Environmental Applications of ZnO Materials.

This review article comprehensively discusses the recent development of various environmental applications of Zinc Oxide (ZnO) semiconductor materials. The synthesis of various nano/micro structured ZnO using different methods and the influence of various preparation conditions on ZnO morphology are discussed. The environmental applications of nano/micro structured zinc oxide as an adsorbent, photocatalyst, and catalyst in catalytic ozonation processes are discussed. The adsorption of various organic pollutants and metal ions on the ZnO surface at different conditions are discussed. The ZnO assisted photocatalytic degradation of pollutants, water splitting, and disinfection under various conditions are reported on. Ozonation in the presence of zinc oxide and its influence on the removal of pollutants are also included.

Recent developments in heterogeneous catalyzed environmental remediation processes.

This article reports on recent developments in heterogeneous AOP processes such as photocatalysis, Fenton-like process and catalytic ozonation. The principle, mechanism, and influence of experimental conditions on the degradation of pollutants in heterogeneous catalytic ozonation and the photocatalytic process were discussed. Introducing solid catalysts substantially increased the efficiency of the ozonation process by producing hydroxyl radicals in the degradation process. The different types of catalyst, catalyst dosage, solution pH, ozone flow rate, water matrix and catalytic reusability and stability are reported on here. The list of various semiconductor materials used as photocatalysts, their light absorption properties, various light sources and surface properties such as surface area, pore size and pore volume as a factor in the photocatalytic degradation of various pollutants are discussed. The review article also discussed the pollutants degraded using these three processes.

Development of high efficiency silica coated ß-cyclodextrin polymeric adsorbent for the removal of emerging contaminants of concern from water.

This article reports the removal of several emerging contaminants (ECs) from water using novel adsorbent comprising of ß-cyclodextrin (ß-CD) coated on silica. Fourteen different adsorbents were synthesized under different experimental conditions using two different crosslinking agents (hexamethylene diisocyanate (HMDI) and epichlorohydrin (EPI)) and co-polymers (glycidoxypropyl trimethoxysilane (GPTS) and aminopropyl triethoxysilane (APTES). The adsorption capacities of the synthesized adsorbents were initially evaluated using 17ß-estradiol, perfluorooctanoic acid (PFOA), and bisphenol-A (BPA) as adsorbates. The adsorbent prepared by using HMDI as crosslinking agent with DMSO as solvent was observed to perform the best, and removed more than 90% of 17ß-estradiol, PFOA, and BPA. Furthermore, the ß-CD loading on the ECs removal was studied which showed that the adsorbate removal increases with increase in loading of ß-CD on the substrate. The best adsorbent was resynthesized in seven batches and its performance was reproducible for the removal of ten steroid hormones. The adsorbent showed very good regeneration potential for four successive adsorption-regeneration cycles to remove steroid hormones and PFOA. A plausible mechanism of adsorption is proposed. The synthesized best adsorbent is characterized using FTIR, HR-TEM, TGA and nitrogen adsorption analysis. The TGA results showed that the adsorbent has thermal stability of upto 300°C.

Fabrication and photocatalytic properties of self-assembled in(OH)3 and In2O3 nano/micro-cubes.

This article reports a novel fabrication method for In(OH)3 from indium oxalate by hydrothermal process. Hydrothermal decomposition of indium oxalate at 180 degrees C for 10 h results in In(OH)3. The influence of hydrothermal experimental conditions such as temperature, time on the formation of indium hydroxide was investigated. The self-assembly process was strongly influenced the experimental conditions. The thermal decomposition of In(OH)3 at 400 degrees C results In2O3. The synthesized In(OH)3 and In2O3 were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), thermal analysis (TGA and DTA), diffuse reflectance spectra (DRS), and nitrogen adsorption analysis. The XRD patterns indicated the formation of well crystallized cubic phase In(OH)3 and In2O3. The FE-SEM results indicated formation of In(OH)3 and porous In2O3 nano/micro-cubes. The photocatalytic activity of the synthesized In(OH)3 was studied under UV light irradiation and results showed that the In(OH)3 photocatalyst was efficient for dye degradation. We proposed a plausible mechanism for the formation of In(OH)3, and In2O3 self-assembly.

Disinfection of water using Pt- and Ag-doped TiO2 photocatalysts.

