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Degradation of the insecticide chlorpyrifos in contaminated soils was investigated using laboratory synthesized zero-valent nano iron (ZVNI) particles. The synthesized ZVNI particles were characterized as nanoscale sized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The zero-valent state (Fe0) of iron was confirmed by EDAX analysis and the morphology of the ZVNI particles was studied by XRD. Batch experiments were conducted by treating the chlorpyrifos contaminated soil with ZVNI, our results indicate that 90% of chlorpyrifos was degraded after 10 days of incubation. Only 32% degradation was observed with micro zero-valent iron (mZVI) and no considerable degradation was attained without ZVNI. The degradation of chlorpyrifos followed the first-order kinetics with a rate constant and a half-life of 0.245 day−1and 2.82 days, respectively. Degradation was monitored at two different pH values, that is, pH 10 and pH 4. Chlorpyrifos degradation rate constant increased as the pH decreases from 10 to 4. The corresponding rate constant and half-lives were 0.43 day−1and 1.57days for pH 4, 0.18 day−1and 3.65 days for pH 10. In addition, an attempt was made by augmenting Al2(SO4)3with ZVNI and it was found that the degradation rate of chlorpyrifos was greatly enhanced and the rate constant was rapidly increased from 0.245 day−1to 0.60 day−1. Hydrolysis and stepwise dechlorination pathway of chlorpyrifos with ZVNI was the dominant reaction.

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MoO3 films were deposited on Corning glass and silicon substrates held at room temperature (303 K) by RF magnetron sputtering of metallic molybdenum target at a fixed oxygen partial pressure of 4x10 -4 mbar and sputter pressure of 4x10 -2 mbar. The as deposited films were annealed in air at different temperatures in the range 473 -673 K. X-ray diffraction studies suggest that the as-deposited and the films annealed at 473 K were amorphous in nature, while those annealed at 573 and 673 K were polycrystalline with mixed phases of αorthorhombic and βmonoclinic MoO3. Scanning electron microscope images of the films annealed at 573 and 673 K exhibited nanoflower like and nanodisk like structures due to improvement in the crystallinity. Fourier transform infrared studies showed the characteristic vibrations of MoO3 with shift in the vibrational modes of Mo = O and Mo -O -Mo with increase of annealing temperature. The optical absorption edge of the films shifted towards lower wavelengths side with increase of annealing temperature. Optical band gap of as-deposited films was 2.98 eV with refractive index 2.01, while those annealed at 673 K showed the optical band gap of 3.15 eV and refractive index of 2.08. The MoO3 films annealed at 673 K were of nanocrystalline with crystallite size of 39 nm with optical band gap of 3.15 eV and refractive index of 2.08 were favorable for electron blocking and hole-selective layers in bulk-heterojuction solar cells.