scholarly journals Green processes for environmental application. Electrochemical ozone production

2001 ◽  
Vol 73 (12) ◽  
pp. 1871-1884 ◽  
Author(s):  
L. M. Da Silva ◽  
L. A. De Faria ◽  
J. F. C. Boodts
Keyword(s):  
Supporting Electrolyte ◽  
Ozone Production ◽  
Specific Power ◽  
Differential Capacity ◽  
Electrolyte System ◽  
Environmental Application ◽  
Detailed Mechanism ◽  
Stationary Conditions ◽  
Electrode Characterization

Several aspects of electrochemical ozone production (EOP) on b-PbO2 were investigated. The morphology of the electrode material was determined in situ using extensive (total, external, and internal differential capacity) and intensive parameters (the morphology factor, j) permitting comparison with results of other laboratories if appropriate electrode characterization parameters are available. The influence of the nature of the supporting electrolyte on the oxygen evolution reaction (OER)/EOP processes was investigated using polarization curves, recorded under quasi-stationary conditions, point-by-point polarization, and chronopotentiometry. The performance of the several b-PbO2/electrolyte system was evaluated using the apparent specific power criterion. A detailed mechanism for EOP is proposed.

Co-solidification of bauxite residue and coal ash into indurated monolith via ambient geopolymerisation for in situ environmental application

2022 ◽  
Vol 422 ◽  
pp. 126925
Author(s):  
Tuan A.H. Nguyen ◽  
Xingyun Guo ◽  
Fang You ◽  
Narottam Saha ◽  
Songlin Wu ◽  
...  
Keyword(s):  
Bauxite Residue ◽  
Coal Ash ◽  
Environmental Application

scholarly journals Central role of nitric oxide in ozone production in the upper tropical troposphere over the Atlantic Ocean and western Africa

2021 ◽  
Vol 21 (10) ◽  
pp. 8195-8211
Author(s):  
Ivan Tadic ◽  
Clara M. Nussbaumer ◽  
Birger Bohn ◽  
Hartwig Harder ◽  
Daniel Marno ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Atlantic Ocean ◽  
General Circulation ◽  
Simulated Data ◽  
Ozone Production ◽  
Mixing Ratios ◽  
Western Africa ◽  
Tropical Troposphere

Abstract. Mechanisms of tropospheric ozone (O3) formation are generally well understood. However, studies reporting on net ozone production rates (NOPRs) directly derived from in situ observations are challenging and are sparse in number. To analyze the role of nitric oxide (NO) in net ozone production in the upper tropical troposphere above the Atlantic Ocean and western Africa, we present in situ trace gas observations obtained during the CAFE-Africa (Chemistry of the Atmosphere: Field Experiment in Africa) campaign in August and September 2018. The vertical profile of in situ measured NO along the flight tracks reveals lowest NO mixing ratios of less than 20 pptv between 2 and 8 km altitude and highest mixing ratios of 0.15–0.2 ppbv above 12 km altitude. Spatial distribution of tropospheric NO above 12 km altitude shows that the sporadically enhanced local mixing ratios (>0.4 ppbv) occur over western Africa, which we attribute to episodic lightning events. Measured O3 shows little variability in mixing ratios at 60–70 ppbv, with slightly decreasing and increasing tendencies towards the boundary layer and stratosphere, respectively. Concurrent measurements of CO, CH4, OH, HO2 and H2O enable calculations of NOPRs along the flight tracks and reveal net ozone destruction at −0.6 to −0.2 ppbv h−1 below 6 km altitude and balance of production and destruction around 7–8 km altitude. We report vertical average NOPRs of 0.2–0.4 ppbv h−1 above 12 km altitude with NOPRs occasionally larger than 0.5 ppbv h−1 over western Africa coincident with enhanced NO. We compare the observational results to simulated data retrieved from the general circulation model ECHAM/MESSy Atmospheric Chemistry (EMAC). Although the comparison of mean vertical profiles of NO and O3 indicates good agreement, local deviations between measured and modeled NO are substantial. The vertical tendencies in NOPRs calculated from simulated data largely reproduce those from in situ experimental data. However, the simulation results do not agree well with NOPRs over western Africa. Both measurements and simulations indicate that ozone formation in the upper tropical troposphere is NOx limited.

In situ determination of the electrochemically active platinum surface area: key to improvement of solid acid fuel cells

2018 ◽  
Vol 6 (6) ◽  
pp. 2700-2707 ◽  
Author(s):  
Felix P. Lohmann-Richters ◽  
Bernd Abel ◽  
Áron Varga
Keyword(s):  
Fuel Cells ◽  
Solid Electrolyte ◽  
Surface Area ◽  
Solid Acid ◽  
Oxide Reduction ◽  
Electrolyte System ◽  
Platinum Surface ◽  
Electrochemically Active

Surface oxide reduction is demonstrated for measuring the active Pt surface area in a solid electrolyte system at 240 °C.