In this article we have reported heterogeneous photocatalytic disinfection using pristine and Ag- and Pt-doped nano TiO2 under near-UV light and solar light irradiation. Disinfection experiments were conducted in slurry reactors with Escherichia coli, artificial light and sunlight. The influence of various amounts of Pt and Ag loading (0.5% to 5%) on the E. coli inactivation was examined and results indicated that 5% Pt-TiO2 and 0.5% Ag-TiO2 showed the highest photocatalytic E. coli inactivation. The Pt- and Ag-doped photocatalysts were characterized using XPS and TEM analysis. The influence of experimental parameters such as various photocatalysts, photocatalyst concentration, reactor geometry effect, pH and temperature on the photocatalytic disinfection was studied. The experimental results show that sunlight or near-UV light with TiO2 photocatalyst strongly inactivates E. coli. The Ag-TiO2 photocatalyst was the most efficient photocatalyst tested for bactericidal activity. A plausible mechanism ofphotocatalysed E. coli inactivation is discussed. In conclusion, the doped nano TiO2 photocatalysts is a potential candidate for E. coli inactivation.

Facile microwave-combustion synthesis of wurtzite CdS nanoparticles.

In this study we first report microwave-combustion synthesis of faceted CdS nanoparticles by using cadmium thiocyanate complex as a single source precursor. This is the first example of a metal-thiocyanate (M-SCN) complex being used as a source for metal sulfides (M-S) preparation in a microwave-combustion process. The synthesized CdS was characterized using X-ray diffraction (XRD), field mission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The by-product assisted combustion synthesis yields CdS nanoparticles with the mixtures of octahedral geometries, hexagonal, and triangle plate morphologies and the sizes were found to be 100 nm to 5 microm. The XRD patterns imply the formation of well crystallized wurtzite CdS. The influence of cadmium and sulfur precursors and microwave irradiation time on the morphology of CdS nanoparticle was also investigated. The cadmium and sulfur precursors strongly influenced the CdS morphology and increasing the microwave irradiation time and intensity has no effect on the CdS morphology. In addition, a plausible mechanism of CdS nanoparticle formation has been proposed in this research.

Template-free synthesis of self-assembled Co3O4 micro/nanocrystals.

In this article, we have reported the fabrication of various morphological porous Co3O4 by thermal decomposition of cobalt oxalate at open atmospheric conditions. Uniform cobalt oxalate microrods and microneedles were synthesized without using any surfactants or templates in large scale. The cobalt oxalate preparation method was played a crucial role on the crystal structure and its morphology. The as prepared cobalt oxalates and its corresponding cobalt oxides were characterized by using the thermogravimetric analysis, X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM) and nitrogen adsorption analysis. The XRD results indicated that the orthorhombic and monoclinic cobalt oxalates were formed in different experimental conditions. The influence of preparation method of cobalt oxalates and cobalt precursors on the final morphology has been investigated. The M-H loop of the Co3O4 porous microrods and microneedles showed the presence of paramagnetic properties at room temperatures. A plausible mechanism of both cobalt oxalates and Co3O4 formation was proposed based on the experimental results.

Image-Based Treatment Planning of the Post-Lumpectomy Breast Utilizing CT and 3TMRI.

Accurate lumpectomy cavity definition is critical in breast treatment planning. We compared contouring lumpectomy cavity volume and cavity visualization score (CVS) with CT versus 3T MRI. 29 patients were imaged with CT and 3T MRI. Seven additional boost planning sets were obtained for 36 image sets total. Three observers contoured the lumpectomy cavity on all images, assigning a cavity visualization score (CVS ) of 1 to 5. Measures of consistency and agreement for CT volumes were 98.84% and 98.62%, for T1 MRI were 95.65% and 95.55%, and for T2 MRI were 97.63% and 97.71%. The mean CT, T1 MRI, and T2 MRI CVS scores were 3.28, 3.38, and 4.32, respectively. There was a highly significant difference between CT and T2 scores (P < .00001) and between T1 and T2 scores (P < .00001). Interobserver consistency and agreement regarding volumes were high for all three modalities with T2 MRI CVS the highest. MRI may contribute to target definition in selected patients.

Template-free synthesis of beta-In2S3 superstructures and their photocatalytic activity.

