Impact of ammonia producing Bacillus sp. on corrosion of cupronickel alloy 90:10

Abstract

The objective of the present investigation is characterization of ammonia producing bacteria (Bacillus sp.) and its impact on biodeterioration of cupronickel alloy 90:10. It is well known that iron sulphate and molybdenum are good inhibitors used in cooling water system. The role of interaction between inhibitor and ammonia producing bacteria on corrosion of cupronickel 90:10 was studied. Cupronickel coupons were immersed in Chavara rare earth containing backwater for a period of six months. The predominated ammonia producing bacteria were isolated from the six months old biofilm. A total of four ammonia producing Bacillus sp. (AG1-EU202683; AG2-EU202684; AG3-EU202685 and AG4-EU202686) were isolated from the biofilm and identified by 16S rRNA gene sequencing. The corrosion rate of cupronickel in water (System I) was in the range of 0.046mm/year and 0.052mm/year. In the control system II (Chavara water and nitrogen free medium without bacteria), the corrosion rate was 0.008 mm/year whereas in the presence of Bacillus sp. AG1 and AG3, the corrosion rate was in the range of 0.023 and 0.030mm/year. These bacteria fixed atmospheric nitrogen for their cell protein synthesis and converted into ammonia. Ammonia enhanced pH and ammonical solution was formed in the presence of Bacillus sp. that acted as an etchant. The presence of some anodic spots in the presence of bacteria was affected by ammonia and underwent pitting 2 corrosion. The present study reveals that Bacillus sp. encourage intergranular attack without any stress to the cooling water system.

Carbonate and Oxalate Crystallization by Interaction of Calcite Marble with Bacillus subtilis and Bacillus subtilis–Aspergillus niger Association

“…It should also be kept in mind that the crystallization of calcium oxalate leads to a decrease in the content of oxalate ions in the medium and may lead to an increase in pH. An increase in pH is often observed also in aging cultures of microorganisms and may be a consequence of the release of nitrogen metabolism products by bacteria, as well as the formation of lysis products of aging cells [5,39,40]. Since the pH increases with time, it can be concluded that the influence of factors contributing to the increase in pH (in particular, the products of nitrogen metabolism) prevails in our experiment.…”

The intensity of biofilm formation by heterotrophic bacteria isolated from soil ferrosphere

“…Since the strains did not show high adhesive properties, they can be expected to participate in corrosion processes due to the influence of ammonium (a product of AMB metabolism), which is considered a corrosive compound (Maruthamuthu et al, 2009;Guo et al, 2022). IRB, similar to SRB, is capable of hydrogen consumption and electrode depolarization (De Windt et al, 2003;Hernández-Santana, 2021), destruction of mineral films of carbon steel surface due to iron-reducing activity, which increases the speed of corrosion processes (Valencia-Cantero & Pena-Cabriales, 2014).…”