Synthesis, characterization and visible light photocatalytic activity of nitrogen-doped zinc oxide nanospheres

Pure and Nitrogen (N)-doped ZnO nanospheres were successfully prepared using microemulsion method. X-ray diffraction (XRD) study indicates formation of nanosized N-doped ZnO with wurtzite phase. Nitrogen incorporation into oxygen site of ZnO causes lattice compression and small peak shift toward lower 2θ value. Raman and Fourier transform infrared (FTIR) measurements revealed the presence of N in ZnO lattice. Scanning electron microscopy (FESEM) study revealed spherical morphology of pure and N-doped ZnO samples. UV–visible spectra show that N-doping significantly enhanced the light absorption capacity of ZnO in the visible region. N-doped ZnO exhibits higher photocatalytic activity compared with that of commercial and pure ZnO nanoparticles. As prepared nanosized N-doped ZnO photocatalyst is highly stable and reusable

Synthesis, characterization and visible light photocatalytic activity of carbon and iron modified ZnO

In the present work visible light active C and Fe modified ZnO photocatalysts were prepared using microemulsion method. The obtained samples were characterized by TG-DTA, XRD, FT-IR, XPS, SEM, EDX, TEM, PL and UV–visible spectroscopy. XRD study reveals that C and Fe modified ZnO have hexagonal wurtzite structure. As the concentration of Fe changes, morphology of ZnO also changes from rod like shape to spherical shape. It was found that C, Fe co-doping improves the photoabsorption capacity of ZnO in visible region (red shift is observed). XPS study reveals that C and Fe are successfully doped into ZnO lattice with Iron in Fe (III) state. PL quenching for C, Fe co-doped ZnO photocatalysts indicates lower recombination rate of excited electrons/holes. As compared to undoped and C doped ZnO, and Fe doped ZnO, the C, Fe co-doped ZnO photocatalysts exhibited much higher photocatalytic activity for 2,4,6-trichlorophenol (TCP) degradation under visible light irradiation. The optimal ratio of Fe is found to be 2.07 wt%. Stability of photocatalyst was investigated up to fourth cycle and is found to be very stable

Visible light photocatalytic degradation of 4-chlorophenol using C/ZnO/CdS nanocomposite

C/ZnO/CdS nanocomposite was synthesized using the microemulsion method. Nanocomposite synthesized in the present work was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) transmission electron microscope (TEM), diffuse reflectance and photoluminescence (PL) spectroscopy. TEM study shows that CdS nanoparticles are successfully anchored on the surface of C doped ZnO nanorods. UV–visible spectrum of C/ZnO/CdS nanocomposite shows a red shift. CdS nanoparticles work as photo sensitizers to expand the photo-response of C doped ZnO to the visible region. Photoluminescence (PL) spectroscopy reveals evidence for interaction between C/ZnO and CdS. PL quenching observed for C/ZnO/CdS nanocomposite is attributed to improved charge separation properties, which increases its photocatalytic efficiency. C/ZnO/CdS nanocomposite exhibits exceptionally high photocatalytic activity for degradation of 4-chlorophenol (CP) via Z-scheme mechanism. C/ZnO/CdS nanocomposite is a highly stable and reusable photocatalyst

Visible light photocatalytic degradation of malachite green using modified titania

Nanoparticles of titanium dioxide co-doped with carbon and iron (III) were prepared using the microemulsion method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence spectroscopy (PL), and UV-visible diffuse reflectance spectroscopy were used to characterize pure and doped TiO2 nanoparticles. Doped C atoms exist as the O–Ti–C structure or interstitial C in TiO2 lattice, while the doped Fe3+ atoms substitute some of Ti4+ to form the Ti–O–Fe structure. In comparison with the pure and C-doped TiO2, all C, Fe co-doped TiO2 samples exhibit a narrower band gap and stronger visible light absorption. The assistance of the C and Fe3+ ion enhances the photocatalytic activity in the visible light region and also inhibits the electron–hole recombination. The photocatalyst co-doped with C and 2.01 wt% Fe shows the excellent photocatalytic activity and degradation efficiency was improved by 78% under visible light irradiation as compared with the pure TiO2. Keywords: Photocatalysis, Microemulsion technique, Titanium dioxide, X-ray methods, Photoluminescenc

Chronic postsurgical pain in Europe: An observational study

BACKGROUND Chronic postsurgical pain (CPSP) is an important clinical problem. Prospective studies of the incidence, characteristics and risk factors of CPSP are needed. OBJECTIVES The objective of this study is to evaluate the incidence and risk factors of CPSP. DESIGN A multicentre, prospective, observational trial. SETTING Twenty-one hospitals in 11 European countries. PATIENTS Three thousand one hundred and twenty patients undergoing surgery and enrolled in the European registry PAIN OUT. MAIN OUTCOME MEASURES Pain-related outcome was evaluated on the first postoperative day (D1) using a standardised pain outcome questionnaire. Review at 6 and 12 months via e-mail or telephonic interview used the Brief Pain Inventory (BPI) and the DN4 (Douleur Neuropathique four questions). Primary endpoint was the incidence of moderate to severe CPSP (numeric rating scale, NRS ≥3/10) at 12 months. RESULTS For 1044 and 889 patients, complete data were available at 6 and 12 months. At 12 months, the incidence of moderate to severe CPSP was 11.8% (95% CI 9.7 to 13.9) and of severe pain (NRS ≥6) 2.2% (95% CI 1.2 to 3.3). Signs of neuropathic pain were recorded in 35.4% (95% CI 23.9 to 48.3) and 57.1% (95% CI 30.7 to 83.4) of patients with moderate and severe CPSP, respectively. Functional impairment (BPI) at 6 and 12 months increased with the severity of CPSP (P<0.01) and presence of neuropathic characteristics (P<0.001). Multivariate analysis identified orthopaedic surgery, preoperative chronic pain and percentage of time in severe pain on D1 as risk factors. A 10% increase in percentage of time in severe pain was associated with a 30% increase of CPSP incidence at 12 months. CONCLUSION The collection of data on CPSP was feasible within the European registry PAIN OUT. The incidence of moderate to severe CPSP at 12 months was 11.8%. Functional impairment was associated with CPSP severity and neuropathic characteristics. Risk factors for CPSP in the present study were chronic preoperative pain, orthopaedic surgery and percentage of time in severe pain on D1. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01467102