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In the present work, CdFe2O4/Al2O3 magnetic nanocomposite photocatalyst is successfully synthesized by simple sol-gel auto-combustion method. The role of this sample is studied as a photocatalyst. The influence of Al2O3 concentration with CdFe2O4 on the photocatalytic property is also studied. We have considered three weight percentage of Al2O3, 5%, 10%, and 20% with CdFe2O4. All the samples are characterized with X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), vibrating sample magnetometer (VSM), UV-Visible, and photoluminescence (PL) spectroscopy techniques. The 10% composite sample showed the lower particle size, higher surface area, enhanced porosity, higher saturation magnetization, and considerable band gap as compared to that of 5% and 20% CdFe2O4/Al2O3 as well as bare CdFe2O4 nanoparticles. The photocatalytic activity of the sample is evaluated towards the degradation of the xylenol orange (XO) dye under UV light. The degradation process of the dye is monitored spectrophotometrically. The performance in terms of removal efficiency is studied by varying the contact time, dye concentration and amount of catalyst. Among the three concentrations of Al2O3, the 10% weight concentration of Al2O3 with CdFe2O4 is found to be the optimal concentration and showed the higher degradation rate. After 30 min photocatalytic reaction, the degradation rate is 92.29% for 10% CdFe2O4/Al2O3 and for bare CdFe2O4, it is 85.79%. This work provides a new reference for designing Al2O3-based spinel ferrite nanocomposites and their role in wastewater management. [ABSTRACT FROM AUTHOR]

Hydrothermal synthesis and comparative gas sensing properties of nanocrystalline ZrO2, 5% yttrium doped ZrO2 (5%Y/ZrO2) and silver coated 5% yttrium doped ZrO2 (Ag-5%Y/ZrO2) and their thick films were reported here for the first time. The obtained polycrystalline products were analyzed by various physical investigative techniques including XRD, TEM and BET surface area. Screen printed thick films of ZrO2 and modified ZrO2 oxides were prepared for gas sensing properties of most toxic combustible and hazardous gases CO, CO2, H2, Cl2, NH3 and H2S at different operating temperatures ranging from 50 to 400 °C. This work investigates the use of ZrO2, 5%Y/ZrO2 and Ag-5%Y/ZrO2 thick film as a gas sensor and the annealing temperature considerably affects the sensitivity of these metal oxides towards NH3 and CO2 gases. The statistical analysis for gas sensitivity towards synthesized catalyst was also carried out. Further, metrological study of Ag-5%Y/ZrO2 sensor as a function of relative humidity (RH) and light intensity with various concentration of CO2 gas is also studied. [ABSTRACT FROM AUTHOR]

Fly ash is one of the coal combustion solid wastes which causes environmental problems around the world. In this context for the first time, this paper reports the conversion of coal fly ash (CFA) into aluminosilicate chlorosodalite, Na8[AlSiO4]6Cl2. The synthesized chlorosodalite was analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, and Brunauer-Emmett-Teller surface area measurements. The synthesized aluminosilicate chlorosodalite material was tested for potential applications for the removal of calcium, magnesium, and copper from their aqueous medium. The catch method was successfully used to study the effect of the initial concentration of metal ions, adsorbent dose, and contact time. The equilibrium data obtained were fitted by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models and showed the affinity order Cu2+ > Ca2+ > Mg2+. The well-known thermodynamic aspects such as the variation in Gibbs free energy (ΔG), entropy (ΔS), and enthalpy (ΔH) were also evaluated. Further the kinetic parameters including the rate constant and the order of sorption process were also determined. [ABSTRACT FROM AUTHOR]

The CdO and modified CdO nanoparticles were synthesized using hydrothermal method. The absorption spectra, crystal phase, surface morphology, particle size, and surface area of CdO and modified CdO nanoparticles were studied by UV–DRS, FT-IR, XRD, SEM, TEM, TGA, PL, and BET surface area analysis. The present paper reports adsorption technique for the removal of chromium (VI) using CdO and modified CdO nanoparticles. The operating variables such as adsorbent dose, nature of adsorbent, adsorbate concentration, contact time, and pH were optimized. The technique was found to be highly useful and cost effective for removal of chromium (VI). The Langmuir and Freundlich models were evaluated using the experimental data and result showed that the Freundlich isotherm fit better than the Langmuir isotherm. [ABSTRACT FROM PUBLISHER]

