scholarly journals Host-Guest Interaction between Herbicide Oxadiargyl and Hydroxypropyl-β-Cyclodextrin

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sofia Benfeito ◽  
Tiago Rodrigues ◽  
Jorge Garrido ◽  
Fernanda Borges ◽  
E. Manuela Garrido
Keyword(s):  
Aqueous Media ◽  
Industrial Effluents ◽  
Ultrapure Water ◽  
Buffer Solutions ◽  
Water Treatment Plants ◽  
Pesticide Formulations ◽  
The Face ◽  
Ph Buffer ◽  
Environmentally Sound ◽  
And Storage

In the face of a growing human population and increased urbanization, the demand for pesticides will simply rise. Farmers must escalate yields on increasingly fewer farm acres. However, the risks of pesticides, whether real or perceived, may force changes in the way these chemicals are used. Scientists are working toward pest control plans that are environmentally sound, effective, and profitable. In this context the development of new pesticide formulations which may improve application effectiveness, safety, handling, and storage can be pointed out as a solution. As a contribution to the area, the microencapsulation of the herbicide oxadiargyl (OXA) in (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) was performed. The study was conducted in different aqueous media (ultrapure water and in different pH buffer solutions). In all cases an increment of the oxadiargyl solubility as a function of the HP-β-CD concentration that has been related to the formation of an inclusion complex was verified. UV-Vis and NMR experiments allowed concluding that the stoichiometry of the OXA/HP-β-CD complex formed is 1 : 1. The gathered results can be regarded as an important step for its removal from industrial effluents and/or to increase the stabilizing action, encapsulation, and adsorption in water treatment plants.

PREDICTIVE SIMULATION AND OPTIMIZATION ORIENTED MODELING FOR THE EXTRACTION OF METAL IONS FROM SOLUTIONS INTO A NOVEL BIS-SCHIFF BASE

2019 ◽  
pp. 1-8
Author(s):  
F. S. Nworie ◽  
S. O. Ngele ◽  
J. C. Onah
Keyword(s):  
Metal Ions ◽  
Metal Concentration ◽  
Acid Concentration ◽  
Aqueous Media ◽  
Industrial Effluents ◽  
Ligand Concentration ◽  
Simulation And Optimization ◽  
Chemometric Technique ◽  
Model Equations ◽  
Level Of Significance

Metal ions present in waste samples, industrial effluents, acid mines and other aqueous media constitute a serious challenge in different human activities. Solvent extraction a technique for preconcentration, separation and identification of trace amount of metal ions coupled with multivariate chemometric technique was used for the determination of Fe(II) and Cr(III) from solutions in the presence of bis(salicylidene)ethylenediamine (SALEN). The influence of main extraction variables affecting the extraction efficiency was simultaneously studied and regression model equations illustrating the relationship between variables predicted. The extraction parameters (time of extraction, acid concentration, ligand concentration, temperature and metal concentration) were optimized using experimental designs with the contributions of the various parameters to extraction of the metal ions bound to the complexone evaluated using SPSS19.0 software. The statistically determined simulated models for the parameters were R2 = 0.946, 0.727, 0.793, 0.53, 0.53, 1.000 and F- values of 70.400, 13. 285, 15.348, 4.646 and 2.569×105 respectively for time of extraction, acid concentration, ligand concentration, temperature and metal concentration for Cr (III). For Fe (II), R2 = 0.243, 0.371, 0.519, 0.446, 1.000 and F-values of 0.964, 2.953, 4.310, 3.216 and 2.516×105 for time of extraction, acid concentration, ligand concentration, temperature and metal concentration respectively. The level of significance of the models as predicted was both lower than 5% making it feasible, efficient, reproducible and accurate. This means that metal ions at the conditions stated could be removed from waste samples, industrial effluents, acid mines and other aqueous media with extension in industrial scale application.

scholarly journals Photocatalytic Degradation of Sulfolane Using a LED-Based Photocatalytic Treatment System

