Influence of UV‐irradiation intensity and exposure duration on the hemobiocompatibility enhancement of a novel synthesized phosphobetaine zwitterions polyethersulfone clinical hemodialysis membranes

2021 ◽  
Author(s):  
Ubong Eduok ◽  
Heloisa Camara ◽  
Amira Abdelrasoul ◽  
Ahmed Shoker
Keyword(s):  
Uv Irradiation ◽  
Exposure Duration ◽  
Irradiation Intensity

scholarly journals UV Irradiation and Ozone Treatment of κ-Carrageenan: Kinetics and Products Characteristics

2020 ◽  
Vol 15 (2) ◽  
pp. 319-330 ◽  
Author(s):  
Aji Prasetyaningrum ◽  
Widayat Widayat ◽  
Bakti Jos ◽  
Yudhy Dharmawan ◽  
Ratnawati Ratnawati
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Uv Irradiation ◽  
Ozone Concentration ◽  
Morphological Properties ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
Irradiation Intensity ◽  
Ft Ir ◽  
Uv Lamp

The low molecular weight (LMW) of sulfated polysaccharides including k-carrageenan, is shows a wide spectrum of biological activities. This research investigates the influence of UV irradiation, ozone (O3), and the combination of O3/UV methods on the depolymerization of k-carrageenan. The depolymerization kinetics of k-carrageenan using the Advanced Oxidation Process (UV/O3) was also studied. Furthermore, the intrinsic viscosity method was used to determine the average molecular weight of the research sample, and a mathematical model was developed to predict the kinetic rate constant, as a function of ozone dosage and UV irradiation intensity. Therefore, the physicochemical and morphological properties of the degraded k-carrageenan were analyzed by FT-IR, SEM, and XRD. The intrinsic viscosity k-carrageenan decreases with increasing UV light intensity and ozone concentration. The combination of UV/O3 treatment appeared to be more effective than the individual approaches, as the highest kinetic rate constant for depolymerization was 1.924×10-4 min-1, using 125 mg/L ozone concentration and 40 mW/cm2 of UV lamp intensity. This research also evaluated the relationship between various experimental conditions, including UV lamp power dissipation and ozone concentration on the reaction kinetics model, and the results suggest that lower effect is contributed by UV irradiation intensity. In addition, FT-IR spectra showed the absence of any significant change in the functional properties of k-carrageenan treated with UV and O3 processes, although the morphological properties of the LMW k-carrageenan were rougher and more porous than the native k-carrageenan. Copyright © 2020 BCREC Group. All rights reserved 

Photocatalytic oxidation of phenolic compounds in wastewater from oil shale treatment

1997 ◽  
Vol 35 (4) ◽  
pp. 165-174 ◽  
Author(s):  
Sergei Preis ◽  
Yelena Terentyeva ◽  
Aleksei Rozkov
Keyword(s):  
Phenolic Compounds ◽  
Uv Irradiation ◽  
Oil Shale ◽  
Photocatalytic Oxidation ◽  
Alkaline Media ◽  
Treated Wastewater ◽  
Model Compounds ◽  
Hollow Glass Microspheres ◽  
Irradiation Intensity ◽  
Untreated Wastewater

Experimental research into the photooxidation of aqueous solutions and wastewaters containing phenolic compounds was undertaken. Titanium dioxide under near-UV irradiation was selected as a photocatalyst. Phenol, p-cresol, resorcinol and 5-methylresorcinol (5-MR) were chosen as model compounds for the experiments with synthetic phenolic solutions. The photooxidative treatment of phenolic solutions was found to be more effective in acidic and strongly alkaline media. No difference was found between shortwave and near-UV irradiation photooxidation abilities. Methylated phenolic substitutes (p-cresol, 5-MR) yield better to photooxidation than non-methylated compounds. The higher the irradiation intensity the lower the photooxidation efficiency. The results obtained from the experiments with model compounds were compared with the results of photooxidative purification of wastewaters produced from the thermal treatment of oil shale in Estonia. Being heavily polluted, the wastewater yields better to photooxidation when slightly diluted with potable water in a 3:1 ratio. Anatase, immobilised onto the surface of buoyant hollow glass microspheres, was less effective than when suspended in a slurry. The photooxidatively pre-treated wastewater showed better biodegradability and lower toxicity to bacteria than untreated wastewater.

scholarly journals The influence of the UV irradiation intensity on photocatalytic activity of ZnAl layered double hydroxides and derived mixed oxides

