Muhammad Khaleeq-ur-Rahman

Micelle-Assisted Synthesis of Al2O3·CaO Nanocatalyst: Optical Properties and Their Applications in Photodegradation of 2,4,6-Trinitrophenol

Calcium oxide (CaO) nanoparticles are known to exhibit unique property due to their high adsorption capacity and good catalytic activity. In this work the CaO nanocatalysts were prepared by hydrothermal method using anionic surfactant, sodium dodecyl sulphate (SDS), as a templating agent. The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3 ·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO. The Al2O3 ·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques. The catalytic efficiencies of these nanocatalysts were studied for the photodegradation of 2,4,6-trinitrophenol (2,4,6-TNP), which is an industrial pollutant, spectrophotometrically. The effect of surfactant and temperature on size of nanocatalysts was also studied. The smallest particle size and highest percentage of degradation were observed at critical micelle concentration of the surfactant. The direct optical band gap of the Al2O3 ·CaO nanocatalyst was found as 3.3 eV.

Solvent controlled synthesis of CaO-MgO nanocomposites and their application in the photodegradation of organic pollutants of industrial waste

Conventional heating method and hydrothermal method were used for the synthesis of CaO nanoparticles and CaO/MgO nanocomposites under solvent control conditions. Ca(NO3)2 and Mg(NO3)2 were used as precursors, amyl alcohol as surface directing agent and NaOH as source of OH−. Different samples of CaO were prepared by conventional heating method in order to investigate the effect of calcination temperature and stirring time. Similarly two different kinds of sets of CaO as well as of CaO/MgO were synthesized under hydrothermal conditions for the investigation of effect of solvent and temperature on catalytic efficiency. Characterizations of these samples were carried out by Powder X-ray Diffractions (XRD), Thermo Gravimetric Analysis (TGA), Field Emission Scanning Electron Microscope (FESEM) Energy dispersive X-ray (EDX) and Fourier Transformed Infrared spectroscopy (FTIR). The synthesized samples of CaO and CaO/MgO were used to degrade methylene blue under UV-Visible conditions, which is an organic pollutant of waste from industries and causing serious health problems. First order data for degradation for methylene blue at λmax = 665 nm was used to quantify the degradation. Effect of solvent was found to be prominent in all samples. Similarly effect of temperature variation was also pronounced on catalytic efficiency as indicated by value of k.

Photodegradation of 2,4,6-trinitrophenol catalyzed by Zn/MgO nanoparticles prepared in aqueous-organic medium

Synthesis of Magnesium oxide (MgO) nanoparticles and zinc deposited magnesium oxide (Zn/MgO) nanoparticles was carried out using hydrothermal and deposition-precipitation method with the variation of 1-Propanol (organic solvent) concentration, sodium hydroxide and urea concentration. The nanoparticles were characterized by using FTIR, TGA, SEM-EDX, TEM and XRD. The photocatalytic efficiency of MgO and Zn/MgO nanoparticles was studied by degradation of 2,4,6-trinitrophenol (TNP), which is highly acute and toxic and causes skin and eyes diseases, liver malfunction and tumor formation. Photodegradation of TNP was carried out under UV irradiation and confirmed by using HPLC and GC-MS. MgO and Zn/MgO nanoparticles that were synthesized by using urea showed higher first-order rate constant (k) value and percentage degradation as compared to nanoparticles that were synthesized using NaOH. It was observed that the concentration of solvent has direct relation with the k value of degradation of TNP.

Development of Latent Fingermarks on Various Surfaces Using ZnO-SiO2 Nanopowder†

Fingermarks are one of the most useful forms of evidence in identification and can provide generalized proof of identity in crime investigation. They are developed using various conventional powders. The novel nanopowder ZnO‐SiO2 was synthesized via the conventional heating method and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX) analysis, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mean particle size of ZnO‐SiO2 nanopowder calculated through TEM was 32.9 nm. The development of fingermarks was carried out by powder dusting and small particle reagent (SPR) methods. Powder dusting method was used for the development of latent fingermarks on various dry, nonporous, and semi‐porous surfaces. The SPR method was also applied to wet nonporous surface. The developed latent fingermarks using ZnO‐SiO2 nanopowder were found to have excellent quality with very clear third‐level ridges detail and had better visibility than commercially available white powder.

