Corrosion inhibition and disinfection of central heating and cooling water systems using in situ generated hydrogen peroxide. (7th September 2022)

• Record Type: Journal Article
• Authors: Cao, Ye; Xu, Yue; Li, Qi; Rose, Ruth-Sarah; Abrahams, Isaac; Jones, Christopher R.; Sheriff, Tippu S.
• Is Part Of: New journal of chemistry. Volume 46:Number 37(2022)
• Page Start: 17880
• Page End: 17888
• Publication Date: 2022-09-07
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d2nj03806d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : MnCl2 ·4H2 O and Tiron (disodium 4, 5-dihydroxy-1, 3-benzenedisulfonate) rapidly remove O2 from aqueous solution at pH 7.50–11.0 and 20–50 °C using hydroxylamine (NH2 OH) as reducing substrate and acts as an anti-corrosion and anti-bacterial formulation. Abstract : MnCl2 ·4H2 O and Tiron (disodium 4, 5-dihydroxy-1, 3-benzenedisulfonate) rapidly remove dioxygen (O2 ) from aqueous solution at a rate of ∼20 mg L −1 min −1 with turnover frequencies (TOFs) of up to 440 000 h −1 in the pH range 7.50–11.0 and at 20–50 °C using hydroxylamine (NH2 OH) as reducing substrate. These solutions remain deoxygenated for several hours despite being open to the atmosphere. During this time there is a steady rise in the concentration of in situ generated hydrogen peroxide (H2 O2 ), reaching ∼12 mM after 17 h. The order of selectivity for selected 1st row transition metals was found to be: Mn(ii ) ≫ Co(ii )∼Cu(ii )∼Fe(ii ). No deuterium isotope effect was observed, which suggests that an electron transfer is the rate determining step. A mechanism is proposed that involves two 1-electron transfers from bound NH2 OH to bound O2 to produce H2 O2 concomitant with two proton transfers from catecholate oxygen atoms. This system can act as an anti-corrosion formulation as the catalytic reduction of O2 results in the removal of O2 from open aqueous solutions and the in situ generated H2 O2 can be used as a biocide e.g. to kill L. pneumophila . Batch experiments were carried out to confirm the feasibility of this system to simultaneously inhibit corrosion and also potentially disinfect central heating and cooling water systems.