•Photocatalytic degradation of dye by Ag modified HAP under visible light.•Study of Fenton like degradation of dye by transition metal ions modified HAP.•Comparison of catalytic systems according to ...Langmuir-Hinshelwood kinetic expression.
The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag3PO4 formation. Apparent reaction rate constant (Kapp) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H2O2, Co-M-HAP(II)/H2O2 and M-HAP (I)/UV systems, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Feasibility of degradation of Triton X-100 as a widely used and resistive surfactant in aqueous media was studied via some homogeneous and heterogeneous AOPs of UV/TiO
2, UV/H
2O
2 and UV/S
2O
8
2−. ...For treatment of solutions containing 20
mg/L of Triton, the optimum obtained conditions are: 5.0
mg/L of nano TiO
2, 270.3
mg/L of KPS, and 34.0
mg/L of H
2O
2 (1
mM of the oxidants), initial natural pH of 5.4 and temperature of 45
°C. Under these conditions, the degradation efficiency for the UV/TiO
2, UV/H
2O
2 and UV/S
2O
8
2− processes exceeds 71.9% (in 60
min), 80.9% (in 60
min) and 98.5% (in only 30
min) respectively. It was found that simultaneous application of these heterogeneous and homogeneous AOPs (UV/TiO
2/H
2O
2 or S
2O
8
2−) is not desirable due to some physico-chemical retarding effects. The influence of temperature on the reactions was examined in the range of 15–45
°C and a kinetic power law model jointed with the Arrhenius equation was introduced. A pseudo first order reaction rate is appropriate for UV/S
2O
8
2− and UV/TiO
2 processes under optimum conditions, while this order for UV/H
2O
2 process is 2.27. Meanwhile, the initial rates of degradation in UV/TiO
2 process can be described well by the Langmuir–Hinshelwood kinetic model. Analysis of energy consumptions (thermal and electrical) revealed that increasing in temperature is an effective factor for lowering the energy cost of the preferred process of UV/S
2O
8
2−.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, optimization of biological decolorization of synthetic dye solution containing Malachite Green was investigated. The effect of temperature, initial pH of the solution, type of algae, ...dye concentration and time of the reaction was studied and optimized using Taguchi method. Sixteen experiments were required to study the effect of parameters on biodegradation of the dye. Each of experiments was repeated three times to calculate signal/noise (S/N). Our results showed that initial pH of the solution was the most effective parameter in comparison with others and the basic pH was favorable. In this study, we also optimized the experimental parameters and chose the best condition by determination effective factors. Based on the S/N ratio, the optimized conditions for dye removal were temperature 25
°C, initial pH 10, dye concentration 5
ppm, algae type
Chlorella and time 2.5
h. The stability and efficiency of
Chlorella sp. in long-term repetitive operations were also examined.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The removal of C.I. Acid Orange 7 (AO7) from aqueous solution under UV irradiation in the presence of ZnO nanopowder has been studied. The average crystallite size of ZnO powder was determined from ...XRD pattern using the Scherrer equation in the range of 33
nm. The experiments showed that ZnO nanopowder and UV light had a negligible effect when they were used on their own. The effects of some operational parameters such as pH, the amount of ZnO nanopowder and initial dye concentration were also examined. The photodegradation of AO7 was enhanced by the addition of proper amount of hydrogen peroxide, but it was inhibited by ethanol. From the inhibitive effect of ethanol, it was deducted that hydroxyl radicals played a significant role in the photodegradation of the dye. The kinetic of the removal of AO7 can be explained in terms of the Langmuir–Hinshelwood model. The values of the adsorption equilibrium constant,
K
AO7, and the kinetic rate constant of surface reaction,
k
c, were 0.354
(mg
l
−1)
−1 and 1.99
mg
l
−1
min
