The Influence of Different Ph Values and High Concentrations of Na2SO4 and NaCl on the Photocatalytic Oxidation (PCO) of Methylene Blue (MB) by Aqueous Suspension of Nano-Sized TiO2

2012 ◽  
Vol 490-495 ◽  
pp. 3892-3896
Author(s):  
Yu Ping Jiang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Oxidation ◽  
High Salinity ◽  
Aqueous Suspension ◽  
Ion Concentration ◽  
Ph Values ◽  
Orthogonal Experiments ◽  
Degradation Rates ◽  
The Difference ◽  
High Concentrations

To study the PCO of high-salinity organic wastewater, nano-sized TiO2 was used for PCO of MB in solutions with different pH values and high concentrations of Na2SO4 or NaCl. The rates of PCO were monitored by total organic carbon (TOC) measurement. The results showed that the degradation rates increased with increasing pH and decreased as the concentration of Na2SO4 or NaCl increased. The difference of degradation rates in Na2SO4 or NaCl aqueous solutions increased as the ion concentration increased. In the orthogonal experiments, the rates decreased remarkably under certain ratios of the ions concentration. The mechanisms were explored in some detail.

scholarly journals Study of photocatalytic activity of TiO2 fluorinated by thermal shock method for the degradation of different dyes

2015 ◽  
Vol 18 (2) ◽  
pp. 121-131
Author(s):  
Khoa Tien Le ◽  
Ngoc Chau Hoang ◽  
Tien Thuy Thai ◽  
Anh Trung Le ◽  
Thinh Nguyen Huu Pham ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Thermal Shock ◽  
Photocatalytic Oxidation ◽  
Organic Dyes ◽  
Cationic Dye ◽  
Solution Ph ◽  
Ph Values ◽  
Methylene Blue Cationic Dye

TiO2 P25 was fluorinated by thermal shock method in order to study the influence of thermal shock fluorination on the surface properties and the photocatalytic activity for the degradation of cationic and anionic organic dyes at different pH values. The surface charge of catalysts was characterized by the pHPZC measurement. The photocatalytic activity of catalysts was evaluated via the degradation of methylene blue (cationic dye) and methyl orange (anionic dye). The results showed that the thermal shock fluorination and the rise of solution pH can increase the surface negative charge of TiO2, which enhanced the adsorption of methylene blue and then improved the photocatalytic degradation of this cationic dye under UV and visible light. On the other hand, after the fluorination, the adsorption of methyl orange on TiO2 was strongly reduced, which limited the photocatalytic oxidation of this anion dye.

scholarly journals Aqueous Photocatalytic Oxidation of Lignin: The Influence of Mineral Admixtures

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Elina Portjanskaja ◽  
Sergei Preis
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Oxidation ◽  
Catalyst Support ◽  
Oxidation Mechanism ◽  
Ion Concentration ◽  
Mineral Admixtures ◽  
Oh Radicals ◽  
Ferrous Ions ◽  
The Difference ◽  
The One

The photocatalytic oxidation (PCO) of UV-irradiated aqueous solutions containing lignin onTiO2was studied for the influence of ferrous ions. The addition ofFe2+, up to 2.8 mgL−1, to the acidic lignin solution leads to the drastic, for about 25%, increase in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in PCO efficiency of lignin. The maximum PCO efficiency, up to 9.2 mgW−1h−1, was observed in neutral and slightly basic media: the oxidation mechanism with OH-radicals seems to prevail. Also, the difference in the PCO performance with a different attachment mode of titanium dioxide on the catalyst support was observed. Sprayed catalyst exhibited 1.5 times higher efficiency than the one attached by submersion, although sprayed one was easily resuspended in acidic lignin solutions. The efficiency of the N-doped photocatalyst active in visible light was observed to be negligible with lignin.

scholarly journals Effect of Shatt Al-Arab Salinity on the Groundwater of Al-Fao and Al-Siba in Southern Iraq