In this article, we have successfully fabricated various morphological beta-Indium sulfide (In2S3) superstructures by using indium thiocyanate complex at acidic pH. All the synthesis has been performed by a template-free, hydrothermal method at 195 degrees C for 3 h. The photocatalytic activity of synthesized In2S3 have been investigated by using UV-B (lamda = 365 nm) light with Methyl Orange dye as a model pollutant. The synthesized photocatalyst was characterized by using XRD, FE-SEM, HR-TEM, DRS spectra and nitrogen adsorption analysis. The influence of indium precursors and solvents on the morphology as well as the surface properties has also been discussed. The XRD result shows that cubic phase beta-In2S3 formed under all experimental conditions. A plausible mechanism of the In2S3 microsphere formation has been discussed based on experimental observations.

Effect of temperature on the formation of macroporous ZnO bundles and its application in photocatalysis.

In this article, the effects of temperature on the formation of macroporous zinc oxide bundles and its photocatalytic activity under a variety of experimental conditions were reported. Thermal decomposition of zinc oxalate dihydrate yields hexagonal wurtzite-type ZnO bundles. Increased the decomposition temperatures resulted in decreased time required for bundle formation, with a corresponding increase in nanoparticles agglomeration. ZnO bundle formation was facilitated up to 200 degrees C after complete decomposition of zinc oxalate into ZnO at 400 degrees C in 15 min. However, low temperature (such as 100 degrees C) was not facilitated nanobundle formation, suggesting the importance of temperature on ZnO bundles formation. In addition, nitrogen adsorption experiments confirmed the presence of macroporous structure in the bundles. The photocatalytic decolorization and adsorption of methylene blue dye (MB) on ZnO bundles were investigated under UV light irradiation. The adsorption and decolorization efficiency of macroporous bundles were higher than the fused bundles. In conclusion, ZnO bundles are efficient and easily recyclable photocatalyst.

Degradation of DMSO by ozone-based advanced oxidation processes.

The present study investigates the oxidation of dimethyl sulfoxide (DMSO) by conventional ozonation and the advanced oxidation processes (AOPs). The major degradation products identified were methanesulfinate, methanesulfonate, formaldehyde, and formic acid in ozonation process. The subsequent degradation of intermediates shows that methanesulfonate is more resistance to ozonation, which reduces the mineralization rate of DMSO. The effect of t-butanol addition and ozone gas flow dosage on the degradation rate was evaluated. The rate constant of the reaction of ozone (k(D)) with DMSO was found to be 0.4162 M(-1)S(-1). In the second part of this study, DMSO degradation and TOC mineralization were investigated using O(3)/UV, O(3)/H(2)O(2) and UV/H(2)O(2) processes. In all theses processes the degradation of target organics is more pronounced than TOC removal. The efficiencies of these processes were evaluated and discussed. The formation of sulfate ion in all AOPs have been identified and compared with other processes. Overall it can be concluded that ozonation and ozone-based AOPs are promising processes for an efficient removal of DMSO in wastewater.

A comparative study of quantum yield and electrical energy per order (E(Eo)) for advanced oxidative decolourisation of reactive azo dyes by UV light.

This paper evaluates the quantum yield and electrical energy per order (E(Eo)) efficiency of Reactive Orange 4 (RO4) and Reactive Yellow 14 (RY14) azo dyes by three advanced oxidation processes (AOPs). Both dyes were completely decolourised by all these processes. The relative decolourisation efficiencies of these processes were in the following order: Fe(2+)/H(2)O(2)/UV>UV/TiO(2)>UV/H(2)O(2). The low efficiency of UV/H(2)O(2) process is mainly due to low UV absorption by hydrogen peroxide at the 365nm. The figure of merit E(Eo) values showed that UV/H(2)O(2) process consumes more electrical energy than the other two processes. The electrical energy consumption is in the following order: UV/H(2)O(2)>UV/TiO(2)>Fe(2+)/H(2)O(2)/UV. At low initial dye concentration higher quantum yield was observed in UV/TiO(2) process, whereas in photo-Fenton process higher quantum yield was observed at high initial dye concentration. The structure of dye molecule also influences the quantum yield and E(Eo) value.

Solar assisted photocatalytic and photochemical degradation of Reactive Black 5.

