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To operationalise the heterogeneous photocatalysis process, the present study investigated the efficiency of TiO2-P25 nanoparticles immobilised on glass beads using the heat attachment method to remove cefazolin (CEF) as an antibiotic contaminant. The characteristics of the glass beads coated with TiO2-P25 nanoparticles were probed by the Scanning Electron Microscopy (SEM) technique. The immobilised TiO2-P25 nanoparticles manifested considerable efficiency in CEF removal in different operational conditions. The impact of various parameters, such as the ultraviolet light radiation time, initial concentration of CEF, light source power, inlet liquid volumetric flow rate, and pH of the solution, on the efficiency of CEF removal were examined. The results reveal that the removal percentage goes up as the irradiation time, volumetric flow rate, pH of the solution, and light source power increase while declining with a rise in the initial concentration of CEF. According to the findings, an initial CEF concentration of 20 mg L−1 is entirely removed by 40 min UV irradiation with a 16 W light source, the volumetric flow rate of 300 mL min−1, and the pH of 9.5. The reaction rate constant and adsorption coefficient of CEF on immobilised TiO2 were estimated at 0.622 mg L−1 min−1 and 0.095 mg−1 L via Langmuir- Hinshelwood kinetics. The outcomes of the mineralisation studies also display a considerable reduction of TOC and evolution of significant mineralisation products, like $$NO_3^ - $$ N O 3 − , $$NO_2^ - $$ N O 2 − , $$NH_4^ + $$ N H 4 + , and $$SO_4^{2 - }$$ S O 4 2 − . The experimental results were modelled by artificial neural networks (ANN). Comparing the experimental results with the ANN-predicted data shows the acceptable efficiency of modelling with ANN. The minimum MSE, R2 value for all data (validation, training, and test), and R2 value for simulated data were obtained at 0.00027811, 0.9971, and 0.9809, respectively. The relative importance of the parameters affecting the process evaluated by the ANN weights indicates that the irradiation time is the most important factor in the photocatalytic removal of CEF. [ABSTRACT FROM AUTHOR]

In this work TiO2-P25 nanoparticles with high surface area have been used as adsorbent for the removal of C.I Acid Red 27 (AR27), as an organic contaminant from aqueous solution. Characteristics of phases and crystallite size of TiO2-P25 nanoparticles were achieved from XRD and the surface area and pore size distribution were obtained from BET and BJH techniques. TiO2-P25 nanoparticles with almost 80% anatase and 20% rutile phases, the average crystallite size of 18 nm, have specific surface area of 56.82 m2 g-1. The effect of various parameters like initial AR27 concentration, pH, contact time and adsorbent dosage has been carried out in order to find desired adsorption conditions. The desired pH for adsorption of AR27 onto TiO2-P25 nanoparticles was 3. The equilibrium data were analyzed with various 2-, 3- and 4-parameter isotherm models. Equilibrium data fitted very well by the 4-parameter Fritz-Schluender model. Results of adsorption kinetics study indicated that the pseudo-second order kinetics provided the best fit with correlation coefficients close to unity.

Essential oils with antimicrobial or antioxidant activities have received extensive attention among customers, manufacturers, and food scientists, especially with rising worries about the safety of synthetic food preservatives. However, like other functional lipid compounds their incorporation into aqueous systems is challenging, due to their less water solubility. Furthermore, their susceptibility to light, moisture, heat, and oxygen origins their less chemical and structural stabilities. Consequently, the present research was aimed to encapsulate the thyme essential oil into nanoliposomes, using a thin layer hydration-sonication technique, which can be a proficient solution for revealed problems. The effects of phospholipid and stabilizing agents' concentrations, namely, lecithin, cholesterol, and glycerol, as main formulation parameters were investigated on characteristics of gained nanoliposomes, using a response surface method. Various empirical models were also developed to predict product characteristics by changing the formulation parameters. According to the numerical multiple optimizations, the best thyme oil nanoliposomes can be gained using equal concentrations of all three components as 1% with a mean particle size of 189.6 nm, PDI of 0.3487, the net zeta-potential of 42.48 mV, and DPPH radical scavenging of 12.72%. The prepared nanoliposomes had acceptable physical but limited chemical stabilities. The antibacterial action of manufactured essential oil nanoliposomes against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus has made them efficient candidates as natural food preservatives. [ABSTRACT FROM AUTHOR]

