Understanding the composition and spatial distribution of biological selenate reduction products for potential selenium recovery

2020 ◽  
Vol 6 (8) ◽  
pp. 2153-2163 ◽  
Author(s):  
Zhiming Zhang ◽  
Yi Xiong ◽  
Huan Chen ◽  
Youneng Tang
Keyword(s):  
Spatial Distribution ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Selenium Nanoparticles ◽  
Elemental Selenium ◽  
Membrane Biofilm Reactor

This work determines the spatial distribution of produced elemental selenium nanoparticles (SeNPs) and selenium sulfides in a membrane biofilm reactor under various operating conditions, and identifies the condition for exclusive SeNPs production.

A membrane biofilm reactor achieves aerobic methane oxidation coupled to denitrification (AME-D) with high efficiency

2008 ◽  
Vol 58 (1) ◽  
pp. 83-87 ◽  
Author(s):  
O. Modin ◽  
K. Fukushi ◽  
F. Nakajima ◽  
K. Yamamoto
Keyword(s):  
Methane Oxidation ◽  
High Efficiency ◽  
Biofilm Reactor ◽  
Practical Application ◽  
Suspended Culture ◽  
Consumption Ratio ◽  
Membrane Biofilm Reactor ◽  
Nitrate Consumption ◽  
Attached Culture ◽  
Aerobic Methanotrophs

Methane would potentially be an inexpensive, widely available electron donor for denitrification of wastewaters poor in organics. Currently, no methanotrophic microbe is known to denitrify. However, aerobic methane oxidation coupled to denitrification (AME-D) has been observed in several laboratory studies. In the AME-D process, aerobic methanotrophs oxidise methane and release organic metabolites and lysis products, which are used by coexisting denitrifiers as electron donors for denitrification. Due to the presence of oxygen, the denitrification efficiency in terms of methane-to-nitrate consumption is usually low. To improve this efficiency the use of a membrane biofilm reactor was investigated. The denitrification efficiency of an AME-D culture in (1) a suspended growth reactor, and (2) a membrane biofilm reactor was studied. The methane-to-nitrate consumption ratio for the suspended culture was 8.7. For the membrane-attached culture the ratio was 2.2. The results clearly indicated that the membrane-attached biofilm was superior to the suspended culture in terms of denitrification efficiency. This study showed that for practical application of the AME-D process, focus should be placed on development of a biofilm reactor.

Influence of operating conditions on population dynamics in nitrifying biofilms

1999 ◽  
Vol 39 (7) ◽  
pp. 5-11 ◽  
Author(s):  
Valentina Lazarova ◽  
Danièle Bellahcen ◽  
Jacques Manem ◽  
David A. Stahl ◽  
Bruce E. Rittmann
Keyword(s):  
Population Dynamics ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Stable Operation ◽  
N Removal ◽  
Wide Range ◽  
Total Nitrogen Removal ◽  
Nitrite Oxidizers

TURBO N® is a circulating-bed biofilm reactor that provides stable operation and high N removal for a wide range of N and BOD loadings. This paper describes the influence of operating conditions on biofilm composition and population dynamics when the TURBO N® is operated to achieve tertiary nitrification, simultaneous carbon and ammonia oxidation and total nitrogen removal when coupled with a pre-denitrification fixed floating bed reactor. In situ specific nitrification rates and respiration tests showed that ammonium and nitrite oxidizers became less active in the biofilm once oxidation of influent BOD became important. Analyses of community structure with oligonucleotide probes targeted to the 16S rRNA showed the same general trends for nitrifiers, but also suggested shifts in the makeup of the ammonium and nitrite oxidizers that could not be detected with respirometry or specific nitrification rates.

scholarly journals ANTIOXIDANT ACTIVITY AND BIOGENIC SYNTHESIS OF SELENIUM NANOPARTICLES USING THE LEAF EXTRACT OF ALOE VERA

