N2O production in the FeII(EDTA)-NO reduction process: the effects of carbon source and pH

2015 ◽  
Vol 38 (7) ◽  
pp. 1373-1380 ◽  
Author(s):  
Jun Chen ◽  
Lei Wang ◽  
Ji Zheng ◽  
Jianmeng Chen
Keyword(s):  
Carbon Source ◽  
No Reduction ◽  
Reduction Process ◽  
N2o Production

scholarly journals Experimental Study on Single Factor, Orthogonal and Characteristics of SRB Particles Fixed by Biologically Activated Lignite

2021 ◽  
Author(s):  
Junzhen Di ◽  
Yangyang Jiang ◽  
Mingjia Wang ◽  
Yanrong Dong
Keyword(s):  
Carbon Source ◽  
Raw Materials ◽  
Reduction Process ◽  
Order Kinetic ◽  
Single Factor ◽  
Isothermal Adsorption ◽  
Optimal Ratio ◽  
Mine Wastewater ◽  
Order Kinetic Model ◽  
Rhodopseudomonas Spheroides

Abstract Aiming at the problems of insufficient supply of carbon source and toxic effect of heavy metal ions in the treatment of acid mine wastewater (AMD) by sulfate reducing bacteria (SRB), immobilized particles were prepared with Rhodopseudomonas spheroides, SRB and lignite as the main raw materials, and the optimal ratio of immobilized particles was determined based on single factor test and orthogonal test. The adsorption experiment of immobilized particles was carried out under the optimal ratio, the reaction kinetic process and adsorption capacity of immobilized particles for different ions were analyzed, and the action mechanism was studied. The results show that lignite not only has good adsorption performance, but also can be used as the carbon source of SRB after degradation by Rhodopseudomonas spheroides, so as to solve the problems of low removal efficiency of AMD by SRB and insufficient supply of carbon source. When the dosage of lignite, Rhodopseudomonas spheroides and SRB is 3%, 10% and 10% respectively, and the particle size of lignite is 200 mesh, the overall treatment effect is the best. The removal rates of SO42-, Zn2+ and Cu2+ are 83.21%, 99.59% and 99.93% respectively, the pH is increased to 7.43, the release of COD is 523 mg/L, and the ORP number is -134 mV. The reduction process of SO42- by immobilized particles conforms to the pseudo first-order kinetics, the isothermal adsorption of Zn2+ more conforms to the Freundlich isothermal adsorption equation, and the adsorption kinetics of Zn2+ more conforms to the pseudo second-order kinetic model.

scholarly journals Certain Environmental Conditions Maximize Ammonium Accumulation and Minimize Nitrogen Loss During Nitrate Reduction Process by Pseudomonas putida Y-9

2021 ◽  
Vol 12 ◽  
Author(s):  
Xuejiao Huang ◽  
Wenzhou Tie ◽  
Deti Xie ◽  
Daihua Jiang ◽  
Zhenlun Li
Keyword(s):  
Carbon Source ◽  
Pseudomonas Putida ◽  
Nitrate Reduction ◽  
Nitrogen Loss ◽  
Expression Patterns ◽  
Nitrate Removal ◽  
Nitrate Assimilation ◽  
Nitrogen Retention ◽  
Reduction Process ◽  
Ammonium Accumulation

