Synthesis of chemical compounds using materials which are compatible with environment, non-toxic and safe, is one of the principles of green chemistry. In this paper, all principles of green chemistry with two new methods for green synthesis of titanium dioxide nanoparticles have collected. Titanium dioxide is a photo catalyst which has various applications especially in green chemistry. This paper is about synthesis of TiO2 nanoparticles first by using Nyctanthes Arbor-Tristis leaves extract and then by a bacteria called Planomicrobium sp. Then the size and morphology of the synthesized nanoparticles by two methods are compared by their scanning electron microscopic (SEM) images.

Objective(s): Quince seed mucilage (QSM) serves as a new source of hydrocolloid which extracted from outer pericarp of Cydonia oblonga seeds upon wetting. It has been traditionally used for the treatment of diseases such as pharyngeal disorder, common cold, colic ulcer, and diarrhea. The aim of the present study was to evaluate the physico-mechanical and antimicrobial properties of quince seed mucilage supplemented with titanium dioxide (TiO2) and Silicon dioxide (SiO2) nanoparticles. Methods: The antimicrobial property of designated QSM against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157: H7 was determined using agar disk diffusion and broth micro-dilution assays. Thickness, tensile strength (TS), puncture force (PF), puncture deformation (PD), swelling index (SI), and color of active QSMs were evaluated using analytical instruments. Results: The films containing TiO2 and SiO2 nanoparticles exhibited good antimicrobial effects against S. aureus, B. subtilis, B. cereus, L. monocytogenes, S. typhimurium, and E. coli O157: H7 ranged 0. 82-6. 88 mm and-2. 78--0. 28 log differences in population (DP) regarding agar disk diffusion and broth microdilution assays, respectively. The presented values, including TS, PF, and PD of QSM films, were in the ranges of 22. 45-35. 81 MPa, 10. 42-15. 49 N, and 15. 53-18. 45 mm, respectively. Conclusions: Application of TiO2 and SiO2 nanoparticles greatly improved the antimicrobial and physico-mechanical properties of the prepared films.

Background and Objectives: Dye is considered as one of the most important environmental pollutants in industrial wastewater due to its harmful effects on both human and environment. This study was aimed to determine Optimum Dioxide Titanium Nanoparticles in Dioxide Titanium /Bentonite Composite for Sono-photocatalytic de-colorization of Methyl Orange dye. Methods: In this study, bentonite was used as the substrate to stabilize titanium dioxide photo-catalyst and the optimum amount of stabilized titanium dioxide nanoparticles in titanium dioxide/ bentonite composite which was evaluated for sono-photocatalytic removal of methyl orange dye. Accordingly, the optimal conditions for the photocatalytic process performance in dye removal included the effect of pH, methyl orange concentrations and nanocomposite doses. Findings: Structural properties of bentonite/titanium Dioxide composites and pure titanium dioxide nanoparticles were investigated using scanning electron microscope (SEM), Diffuse Reflectance Spectroscopy (DRS) and X-ray diffraction (XRD). Finally, the possibility of reuse of photo-catalyst was investigated in three periods. Based on SEM results, reducing the amount of titanium dioxide reduced the number of nanoparticles formed on the bentonite surface. XRD and DRS analyses showed successful composite formation. The optimum amount of titanium dioxide nanoparticles in titanium dioxide/bentonite composite was obtained for sono-photocatalytic dye removal of methyl orange with the titanium dioxide powder to bentonite ratio of 1: 2. 5 in the primary mixture. Discussion and Conclusion: The study showed that increasing the amount of photo-catalyst in the reaction medium increased the speed and efficiency of the dye removal but its excessive increase had a negative effect on the reaction. The best conditions for dye degradation were obtained using titanium dioxide/bentonite nanocomposite at pH 4. According to the results, the increase in concentration increased dye removal time. Finally, the sono-photocatalytic composite efficiency was acceptable after three times of reuse.

Nowadays green synthesis of metal nanoparticles is a developing area of research. In this study, titanium dioxide nanoparticles were biosynthesized using an aqueous solution of Echinacea purpurea herba extract as a bioreductant. This is novel and interesting method for synthesis of TiO2 nanoparticles. The prepared titanium dioxide nanoparticles were characterized using ultraviolet–visible spectroscopy (UV-VIS), transmission electron microscopy (SEM), total reflection X-Ray fluorescence analysis (TXRF) and Fourier-transform infrared spectroscopy (FTIR). The size of TiO2 nanoparticles was found to be in the range of 120 nm. Moreover, the alkaline reaction of the solution (pH=8) resulted in the increase in absorbance (280 nm), which facilitates the growth of the number of TiO2 nanoparticles in the studied solution. Also, synthesis of TiO2 nanoparticles using green resources like Echinacea purpurea herba is a better alternative to chemical synthesis, since this green synthesis is pollutant-free and eco-friendly.