Ex situ and in situ characterization studies of spin-coated TiO2 film electrodes for the electrochemical ozone production process

2009 ◽  
Vol 55 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Kenta Kitsuka ◽  
Kazuhiro Kaneda ◽  
Mineo Ikematsu ◽  
Masahiro Iseki ◽  
Katsuhiko Mushiake ◽  
...  
Keyword(s):  
Production Process ◽  
Tio2 Film ◽  
Ozone Production ◽  
Ex Situ ◽  
In Situ Characterization ◽  
Characterization Studies

scholarly journals Characterization of ozone production in San Antonio, Texas, using measurements of total peroxy radicals

2019 ◽  
Vol 19 (5) ◽  
pp. 2845-2860 ◽  
Author(s):  
Daniel C. Anderson ◽  
Jessica Pavelec ◽  
Conner Daube ◽  
Scott C. Herndon ◽  
Walter B. Knighton ◽  
...  
Keyword(s):  
San Antonio ◽  
Peroxy Radical ◽  
Ozone Production ◽  
Peroxy Radicals ◽  
Entire Region ◽  
Volatile Organic ◽  
In Situ Observations ◽  
Study Sites

Abstract. Observations of total peroxy radical concentrations ([XO2] ≡ [RO2] + [HO2]) made by the Ethane CHemical AMPlifier (ECHAMP) and concomitant observations of additional trace gases made on board the Aerodyne Mobile Laboratory (AML) during May 2017 were used to characterize ozone production at three sites in the San Antonio, Texas, region. Median daytime [O3] was 48 ppbv at the site downwind of central San Antonio. Higher concentrations of NO and XO2 at the downwind site also led to median daytime ozone production rates (P(O3)) of 4.2 ppbv h−1, a factor of 2 higher than at the two upwind sites. The 95th percentile of P(O3) at the upwind site was 15.1 ppbv h−1, significantly lower than values observed in Houston. In situ observations, as well as satellite retrievals of HCHO and NO2, suggest that the region was predominantly NOx-limited. Only approximately 20 % of observations were in the VOC-limited regime, predominantly before 11:00 EST, when ozone production was low. Biogenic volatile organic compounds (VOCs) comprised 55 % of total OH reactivity at the downwind site, with alkanes and non-biogenic alkenes responsible for less than 10 % of total OH reactivity in the afternoon, when ozone production was highest. To control ozone formation rates at the three study sites effectively, policy efforts should be directed at reducing NOx emissions. Observations in the urban center of San Antonio are needed to determine whether this policy is true for the entire region.

A Novel Approach of In-Situ Electrobiosynthesis of Metal Oxide Nanoparticles Using Crude Plant Extract as Main Medium for Supporting Electrolyte

2019 ◽  
Vol 19 ◽  
pp. 1441-1445 ◽  
Author(s):  
Norzahir Sapawe ◽  
Mohd Ariff Rustam ◽  
Muhammad Hafizan Hakimin Mahadzir ◽  
Mohamad Kamal Ezzat Mohamad Lani ◽  
Azizzami Raidin ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Plant Extract ◽  
Supporting Electrolyte ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Novel Approach ◽  
Crude Plant Extract ◽  
Main Medium

scholarly journals Anionic polyacrylamide as a substance strengthening the Pb(II) immobilization on the kaolinite surface

2019 ◽  
Vol 17 (2) ◽  
pp. 1101-1112 ◽  
Author(s):  
G. Fijałkowska ◽  
K. Szewczuk-Karpisz ◽  
M. Wiśniewska
Keyword(s):  
Heavy Metal ◽  
Potentiometric Titration ◽  
Electrophoretic Mobility ◽  
Supporting Electrolyte ◽  
Ion Concentration ◽  
Macromolecular Compound ◽  
Electrolyte System ◽  
Kaolinite Surface ◽  
The Impact ◽  
Anionic Polyacrylamide

Abstract The main purpose of the study was to examine lead(II) ion immobilization on the kaolinite surface and determine the effect of soil flocculant (macromolecular compound) on this process. For this reason, the adsorption measurements of anionic polyacrylamide and/or Pb(II) ions on the kaolinite surface were performed. Moreover, the impact of heavy metal on electrokinetic and stability properties of kaolinite/polyacrylamide/supporting electrolyte system was determined. It was done based on the results of potentiometric titration, electrophoretic mobility, and absorbance measurements. The most important conclusions of the study were as follows: (1) kaolinite is an effective Pb(II) adsorbent when ion concentration in the environment equals 1 or 10 ppm (it adsorbs 80% and 72% of the ions, respectively), (2) when Pb(II) concentration in the environment is 100 ppm, kaolinite adsorbs only 29% of the ions, and (3) anionic polyacrylamide may strengthen the Pb(II) adsorption on the kaolinite surface (in the presence of 100 ppm AN PAM 30% and 1 ppm Pb(II), even 96% of the ions are adsorbed). Due to the above process, the bioavailability of heavy metal for organisms is considerably limited. Graphic Abstract

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