In situ AFM observations of Ca–Mg carbonate crystallization catalyzed by dissolved sulfide: Implications for sedimentary dolomite formation

2013 ◽  
Vol 105 ◽  
pp. 44-55 ◽  
Author(s):  
Fangfu Zhang ◽  
Chao Yan ◽  
H. Henry Teng ◽  
Eric E. Roden ◽  
Huifang Xu
Keyword(s):  
Dissolved Sulfide ◽  
Dolomite Formation

Comparing in situ colorimetric DET and DGT techniques with ex situ core slicing and centrifugation for measuring ferrous iron and dissolved sulfide in coastal sediment pore waters

Chemosphere ◽  
2017 ◽  
Vol 188 ◽  
pp. 119-129 ◽  
Author(s):  
Nadeeka Rathnayake Kankanamge ◽  
William W. Bennett ◽  
Peter R. Teasdale ◽  
Jianyin Huang ◽  
David T. Welsh
Keyword(s):  
Ferrous Iron ◽  
Coastal Sediment ◽  
Ex Situ ◽  
Pore Waters ◽  
Dissolved Sulfide

In situ detection of intermediates from the interaction of dissolved sulfide and manganese oxides with a platinum electrode in aqueous systems

2017 ◽  
Vol 14 (3) ◽  
pp. 178 ◽  
Author(s):  
Yao Luo ◽  
Yougang Shen ◽  
Lihu Liu ◽  
Jun Hong ◽  
Guohong Qiu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Manganese Oxides ◽  
Platinum Electrode ◽  
Aqueous Systems ◽  
Oxidation Peak ◽  
Peak Current ◽  
Oxidation Peak Current ◽  
Dissolved Sulfide ◽  
In Situ Detection

Environmental contextDissolved sulfide results in soil acidification and subsequent contaminant leaching via oxidation processes, usually involving manganese oxides. In this work, redox processes were monitored in situ by cyclic voltammetry and HS– concentrations were semi-quantitatively determined. The method provides qualitative and semi-quantitative assessment for dissolved sulfide and its oxidation intermediates in aqueous systems. AbstractDissolved sulfide can be oxidised by manganese oxides in supergene environments, while the intermediates including S0, S2O32– and SO32– are easily oxidised by oxygen in air, resulting in some experimental errors in conventional analyses. In this work, the electrochemical behaviours of HS–, S2O32– and SO32– on a platinum electrode were studied by cyclic voltammetry and constant potential electrolysis, and in situ detection of the intermediates was conducted in aqueous systems of HS– and manganese oxides. The results showed that HS– was first oxidised to S0, and then transformed to SO42–. The peak current for the oxidation of HS– to S0 had a positive linear correlation with the used starting HS– concentration. S2O32– and SO32– were directly electrochemically oxidised to SO42–. The oxidation current peak potentials at 0, 0.45 and 0.7V were respectively observed for HS–, S2O32– and SO32– at pH 12.0. Cyclic voltammetry was conducted to monitor the redox processes of HS– and manganese oxides. The oxidation peak current of HS– to S0 decreased, and that of S2O32– to SO42– was observed to increase as the reaction proceeded. The rate of the decrease of the oxidation peak current of HS– indicated that the oxidation activity followed the order of birnessite>todorokite>manganite.

scholarly journals Calcite and dolomite formation in the CM parent body: Insight from in situ C and O isotope analyses

2019 ◽  
Vol 260 ◽  
pp. 275-291 ◽  
Author(s):  
M. Telus ◽  
C.M.O'D. Alexander ◽  
E.H. Hauri ◽  
J. Wang
Keyword(s):  
Parent Body ◽  
O Isotope ◽  
Dolomite Formation ◽  
Isotope Analyses

Continuous measurement of dissolved sulfide in sewer systems

2008 ◽  
Vol 57 (3) ◽  
pp. 375-381 ◽  
Author(s):  
L. Sutherland-Stacey ◽  
S. Corrie ◽  
A. Neethling ◽  
I. Johnson ◽  
O. Gutierrez ◽  
...  
Keyword(s):  
Waste Water ◽  
Hydrogen Sulfide ◽  
Sample Preparation ◽  
Continuous Measurement ◽  
Sewer Systems ◽  
Low Concentrations ◽  
Dissolved Sulfide ◽  
High Concentrations ◽  
No Sample Preparation

Sulfides are particularly problematic in the sewage industry. Hydrogen sulfide causes corrosion of concrete infrastructure, is dangerous at high concentrations and is foul smelling at low concentrations. Despite the importance of sulfide monitoring there is no commercially available system to quantify sulfide in waste water. In this article we report on our use of an in situ spectrometer to quantify bisulfide in waste water and additional analysis with a pH probe to calculate total dissolved sulfide. Our results show it is possible to use existing commercially available and field proven sensors to measure sulfide to mg/l levels continuously with little operator intervention and no sample preparation.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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