Exactly Embedded Wavefunction Methods for Characterizing Nitrogen Reduction Catalysis

2015 ◽  
Author(s):  
III Miller ◽  
Thomas F.
Keyword(s):  
Nitrogen Reduction ◽  
Wavefunction Methods

Promoting Nitrogen Electroreduction to Ammonia with Bismuth Nanocrystals and Potassium Cations in Water

2020 ◽  
Author(s):  
Jaecheol Choi ◽  
Hoang-Long Du ◽  
Manjunath Chatti ◽  
Bryan H. R. Suryanto ◽  
Alexandr Simonov ◽  
...  
Keyword(s):  
Electrocatalytic Activity ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Reduction Reaction ◽  
Nitrogen Reduction ◽  
Aqueous Electrolyte Solutions

We demonstrate that bismuth exhibits no measurable electrocatalytic activity for the nitrogen reduction reaction to ammonia in aqueous electrolyte solutions, contrary to several recent reports on the highly impressive rates of Bi-catalysed electrosynthesis of NH<sub>3</sub> from N<sub>2</sub>.

A seven year plan for upgrading the 200.000 p.e. treatment plant of Uppsala, Sweden

1994 ◽  
Vol 29 (12) ◽  
pp. 117-127
Author(s):  
Jan Erik Lind ◽  
Ernst Olof Swedling
Keyword(s):  
Cost Efficiency ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Working Environment ◽  
Regional Environment ◽  
Nitrogen Reduction ◽  
Total Investment ◽  
Close Cooperation ◽  
The Cost

The sewage treatment plant of Uppsala was originally built in 1946 and has since then been extended and upgraded several times up to 1972 when the last major upgrading was completed. In 1987 it was decided to renew the treatment plant for at least another 20-30 years of operation and to upgrade the biological process to include nitrogen reduction. A 7 year plan covering some 18 items with a total investment cost of approximately 120 MSEK was set in action during 1987. The aim was to raise the cost efficiency by introducing modern techniques, new machinery, a better working environment and a better understanding of the processes used. The need to keep the plant in operation during reconstruction work has caused difficulties, delays and unforseen costs but a close cooperation between all parties concerned (operators, contractors, engineers and the regional environment administration) has solved most of the problems. Experiences so far include an improved effluent quality, a better cost efficiency, a healthier and more engaged operating staff. A research team has been engaged to develop and introduce a nitrogen reduction scheme in the activated sludge process. This has been a challenging and fruitful experience.

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

The nitrogen reduction in eutrophic water column driven by Microcystis blooms

2020 ◽  
Vol 385 ◽  
pp. 121578 ◽  
Author(s):  
Yingshi Shen ◽  
Yingying Huang ◽  
Jun Hu ◽  
Panpan Li ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Water Column ◽  
Nitrogen Reduction ◽  
Eutrophic Water ◽  
Microcystis Blooms

Boosting electrochemical nitrogen reduction reaction performance of two-dimensional Mo porphyrin monolayers via turning the coordination environment

2021 ◽  
Vol 23 (7) ◽  
pp. 4178-4186
Author(s):  
Shiqiang Liu ◽  
Zhiwen Cheng ◽  
Yawei Liu ◽  
Xiaoping Gao ◽  
Yujia Tan ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Reduction Reaction ◽  
Metal Catalysts ◽  
Two Dimensional ◽  
Coordination Environment ◽  
Nitrogen Reduction ◽  
Reaction Performance ◽  
Conversion Efficiencies

Designing atomically dispersed metal catalysts for the nitrogen reduction reaction (NRR) is an effective approach to achieve better energy conversion efficiencies.

Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency

2021 ◽  
pp. 2100812
Author(s):  
Karthik Peramaiah ◽  
Vinoth Ramalingam ◽  
Hui‐Chun Fu ◽  
Merfat M. Alsabban ◽  
Rafia Ahmad ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Carbon Nitride ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction

Zr-doped α-FeOOH with High Faradaic Efficiency for Electrochemical Nitrogen Reduction Reaction

2021 ◽  
pp. 150801
Author(s):  
Jiabin Tan ◽  
Xiaobo H ◽  
Fengxiang Yin ◽  
Xin Liang ◽  
Guoru Li ◽  
...  
Keyword(s):  
Reduction Reaction ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction
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