Realizing the smallest nitrogen loss is a challenge in the nitrate reduction process. Dissimilatory nitrate reduction to ammonium (DNRA) and nitrate assimilation play crucial roles in nitrogen retention. In this study, the effects of the carbon source, C/N ratio, pH, and dissolved oxygen on the multiple nitrate reduction pathways conducted by Pseudomonas putida Y-9 are explored. Strain Y-9 efficiently removed nitrate (up to 89.79%) with glucose as the sole carbon source, and the nitrogen loss in this system was 15.43%. The total nitrogen decrease and ammonium accumulation at a C/N ratio of 9 were lower than that at 12 and higher than that at 15, respectively (P < 0.05). Besides, neutral and alkaline conditions (pH 7–9) favored nitrate reduction. Largest nitrate removal (81.78%) and minimum nitrogen loss (10.63%) were observed at pH 7. The nitrate removal and ammonium production efficiencies of strain Y-9 increased due to an increased shaking speed. The expression patterns of nirBD (the gene that controls nitrate assimilation and DNRA) in strain Y-9 were similar to ammonium patterns of the tested incubation conditions. In summary, the following conditions facilitated nitrate assimilation and DNRA by strain Y-9, while reducing the denitrification: glucose as the carbon source, a C/N ratio of 9, a pH of 7, and a shaking speed of 150 rpm. Under these conditions, nitrate removal was substantial, and nitrogen loss from the system was minimal.

scholarly journals Experiment and simulation study of the effect of ethanol and compound additives on the urea-based selective non-catalytic reduction process under moderate temperature conditions

2018 ◽  
Vol 5 (10) ◽  
pp. 180969
Author(s):  
Bang Wu ◽  
Ge Pu ◽  
Jiantai Du
Keyword(s):  
Simulation Study ◽  
No Reduction ◽  
Flow Reactor ◽  
Catalytic Reduction ◽  
Reduction Process ◽  
Inhibitory Effect ◽  
Ethanol Decomposition ◽  
Entrained Flow Reactor ◽  
Temperature Window ◽  
Experiment And Simulation

An experiment and simulation study of the effect of using liquid additives on the selective non-catalytic reduction (SNCR) process is presented, providing a novel way for plants reducing NO X emissions. An experimental study is conducted in an entrained flow reactor, and CHEMKIN is applied for simulation study. Ethanol additive can effectively shift the temperature window of the NO X OUT process to a lower range and the NO X OUT efficiency ranges from 29 to 56% at 700–800°C. Furthermore, ethanol additive has a significant inhibitory effect on ammonia slip. Na 2 SO 4 and C 2 H 5 OH can be combined into a compound additive, which has a synergistic effect on NO reduction. The addition of methanol can greatly promote denitrification efficiency from 650°C to 725°C, indicating the potential of compound additives in NO reduction. The HNCO + OH = H 2 O + NCO pathway is also proven to be enhanced for ethanol decomposition, thereby providing OH•, which is active in NO reduction. Finally, the reaction routes for ethanol on the urea-based SNCR process at the proper temperature are proposed.

BNP test to evaluate the influence of C/N ratio on N2O production in biological denitrification

2000 ◽  
Vol 42 (3-4) ◽  
pp. 23-27 ◽  
Author(s):  
Y.-C. Chung ◽  
M.-S. Chung
Keyword(s):  
Carbon Source ◽  
Conversion Rate ◽  
Carbon Sources ◽  
Gas Production ◽  
Test Results ◽  
Carbon Consumption ◽  
Nitrogen Gas ◽  
N2o Production ◽  
Potential System ◽  
Nitrogen Potential

With sufficient carbon sources in the influence to the anoxic stage, the total gas production rate in the BNP (Biolofical Nitrogen potential) system is rapid with a specific gas production of 3.83 mL/g-VSS-hr. The conversion of nitrate to nitrogen gas is accomplished through three steps: nitrate (NO3-) to nitrite (NO2-) to nitrous oxide (N2O), and nitrogen gas (N2). The BNP test results indicate that the optimal C/N ratios are 4.5±0.2, 3.1±0.4, and 2.0±0.2 for these three steps with carbon consumptions being 30%, 24%, and 46% of the total denitrification carbon consumption. With different concentrations of the influent nitrate, the optimal C/N ratios are 5.3∼5.6, 4.3∼4.7, 3.9∼4.0, and 2.5∼2.7 for 25, 50, 100, and 200 mg/L NO3--N, respectively. The conversion rate of N2O under conditions of sufficient carbon source is 0.005%. If the carbon source becomes insufficient, the N2O conversion rate may increase 100 times to 0.5%.