−1, respectively. The electrical energy consumption per order of magnitude for photocatalytic degradation of AO7 was lower in the UV/ZnO/H
2O
2 process than that in the UV/ZnO process. Accordingly, it could be stated that the complete removal of color, after selecting desired operational parameters could be achieved in a relatively short time, about 60
min.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study investigates the evaluation of specific electrical energy consumption (SEEC) and the influence of operating parameters on the color removal efficiency of a dye solution containing C.I. ...Acid Yellow 23 by electrocoagulation process. Firstly, the operational parameters including current density, initial dye concentration, initial pH and time of electrolysis were optimized. Then the effects of the conductivity, the interelectrode distance and the area of cross-section of the electrodes on specific electrical energy consumption (SEEC) were studied under the optimum conditions. Our results indicated that for a solution of 50
mg/l C.I. Acid Yellow 23, almost 98% color and 69% chemical oxygen demand (COD) were removed, when the pH was about 6, the time of electrolysis was 5
min and the current density was approximately 112.5
A/m
2. In addition, the results of our study revealed that when the conductivity and area of cross-section of the electrodes increased and interelectrode distance decreased, the cell voltage and specific electrical energy consumption would be decreased.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Despite meloxicam's many benefits, it will cause many drawbacks if the meloxicam release rate is not controlled. Accordingly, we introduced a technique based on the electrospinning process to control ...the release rate and also to reduce side effects. For this purpose, different nanofibers were used as drug couriers. Nanofibers were prepared using polyurethane, polyethylene glycol, and light curable poly (ethylene glycol) diacrylate (PEGDA) by electrospinning. In fact, light curable poly (ethylene glycol) diacrylate (PEGDA) was synthesized as a hydrophilic functional group. Next, PEGDA and polyurethane were used simultaneously to fabricate the drug carrier nanofiber in a single processing step, and the electrospinning apparatus was equipped with a blue light source for in-situ photopolymerization during the electrospinning process. The molecular structures of nanofibers and PEGDA were investigated by FT-IR,
H NMR,
C NMR, SEM, TEM, XRD, and DSC analyses. Finally, we reduced in vitro drug release to 44% within ten hours, while the minimum release of meloxicam from the tablet was 98%.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The photooxidative decolorization of C.I. Basic Yellow 2 (BY2), was investigated using UV radiation in the presence of peroxydisulfate (S
2
O
8
2−
) in a rectangular photoreactor at experimental ...condition. S
2
O
8
2−
and UV-light showed negligible effect when they were used independently. Removal efficiency of BY2 was sensitive to the operational parameters such as initial concentrations of S
2
O
8
2−
, BY2, light intensity, flow rate and pH. The conversion ratios of BY2 at the volumetric flow rates of 330, 500 and 650 ml/min were 84%, 79%, 51% in 30 min, respectively. Our results showed that light intensity was a beneficial parameter for dye removal. The results showed that in the presence of S
2
O
8
2−
, the photooxidation quantum yield obtained was higher than direct photolysis quantum yield, suggesting that photodecay of BY2 was dominated by photooxidation. The electrical energy per order (
E
EO
) values for decolorization of BY2 solution was calculated. Results show that applying a desired peroxydisulfate concentration can reduce the
E
EO
.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•CuZnTi-LDHs with different Cu2+/Zn2+ mole ratios are synthesized.•The substitution of Cu2+ improves the sonocatalytic properties of CuZnTi-LDHs.•Substitution of Cu2+ in LDH layers can narrow down ...the band gap energy of ZnTi-LDH.•CuZnTi-LDH (1:1) exhibits the best sonocatalytic activity.•The probable mechanism for sonocatalytic properties enhancement by Cu2+ substitution has been discussed.