Synthesis, structural properties and catalytic activity of MgO-SnO 2 nanocatalysts

Surfactant controlled synthesis of magnesium oxide-tin oxide (MgO-SnO2) nanocatalysts was carried out via the hydrothermal method. Concentration of sodium dodecyl sulfate (SDS) was varied while all other reaction conditions were kept constant same for this purpose. Furthermore, MgO-SnO2 nanocatalysts were also prepared by changing the precursor’s concentration. These precursors are magnesium nitrate Mg(NO3)2 · 6H2O and tin chloride (SnCl4 · 5H2O). The influence of these reaction parameters on the sizes and morphology of the nanocatalysts were studied by using Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy-Energy dispersive X-ray (SEM-EDX), Powder X-ray diffraction (XRD), Transmission electron microscopy and Thermo gravimetric analysis (TGA). The catalytic efficiency of MgO-SnO2 was checked against 2,4-dinitrophenylhydrazine (DNPH), which is an explosive compound. The nanocatalysts were found as a good catalyst to degrade the DNPH. Catalytic activity of nanocatalysts was observed up to 19.13% for the degradation DNPH by using UV-spectrophotometer.

Solvent Controlled Synthesis of Tin Oxide Nanocatalysts and their Applications in Photodegradation of Environmental Hazardous Materials

Solvent controlled synthesis of tin oxide nanocatalysts were prepared via the hydrothermal method. To study the effect of solvent on the particle size of tin oxide and their catalytic efficiency on photodegradation of environmental hazardous materials, the synthesis was carried out at different concentrations of solvent (isoamyl alcohol) keeping all other reaction conditions constant. The nanoparticles were characterized by FourierTransmission Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Diffraction and Thermogravimetric analysis. Prepared nanoparticles were applied as nanocatalyst under UV-visible light for the photodegradation of methyl green,which is an abundant organic pollutant of industrial waste water. Photodegradation activities of the nanocatalysts were measured in three different ways, i. pseudo first order rate constant, “k”. ii. percentage degradationand iii. degradation rate. Effect of solvent was quantitatively explained in term of double sphere model of ion-ion interaction. Degradation of pollutants was also monitored by High Performance Liquid Chromatography.

Template assisted synthesis of CaO-SnO 2 nanocomposites

Calcium oxide (CaO) and tin oxide (SnO2) with nanodimension have attracted significant attention as effective chemosorbents for toxic compounds. Hydrothermal method was used for the synthesis of highly porous CaO-SnO2 nanocomposites by using sodium dodecylsulfate surfactant as a templating agent. Effect of concentration of surfactant as well as its critical micelle concentration (CMC) on the particle size of the nanocomposites was investigated. X-ray diffraction (XRD) was used to determine the crystal phases of these nanocomposites and particle size and morphology was identified by using transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray (SEM/EDX) respectively. Furthermore thermo gravimetric analysis (TGA) and fourier transform infrared (FTIR) spectroscopy techniques were also used to characterize the CaO-SnO2 nanocomposites.

Micelle assisted synthesis of La2O3 nanoparticles and their applications in photodegradation of bromophenol blue

Lanthanum Oxide (La2O3) nanoparticles were synthesized by precipitation method using alkylbenzyl dimethyl ammonium chloride (Benzalkonium chloride) surfactant. The critical micelle concentration (CMC) value of the surfactant was determined using conductance and surface tension methods. The nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. Crystallite size and geometry of La2O3 nanoparticles, established through XRD, are 40 nm and hexagonal, respectively. The optical property was calculated using solid phase UV-visible absorption spectrophotometer with band gap of 4.2 eV. Photocatalytic efficiency of La2O3 nanoparticles was studied against bromophenolblue (organic pollutant) with and without UV radiations. Percentage degradation and first order rate constant values were determined as 24.7% and 0.0942 min–1 without irradiation and that they were 50.4 % and 0.0941 min-1with irradiation, respectively.

Hydrothermal synthesis of leucite nanoparticles using anionic surfactant: Structural evaluation and catalytic properties

Surfactant-assisted synthesis of leucite (KAlSi2O6) nanoparticles was carried out by a hydrothermal method using an anionic surfactant at variable temperatures and surfactant concentrations. The newly synthesized leucite nanoparticles were characterized by FTIR, TGA, XRD, FESEM, and TEM. These nanoparticles have a wide and direct band gap at their smallest particle size (Eg = 3.30 eV), showing a significant quantum confinement effect. Samples of leucite were prepared at 180°C with different SDS concentrations 0.006, 0.007, 0.008, 0.009, and 0.01 M and were used to degrade methylene blue under ultraviolet radiations. These samples degraded methylene blue to 18.5, 31.7, 45.81, 31.61, 30.1%, respectively. The most effective catalyst is the one which was synthesized at 200°C and the CMC value of the surfactant (sodium dodecyl sulfate) having the percentage degradation of 49.1%.