scholarly journals Modified lead dioxide for organic wastewater treatment: Physicochemical properties and electrocatalytic activity

2019 ◽  
Vol 84 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Olesia Shmychkova ◽  
Tatiana Luk’yanenko ◽  
Larisa Dmirtikova ◽  
Alexander Velichenko

An investigation is reported on lead dioxide electrodeposition from methanesulfonate electrolytes additionally containing Ni2+ ions. It is shown that lead dioxide electrodes micromodified by nickel have different physico-chemical properties vs. nonmodified PbO2-anodes that are formed during the deposition. Electrocatalytical reactivity of electrodes involved in comparison to both the oxygen evolution, as well as to the electrooxidation of 2,4- dichlorophenoxyacetic (2,4-D) acid is investigated. Processes of electrochemical oxidation of 2,4-D on various materials occur qualitatively with the same mechanism and differ only in the rate. It is shown that the Ni-PbO2-anode possesses the highest electrocatalytic activity: the destruction rate of 2,4-D on it increases in 1.5 times in comparison with nonmodified lead dioxide. The COD of a 0.4 mM solution of 2,4-D, determined by the dichromate method, is 90.0 mg dm-3 which is 94 % of the theoretical value.

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 678
Author(s):  
Stefano Alberti ◽  
Irene Basciu ◽  
Marco Vocciante ◽  
Maurizio Ferretti

In this contribution, the photoactivity upon activation by simulated sunlight of zinc oxide (ZnO) obtained from two different synthetic pathways (Acetate and Nitrate) is investigated for water purification. Different reagents and processes were exploited to obtain ZnO nanoparticles. Products have been characterized by means of X-Ray Diffraction, Scanning Electron Microscopy along with Energy Dispersive Spectrometer, Dynamic Light Scattering, and Diffuse Reflectance Measurements, to highlight the different outcomes ascribable to each synthesis. A comparison of characteristics and performances was also carried out with respect to commercial ZnO. Nanoparticles of this semiconductor can be obtained as aggregates with different degrees of purity, porosity, and shape, and their physical-chemical properties have been addressed to the specific use in wastewater treatment, testing their effectiveness on the photocatalytic degradation of methylene blue (MB) as a model pollutant. Excluding the commercial sample, experimental results evidenced a better photocatalytic behavior for the ZnO Nitrate sample annealed at 500 °C, which was found to be pure and stable in water, suggesting that ZnO could be effectively exploited as a heterogeneous photocatalyst for the degradation of emerging pollutants in water, provided that thermal treatment is included in the synthetic process.


2021 ◽  
Vol 134 (3) ◽  
pp. 11-17
Author(s):  
I. G. Yashchenko ◽  
◽  
Y. M. Polishchuk ◽  

The article is devoted to the urgent problem of studying the features of the properties of poorly studied oils at great depths (more than 4,500 m), the need for development of which is caused by the continuing decline in oil production in traditional oil producing provinces. The analysis of the spatial distribution of reserves across the continents and countries of deep-seated oils and changes in their physico-chemical properties and the occurrence conditions, which made it possible to identify their main features. The studies used information on 21067 oil samples from 167 oil-bearing basins of the world, obtained from the database on the physicochemical properties of oils. The features of the physicochemical properties of deep-seated oils have been established, which are manifested in a decrease in the density and viscosity of oils, in a decrease in the content of sulfur and asphalt-resinous substances, and in an increase in the content of light fractions and oil gas in comparison with oils of small and medium depths.


RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19828-19836 ◽  
Author(s):  
Li Yuan ◽  
Jiamei Yu ◽  
Jianlou Mu ◽  
Tong Shi ◽  
Quancai Sun ◽  
...  

This work studied the effects of KGM with different degrees of deacetylation (DDs) on the physicochemical properties of silver carp (Hypophthalmichthys molitrix) surimi gels.


2018 ◽  
Vol 6 (30) ◽  
pp. 14663-14674 ◽  
Author(s):  
Sander Ratso ◽  
Nastaran Ranjbar Sahraie ◽  
Moulay Tahar Sougrati ◽  
Maike Käärik ◽  
Mati Kook ◽  
...  

We study the physico-chemical properties and electrocatalytic activity towards oxygen reduction of two Fe–N–C catalysts based on carbide derived carbon.


