Topic
Ammonia
About: Ammonia is a research topic. Over the lifetime, 16217 publications have been published within this topic receiving 271940 citations. The topic is also known as: NH3 & azane.
Papers published on a yearly basis
Papers
More filters
TL;DR: A maximum nitrification efficiency of 71% was achieved when bicarbonate was added, the removals of COD and phenols being almost similar to those obtained in the absence of nitrification, as the alkalinity of the wastewater was very low.
152 citations
TL;DR: It was concluded that ammonia removal through air stripping at the alkaline pH could be a viable option for preventing the failure of anaerobic digestion of the raw piggery wastewater and a high concentration of sodium ion originated from sodium hydroxide for pH adjustment inhibited methane production.
152 citations
TL;DR: The transport of nitrogen across the rumin epithelium is characterized by absorption of ammonia from the rumen and by an influx of urea into the rumens, both of which are large and exhibit wide variation.
Abstract: The transport of nitrogen across the rumen epithelium is characterized by absorption of ammonia from the rumen and by an influx of urea into the rumen. The transport rates of both compounds are large and exhibit wide variation. The transport of ammonia occurs in two forms: in the lipophilic form as NH3, the magnitude of which is linearly related to the pH in the ruminal fluid at pH values above 7, while at a physiological pH of 6.5 or lower, ammonia is predominantly absorbed as NH4+ via putative potassium channels in the apical membrane. The uptake of NH4+ depends on the potential difference of the apical membrane, Pda, and shows competition with K uptake. The pathway for basolateral exit of NH4+ is unknown. Hence, the relative transport rates of NH3 or NH4+ are determined by the ruminal pH according to the Henderson-Hasselbalch equation. Transport of ammonia interacts with the transport of Na and Mg mainly via changes of the intracellular pH. Urea recycling into the rumen has been known for many years and the transport across the rumen epithelium is mediated via urea transporters in the luminal and basolateral membrane of the epithelium. Transport of urea occurs by simple diffusion, but is highly variable. A significant increase of urea influx is caused by the fermentation products CO2 and short-chain fatty acids. Conversely, there is some evidence of inhibition of urea influx by ruminal ammonia. The underlying mechanisms of this modulation of urea transport are unknown, but of considerable nutritional importance, and future research should be directed to this aspect of ruminal transport.
152 citations
TL;DR: It was found that the gaseous ammonia loss from the large-pellet urea (tablets) was markedly lower than that from the small-pellets urea during the first two weeks of exposure, and this difference in cumulative ammonia loss decreased successively on extending the observation period.
Abstract: Using diluted phosphoric acid- and glycerol-treated polyurethane plastic foam discs as static ammonia absorbers, the extent of ammonia loss from applied urea was determined on forest soil under field conditions. The investigation, which primarily involved a comparison of urea materials of two different pellet sizes (2–4 mg and 2060 mg urea per pellet, respectively), extended over a period of 28 days. The urea was applied to the soil surface at a rate of 200 kg N per hectare. It was found that the gaseous ammonia loss from the large-pellet urea (tablets) was markedly lower than that from the small-pellet urea during the first two weeks of exposure. On extending the observation period to four weeks, this difference in cumulative ammonia loss decreased successively. After 28 days' exposure, at a daily mean temperature of 13°C, the volatile loss amounted to 20 and 22 per cent, respectively. An addition of 5% (w/w) of a solution of concentrated orthophosphoric acid, or a fine-crystalline ortho-boric acid to the large-pellet urea, resulted in a reduction of the loss to half the value. The possibilities of controlling the ammonia loss from urea by combining the large pellet size with the addition of urease inhibitors are discussed. re]19721012
151 citations
TL;DR: In this article, it was shown that the un-ionized ammonia molecule and not the ammonium ion is the form of the toxicant harmful to fish, and the amount of unionised ammonia in the water was quantified.
Abstract: Previous studies have shown that the un-ionized ammonia molecule and not the ammonium ion is the form of the toxicant harmful to fish. Prior attempts to quantify the amount of un-ionized ammonia in...
151 citations