Pooja Dhiman

Magnetically recoverable ZrO2/Fe3O4/chitosan nanomaterials for enhanced sunlight driven photoreduction of carcinogenic Cr(VI) and dechlorination & mineralization of 4-chlorophenol from simulated waste water

In this laboratory-scale experiment we report the treatment of carcinogenic Cr(VI) and 4-chlorophenol by ferromagnetic ZrO2/Fe3O4 nano-heterojunctions supported on chitosan. A combination of different semiconductors with different photo-activities has proven to be a tested and effective technique for harnessing solar light in waste water treatment. The prepared heterojunction and its composite with chitosan has been characterized by X-Ray Diffraction (XRD), Fourier Transform Infra Red spectroscopy (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), Small Area Electron Diffraction (SAED), Vibrating Sample Magnetometry (VSM), Energy Dispersive X-ray analysis (EDX), UV-visible spectrophotometry and Brunauer–Emmet–Teller surface area analysis (BET). Treatment of chlorophenols is challenging because of their hydrophobicity and stability. In our study we have reported excellent results for the dechlorination of 4-chlorophenol and the results were analyzed in terms of Liquid Chromatography-Mass Spectrometry (LC-MS), Chemical Oxygen Demand analysis (COD) and emission. 88.6% of 4-CP degradation was achieved in the presence of ZrO2/Fe3O4/chitosan in 3 h under sunlight and a reduction of 90.2% for Cr(VI) was obtained. The heterojunction formation leads to charge separation and decreased recombination of charge carriers. The synergistic effects of charge separation in the heterojunction, alcohols, peroxide, magnetism and adsorption with essential explanation of mechanisms make this study important and promising.

Structural, optical and magnetic properties of perovskite (La1−xSrx)(Fe1−xNix)O3, (x = 0.0, 0.1 & 0. 2) nanoparticles

Nanoparticles (NPs) of (La1−xSrx)(Fe1−xNix)O3, (x = 0.0, 0.1 & 0.2) with orthorhombic perovskite structure was successfully prepared through the sol-gel combustion method. The structural, optical and magnetic properties of the NPs were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive x-ray spectrometer (EDS), UV-Vis. Spectrometer and magnetization measurements. The crystallite size was estimated from x-ray diffraction (XRD) patterns, which decreases with increase in Sr and Ni contents and SEM images exhibit formation of agglomerated NPs for pure and doped samples. The absorbance has a tendency to increase with the increase in dopant concentration and band gap increases with Sr and Ni contents. Magnetization measurement revealed ferromagnetic nature of all samples at room temperature.

Structural and Magnetic Studies of Co0.6Zn0.4Fe2O4 Nanoferrite Synthesized by Solution Combustion Method

Co0.6Zn0.4Fe2O4 nanomagnetic system is prepared by solution combustion method. The powder sample is characterized by X-ray diffraction (XRD), transmission electron microscope analysis (TEM), Fourier transform infrared spectroscopy (FTIR), Mössbauer spectroscopy, and superconducting quantum interference device (SQUID; at low and room temperatures). The average crystallite sizes of the prepared samples obtained from XRD is 22 nm, which is well confirmed by the size obtained from TEM. The magnetic study shows that sample is ferromagnetic at room temperature. This result is also supported by Mössbauer spectrum obtained at room temperature.

Aerogels and metal–organic frameworks for environmental remediation and energy production

Environmental pollution and climate change are requiring new methods to clean pollutants and produce sustainable energy. Aerogels and metal organic frameworks are emerging as advanced porous materials with higher functionality, high surface area, high porosity and flexible chemistry. Aerogels are dried gels prepared using the sol–gel procedure, whereas metal organic frameworks are networks of organic ligands and metal ions connected by coordination bonds. Applications of aerogels include the removal of heavy metals, CO2 capture and reduction, photodegradation of pollutants, air cleanup and water splitting. This article reviews the synthesis and types of aerogels and metal organic frameworks, and the application to pollutant removal, energy production including hydrogen, methane reforming, CO2 conversion and NOx removal.

Rietveld-refinement and optical study of the Fe doped ZnO thin film by RF magnetron sputtering

Fe Doped ZnO Dilute Magnetic Semiconductor thin film prepared by RF magnetron sputtering on glass substrate and Influence of 3% Fe-doping on structural and Optical properties has been studied. The Rietveld-refinement analysis shows that Fe doping has a significant effect on crystalline structure, grain size and strain in the thin film. Two dimensional and three-dimensional atom probe tomography of the thin film shows that Fe ions are randomly distributed which is supported by Xray Diffraction (XRD). Fe-doping is found to effectively modify the band gap energy up to 3.5 eV.

Ni, Fe Co-doped ZnO nanoparticles synthesized by solution combustion method

This paper outlines the synthesis and characterization of Ni-Fe co-doped ZnO nanoparticles by facile solution combustion method. The structural characterization by XRD confirmed the phase purity of the samples. Surface morphology studied by scanning electron microscope revealed cubic type shape of grains. EDS analysis conformed the elemental composition. Higher value of DC electrical conductivity and less band gap for co-doped ZnO from UV-Vis studies confirmed the change in defect chemistry of ZnO Matrix.

Structural and electrical properties of Fe doped ZnO nanoparticles synthesized by solution combustion method

The samples of Zn1-xFex O (0≤x≤0.04) were prepared by simple solution combustion method. The structural characterization by XRD and TEM confirmed the phase purity of the samples and reduction in the particle size with increase in the Fe concentration in the ZnO. Room temperature measurement of DC electrical conductivity was found to decrease with increase of Fe content.