In this study, La and Mg doped, and co-doped ZnO nanoparticles were prepared using the sol-gel method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and N2 physisorption techniques. The XRD results indicated that the prepared nanoparticles can be well adopted by the hexagonal wurtzite structure crystal and there are no second impurity peaks. Studies of the FESEM, EDX and TEM have shown that the samples have uniform spherical-like morphology with a homogenous distribution. The incorporation of La and Mg into the ZnO lattice had no effect on the morphology of the nanoparticles, but a reduction in the size of the grains (≈ 14 nm to ≈ 7 nm) was observed due to the insertion of these ions. The results of N2 physisorption indicated that there was an increase in BET surface area and pore volume for doped and co-doped samples. The results of DRS showed an increase in band gap energy and a blue shift at the absorption edge for doped and co-doped samples. The photocatalytic activity of the prepared catalysts was evaluated in the removal of RhB under UVA irradiation. The results showed that Mg5%-La5%/ZnO had the highest photoactivity (91.18 %) among all samples. [ABSTRACT FROM AUTHOR]

In this study, TiO2 nanowires (TNWs) were synthesized through hydrothermal method and were characterized using X‐Ray diffraction (XRD), transmission electron microscopy (TEM) and BET techniques. Monoclinic TiO2 (B) is the dominant phase of TNWs up to 600°C which is completely transformed into a highly crystalline anatase phase at 800°C. The photocatalytic activity of TNWs, prepared at various calcination temperatures, was investigated in the removal of Rhodamine B as an organic model pollutant. The results indicated that the photocatalytic activity of TNWs, prepared at 800°C calcination temperature, was better than that of other samples and even TiO2–P25 nanoparticles. [ABSTRACT FROM AUTHOR]

In this article, response surface methodology (RSM) was used to obtain optimum conditions for removal of p-nitrophenol (PNP) by UV/H2O2 process using spinning disk photoreactor (SDP). For this purpose, the effect of five independent variables, the initial concentration of PNP, the initial concentration of H2O2, pH, solution volume, and irradiation time on the PNP removal percent, was investigated. Central composite design, one of the response surface techniques used for process optimization. The results showed a good agreement between the RSM predicted and experimental data with "R2" and "Adjusted R2" of 0.9692 and 0.9480, respectively. In addition, "Predicted R2" of 0.8909 is in reasonable agreement with "Adjusted R2" of 0.9488. At optimal conditions, that is, PNP concentration of 20.78 mg L−1, H2O2 concentration of 1355.83 mg L−1, solution volume of 566.08 mL, irradiation time of 12.30 min, and pH of 4.59 the removal percent predicted by RSM is 100% which has good correspondence with its experimental value (98.67%). [ABSTRACT FROM AUTHOR]

In this study, Mg-doped ZnO nanoparticles with 2% Mg content were synthesized by sol-gel method. The structure and morphology of the nanoparticles were characterized by TEM, BET and UV-Vis absorbance techniques. From TEM image, it was found out that the nanoparticles had uniform size and uniform distribution. BET analysis revealed that in comparison with pure ZnO, Mg 2%/ZnO nanoparticles had a higher specific surface area. Based on UV-Vis absorbance analysis, Mg 2%/ZnO nanoparticles shifted to a lower wavelength (blue-shift), showing a high photocatalytic activity under UV light irradiation. The central composite design under the response surface methodology (RSM) was used for optimization of the photocatalytic removal of Rhodamine B (RhB) with Mg 2%/ZnO nanoparticles. The results showed that there was a good agreement between the predicted data from RSM and the experimental data with a correlation coefficient of 0.9354. The determined optimum values for removal of RhB were as follows: Mg 2%/ZnO nanoparticles dosage of 500 mg L-1, initial RhB concentration of 6 mg L-1, the irradiation time of 6 min, and pH = 8. In order to get more information about photocatalytic activity of the prepared Mg 2%/ZnO nanoparticles, a comparison was made between the photocatalytic activity in this study and that reported by other researchers. The results revealed the synthesized Mg 2%/ZnO nanoparticles had considerable photocatalytic activity. [ABSTRACT FROM AUTHOR]