which are impurities that cause a decrease in the concentration of the oxidizing agent, are mixed in the sulfuric acid solution.

YAMAKAWA HARUYOSHI (JP)
ISERI HAJIME (JP)

PCT/JP2020/034956

May 14, 2021

September 15, 2020

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KURITA WATER IND LTD (JP)

C25F7/00; C25D11/08; H01L21/304

JPS63153825A	1988-06-27
JP2008084903A	2008-04-10
JPH0790628A	1995-04-04
JPH0964005A	1997-03-07
JPH1136089A	1999-02-09
US6605548B1	2003-08-12

HAYAKAWA Yuzi et al. (JP)

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