The effect of three commercial types of titanium dioxide (TiO2) with primary particle sizes of 20 to 50 nm have been used for different sunscreens formulations. The efficiency of these sunscreens formulations, such as Sun Protection Factor (SPF), UVAPF and critical wavelength (λc) were tested. Oil/water creams with 5%, 10%, and 20% concentrations of each type of TiO2 were prepared, and SPF, UVAPF and λc were measured using both in vitro and in vivo methods. Because the samples have been aggregate and made the agglomerations, the milling and hemogenation methods have been used for decrease size of particles. In vitro analysis demonstrated that submicron-sized TiO2 cream had a lower SPF value than nanosized TiO2 formulations of the same concentration. In vivo experiments confirmed this result, and a strong correlation between in vitro and in vivo measurements was observed. Furthermore, the SPF values of nanosized TiO2 sunscreen were concentration-dependent in the range of 5% to 20%. Scanning electron microscopy results indicate that the higher SPF of nanosized TiO2 formulations may be due to the formation of multilayer agglomerates by small particles at nano-scales, leading to a reduced void space between particles and a more efficient barrier to protect skin from sunlight.

Background and Objectives: Dye is considered as one of the most important environmental pollutants in industrial wastewater due to its harmful effects on both human and environment. This study was aimed to determine Optimum Dioxide Titanium Nanoparticles in Dioxide Titanium /Bentonite Composite for sono photo catalytic de-colorization of Methyl Orange dye. Methods: In this study, bentonite was used as the substrate to stabilize titanium dioxide photo catalyst and the optimum amount of stabilized titanium dioxide nanoparticles in titanium dioxide/ bentonite composite was evaluated for sono photo catalytic removal of methyl orange dye. Accordingly, the optimal conditions for the photo catalytic process performance in dye removal included the effect of pH, methyl orange concentrations and nanocomposite doses. Findings: Structural properties of bentonite/titanium dioxide composites and pure titanium dioxide nanoparticles were investigated using scanning electron microscope (SEM), Diffuse Reflectance Spectroscopy (DRS) and Xray diffraction (XRD). Finally, the possibility of reuse of photo catalyst was investigated in three periods. Based on SEM results, reducing the amount of titanium dioxide reduced the number of nanoparticles formed on the bentonite surface. XRD and DRS analyses showed successful composite formation. The optimum amount of titanium dioxide nanoparticles in titanium dioxide/bentonite composite was obtained for sono photo catalytic dye removal of methyl orange with the titanium dioxide powder to bentonite ratio of 1: 2. 5 in the primary mixture. Discussion and Conclusion: The study showed that increasing the amount of photo catalyst in the reaction medium increased the speed and efficiency of the dye removal but its excessive increase had a negative effect on the reaction. The best conditions for dye degradation were obtained using titanium dioxide/bentonite nanocomposite at pH 4. According to the results, the increase in concentration increased dye removal time. Finally, the sono photo catalytic composite efficiency was acceptable after three times of reuse.

Titanium dioxide such as the other engineered nanomaterials has uncommon properties and if the various form of them to be released in the environment tobecome a new class of pollutants and a threat to public health and ecosystem. This research carried out to investigation of titanium dioxide nanoparticles effect on germination and cytogenetical trait of under division cells of Hordeum vulgar var valfajr under in vitro condition. Germination of barley seeds in the presence of different concentrations of titanium dioxide (10, 25, 50, 100 milligram per liter) was carried out in presence of -control and in form of random complete blocks design. Trait of germination speed, speed growth of radicle and plumule, length and number of root and stem also the index of mitosis, metaphase and chromosomal abbrations such as anaphase bridge, chromosome fragment, sticky telophase and micronuclei was measured. Result showed that titanium nanoparticle has significant effect on chromosome abberration of barley and induced abberration index in treated cells in compared with control while does not affect on other cytogenetical index and germination trait.It seems titanium dioxide nanoparticles is competent to damage of eukaryotic genetical material and bring notice to the environmental safety facet is important.