Aluminosilicate azide cancrinite, Na8[AlSiO4]6(N3)2.4(H2O)4.6, has been prepared for the first time from zeolite-A, followed by hydrothermal processing at low temperature. After crystallization, the sample was characterized by appropriate physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface area. In the present study, attention was focused on investigating the removal performance of heavy metal ions (Cd2+, Pb2+, and Ni2+) in aqueous solution on pure aluminosilicate azide cancrinite. The kinetics of the process and sorption capacity of the adsorbent was determined in relation to the effect of various factors affecting on the adsorption process. The parameters in this study included contact time, metal ion concentration, temperature, and adsorbent dosage. The removal mechanism of metal ions followed adsorption and ion exchange process. Adsorption data has been interpreted in terms of Langmuir and Freundlich equations. The selectivity of the studied metal ions was determined as Pb2+ > Cd2+ > Ni2+. Thermodynamic parameters, i.e., equilibrium constant (Kc), free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) for adsorption, were computed from the experimental data. [ABSTRACT FROM AUTHOR]

This study investigated the chemical modification of F-class coal fly ash (CFA) to an iodate enclathrated aluminosilicate sodalite, Na8[AlSiO4]6(IO3)2, cubic P43n, has been synthesized by hydrothermal treatment followed by fusion of CFA with NaOH. The fused mass was mixed with excess NaIO3 and hydrothermally treated at 100°C. Infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, and inductively coupled plasma spectroscopy methods were used to characterize the obtained sodalite. Sorption behavior of heavy metals (Cd2+, Pb2+, and Zn2+) from aqueous solution on iodate sodalite was examined. The Freundlich and Langmuir isotherms are evaluated for iodate sodalite. These models were fitted to the curves of heavy metals ion solutions to estimate the Freundlich (Kf) and Langmuir (Qo) adsorption parameters. These values followed the same trend of the batch experiments. The maximum sorption capacity of sodalite increased in the order Pb2+>Cd2+ >Zn2+ at the same condition. The effect of different parameters, such as contact time, and temperature were also investigated. The present investigation also revealed that iodate sodalite as sorbents can serve as low-cost adsorbent with higher sorption capacities towards heavy metals. [ABSTRACT FROM AUTHOR]

One-pot synthetic gallosilicate nitrate cancrinite (CAN) framework topology have been synthesized under hydrothermal conditions at 100 oC. The synthesized product was characterized by, X-ray powder diffraction, IR, Raman and 29Si, 23Na MAS NMR spectroscopy, SEM and thermogravimetry. The crystal structure refinement of pure nitrate cancrinite has been carried out from X-ray data using Rietveld refinement method. Gallosilicate cancrinite Na8[GaSiO4]6(NO3)4(H2O)6 crystalline hexagonal with space group P63 and a = 12.77981 Å (2), c = 5.20217 Å (1), (Rwp = 0.0696 Rp = 0.0527). The results by MAS NMR spectroscopy confirmed the alternating Si, Ga ordering of the gallosilicate framework for a Si/Ga ratio of 1.0. A distribution of the quadrupolar interaction of the sodium cations caused by the enclatherated water molecules and motional effects can be suggested from the 23Na MAS NMR. Thermogravimetric investigation shows the extent of nitrate entrapment, stability within the cancrinite cage and decomposition properties. SEM clearly shows the hexagonal needle shaped crystals of nitrate cancrinite. [ABSTRACT FROM AUTHOR]

One-pot synthetic gallosilicate nitrate cancrinite (CAN) framework topology have been synthesized under hydrothermal conditions at 100 oC. The synthesized product was characterized by, X-ray powder diffraction, IR, Raman and 29Si, 23Na MAS NMR spectroscopy, SEM and thermogravimetry. The crystal structure refinement of pure nitrate cancrinite has been carried out from X-ray data using Rietveld refinement method. Gallosilicate cancrinite Na8[GaSiO4]6(NO3)4(H2O)6 crystalline hexagonal with space group P63 and a = 12.77981 Å (2), c = 5.20217 Å (1), (Rwp = 0.0696 Rp = 0.0527). The results by MAS NMR spectroscopy confirmed the alternating Si, Ga ordering of the gallosilicate framework for a Si/Ga ratio of 1.0. A distribution of the quadrupolar interaction of the sodium cations caused by the enclatherated water molecules and motional effects can be suggested from the 23Na MAS NMR. Thermogravimetric investigation shows the extent of nitrate entrapment, stability within the cancrinite cage and decomposition properties. SEM clearly shows the hexagonal needle shaped crystals of nitrate cancrinite. [ABSTRACT FROM AUTHOR]