2012 ◽  
Vol 18 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Milica Hadnadjev-Kostic ◽  
Tatjana Vulic ◽  
Dmitar Zoric ◽  
Radmila Marinkovic-Neducin
Keyword(s):  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Layered Double Hydroxides ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Uv Light ◽  
Light Irradiation ◽  
Irradiation Intensity ◽  
Uv Light Irradiation ◽  
Double Hydroxides

Layered double hydroxides (LDHs) have been studied to a great extent as environmental-friendly complex materials that can be used as photocatalysts or photocatalyst supports. ZnAl layered double hydroxides and their derived mixed oxides were chosen for the investigation of photocatalytic performances in correlation with the UV intensities measured in the South Pannonia region. Low supersaturation coprecipitation method was used for the ZnAl LDH synthesis. For the characterization of LDH and thermal treated samples powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), nitrogen adsorption-desorption were used. The decomposition of azodye, methylene blue was chosen as photocatalytic test reaction. The study showed that the ZnAl mixed oxide obtained by thermal decomposition of ZnAl LDH has stable activity in the broader UV light irradiation range characterizing the selected region. Photocatalytic activity could be mainly attributed to the ZnO phase, detected both in LDH and thermally treated samples. The study showed that the ZnAl mixed oxide obtained by the calcination of ZnAl LDH has a stable activity within the measured UV light irradiation range; whereas the parent ZnAl LDH catalyst did not perform satisfactory when low UV irradiation intensity is implied.

Effect of UV Irradiation on the Migration of DEHP from Food-Grade PVC Film into Packaged Ground Meat

2012 ◽  
Vol 601 ◽  
pp. 94-98
Author(s):  
Shuang Ling Zhang
Keyword(s):  
Uv Irradiation ◽  
Fat Content ◽  
Ground Meat ◽  
Safety Risk ◽  
Food Grade ◽  
Irradiation Intensity ◽  
Pvc Film ◽  
Packaged Food ◽  
Ethylhexyl Phthalate ◽  
Control Samples

Effect of UV irradiation on the migration of di-2-ethylhexyl phthalate (DEHP) plasticizers from food-grade PVC film into packaged ground meat that had various levels of fat content (i.e. 10%, 20%, 30%, and 40%) was studied. After 20 h of UV irradiation (intensity 900µW cm-2)，the amount of migrated DEHP had a dramatic increase by 2.55, 2.75, 2.18 and 2.16 times in comparison to that in control samples having a fat content of 10%, 20%, 30% and 40%, respectively. The migration was intensified greatly by the UV irradiation of 8 to 12 h. There were 220.10 mg kg-1, 245.88 mg kg-1, 291.18 mg kg-1, and 357.40 mg kg-1 DEHP migrating from the PVC film into the ground meat during these periods, which contributed a large proportion to the final total amounts of DEHP, being 66.6%, 57.5%, 60.6% and 68.7% of 20 h of UV irradiation, for the ground meat of fat content of 10%, 20%, 30% and 40%, respectively. These results indicate that safety risk of packaged food will increase when the packaged food is under UV irradiation.

Effect of UV Intensity and Wavelengh on Photocatalytic Degradation of Polycyclic Aromatic Hydrocarbons

2011 ◽  
Vol 233-235 ◽  
pp. 466-469
Author(s):  
Li Hong Zhang ◽  
Cheng Bin Xu ◽  
Zhong Lin Chen ◽  
Xue Mei Li
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Photocatalytic Degradation ◽  
Light Source ◽  
Uv Irradiation ◽  
Aromatic Hydrocarbons ◽  
Uv Light ◽  
Irradiation Intensity ◽  
Degradation Rates ◽  
Polycyclic Aromatic

The photocatalytic degradation of pyrene (PYRE) and benzo[a]pyrene (BaP) on soil surfaces in the presence of Fe2O3 using ultraviolet (UV) light source was investigated in a photo chamber, in which the temperature was maintained 30 . The effects of UV irradiation intensity and UV wavelength on the degradation performance of polycyclic aromatic hydrocarbons (PAHs) were studied. The results show that with the intensity of UV irradiation being enhanced, the photocatalytic degradation rates of PAHs were increased. Photocatalytic degradation rates of PYRE and BaP on soil surfaces with 5% Fe2O3 were different at UV irradiation wavelengths of 254, 310 and 365 nm, respectively.