The photocatalytic oxidative degradation of Reactive Black 5 (RB 5) has been investigated using TiO(2)-P25 as photocatalyst and sunlight as irradiation source in slurry form. The degradation was carried out at different experimental conditions to optimize the parameters such as amount of catalyst, concentration of dye and pH. A complete degradation of 3.85 x 10(-4) M dye solution under solar irradiation was observed in 3.5 h. The photochemical degradation using hydrogen peroxide results in the partial removal of the dye.

TiO2-UV photocatalytic oxidation of Reactive Yellow 14: effect of operational parameters.

The photocatalytic decolourisation and degradation of an azo dye Reactive Yellow (RY14) in aqueous solution with TiO(2) as photocatalyst in slurry form has been carried out using UV-A radiation (365 nm). The effect of various parameters such as catalyst loading, radiation intensity and initial dye concentration on the dye removal was investigated to find optimum conditions. The decolourisation and degradation kinetics have been analysed. Both follow modified Langmuir-Hinshelwood kinetic (L-H) model. A study on the effect of electron acceptors on photooxidation reveals that both decolourisation and degradation increase in the presence of H(2)O(2), (NH(4))(2)S(2)O(8), KBrO(3), to certain dosage beyond which the enhancement effect is negligible. But negative effects are observed in the presence of NaCl or Na(2)CO(3).

Diltiazem enhances tumor blood flow: MRI study in a murine tumor.

PURPOSE: Diltiazem, a calcium-channel blocker, is known to differentially influence the radiation responses of normal and murine tumor tissues. To elucidate the underlying mechanisms, the effects of diltiazem on the radiation response of Ehrlich ascites tumor (EAT) in mice have been investigated, and the hemodynamic changes induced by diltiazem in tumor and normal muscle have been studied using magnetic resonance imaging (MRI) techniques. METHODS AND MATERIALS: Ehrlich ascites tumors were grown subcutaneously in Swiss albino strain A mice. Dynamic gadodiamide and blood oxygen level dependent (BOLD) contrast enhanced 1H MR imaging studies of EAT and normal muscle were performed after administration of diltiazem in mice using a 4.7 Tesla MR scanner. Tumor radiotherapy experiments (total dose = 10 Gy, 0.4-0.5 Gy/min, single fraction) were carried out with 30 min preadministration of diltiazem (27.5 or 55 mg/kg i.p.) to EAT-bearing mice using a teletherapy machine. RESULTS: The diltiazem+ radiation treated group showed significant tumor regression (in approximately/= 65% of the animals) and enhanced animal survival. MR-gadodiamide contrast kinetics revealed a higher magnitude of signal enhancement in diltiazem treated groups as compared to the controls. The observed changes in the magnitude of kinetic parameters were the same for both tumor and normal muscle. BOLD-MR images at 30 min after diltiazem administration showed a 25% and 8% (average) intensity enhancement from their basal values in tumor and normal muscle regions, respectively. The control group showed no significant changes. CONCLUSION: The present studies demonstrate the radiosensitization potential of diltiazem in the mice EAT model. The enhanced radiation response observed with diltiazem correlates with the diltiazem-induced increase in tumor blood flow (TBF) and tumor oxygenation. The present results also demonstrate the applications of BOLD-MR measurements in investigating the alterations in tumor oxygenation status.

Binding of monomeric and oligomeric porphyrins to human glioblastoma (U-87MG) cells and their photosensitivity.

The binding of monomeric (Hp) and oligomeric (PHE) forms of porphyrin to glioblastoma (U-87MG) cells and the photosensitization of these cells have been studied. Upon binding to U-87MG cells, Hp and PHE exhibited fluorescence bands at 615 and 636 nm, respectively. The fluorescence and absorption spectra of Hp, HpD and PHE, measured in different solvents, suggest that the 615 nm band may arise due to the binding of monomeric as well as aggregated forms of porphyrin to the hydrophilic sites in the cells whereas the 636 nm band may be due to the binding of an aggregated form of porphyrin to the hydrophobic sites. The photosensitivity of cells and photo-induced lipid peroxidation were measured as a function of light dose. Cells were found most photosensitive to PHE followed by HpD and Hp. The photosensitivity of cells correlates well with the fluorescence intensity of cell bound dye at 636 nm. These results suggest that the binding of the oligomeric component of HpD to hydrophobic sites in the cells is responsible for the enhancement in the photosensitivity.