Effect of γ-Radiation on Physico-Chemical Properties of Lanthanum Cobaltate (LaCoO3)

1989 ◽  
Vol 157 ◽  
Author(s):  
B. Srinivas ◽  
V.R.S. Rao ◽  
J.C. Kuriacose

ABSTRACTThe influence of γ-radiation on LaCoO3, for the catalytic decomposition of H2O2 has been studied. ESR and XPS studies of γ-irradiated LaCoO3, snowed, the formation of chemisorbed oxygen (O2) and reduction of Co2+ to Co . γ-irradia]:ion of LaCoO3. causes a decrease in electrical conductivity due to the trapping of charge carriers by the chemisorbed oxygen. SEM photographs of the Y-irradiated sample pellets reveal surface cracks and surface corrosion due to the diffusion of transition metal to surface. The enhancement in the catalytic activity for the decomposition of H2O2 is found to be directly proportional to the reduced metal content.

2019 ◽  
Vol 948 ◽  
pp. 14-19
Author(s):  
Rizqi Amaliyah Fitri ◽  
Suratman Adhitasari ◽  
Suherman

The Influence of Physico-chemical properties on heavy metals contenton the Illegal Land Fill at Kadisoka, Sleman, Yogyakarta has been carried out. The aims of this research are to evaluatethe metal concentrationin the soil, analyze the physicochemical properties including water and ash contents, pH, electrical conductivity, total organic carbon, cation exchange capacity; and to find out the maximum heavy metals contentthe soil samples.Soil samples were divided into three samples based on places where they were taken in the landfill area, namely sample I, II and III. Heavy Metals content in the solution were measured by Atomic Absorption Spectrophotometer (AAS).The results showed the highest heavy metal content in soil was Zn. Sample II had the highest Zn value at 1,199 mg kg-1, whereas sample I had the lowest total Zn content of 708.54 mg kg-1.


2011 ◽  
Vol 04 (02) ◽  
pp. 123-127 ◽  
Author(s):  
MUNEHIRO KIMURA ◽  
KONRAD ŚWIERCZEK ◽  
JACEK MARZEC ◽  
JANINA MOLENDA

In this work we present results of measurements of structural (XRD), microstructural (SEM, EDX, TEM) and transport (electrical conductivity, Seebeck coefficient) properties as well as results of Mössbauer and FTIR spectroscopy studies of phospho-olivine materials with assumed chemical composition Li 1-3x Al x FePO 4 (x = 0, 0.001, 0.005, 0.01, 0.02, 0.05 and 0.1). Based on the performed research, possibility of lithium sublattice doping by Al is discussed. Additionally, initial results of electrochemical tests of lithium batteries with obtained, phospho-olivine based cathode materials are provided.


2018 ◽  
Vol 10 (7) ◽  
pp. 196 ◽  
Author(s):  
Rogério Marcos de Oliveira Alves ◽  
Jacqueline Lemos Viana ◽  
Henrique de Abreu Cerqueira Sousa ◽  
Ana Maria Waldschmidt

The physico-chemical properties of honey produced by the stingless bee Melipona mondury from Atlantic Forest in the state of Bahia, northeastern Brazil were evaluated. The evaluated characteristics included: water content, electrical conductivity, pH, acidity, water activity, ashes, diastase, hydroxymethylfurfural (HMF), reducing sugars and saccharose values. The honey samples showed mean values of 29.18% for moisture; 391.5 μS for electrical conductivity; pH of 4.06; 34.3 meq kg-1 for acidity; 0.73 for water activity; 0.18% for ashes; 4.05 (Goethe unit) for diastase; 1.60% for HMF; 65.42% for reducing sugars; and 2.14% of saccharose. Only the diastase activity was above the limits accepted by the Technical Regulation for Identity and Quality of Honey (Brazilian Ministry of Agriculture and Supplies). Most parameters are according to those reported in honeys from other species of stingless bees in Brazil.


2021 ◽  
Author(s):  
Johannes Neuhaus ◽  
Erik von Harbou ◽  
Hans Hasse

Battery performance strongly depends on the choice of the electrolyte-solvent system. Lithium bis(fluorosulfonyl)imide (LiFSI) is a highly interesting novel electrolyte. Information on physico-chemical properties of solutions of LiFSI, however, is scarce. Therefore, the density, shear viscosity, and electrical conductivity of solutions of LiFSI in three pure solvents that are interesting for battery applications: dimethyl carbonate (DMC), ethylene carbonate (EC), and propylene carbonate (PC), were studied experimentally at temperatures between 273 K and 333 K at 1 bar and concentrations of LiFSI up to 0.45 mol mol−1 in the present work. Empirical correlations of the experimental data are provided. The comparison of the data of this work with the corresponding LiPF6 data underpins the attractiveness of LiFSI as an electrolyte in lithium ion batteries.


Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 89 ◽  
Author(s):  
Jian Li ◽  
Pablo Jiménez-Calvo ◽  
Erwan Paineau ◽  
Mohamed Nawfal Ghazzal

The photo-conversion efficiency is a key issue in the development of new photocatalysts for solar light driven water splitting applications. In recent years, different engineering strategies have been proposed to improve the photogeneration and the lifetime of charge carriers in nanostructured photocatalysts. In particular, the rational design of heterojunctions composites to obtain peculiar physico-chemical properties has achieved more efficient charge carriers formation and separation in comparison to their individual component materials. In this review, the recent progress of sulfide-based heterojunctions and novel nanostructures such as core-shell structure, periodical structure, and hollow cylinders is summarized. Some new perspectives of opportunities and challenges in fabricating high-performance photocatalysts are also discussed.


Author(s):  
S. L. Gbarakoro ◽  
T. N. Gbarakoro ◽  
W. L. Eebu

Aim: This research work aimed to determine the impact of industrial effluent discharge on the physicochemical properties of Aleto Stream, Eleme and Rivers State. Study Design: Random sampling technique was applied in this study. The study area was divided into three sites; upstream, downstream all of Aleto Stream and Agbonchia Stream which serves for the control experiment. Water samples for eleven physical and six chemical parameters were collected in a Completely Randomized Design. Place and Duration of Study: This study was carried out on Aleto and Agbonchia streams at Eleme, Rivers State, Nigeria from 2017 to 2018. Methodology: Two samples were collected; one sample at the Aleto stream where the industrial effluent is being channelled into the stream and the other sample was collected from Agbonchia stream, which was used as a control. In the Aleto Stream, sampling was made at two points; point A (upstream) point B (downstream) and each of these points had their Physico-chemical properties tested while only one sample was collected from the Agbonchia Stream. Physico-chemical properties were analyzed in the samples using pH meter for pH, Turbidity meter for turbidity, Conductivity meter for electrical conductivity, phosphate by colourimetric method, total dissolved solids (TDS) and total suspended solids (TSS) by gravimetric method, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) by standard method, chloride, alkalinity, dissolved oxygen (DO), calcium hardness, total hardness by titrimetric method, colour, odour and taste by sensory method. Results: Results obtained on the Physico-chemical properties had varying concentrations of Temperature, Total hardness, Chloride, Alkalinity, DO and Phosphate that were within world health organization (24)  and Federal Ministry of Environment (1991) permissible limits on both upstream and downstream with values ranging from 29.0-23.7oC, 360-125 mg/l, 120-100 mg/l, 36-30 mg/l, 4.9-4.4 mg/l, 1.92-1.2 mg/l respectively while Electrical conductivity, Turbidity, TSS, TDS, Calcium hardness, COD, BOD, Colour, Taste and Odour were above permissible limits on both upstream and downstream with values ranging from 1660-1700 mg/l, 83-112NTU, 82-80 mg/l, 910-914 mg/l, 1590-1900 mg/l, 100-165 mg/l, 4.36-3.88 mg/l respectively. The pH values ranged from 9.0-6.3 mg/l showing a result on the upstream to be alkaline while the downstream was slightly acidic. The increase in the above parameters above their permissible limits is as a result of the impact of industrial effluent discharges drained into the stream. This indicates that the stream is unfit for both human and aquatic inmates. Conclusion: Therefore, proper management of this effluent should be ensured and an acute test with lethal concentration (LC50) as the endpoint is recommended to determine the degree of toxicity of the effluent waste.


2019 ◽  
Vol 20 (1) ◽  
pp. 77-82
Author(s):  
A.L. Stepura ◽  
O.I. Aksimentyeva ◽  
P.Yu. Demchenko

Features of crystal structure, electrical conductivity and thermal stability of poly-ortho-toluidine (PoTi) samples, obtained with method of oxidative polymerization in the environment of sulfuric and toluenesulfonic acids (TSA), were investigated. It was discovered that PoTi-TSA samples are characterized withhigh crystallinity. According to the physico-chemical analysis, doping samples with TSA causes increase of PoTi thermal stability, electrical conductivity and sensor sensitivity on the contrary to samples doped with sulfuric acid. Based on temperature dependence of specific resistance, were calculated the values of the conductivity activation energy, which are within the limits of 0.2-0.4 eV depending on the type of dopant.


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