Sentences with phrase «oxidation of ammonia»

Nitrification, the oxidation of ammonia via nitrite to nitrate, has always been considered to be a two - step process catalysed by chemolithoautotrophic microorganisms oxidising either ammonia or nitrite.

Microbiologists used to think that two distinct groups of bacteria were responsible for the stepwise oxidation of ammonia to nitrate via nitrite.

Wang's research group designed a five - metal catalyst based on these high - entropy - alloy nanoparticles and demonstrated superior catalytic performance for selective oxidation of ammonia to nitrogen oxide, a reaction used by the chemical industry to produce nitric acid, an important chemical in the large - scale production of fertilizers and other products.

They were able to achieve 100 percent oxidation of ammonia and 99 percent selectivity toward desired products with the high entropy alloy nanoparticles, proving their ability as highly efficient catalysts.

Not exact matches

To demonstrate one potential use of the nanoparticles, the research team used them as advanced catalysts for ammonia oxidation, which is a key step in the production of nitric acid (a liquid acid that is used in the production of ammonium nitrate for fertilizers, making plastics, and in the manufacturing of dyes).

They cranked them up even more — to 200 microns per second (equivalent to 100 of the nanomachine's body lengths)-- by also adding hydrazine, an ammonia - derived chemical compound that accelerates hydrogen peroxide oxidation.

«This study shows for the first time that the oxidation of hydrogen sulfide and ammonia from the bottom waters could be a major contributor to lower pH in coastal oceans and may lead to more rapid acidification in coastal waters compared to the open ocean,» said Cai, the paper's lead author and an expert in marine chemistry and carbon's movement through coastal waters.

The seasonal distribution of marine Crenarchaeota in the oxic and ammonia - rich surface waters off Palmer Station, Antarctica [4], as well as a correlation of increasing crenarchaeal abundance with a nitrite (NO2 −) maximum are both consistent with the hypothesis that marine Crenarchaeota are capable of ammonia oxidation [25].

Citation: Hallam SJ, Mincer TJ, Schleper C, Preston CM, Roberts K, Richardson PM, et al. (2006) Pathways of Carbon Assimilation and Ammonia Oxidation Suggested by Environmental Genomic Analyses of Marine Crenarchaeota.

In particular, ammonia oxidation rates in seawater have been shown to decline by 3 — 44 % as a linear function of decreasing pH, in both in situ and experimental studies covering a range of pH values (from 6.0 to approx. 8.10)[6 — 9].