Effect of UV-irradiation intensity on graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on orthopedic bearing substrate

2013 ◽  
Vol 102 (9) ◽  
pp. 3012-3023 ◽  
Author(s):  
Masayuki Kyomoto ◽  
Toru Moro ◽  
Shihori Yamane ◽  
Masami Hashimoto ◽  
Yoshio Takatori ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Graft Polymerization ◽  
Irradiation Intensity

scholarly journals Photochemical Oxidation Process of Copper from Electroplating Wastewater: Process Performance and Kinetic Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1276
Author(s):  
Aji Prasetyaningrum ◽  
Teguh Riyanto ◽  
Mohamad Djaeni ◽  
Widayat Widayat
Keyword(s):  
Uv Irradiation ◽  
Ph Value ◽  
Photochemical Oxidation ◽  
Order Kinetic ◽  
Solid Product ◽  
Electroplating Wastewater ◽  
X Ray ◽  
Irradiation Intensity ◽  
High Production Rate ◽  
Uv Ozone

An investigation of the process of ozone combined with ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of copper (Cu) from electroplating wastewater. The effects of operating parameters, including initial Cu concentration, ozone dosage, UV irradiation intensity, and pH value on the photochemical oxidation of Cu have been studied comprehensively. The Cu concentration during the reaction was identified using atomic absorption spectroscopy (AAS) method. The solid product was analyzed using X-ray diffraction (XRD) and scanning electron microscope–energy-dispersive X-ray (SEM–EDX) methods. It was found that the UV-Ozone process has high performance on Cu removal compared to UV and Ozone processes due to the high production rate of HO• radicals. It was also found that the solid product from the UV-Ozone process was CuO monoclinic crystal phase. The initial Cu concentration, ozone dosage, and pH value were significantly affected the Cu removal efficiency. On the other hand, the UV irradiation intensity was not significant; however, it has responsibility in promoting the ozone photolysis. The kinetics model for the photochemical oxidation of Cu was established following the first-order kinetic model. Furthermore, the reaction mechanism was also developed.

Physicochemical WPC Modification Techniques

2021 ◽  
Vol 887 ◽  
pp. 144-150
Author(s):  
A.E. Shkuro ◽  
A.V. Artyomov ◽  
A.V. Savinovskikh
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Benzoyl Peroxide ◽  
Uv Irradiation ◽  
Polymer Matrix ◽  
Brinell Hardness ◽  
Physical And Mechanical Properties ◽  
Irradiation Intensity ◽  
Wood Polymer ◽  
Wood Polymer Composites

The paper studies issues related to physicochemical and chemical techniques for the modification of wood-polymer composites with a thermoplastic polymer matrix (WPCs) to improve their physical and mechanical properties. The physicochemical modification was performed by photochemical crosslinking with the exposure of WPC specimens to UV irradiation. Chemical modification was performed by introducing benzoyl peroxide into the material composition, leading to chemical crosslinking of polyethylene macromolecules of the WPC polymer matrix. As a result of the study, quantitative characteristics of the effect of the benzoyl peroxide content in the composite, as well as the WPC specimen UV irradiation intensity and duration on the basic physical and mechanical properties of the material have been obtained. The efficiency of physicochemical techniques for modifying WPCs has been estimated by changing the specimen properties such as Brinell hardness, water absorption, and impact strength. It has been found that the Brinell hardness increases by 80 % as compared to unmodified WPC specimens. Effective modification of wood-polymer composites with polymer matrices based on high-density polyethylene may lead to a significant improvement in the quality of products made of these materials.

scholarly journals Two-Quantum Photoprocesses in DNA and RNA Biopolymers Under Powerful Picosecond Laser UV Irradiation

1984 ◽  
Vol 4 (1-6) ◽  
pp. 297-303 ◽  
Author(s):  
David N. Nikogosyan ◽  
Gagik G. Gurzadyan
Keyword(s):  
Uv Irradiation ◽  
Qualitative Difference ◽  
Picosecond Laser ◽  
Strand Breaks ◽  
Irradiation Intensity ◽  
Dna And Rna ◽  
Saturation Intensity ◽  
Phosphate Chain ◽  
Single Strand Breaks ◽  
Cross Links

Two-quantum photoreactions taking place under picosecond laser UV irradiation of DNA and RNA biopolymers were investigated. Despite of qualitative difference in two-step photoprocesses concerned (single-strand breaks formation in plasmid pBR 322 DNA, induction of breaks in TMV RNA sugar-phosphate chain, cross-links formation in DNA of CD phage) similar dependences of the quantum yield of the effects studied on the irradiation intensity can be observed with saturation in the region of 3 · 1011−3 · 1012 W/m2. The saturation intensity is one or two orders lower than in the case of irradiation of single monomers - nucleic acid bases.

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