Imad Hamadneh

Characterization of TiO2-Chitosan/Glass photocatalyst for the removal of a monoazo dye via photodegradation-adsorption process.

In this paper, the newly explored TiO(2)-Chitosan/Glass was suggested as a promising alternative material to conventional means of wastewater treatment. Characterization of TiO(2)-Chitosan/Glass photocatalyst was studied with SEM-EDX, XRD, and Fourier transform infrared spectroscopy (FTIR) analysis. The combination effect of photodegradation-adsorption process for the removal of methyl orange (MO), an acid dye of the monoazo series occur promisingly when four layers of TiO(2)-Chitosan/Glass photocatalyst was used for MO removal. Approximately, 87.0% of total MO removal was achieved. The reactive -NH(2), -OH, and metal oxide contents in the prepared photocatalyst responsible for the photodegradation-adsorption effect were confirmed by FTIR study. Similarly, MO removal behavior was well supported by SEM-EDX and XRD analysis. Significant dependence of MO removal on the TiO(2)-Chitosan loading can be explained in terms of relationship between quantum yield of photocatalytic reactions and photocatalyst structure/activity. Hence, the research work done thus far suggests a new method, having both the advantages of photodegradation-adsorption process in the abatement of various wastewater pollutants.

A study on removal characteristics of o-, m-, and p-nitrophenol from aqueous solutions by organically modified diatomaceous earth

AbstractThe natural diatomaceous earth (DAT) was modified with surfactant of hexadecyltrimethylammonium bromide (HDTMABr) to form organic-modified diatomaceous earth (DAT-HDTMABr). The DAT and DAT-HDTMABr were characterized by X-ray fluorescence, X-ray diffraction, FT-IR and DTA-TG. The surface area was determined using Brunauer, Emmett, and Teller adsorption method. Cation exchange capacity was estimated using an ethylenediamine complex of copper method, and the modifier loading was calculated from the total carbon analysis. The ability of raw and organomodified diatomaceous earth to remove o-nitrophenol (ONP), m-nitrophenol (MNP), and p-nitrophenol (PNP) from aqueous solutions has been carried out at predetermined equilibration time, adsorbent amount, pH, and temperatures using a batch technique. The removal of ONP, MNP, and PNP from aqueous solutions by modified clay seems to be more effective than unmodified sample. The experimental equilibrium adsorption data were analyzed by four widely used two par...

EFFECT OF NANO-SIZED OXALATE PRECURSOR ON THE FORMATION OF GdBa2Cu3O7-δ PHASE VIA COPRECIPITATION METHOD

The formation of GdBa2Cu3O7-δ(Gd123) from metal oxalate precursor with average grain size less than 40 nm using the coprecipitation method is reported. The coprecipitated powders were heated at 900°C for 12 hours, pelletized and then sintered at 920°C for 15, 20 and 25 hours, respectively. All samples showed a dominant Gd123 phase with the orthorhombic structure. The amount of impurity phase Gd2BaCuO5(Gd211) can be controlled by varying the sintering time. This work shows that nano-sized oxalate powders produced via coprecipitation method can be an effective technique to synthesize high quality GdBa2Cu3O7-δ samples where the amount of (Gd211) can be controlled by varying the sintering duration. The percentage of Gd211 impurity decreased with increase in sintering time. This result is useful in utilizing the Gd211 phase as pinning center in enhancing the transport properties.

Superconductivity of REBa2Cu3O7-δ (RE= Y, Dy, Er) ceramic synthesized via coprecipitation method

The REBa2Cu3O7-δ (RE= Y, Dy, Er) superconducting ceramics have been prepared via coprecipitation(COP) method from nearly saturated solutions of metal acetates and 2- propanol solution of oxalic acid. The metal oxalates powders were subjected to thermal treatment of 12 hours calcination at 900oC. The pelletized powder was sintered for 15 hr at 920oC. All samples showed a single step transition in the R-T curves. The TC(R=0) for samples Dy123, Y123and Er123 and were 93 K, 91 K and 90 K, respectively. XRD data showed single phase of an orthorhombic structure for all samples. SEM micrographs showed large grain sizes that are randomly distributed. These results showed that COP method using metal oxalates starting powders is very effective to synthesize high quality superconductors and shorten the sintering time required due to the formation of sub micron oxalate powders.

Effect of nano sized oxalate precursor on the formation of REBa2Cu3O7−δ (RE= Gd, Sm, Ho) ceramic via coprecipitation method

The formation REBa2Cu3O7−δ (RE= Gd, Sm and Ho) superconducting ceramics from metal oxalate precursors with average grain size less than 50 nm using the coprecipitation method is reported. The metal oxalate powders were heated at 900oC for 12 hours, pelletized and then sintered at 920°C for 15 hr. The high-TC phase was observed for all samples as an evidence for the single step transition of (R-T) curves. The TC(R=0) for samples Gd123, Ho123 and Sm123 were 95 K, 93 K, 91 K, respectively. XRD data showed single phase of an orthorhombic structure for Sm123 and Ho123 samples, small amount of impurities (Gd211) phase were detected for Gd123. SEM micrographs showed large grain sizes that are randomly distributed. These results showed that COP method using nano sized metal oxalates starting powders is very effective to synthesize high quality superconductors and shorten the sintering time required. The formation Gd211 phase for the Gd123 sample might act as a pinning centre explaining the enhancement of the transport properties.

