Applying in-situ visible photopolymerization for fabrication of electrospun nanofibrous carrier for meloxicam delivery.

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, 1H NMR, 13C 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%.

Homogeneous and heterogeneous AOPs for rapid degradation of Triton X-100 in aqueous media via UV light, nano titania hydrogen peroxide and potassium persulfate.

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/TiO2, UV/H2O2 and UV/S2O8 2-. For treatment of solutions containing 20 mg/L of Triton, the optimum obtained conditions are: 5.0 mg/L of nano TiO2, 270.3 mg/L of KPS, and 34.0 mg/L of H2O2 (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/TiO2, UV/H2O2 and UV/S2O8 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/TiO2/H2O2 or S2O8 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/S2O8 2- and UV/TiO2 processes under optimum conditions, while this order for UV/H2O2 process is 2.27. Meanwhile, the initial rates of degradation in UV/TiO2 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/S2O8 2-.

Photo-assisted hetero-fenton decolorization of azo dye from contaminated water by Fe-Si mixed oxide nanocomposite.

An aerogel of silica gel dopeyd with 2.86 wt% Fe was prepared by an alkoxide sol-gel method and using tetraethyl orthosilicate as a precursor material. The synthesized aerogel was calcined at 500 degress C to produce nanoparticle solids, and was characterized by XRD, FT-IR and SEM. The nanosized iron-silica gel mixed oxide was tested in the photooxidation of the azo dye Acid Red 14 (AR 14) using 30% aqueous hydrogen peroxide as oxidant and UV light. The 2.86 wt% Fe-loaded SiO2 showed very good efficiency in the decolorization of AR 14. The effects of various parameters including solution pH, catalyst, oxidant and initial dye concentrations on photodegradation were investigated and the optimum conditions were determined. The catalyst was resistant to leaching and could be recycled several times without appreciable loss of activity.

Removal of C.I. Basic Yellow 2 from aqueous solution by low-cost adsorbent: hardened paste of Portland cement.

The adsorption of C.I. Basic Yellow 2 (BY2) from aqueous solutions on to hardened paste of Portland cement (HPPC) as a low-cost adsorbent and its adsorption kinetics at different conditions were studied. The adsorption process was followed by an online spectrophotometric analysis system, which consisted of a UV-Vis spectrophotometer, a designed spectrophotometric cell, a peristaltic pump and a glass reactor. The effect of experimental parameters, including initial dye concentration, mass of HPPC, initial pH and temperature, on adsorption was studied over a 30 miin adsorption period. For the kinetic study, the obtained data were treated according to various kinetic models. The results revealed that the experimental data were better fitted to the first-order kinetics model than to the second-order and intraparticle diffusion models. Equilibrium isotherms for the adsorption of BY2 on HPPC were analysed by Freundlich and Langmuir isotherms equations using the linear correlation coefficient. The Freundlich isotherm gave the best correlation of adsorption.

Enhanced sonocatalytic performance of ZnTi nano-layered double hydroxide by substitution of Cu (II) cations.

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.

Removal of C.I. Acid Orange 7 from aqueous solution by UV irradiation in the presence of ZnO nanopowder.

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(2)O(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.

Biodegradation of dye solution containing Malachite Green: optimization of effective parameters using Taguchi method.

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 degrees C, initial pH 10, dye concentration 5 ppm, algae type Chlorella and time 2.5h. The stability and efficiency of Chlorella sp. in long-term repetitive operations were also examined.

Decolorization of C.I. Acid Yellow 23 solution by electrocoagulation process: investigation of operational parameters and evaluation of specific electrical energy consumption (SEEC).

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 50mg/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 5min and the current density was approximately 112.5A/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.

Interaction between deferiprone and human serum albumin: multi-spectroscopic, electrochemical and molecular docking methods.

The interactions between deferiprone (DEP) and human serum albumin (HSA) have been investigated systematically by fluorescence, Circular dichroism (CD) spectroscopy, UV-Vis absorption spectroscopy, electrochemistry and molecular modeling methods. The fluorescence quenching observed is attributed to the formation of a complex between HSA and DEP, and the reverse temperature effect of the fluorescence quenching has been found and discussed. The thermodynamic parameters, enthalpy changes (ΔH) and entropy change (ΔS) were calculated, according to the Van't Hoff equation. These data suggested that hydrophobic interaction was the predominant intermolecular forces stabilizing the complex, which was in good agreement with the results of molecular modeling study. The primary binding pattern is determined by hydrophobic interaction occurring in Sudlow's site I of HSA. DEP could slightly change the secondary structure and induce unfolding of the polypeptides of protein. An average binding distance of ∼2.88 nm has been determined on the basis of the Förster's resonance energy theory (FRET).

The photooxidative destruction of C.I. Basic Yellow 2 using UV/S2O8(2-) process in a rectangular continuous photoreactor.

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).

The photo-oxidative destruction of C.I. Basic Yellow 2 using UV/S(2)O(8)(2-) process in an annular photoreactor.

The photo-oxidative decolorization of C. I. Basic Yellow 2 (BY2), was investigated using UV radiation in the presence of peroxydisulfate (S(2)O(8)(2-)) in an annular photoreactor at different conditions. 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 and pH. The conversion ratios of BY2 at the volumetric flow rates of 330, 500 and 650 mLmin(- 1) were 84%, 78%, 69% in 1 h, respectively. The results showed that in the presence of S(2)O(8)(2-), the photooxidation quantum yield obtained higher than direct photolysis quantum yield, suggesting that photodecay of BY2 was dominated by photooxidation. The electrical energy per order (EE/O) values for decolorization of BY2 solution was calculated. Results show that applying an optimum peroxydisulfate concentration can reduce the EE/O.

Immobilization of TiO2 nanopowder on glass beads for the photocatalytic decolorization of an azo dye C.I. Direct Red 23.

TiO2 supported on glass beads was prepared and its photocatalytic activity was determined by photooxidation of the commercial textile dye, C.I. Direct Red 23, in aqueous solution illuminated by a UV-C lamp (30 W). The progress of photocatalytic decolorization of the C.I. Direct Red 23 was studied by measuring the absorbance at lambda(max) = 507 nm by UV Vis spectrophotometer. The experiments indicated that both UV light and TiO2 were needed for the effective destruction of the dye. The effect of pH on the rate of decolorization efficiency was followed in the pH range 2-12. Acidic pH range was found to favor the decolorization rate. The addition of a proper amount of hydrogen peroxide improved the decolorization, whereas the excess hydrogen peroxide quenched the formation of hydroxyl radicals (*OH). The electrical energy consumption per order of magnitude for photocatalytic decolorization of the dye was lower in the UV/TiO2/H2O2 process than that in the UV/TiO2 process. In the real wastewater sample the efficiency of the method was determined by measuring the changes in the absorption spectra of the dye solution during photodegradation. Our results indicated that during the photooxidation process, the decolorization efficiency was more than 80% at irradiation time of 3 h.