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 624
Author(s):  
Sripriya Dharwadkar ◽  
Linlong Yu ◽  
Gopal Achari
Keyword(s):  
Photocatalytic Degradation ◽  
Oil And Gas ◽  
Light Emitting Diode ◽  
Tap Water ◽  
Aqueous Media ◽  
Ultrapure Water ◽  
Light Emitting ◽  
Degradation Rates ◽  
Reduced Graphene ◽  
The Impact

Sulfolane is an emerging industrial pollutant detected in the environments near many oil and gas plants in North America. So far, numerous advanced oxidation processes have been investigated to treat sulfolane in aqueous media. However, there is only a few papers that discuss the degradation of sulfolane using photocatalysis. In this study, photocatalytic degradation of sulfolane using titanium dioxide (TiO2) and reduced graphene oxide TiO2 composite (RGO-TiO2) in a light-emitting diode (LED) photoreactor was investigated. The impact of different waters (ultrapure water, tap water, and groundwater) and type of irradiation (UVA-LED and mercury lamp) on photocatalytic degradation of sulfolane were also studied. In addition, a reusability test was conducted for the photocatalyst to examine the degradation of sulfolane in three consecutive cycles with new batches of sulfolane-contaminated water. The results show that LED-based photocatalysis was effective in degrading sulfolane in waters even after three photocatalytic cycles. UVA-LEDs displayed more efficient use of photon energy when compared with the mercury lamps as they have a narrow emission spectrum coinciding with the absorption of TiO2. The combination of UVA-LED and TiO2 yielded better performance than UVA-LED and RGO-TiO2 for the degradation of sulfolane. Much lower sulfolane degradation rates were observed in tap water and groundwater than ultrapure water.

A Theoretical and Experimental Approach to E-pH Diagram for the Niobium-Water System

CORROSION ◽  
10.5006/3871 ◽  
2021 ◽  
Author(s):  
Rodney Santandrea ◽  
Simone BRASIL ◽  
Leila Reznik ◽  
Ladimir Carvalho ◽  
Luiz Miranda
Keyword(s):  
Experimental Approach ◽  
Ph Monitoring ◽  
Aqueous Media ◽  
Water System ◽  
Chemical Species ◽  
Polarization Curves ◽  
Buffer Solutions ◽  
Excellent Corrosion Resistance ◽  
Experimental Diagram ◽  
Selection Of

E-pH diagrams are usually built from thermodynamic databases available in the literature or from specific software. However, depending on the conditions and the chemical species defined for elaborating a diagram, it may present completely different immunity, passivation, and corrosion domains. In order to obtain a result closer to a real system, experimental E-pH diagrams can be built from polarization curves obtained in the evaluated conditions. This work discloses the construction of a diagram for the Nb-H<sub>2</sub>O system at 25°C from theoretical study and the specific selection of chemical species in the solutions through computer simulations. The polarization curves for the construction of the experimental diagram were gathered without the use of buffer solutions and under pH monitoring in the solution bulk throughout all assays. The methodology proposed was considered adequate since, from experimental data, a final result compatible with the classic diagram for the Nb-H<sub>2</sub>O system and the excellent corrosion resistance of niobium in aqueous media were achieved.

scholarly journals Colour properties of cigarette smoke-exposed cotton and silk fabrics and their nicotine release

2018 ◽  
Vol 69 (04) ◽  
pp. 328-333
Author(s):  
NONGNUCH WANTANEEPORN ◽  
SUWANRUJI POTJANART ◽  
SETTHAYANOND JANTIP
Keyword(s):  
Cigarette Smoke ◽  
Cotton Fabric ◽  
Potential Risk ◽  
Aqueous Media ◽  
Colour Change ◽  
Colour Properties ◽  
Buffer Solutions ◽  
Colour Strength ◽  
Dyed Fabrics ◽  
Silk Fabrics

Exposure to cigarette smoke caused colour change to undyed cotton and silk fabrics by a yellowing effect. The degree of yellowing was more dominant on cotton fabric. When the dyed fabrics were subjected to cigarette smoke, a more pronounced effect was observed on the pale shade dyed fabrics. Shade alteration was inversely related to the colour strength of the dyed fabrics. In addition, a longer exposure time also induced colour change in the fabrics while the colour strength of the dyed fabrics was unaffected. Nicotine release from the cigarette smoke-exposed fabrics in the wet state was studied in different aqueous media, viz. water, buffer solutions (pH 5.5 and 8.0) and artificial sweats (acid and alkaline) in order to reflect the potential risk to textile users of the toxicants from textiles contaminated with cigarette smoke.