2021 ◽  
Vol 54 (1E) ◽  
pp. 114-122
Author(s):  
Shahad Abdul-Hameed ◽  
Amal Jabbar Hatem
Keyword(s):  
Electrical Conductivity ◽  
High Salinity ◽  
Saline Water ◽  
Arabian Gulf ◽  
Karun River ◽  
Ph Values ◽  
High Concentrations ◽  
Extent Of Damage ◽  
Southern Iraq ◽  
Very High

This study was conducted to estimate the extent of damage to the population in Basra, southern Iraq, specifically the areas adjacent to the Shatt al-Arab and the Arabian Gulf, which are the Al-Fao district and the Al-Siba region. They are affected by the progression of saline water resulting from the lack of water imports and the Karun River interruption, which led to high concentrations of salts in the Shatt Al-Arabs. Consequently, its effect on lands and all life types in these areas requires correcting a map of the study area to drop the groundwater sites as well as calculate the total dissolved salts, electrical conductivity and pH. This study concluded that the groundwater contains very high percentages of total dissolved solids (2880–10415 mg/l) and electrical conductivity (4450–14190 µs/cm). As it has very high salinity, so it is not suitable for drinking, irrigation, or industry. The values of the pH values (7.1-7.5) indicate that it is a light alkaline.

scholarly journals Effect of electrolyte conductivity and local electric field inhomogeneity on heating of an aqueous suspension of solid-state nanoparticles

2021 ◽  
Vol 2058 (1) ◽  
pp. 012019
Author(s):  
A A Grigoriev ◽  
I N Zavestovskaya ◽  
Yu V Kargina ◽  
A Yu Kharin ◽  
A P Kanavin ◽  
...  
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Radio Frequency ◽  
Heat Release ◽  
Aqueous Suspension ◽  
Dielectric Constants ◽  
Ion Concentration ◽  
Radio Frequency Radiation ◽  
Proposed Model ◽  
The Difference

Abstract This work theoretically investigates the process of heat release in an electrolyte near a solid-state nanoparticle when exposed to an external radio-frequency electromagnetic field. The effect on the heat release of the effect of a change in the electrical conductivity of the electrolyte near the nanoparticle due to the redistribution of the ion concentration and the inhomogeneity of the electric field caused by the difference in the dielectric constants of the electrolyte and the nanoparticle is taken into account. The proposed model can be useful for choosing the optimal parameters of nanoparticles and radio frequency radiation when used in biomedicine for tumor hyperthermia.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Comparative Analysis of Different Local Anesthetic Solutions Available in Market: An In Vitro and Clinical Study

2021 ◽  
Author(s):  
Eisha Imran ◽  
Faisal Moeen ◽  
Beenish Abbas ◽  
Bakhtawar Yaqoob ◽  
Mehreen Wajahat ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Local Anesthetic ◽  
Compositional Analysis ◽  
Bacterial Activity ◽  
Similar Composition ◽  
Ph Values ◽  
Significant Difference ◽  
The Mean ◽  
The Difference

Abstract Objectives The study aimed to evaluate and compare various commercially available local anesthetic solutions. Materials and Methods A total of 150 commercially available local anesthetic cartridges of similar composition (2% lidocaine with epinephrine 1:100,000) were randomly collected and divided into 3 groups. The designations of groups were selected from their product names such that each group consisted of 60 cartridges. Group S (Septodont, France) Group M (Medicaine, Korea) and Group H (HD-Caine, Pakistan). The samples were divided into five sub-groups, each consisting of 10 cartridges from each group to investigate each parameter. Results The acquired data was statistically analyzed and compared (using SPSS version 12). Compositional analysis revealed a non-significant (P>0.05) difference when the three Groups were compared with standard lidocaine and epinephrine solutions. The mean pH values of samples from group S, M and H respectively fell within the range of pH values of commercially available solutions. Non-significant difference in EPT values of Group S and H was found when efficacy was compared (p = 0.3), however a significant difference (p < 0.01) was observed in contrast to Group M. Anti-bacterial activity was observed in all the group and a non-significant difference in cell viability values of Group S and M was found (p = 0.6), while the difference was significant in comparison to Group H. Conclusion Within the limitations of these investigations, it appears that the properties of different manufacturers fall within the recommended ranges as mentioned in literature and do not appear to be statistically different in the variables we have tested.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Effects of Surface Properties and Solvent PH Values on the Adsorption/Desorption Abilities of Mesoporous SBA-15 to Methylene Blue Molecules