Adsorption of Pb(II) on raw and organically modified Jordanian bentonite

Abstract A comparative study using bentonite (BT), hexadecyltrimethylammonium-modified bentonite (BT-HDTMA) and phenyl fatty hydroxamic acid-modified bentonite (BT-PFHA) as adsorbents for the removal of Pb(II) has been proposed. These adsorbents were characterized by X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy and surface area measurement. Cation exchange capacity was also determined in this study. The adsorbent capabilities for Pb(II) from aqueous solution were investigated, and the optimal experimental conditions including adsorption time, adsorbent dosage, the initial concentration of Pb(II), pH and temperature that might influence the adsorption performance were also investigated. The experimental equilibrium adsorption data were tested by four widely used two-parameter equations, the Langmuir, Freundlich, Dubinin- Radushkevich (D-R) and Temkin isotherms. The monolayer adsorption capacities of BT, BT-HDTMA and BT-PFHA for Pb(II) were 149.3, 227.3 and 256.4 mg/g, respectively. The experimental kinetic data were analysed by pseudo-first order, pseudo-second order and intraparticle diffusion kinetics models. The experimental data fitted very well with the pseudo-second order kinetic model. Determination of the thermodynamic parameters, ΔG, ΔH and ΔS showed the adsorption to be feasible, spontaneous and exothermic.

EFFECT OF HEAT TREATMENT OF HoBa2Cu3O7-δ CERAMICS SUPERCONDUCTOR SYNTHESIZED FROM NANO-COPRECIPITATED POWDERS

Nano-sized metal oxalate precursors was thermally treated and investigated to produce high temperature superconducting ceramics with a formula of HoBa2Cu3O7-δ (Ho-123). The nano metal oxalate powders were subjected to different heat treatments at various temperatures for the phase formation study. The high-TC phase was observed for all samples as an evidence for the single step transition of (R–T) curves. The TC(R = 0) for Ho123 is 91 K and 90 K for samples sintered at 920°C, 930°C and 88 K for samples sintered at 940°C and 950°C, respectively. XRD data showed single phase of an orthorhombic structure where a small amount of none superconducting phase Ho2BaCuO5(Ho211) phase was detected. The Ho211 phase was increased as sintering temperature increased due to the decomposition process and affected the transport properties. SEM micrographs showed large grain sizes that are randomly distributed. However, the grain size decreased as the sintering temperature increased which resulted in the formation of weak-links and hence decreases the transport properties. Using nano-sized metal oxalate precursors simplified the formation of HTSC materials with less processing temperatures which could be beneficial in superconducting tape industry. In addition, control of the sintering temperature lead to the formation of Ho123 phase with optimum amount of Ho211 phase which acts as pinning centers and improves the transport properties.

Phenol adsorption on biochar prepared from the pine fruit shells: Equilibrium, kinetic and thermodynamics studies

Biochar samples were prepared from pine fruit shell (PFS) biomass using slow pyrolysis for 1 h at three different temperatures (350, 450 and 550°C). Batch experiments were carried out for the biosorption of phenol onto these biochars. The effect of biosorption experimental parameters such as adsorbent dosage, ionic strength, initial solution pH, contact time and temperatures has been investigated. Experimental equilibrium data were fitted to Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms by non-linear regression method. The experimental kinetic data were also fitted to Lagergren pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models by non-linear regression method. Determination coefficient (R2), chi-squared (χ2) and error function (Ferror%) were used to determine the optimum isotherm and kinetic by non-linear regression method. Kinetics results were best described by pseudo-second order model for phenol onto three biochars. Thermodynamic parameters were estimated and implied that the adsorption process is spontaneous and exothermic in nature.

Synthesis and Characterization of New Polyamides Containing Symmetrical and Unsymmetrical Thiadiazole Rings

Diamino derivatives of thiadiazole namely, 2,5-diamino-1,3,4-thiadiazole and 3,5-diamino-1,2,4-thiadiazole were synthesized and characterized. Polyamides were synthesized by condensation of the two diamino derivatives with diacide chlorides. The structures of polyamides were verified by elemental analysis, FTIR, 1H-NMR, 13C-NMR and mass spectroscopy. The polyamides possess good solubility in aprotic organic solvents such as DMF, DMAC, DMSO and NMP at room temperature. Intrinsic viscosity measurements indicate that the polyamides synthesized have moderate molecular weights. The thermal stability of these polyamides in nitrogen atmosphere is relatively good, especially for those polyamides containing phenylene ring in the backbone. Compared to the structurally related Kevlar aramide, using 2,5-diamino-1,3,4-thiadiazole and 3,5-diamino-1,2,4-thiadiazole instead of p-phenylene diamine results in reducing the melting points of polyamides to below 350 °C.

Synthesis of Bi1.6Pb0.4Sr2Ca2Cu3O10+δ-(Dy2O3)x Added with Magnetic Nanoparticles Dy2O3 Dysprosium Oxide (0.0≤x≤0.1) via Co-Precipitation Method

Superconducting study present the properties of small weight percent of magnetic nanoparticles Dy2O3 from x = 0.0 to 0.10 added in Bi1.6Pb0.4Sr2Ca2Cu3O10+δ (Dy2O3)x. It is found, the form size of magnetic nanoparticles Dy2O3 is spherical, nano Dy2O3 particles will enter easily into the Bi, Pb-2223 superconductor. From here it is early to conclude the inducing of Dy atoms into the Bi, Pb-2223 crystal structure because Bi-based superconductors are known for their strong anistropic properties and extremely short coherence length (ξ) as long there are significant change in it microstructure, lattice parameter and the normal state conductivity of the system. The characterization on critical temperature (Tc) and transport critical current density (Jc) of magnetic nanoparticles Dy2O3 added to enhance the optimum amount levels added. The maximum Tc achieved Tc-(R=0) 109 K (for x = 0.4) as samples respectively compared to the pure samples. This results will discussed directly to the basis properties changes in Bi, Pb-2223 with addition of magnetic nanoparticles of Dy2O3.