2017 ◽  
Vol 9 (4) ◽  
pp. 147 ◽  
Author(s):  
Jay Vyas ◽  
Shafkat Rana
Keyword(s):  
Antioxidant Activity ◽  
Aloe Vera ◽  
Selenium Nanoparticles ◽  
Spherical Particles ◽  
Elemental Selenium ◽  
Biogenic Synthesis ◽  
Transmission Electron ◽  
Ft Ir ◽  
Ir Analysis ◽  
Chemoprevention Agent

Objective: The objective of this present study were to the biogenic synthesis of selenium nanoparticles using Aloe vera extract and check it’s antioxidant potential by ABTS, DPPH and FRAP assays.Methods: In this study we investigated the clove of Aloe vera, which is used for the synthesis of selenium nanoparticles were characterized by using UV-Visible (UV-VIS) spectrophotometer, Transmission electron microscopy (TEM), Fourier transform spectroscopy (FTIR) and Energy dispersive X-Ray spectroscopy (EDAX) and ABTS, DPPH and FRAP assays for checked it’s antioxidant potential.Results: The present study was carried out to synthesis of Selenium nanoparticles using extract of Aloe vera. UV-Vis Spectra at 350 nm with Aloe vera extract and observed as hollow and spherical particles in size ranging 7-48 nm which is found more stable more than two months. EDAX analysis was carried out to check the presoak of Selenium in nanoparticles. Results of EDAX, confirmed its present. TEM and SEAD represented addition evidence of formation of nanoparticles whereas SEAD indicates the particles were crystalline in nature. FT-IR analysis was carried out to identify the possible bio molecules and Aloe vera extract-metal ions interaction responsible for formation and stabilization of selenium nanoparticles. FRAP, ABTS and DPPH assay results sequester that Selenium nanoparticles prepared using Aloe vera extract possess more activity than extract alone.Conclusion: The bio molecules of Aloe veraextract acted as stabilizing as well as capping agent leading to the formation of Selenium nanoparticles. Selenite has been proven to have antioxidant activity and is being used as chemoprevention agent in cancer diagnosis but same time it is toxic also. Elemental Selenium i.e. Selenium nanoparticles are less toxic form of selenium. 

Spatial Distribution of Radiant Intensity from Primary Sources for Atomic Absorption Spectrometry. Part I: Hollow Cathode Lamps

1995 ◽  
Vol 49 (4) ◽  
pp. 413-424 ◽  
Author(s):  
Albert Kh. Gilmutdinov ◽  
Bernard Radziuk ◽  
Michael Sperling ◽  
Bernhard Welz ◽  
Konstantin Yu. Nagulin
Keyword(s):  
Spatial Distribution ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Intensity Distribution ◽  
Hollow Cathode ◽  
Imaging System ◽  
Absorption Spectrometry ◽  
Operating Conditions ◽  
Radiant Intensity ◽  
Warm Up

The spatial distribution of radiant intensity from hollow cathode lamps used as radiation sources in atomic absorption spectrometry is investigated with a digital photodiode array imaging system. Intensity distribution over the cross section of each lamp is measured for both atomic and ionic lines of the analyte and the filler gas. The shape of the distribution is strongly dependent on the hollow cathode diameter. In small cathodes the distribution has the shape of a paraboloid with maximum intensity at the hollow cathode axis for all of the recorded lines. The intensity distributions of lines emitted from large cathodes are nonparaboloid and in some cases have a minimum at the cathode axis and a maximum concentric to the cathode walls. It is shown that the intensity distribution for a given lamp has practically the same shape for all currents applied. Data on the evolution of the intensity distribution during warm-up of the lamps and under various operating conditions are presented.

Accumulation of red elemental selenium nanoparticles and their biological effects in Nicotinia tabacum

2012 ◽  
Vol 68 (3) ◽  
pp. 525-531 ◽  
Author(s):  
Eva Domokos-Szabolcsy ◽  
Laszlo Marton ◽  
Attila Sztrik ◽  
Beata Babka ◽  
Jozsef Prokisch ◽  
...  
Keyword(s):  
Biological Effects ◽  
Selenium Nanoparticles ◽  
Elemental Selenium
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