2012 ◽  
Vol 518-523 ◽  
pp. 352-355
Author(s):  
Hui Liu ◽  
Hong Liang Li ◽  
Meng Xue Wang ◽  
Jing Jing Sang ◽  
Xiu Song Zhao
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Properties ◽  
Weak Base ◽  
Adsorption Ability ◽  
Ph Values ◽  
Model Molecule ◽  
Adsorption Desorption

Methylene blue (MB) was used as model molecule to investigate the effects of surface properties and solvent pH values on the adsorption and desorption (or release) behaviors of mesoporous SBA-15 materials. It was found that the treatment of SBA-15 with a pH 7.8 aqueous solution can enhance the adsorption rate and capacity in comparison with the pristine SBA-15. The effect of pH values on MB releasing from the weak base treated SBA-15 and the pristine one have been studied and been compared in pH values range from 0.5 to 7.0. Both of them showed a maximum releasing rate at about pH 2 and all of the treated SBA-15 samples showed a higher releasing quantity than the pristine ones. The influence mechanisms of base treatment on the adsorption ability and that of pH values on the releasing properties of SBA-15 samples have been analyzed and been discussed based on the composition, the morphology, the surface area and pore size distribution and adsorption/desorption measurements.

scholarly journals Thunderstorm outflows preceding epidemics of asthma during spring and summer

Thorax ◽  
2001 ◽  
Vol 56 (6) ◽  
pp. 468-471
Author(s):  
G B Marks ◽  
J R Colquhoun ◽  
S T Girgis ◽  
M Hjelmroos Koski ◽  
A B A Treloar ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Ground Level ◽  
Fold Increase ◽  
Underlying Mechanism ◽  
Detailed Examination ◽  
Asthma Exacerbations ◽  
Eastern Australia ◽  
The Difference ◽  
High Concentrations ◽  
Thunderstorm Outflow

BACKGROUNDA study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism.METHODSA case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations.RESULTSThunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4–12 fold increase in the ambient concentration of grass pollen grains.CONCLUSIONSThese findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.

scholarly journals The genomic sequence ofExiguobacterium chiriqhuchastr. N139 reveals a species that thrives in cold waters and extreme environmental conditions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3162 ◽  
Author(s):  
Ana Gutiérrez-Preciado ◽  
Carlos Vargas-Chávez ◽  
Mariana Reyes-Prieto ◽  
Omar F. Ordoñez ◽  
Diego Santos-García ◽  
...  
Keyword(s):  
Acid Metabolism ◽  
High Salinity ◽  
Genomic Sequence ◽  
Ultraviolet B ◽  
Comparative Genomic ◽  
Ultraviolet B Radiation ◽  
Genomic Analyses ◽  
High Concentrations ◽  
And Coping ◽  
Cold Lake

We report the genome sequence ofExiguobacterium chiriqhuchastr. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of theExiguobacteriumgenomes available suggest that our strain belongs to the same species as the previously reportedE. pavilionensisstr. RW-2 andExiguobacteriumstr. GIC 31. We describe this species and propose thechiriqhuchaname to group them. ‘Chiri qhucha’ in Quechua means ‘cold lake’, which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bpE. chiriqhuchastr. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that conferE. chiriqhuchastr. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals, high ultraviolet B radiation, scavenging for phosphorous and coping with high salinity. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina.

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