In this research, a series of CuZnTi-LDHs with different Cu2+/Zn2+ molar ratio were synthesized by co-precipitation method with the purpose of improving the sonocatalytic performance of ZnTi-LDH. All the LDH samples were synthesized by a facile co-precipitation process. The as-prepared LDHs were characterized by Powder X-ray diffraction (XRD), Field emission-scanning electron microscopy (FESEM), Transition electron microscopy (TEM), Brunauer-Emmelt-Teller (BET) analysis, and UV-visible diffuse reflectance spectroscopy (DRS) analysis. The results showed that Cu2+ substitution can significantly enhance the sonocatalytic properties of ZnTi-LDH. The Methylene blue degradation percentage over ZnTi-LDH reached 30% in 90 min, whilst this percentage reaches 71% over CuZnTi-LDH (1:1). The role of the Cu2+ incorporation on the observed enhancement in sonocatalytic performance was revealed by investigating the effect of radical scavengers on degradation efficiency and DRS spectra of ZnTi-LDH and CuZnTi-LDH (1:1). Benzoquinone (BQ), ammonium oxalate and tert-Bu lead to 22.5%, 53.5% and 74.6% decrease in degradation percentage by CuZnTi-LDH (1:1). However, the degradation efficiency showed 16.6%, 3.3% and 63.3% reduction in the presence of BQ, ammonium oxalate and tert-Bu respectively, in dye degradation by ZnTi-LDH. DRS spectra demonstrated that the band gap of the LDH decreases by Cu2+ substitution. The effect of operational parameters on sonodegradation was investigated as well. The kinetics of sonodegradation reaction obeyed the first order reaction kinetics with R2 of 0.95.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, the dielectric breakdown strength of magnetic nanofluids based on transformer mineral oil for use in power systems is reviewed. Nano oil samples are obtained from dispersion of the ...magnetic nanofluid within uninhibited transformer mineral oil NYTRO LIBRA as the base fluid. AC dielectric breakdown voltage measurement was carried out according to IEC 60156 standard and the lightning impulse breakdown voltage was obtained by using the sphere–sphere electrodes in an experimental setup for nano oil in volume concentration of 0.1–0.6%. Results indicate improved AC and lightning impulse breakdown voltage of nano oil compared to the base oil. AC test was performed again after applying impulse current and result showed that nano oil unlike the base oil retains its dielectric properties. Increase the dielectric strength of the nano oil is mainly due to dielectric and magnetic properties of Fe3O4nanoparticles that act as free electrons snapper, and reduce the rate of free electrons in the ionization process.
•Transformer oil-based nanofluid is produced by dispersion of nanoparticles within the mineral transformer oil.•The use of magnetic nanoparticles in transformer oil at optimum volume fraction improves breakdown voltage of nano oil compared to the base oil.•Magnetic nanoparticles by trapping and capture the free electrons, decrease the speed of expansion of steamers, and delay breakdown.•Transformer oil containing magnetic nanoparticles can be a good alternative to transformer mineral oil uappropriate volume concentrations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A highly durable thin film composite membrane was fabricated using composite nanofibers including sulfonated polyvinylidene fluoride and polyvinylidene fluoride (S-PVDF-PVDF) as a supporting layer, ...electrosprayed sodium alginate (SA) among the S-PVDF-PVDF nanofibers as a mid-layer, and a thin film polyamide (PA) as a top layer. To prepare the mid-layer of SA, three weight percentages (0.25, 1.5, and 3%) were used. The chemical structure, morphology, and properties of the membranes were characterized using
1
H-NMR, FT-IR, SEM, contact angle, tensile, and water uptake analysis. Eventually, the S-PVDFPVDF/(S-PVDF-PVDF)SA(3%)/PA composite membrane was reported as the optimum membrane; its water flux and salt rejection for MgSO
4
were 4.29 L m
2
h
−1
and 84%, respectively. This membrane, in addition to the high water flux compared to the S-PVDF-PVDF membrane, and salt rejection at the same level, had higher strength and durability (36.82 MPa) compared to the S-PVDFPVDF membrane (22.10 MPa). Also, the mid-layer of the membrane increased the durability and stability of the thin film layer and made it possible to use the membrane repeatedly.
The main aim of this research is the improvement of the performance in desalination of polyamide (PA) thin film composite nanofiltration membranes by modification of nanofibrous polyvinylidene fluoride as a support layer.
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