DFT modelling of the NO reduction process at the Cu-doped SrTiO3(1 0 0) stepped surface

2020 ◽  
Vol 511 ◽  
pp. 119813
Author(s):  
Silvia Carlotto ◽  
Andrea Vittadini ◽  
Maurizio Casarin
Keyword(s):  
No Reduction ◽  
Reduction Process ◽  
Stepped Surface ◽  
Dft Modelling

DFT Study of NO Reduction Process on Ag/γ-Al2O3 Catalyst: Some Aspects of Mechanism and Catalyst Structure

2020 ◽  
Author(s):  
Vitaly E. Matulis ◽  
Ekaterina G. Ragoyja ◽  
Oleg A. Ivashkevich ◽  
Dmitry A. Lyakhov ◽  
Dominik Michels
Keyword(s):  
No Reduction ◽  
Reduction Process ◽  
Dft Study ◽  
Catalyst Structure ◽  
Al2o3 Catalyst

An Experimental Study on Nitric Oxide Reduction through Coal-Biomass Blend Reburning

2011 ◽  
Vol 383-390 ◽  
pp. 3017-3021 ◽  
Author(s):  
Sheng Li Niu ◽  
Kui Hua Han ◽  
Chun Mei Lu
Keyword(s):  
Nitric Oxide ◽  
No Reduction ◽  
Reduction Process ◽  
Experimental System ◽  
Drop Tube ◽  
Drop Tube Furnace ◽  
Reduction Efficiency ◽  
Nitric Oxide Reduction ◽  
Biomass Blend ◽  
Fuel Fraction

Nitric oxide (NO) reduction through coal, biomass and their blend reburning is conducted on a drop tube furnace experimental system and it is proved to be feasible of using the coal-biomass blend as the reburning fuel. For a high NO reduction efficiency, the excess air ratio in the reburning zone should be less than 0.9 and the reaction temperature is required to be higher than 1373K. 50-60% of the biomass percentage in the blend is enough for an acceptable efficiency. At the same time, for a thorough NO reduction process, the reburning fuel fraction and the residence time in the reburning zone must be guaranteed about 20% and 0.6-0.8s, respectively. Also, when the initial NO concentration is excess 600ppm, the efficiency is varied little at different NO concentrations.

The Influence of Coal and Reduction Process Parameters in Producing Iron Nugget

2013 ◽  
Vol 789 ◽  
pp. 517-521 ◽  
Author(s):  
Johny Wahyuadi Soedarsono ◽  
Adji Kawigraha ◽  
Rianti Dewi Sulamet-Ariobimo ◽  
M. Amryl Asy'ari ◽  
Andre Yosi ◽  
...  
Keyword(s):  
Carbon Source ◽  
Iron Ore ◽  
Iron Reduction ◽  
Reduction Process ◽  
High Quality ◽  
Composite Pellet ◽  
Iron And Steel ◽  
Iron Metal ◽  
Iron Nugget ◽  
Weak Peak

Limitation of iron ore reserve having high quality ore and of energy has enhanced development in iron and steel producing technology and method. The ITmk3 process is one of iron making technology that can cope with the problems. It uses composite pellet as feeding material. In this process the ratio between iron and carbon are very important. Carbon holds an important role in the reduction process of iron. The transformation from iron oxides to iron metal will complete if composite pellet contains enough carbon. This paper discusses the influence of carbon ratio in iron reduction process. Nickel saprolite and coal are used as iron and carbon source. They are grinded, crushed, sieved, mixed and formed in cylinders. The weight ratios of ores to coal are 1:1 and 2:1. The reduction held in a furnace at 1100OC for 60 minutes and 1250OC for 120 minutes. The results show that the reduction could not complete. Weak peak of FeNi is due to reduction process do not immediately follow the dehydroxylation process.

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