Roles of titanium dioxide and ion-doped titanium dioxide on photocatalytic degradation of organic pollutants (phenolic compounds and dyes) in aqueous solutions: A review

Highly effective Fe-doped TiO2 nanoparticles photocatalysts for visible-light driven photocatalytic degradation of toxic organic compounds

Gamma radiation/H2O2 treatment of a nonylphenol ethoxylates: Degradation, cytotoxicity, and mutagenicity evaluation.

Cytotoxicity and mutagenicity of textile effluents, treated by gamma radiation in combination hydrogen peroxide was investigated. The Allium cepa , heamolytic, brine shrimp bioassays were used for cytotoxicity evaluation, whereas mutagenicity was tested using Ames tests. Textile effluents were irradiated to the gamma radiation absorbed doses of 5 kGy, 10 kGy and 15 kGy in combination with 20 mM hydrogen peroxide. Before treatment, textile effluents showed a significant cytotoxicity and mutagenicity signs and reduced significantly after treatment. A. cepa showed reduction in cytotoxicity 50%, whereas 56–59% in case of heamolytic test and up 93% reduction in cytotoxicity was recorded by brine shrimp assays. The mutagenicity of gamma radiation treated effluents reduced up to 59% and 54% in case of TA98 and TA100, respectively. Results revealed that the gamma radiation in combination with hydrogen peroxide can be implemented for the detoxification of textile effluents.

Cytotoxicity and mutagenicity evaluation of gamma radiation and hydrogen peroxide treated textile effluents using bioassays

In the present work, bare TiO2 and different molar concentrations of iron (Fe3+)-doped TiO2 photocatalysts (0.05−1 mol % Fe) were prepared by a simple precipitation method for photocatalytic hydrogen production and degradation of organic pollutants (MO and 4-CP) under light irradiation of λ ≥ 320 nm. XRD revealed the presence of anatase phase for both bare TiO2 and Fe doped titania. Based on the XPS results, Fe3+ ions are hardly seen may be attributed to the location of iron inside the titania matrix rather than their appearance at the surface. UV–vis-DRS of the doped titania demonstrated a redshift toward visible region owing to the reduced bandgap energy. N2 adsorption results showed that the doped materials have higher surface area compared to bare TiO2 due to decrease particle size. Importantly, electrochemical experiments (electrochemical impedance spectroscopy (EIS), photocurrent (PC), and photoluminescence (PL)) revealed that higher photogenerated charge carrier separation efficiency of iron-doped titania. Results showed that the 0.1 mol % Fe doped TiO2 exhibited the highest photocatalytic activity for both degradation and H2 evolution reactions. Furthermore, high surface area, small particle size and enhanced visible-light absorption as well as improved charge transfer and separation are believed to be responsible for the improvement of photocatalytic activity of the doped materials.

Enhanced photocatalytic hydrogen production and degradation of organic pollutants from Fe (III) doped TiO2 nanoparticles

Degradation and detoxification of aqueous nitrophenol solutions by electron beam irradiation

The positron lifetime technique was employed to study vacancy-type defects in 8 MeV electron-irradiated n-type 6H silicon carbide. A long-lifetime component having a characteristic lifetime of 223–232 ps was observed in the irradiated sample and was attributed to the VCVSi divacancy. Other positron traps, which dominated at low temperatures, were observed to compete with the VCVSi for trapping positrons. A positron trapping model involving a positron shallow trap, a negatively charged monovacancy and the VCVSi divacancy was found to give a good description of the temperature-dependent positron lifetime data of the 1200 ◦ C annealed sample. The identity of the monovacancy could not be unambiguously determined, but its lifetime was found to be in the range 160–172 ps.

/pdf/positron-lifetime-studies-on-8-mev-electron-irradiated-n-9t3bfgwjut.pdf

Positron lifetime studies on 8 MeV electron-irradiated n-type 6H silicon carbide

The defect changes in 6H-SiC after annealing and 10MeV electron irradiation have been studied by using a variable-energy positron beam. It was found that after annealing, the defect concentration in n-type 6H-SiC decreased due to recombination with interstitials. When the sample was annealed at 1400°C for 30min in vacuum, a 20-nm thickness Si layer was found on the top of the SiC substrate, this is a direct proof of the Si atoms diffusing to surface when annealed at high temperature stages. After 10MeV electron irradiation, for n-type 6H-SiC, the S parameter increased from 0.4739 to 0.4822, and the relative positron-trapping rate was about 27.878 times of the origin sample, this shows that there are some defects created in n-type 6H-SiC. For p-type 6H-SiC, it is very unclear, this may be because of the opposite charge of vacancy defects.

http://staff.ustc.edu.cn/~bjye/ye/papers/2003-1.pdf

Vacancy in 6H-Silicon Carbide Studied by Slow Positron Beam

Twelve MeV electron beams were used to irradiate common P + NN + diodes (1 A and 1 kV) in order to transfer them into high frequency rectifying ones. Some interesting results have been obtained. It seems that this method is superior to the traditional gold-doping technique in controlling precisely the lives of the minority carriers. Compared with the later electron beam irradiation made the reverse recovery time ( t rr ) and FWD-voltage ( V F ) of the diodes better consistent and repeatable. The high temperature performance was also obviously improved. The qualified rate of diodes was enhanced by more than 30%.

Hang Desheng

Papers

Degradation and detoxification of aqueous nitrophenol solutions by electron beam irradiation

Positron lifetime studies on 8 MeV electron-irradiated n-type 6H silicon carbide

Vacancy in 6H-Silicon Carbide Studied by Slow Positron Beam

Using 12 MeV electron beams to develop silicon P+NN+ high frequency rectifying diodes