One-pot sonochemical synthesis of CdS-reduced graphene oxide composite and its application for photocatalytic degradation of methylene blue

614-618A one-pot synthesis of CdS-reduced graphene oxide (RGO) composite via sonochemical reduction of graphite oxide and simultaneous CdS formation is reported. The composite is characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy and UV-vis absorption spectroscopy and its photocatalytic performance is evaluated for the degradation of methylene blue. Results show that in the composite the RGO nanosheets are densely decorated by CdS nanoparticles, displaying a good combination between RGO and CdS. The CdS-RGO composite exhibits enhanced photocatalytic performance for the dye degradation with a maximum removal rate of 96% under visible light irradiation due to increased light absorption intensity as well as the reduced electron-hole pair recombination in CdS

Photo-catalytic reduction of chromium in aqueous solution by Fe³⁺ doped TiO₂ nanoparticles

513-515The present study deals with the photo-catalytic reduction of Cr (VI) by TiO2 nanoparticles. A detailed adsorption study of Cr (VI) by Fe3+ doped TiO2 at different pH shows that the adsorption of chromium by TiO2 nanoparticles is governed by charge of TiO2 nanoparticles. which depends on the pH of solution. Kinetic studies show that reduction and adsorption of Cr (VI) by Fe3+ doped TiO2 are not similar. Photocatalytic reduction of Cr (VI) by Fe3+ doped TiO2 is more feasible at low pH. Fe3+ doped TiO2 nanoparticles accelerate the reduction rate of Cr (VI) to Cr (III) than commercially available TiO2 particles

Photocatalytic Degradation of Thiram (Fungicides) under Visible Light Irradiation

Pesticides in the different form are toxic to the environment and removal of its form the various sources is a difficult task. The thiram undergoes photocatalytic degradation under visible light when prepared TiO2∼PVA polymer composite was used as a photocatalyst. The data represent that prepared TiO2∼PVA polymer composite is a more efficient photocatalyst than the neat TiO2. Photocatalytic efficiency of prepared TiO2∼PVA polymer composite was measured in term of no adsorption of pollutant, higher degradation rate and act as a photocatalyst under visible light irradiation. 150 minutes are required for the complete degradation of the thiram. The end products of photocatalytic degradation of thiram are CO2, nitrate and sulphate

Undoped, single phase barite BaCrO₄ photocatalyst for the degradation of methylene blue under visible light

54-58The photoassisted degradation of a phenothiazine dye, methylene blue, has been examined in aqueous dispersions under visible irradiation at wavelengths greater than 400 nm with BaCrO4 and bare TiO2. Spectral changes during the photocatalytic degradation of methylene blue suggest that the de-methylation is an initiation process of photocatalysis reaction followed by ring opening and finally mineralisation into mineral acid and water. Comparative study shows that BaCrO4 is a better photocatalyst than bare TiO2 under visible light irradiation. COD analysis suggests that the degradation of methylene blue is due to photocatalysis and not due to any other reason. Catalytic poisoning is observed for both the photocatalysts.</b

One pot synthesis of copper nanoparticles at room temperature and its catalytic activity

A facile reduction approach with sodium borohydride as a reducing agent and starch as a stabilizing agent leads to monodispersed Cu nanoparticles in aqueous medium at an ambient condition. The synthesized nanoparticles are highly pure with no traces of CuO found on surface. They are uniform in size in the range of 40–80 nm. The Cu nanoparticles have a FCC structure as characterized by powder X-ray diffraction (XRD). Transmission electron microscopy (TEM) images show that they are arranged in a regular array which is separated by starch thin layer which controls the growth as well as stabilizes the Cu nanoparticles from air oxidation. The catalytic activity of prepared Cu nanomaterial was tested in Ullman reaction for the synthesis of biphenyl from iodobenzene. We have shown in this paper that the size as well as exposed surface area of the copper nanoparticles is responsible for the increase in yield of biphenyl up to 92%. This is higher compare to the 40% yield with the normal size copper powder under the same reaction condition

Comparison of Presentation and Prognosis of Takayasu Arteritis with or without Stroke or Transient Ischemic Attack—A Retrospective Cohort Study

Takayasu arteritis (TAK) could cause a stroke or transient ischemic attack (TIA) in young individuals due to inflammatory vascular occlusion or intracerebral hemorrhage. We compared the clinical presentation, angiographic features, longitudinal patterns of disease activity, medical treatments, and survival in 34 TAK patients with stroke/TIA and 157 without stroke/TIA from a single-center retrospective cohort. TAK patients with stroke/TIA were older (p = 0.044) with a greater proportion of males (p = 0.022), more frequent vision loss (odds ratio (OR) for stroke/TIA vs. without stroke TIA 5.21, 95% CI 1.42–19.14), and less frequent pulse or blood pressure inequality (OR 0.43, 95% CI 0.19–0.96) than TAK patients without stroke/TIA. Hata’s angiographic type IIa was more common in TAK patients with stroke/TIA (OR 11.00, 95%CI 2.60–46.58) and type V in TAK patients without stroke/TIA (OR 0.27, 95% CI 0.12–0.58). Cyclophosphamide was used more often in TAK patients with stroke/TIA (p = 0.018). Disease activity at baseline, 6, 12, and 24 months of follow-up was mostly similar for both groups. Risk of mortality was similar in TAK patients with or without stroke/TIA (hazard ratio unadjusted 0.76, 95% CI 0.15–3.99; adjusted for gender, age of disease onset, delay to diagnosis, baseline disease activity, and the number of conventional or biologic/targeted synthetic immunosuppressants used 1.38, 95% CI 0.19–10.20) even after propensity score-matched analyses. Stroke or TIA does not appear to affect survival in TAK patients adversely