A Novel Metal-Containing Mesoporous Silica Composite for the Decolorization of Rhodamine B: Effect of Metal Content on Structure and Performance.

A series of novel MnxFey@SiO2 (x,y = 1-20%) nanocomposites were synthesized for the first time via the sol-gel/combustion method with different content of precursors (Mn and Fe acetate salts). The effect of precursor content and ratio on physicochemical properties were observed by various characterization methods. Moreover, Rhodamine B (RhB) was chosen as the target pollutant to test the performance of these nanocomposites under a photocatalytic Fenton-like reaction. The results showed that the nanocomposite morphology improved by increasing Fe and Mn content. In this study, interesting behavior was observed in BET results which were different from the fact that increasing metal content can decrease the surface area. This study revealed that one metal could be more critical in controlling the properties than another. Moreover, the precursor ratio appears to have a more tangible effect on the surface area than the effect of precursor content. Among all synthesized nanocomposites, Mn1Fe5@SiO2 showed the highest surface area of 654.95 m2/g. At optimum batch conditions (temp = 25 °C, catalyst dosage = 1 g L-1, H2O2 = 75 mmolL-1, and initial RhB concentration = 50 mg L-1), complete removal (simultaneous adsorption/degradation) occurred using Mn1Fe5@SiO2 at neutral pH. This study showed that the designed nanomaterial could be used as a dual functional adsorbent/photocatalyst in different environmental applications.

Sustainable Removal of BTEX Gas Using Regenerated Metal Containing SiO2.

In the last decades, the removal of benzene, toluene, ethylbenzene, and xylene (BTEX) has been considered a major environmental crisis. In this study, two novel nanocomposite materials (Fe2O3/SiO2 and Fe2O3-Mn2O3/SiO2) that have regeneration ability by UV irradiation have been fabricated to remove BTEX at ambient temperature. This research revealed that both nanocomposites could remove more than 85% of the BTEX in the first cycle. The adsorption capacities followed the order of ethylbenzene > m-xylene > toluene > benzene as in the molecular weight order. The reusability test using UV irradiation showed that the performance of Fe2O3/SiO2 decreased drastically after the fifth cycle for benzene. On the other hand, when Mn is located in the nanocomposite structure, Fe2O3-Mn2O3/SiO2 could maintain its adsorption performance with more than 80% removal efficiency for all the BTEX for ten consecutive cycles. The difference in the reusability of the two nanocomposites is that the electron energy (from the valence band to the conduction band) for BTEX decomposition is changed due to the presence of manganese. This study provides a promising approach for designing an economical reusable nanomaterial, which can be used for VOC-contaminated indoor air.

Rapid surface degradation of co-axially arranged polypropylene globules by nanoporous carbonized TiO2 assisted with UV-C.

The degradation of plastics, especially polypropylene (PP), is difficult since it is the most hydrophobic polymer. Photocatalytic degradation of PP films has been reported to be one of the most efficient degradation techniques. However, it is still insignificant to employ it in field applications. In this study, TiO2 nanoparticles supported on amorphous carbon with nanoporosity (TiO2@NC) are used as a photocatalyst to degrade macro-sized co-axially oriented PP globules under the influence of UV-C irradiation. Surface characterization such as SEM, ATR-FTIR, and XPS of the PP globules was performed. The SEM images distinctly showed the surface degradation phenomenon. Interestingly, the ATR-FTIR spectra demonstrated a significant rise in the band intensity in the -OH radical region and fairly in the CO region as well, with the increase in the photocatalytic time. Surprisingly, in the XPS spectra, the intensity of C-1s spectra kept on falling, and the intensity of O-1s spectra kept on rising with the increase in the photocatalytic time. The higher surface area due to nanoporosity of TiO2@NC enhanced the photocatalytic degradation of PP globules than previously reported studies. TiO2@NC seems to be a potential catalyst for the degradation of different types of polymers.

Photocatalytic Degradation of Organic Pollutants over MFe2O4 (M = Co, Ni, Cu, Zn) Nanoparticles at Neutral pH.

In this study, we report a surfactant-mediated synthesis of ferrites (MFe2O4: M = Co, Ni, Cu, Zn) using the co-precipitation-oxidation method. The band gap calculated from UV-Visible diffuse reflectance spectra were found in the range of 1.11-1.81 eV. These ferrite nanocatalysts were studied for the photocatalytic degradation of multiple organic dyes in a 32 W UV-C/H2O2 system. All the four ferrites showed an excellent dye degradation rate in the range of 2.065-2.417 min-1 at neutral pH. In the optimized condition, NiF was found to degrade 89%, 92%, 93%, and 78% of methylene blue, methyl orange, bromo green, and methyl red, respectively within 1 min of UV-irradiation. A 40% TOC removal was recorded after 5 min of degradation reaction, which increased to 60% after 50 min. Mechanism elucidated by scavenger studies and fluorescence spectroscopy revealed that •OH and holes were the primary reactive radicals responsible for the degradation process. Ferrite photocatalysts showed an insignificant performance loss in seven consecutive cycles. The photocatalyst was found efficient in the presence of a high concentration of salts. Thus, it was concluded that these photocatalysts are highly suitable for the remediation of dye-contaminated wastewater.

Attachment Style, Perceived Loneliness, and Psychological Well-Being in Smoking and Non-Smoking University Students.

The growing rate of smoking cigarettes among the youths necessitates examining its contributing factors. Accordingly, we aimed to compare smoking and nonsmoking university students in their attachment styles, perceived loneliness, and psychological well-being. To this end, we recruited 100 current smokers and 100 nonsmoking students by using a convenience sampling method from Shahid Beheshti University, Tehran, Iran. All participants completed the Adult Attachment Scale, Loneliness Scale, and General Health Questionnaire. Data analysis indicated that compared to nonsmokers, smokers had a more anxious attachment style and they felt lonelier. Moreover, current results showed that smokers suffered from higher rates of psychological problems than nonsmokers. These results suggest that smoking is influenced by a set of psychological factors and therefore, prevention and treatment programs targeting these factors may be effective in reducing the rate of smoking cigarettes among university students.