scholarly journals Visible Light Induced Enhanced Photocatalytic Degradation of Industrial Effluents (Rhodamine B) in Aqueous Media Using TiO2Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
J. O. Carneiro ◽  
A. P. Samantilleke ◽  
P. Parpot ◽  
F. Fernandes ◽  
M. Pastor ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Colloidal Stability ◽  
Titanium Dioxide Nanoparticles ◽  
Aqueous Media ◽  
Research Work ◽  
Industrial Effluents ◽  
Intermediate Compound ◽  
X Ray Diffraction ◽  
Textile Materials

In recent years, new textile materials have been developed through the use of nanotechnology-based tools. The development of textile surfaces with self-cleaning properties has a large combined potential to reduce the environmental impact related to pollution. In this research work, three types of textiles substrates (cotton, Entretela, and polylactic acid (PLA)) were functionalized with titanium dioxide nanoparticles (TiO2) using chemical and mechanical processes (padding). During the functionalization process, two different methods were used, both of which allowed a good fixation of nanoparticles of TiO2on textile substrates. The samples were examined for morphology and for photocatalytic properties under visible light irradiation. A study aimed at evaluating the effect of pH of the aqueous solution of TiO2nanoparticles was performed in order to promote interaction between TiO2and the dye solution rhodamine B (Rh-B). The TiO2nanoparticles were characterized by X-ray diffraction (XRD). The measurement of the zeta potential of the TiO2nanoparticle solution proved to be always positive and have low colloidal stability. Chromatography (HPLC and GC-MS) analyses confirm that oxalic acid is the intermediate compound formed during the photodegradation process.

Effect of CMP Pad Exposure to Aqueous Media on the Pad Properties. Part 1. Dynamic Mechanical and Modulated DSC Analysis

2002 ◽  
Vol 732 ◽  
Author(s):  
A. Tregub ◽  
M. Moinpour ◽  
J. Sorooshian
Keyword(s):  
Aqueous Media ◽  
Mechanical Analysis ◽  
Fickian Diffusion ◽  
Modulated Dsc ◽  
Buffer Solution ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Ph Buffer Solution ◽  
Ph Buffer

AbstractSoaking of polyurethane-based CMP pad in oxide slurry, de-ionized water, and pH buffer solution, and its effect on thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis and Modulated Differential Scanning Calorimetry. Pad softening due to soaking was established, and softening mechanisms are discussed. Diffusion of the aqueous medias to polyurethane pad was described using Fickian diffusion model.

Morphological and Electrical Properties of Silicon Dioxide-Based Interdigitated Electrode Arrays

2015 ◽  
Vol 1109 ◽  
pp. 253-256 ◽  
Author(s):  
M.A. Farehanim ◽  
U. Hashim ◽  
Norhayati Soin ◽  
A.H. Azman ◽  
S. Norhafiezah ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Silicon Dioxide ◽  
Ph Value ◽  
Ph Measurement ◽  
Electrode Arrays ◽  
Interdigitated Electrode ◽  
Buffer Solutions ◽  
Ph Values ◽  
Ph Buffer ◽  
Higher Sensitivity

The electrical performances of silicon dioxide-based Interdigitated electrodes (IDEs) as biosensor were developed. The IDEs was made up by two individually addressable Interdigitated comb-like finger structure have frequently been suggested as a biosensor which promises higher sensitivity compared to conventional parallel electrodes. The purpose of this paper was to investigate the capacitance test and impedance test to taken with various pH solution to observe the response of the sensor with different pH values. Purchased pH buffer solutions which varied from pH2 to pH10 are dropped on the microelectrode and the effect on it is investigated for the application in pH measurement. This research has proven that increase in pH value from acidic to alkaline is proportional with capacitance. The measured values of capacitance with respect to each pH concentrations applied during the measurements were repeatable and reproducible.

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