2020 ◽  
Vol 12 (1) ◽  
pp. 105-107 ◽  
Author(s):  
Amar Nath ◽  
P. P. Pande

Now-a-days synthetic polyelectrolytes are frequently used by the industries in the treatment of industrial effluents. Such materials have a variety of properties such as easily changeable structure as per the specific requirement, higher purity, highstability and have more efficiency than the natural polymers. These polymers do not add any solid residue in the sludge, exhibit no change in the physico-chemical properties of the treated water and therefore this water may be recycled. Polyacrylamide is a synthetic polyelectrolyte which is hydrophilic in nature and insoluble in organic solvents. It has very high affinity towards the suspended particles present in water. Therefore, polyacrylamide based polymers are highly effective for the flocculation of suspended contaminated particle present in the effluents. Polyacrylamide is very important polymer for wastewater treatment which enhances the flocculation potential by modification of its nature into non-ionic, anionic and cationic forms.


2020 ◽  
Vol 13 (1/2) ◽  
pp. 29-35
Author(s):  
Tatiana LUK’YANENKO ◽  
◽  
Olesia SHMYCHKOVA ◽  
Svitlana ZAHORULKO ◽  
Alexander VELICHENKO ◽  
...  

Author(s):  
Meysam Shirmohammadi ◽  
Esmat Mohammadinasab ◽  
Zakiyeh Bayat

: In the present study the applicability of various molecular descriptors was tested for the QSPR study on 40 quinolones derivatives. The relationship between some of the molecular indices with physicochemical properties such as refractive index (n), polarizability (α) and HOMO-LUMO energy gap (ΔEH-L) was represented. At first, the chemical structure of quinolones derivatives was optimized by Gaussian 98 program and ab initio method at the #HF/6-31++G**level, and then the physicochemical properties such as refractive index, polarizability and HOMO-LUMO energy gap were calculated. Genetic algorithm using multiple linear regression (GA-MLR) with backward method by SPSS software was used for obtaining properties. The analytical powers of the established theoretical models were discussed using leave-one-out (LOO) cross-validation technique. A multi-parametric equation containing maximum three descriptors with suitable statistical qualities was obtained for predicting the studied properties.


2014 ◽  
Vol 79 (2) ◽  
pp. 133-150
Author(s):  
Adriana Isvoran ◽  
Dana Craciun ◽  
Alecu Ciorsac ◽  
Nahuel Perrot ◽  
Veronica Beswick ◽  
...  

We performed a bioinformatics study to predict and compare the structural and functional properties of human caveolins: caveolin-1, -2 and -3. The computed local physico-chemical properties, predictions of their secondary structure elements and interacting partners of caveolin-2 and -3 are compared to experimentally proved structural and functional properties of caveolin-1. These data combined with the sequences alignment of the three caveolins, allowed predicting and characterizing the functional domains of caveolin-2 and -3. The hydrophobic regions of these proteins are highly similar in sequences and physicochemical properties and it is in good agreement with their known membrane locations and functions. The most divergent in sequences and properties are the C-terminal regions of caveolins suggesting that they might be responsible for their distinct predicted interactions, with direct consequences on signalling processes.


2019 ◽  
Vol 37 ◽  
Author(s):  
A.C.D. GUIMARÃES ◽  
K.F. MENDES ◽  
T.F. CAMPION ◽  
P.J. CHRISTOFFOLETI ◽  
V.L. TORNISIELO

ABSTRACT: Leaching intensity depends on the physicochemical properties of soils and herbicides. Consequently, a good understanding of this process is essential to determine mitigation measures to reduce or eliminate the risk of water contamination around areas with sugarcane crops. Therefore, the objective of this study was to analyze the leaching of ametryn, diuron, hexazinone, and metribuzin by using columns in five soils with different physicochemical properties cultivated with sugarcane. The radiolabeled herbicides with 14C were evaluated at six soil depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.25, and 0.25-0.30 m) and in the leachate after 200 mm rainfall simulation for 48 h. Herbicide leaching was mostly affected by soil type. Ametryn and diuron were reported in the highest amount (>87%) on the topsoil (0-0.05 m), which was indicative of the low leaching of these two herbicides in the soil profile. Thus, these herbicides can contaminate surface water by runoff. Leachate percentage was always <0.3% for ametryn, diuron, and metribuzin; this was also the case for hexazinone in two out of the five soils. Hexazinone proved to be a potential contaminant of groundwater and metribuzin presented high leaching in the soil profile. Previous knowledge of the physico-chemical properties of soils cultivated with sugarcane is essential to recommend the use of these herbicides in weed management.


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