A.A. Hanna’s research while affiliated with National Center for Atmospheric Research and other places

Copper- Metal organic framework (Cu-MOF) and melamine/ Cu-MOF (MCu-MOF) samples were prepared by the hydrothermal process. The produced powder was dried and characterized by using the FTIR, X-ray techniques. The thermal gravimetry (TG) analysis was performed to detect the thermal stability of the product. On other hand, the morphology and the surface area of the powder were carried. The bioactivity of the powder was carried by measuring the inhibition zone diameter around samples in (mm). The results of characterization showed that the formation of Cu-MO and melamine/ Cu-MOF in crystalline state in both samples, the surface area of Cu-MOF is equal to 1350 m 2 g -1 while increase to 1410 m 2 g -1 by incorporate by melamine into the Cu-MOF. The thermal behavior (TG) of the Cu-MOF showed three sequence stages attributed to the moisture evaporation, degradation of the Cu-MOF and forming the Cu-O as end product respectively. For melamine incorporated to Cu-MOF (MCu-MOF), the TG profile shows that the split of the main degradation into two parts resulting from the presence of melamine. The bioactivities of the both samples were tested against microbial strains. The results showed that the Cu-MOF and MCu-MOF have insignificant antimicrobial activity against gram positive of bacteria and Fungi. While for gram negative of bacteria it is observed a considerable effect.

The aim of this work is recovery the chromium content from the tannery wastewater to decrease the environmental pollution. Also, benefit the extracted chromium compound by study their electrical behavior to be used as humidity sensor device. The chromium content was extracted as a solid power by using MgO for precipitation. The prepared dry powder was characterized by different process. The results of the characterizations indicate that the chromium content precipitated as MgCr 2 O 4 . The efficiency of separation reaches to 99.98%. The crystalline size was calculated by applying Scherer equation, the calculation indicate that the MgCr 2 O 4 formed in nano-sized particles and affected markedly with calcinations. As the calcination temperatures increase from 300 to 900 °C the crystalline size increases from 44.1 to 70.6 nm, this may due to growth the crystals by calcinations. To study the evaluation of MgCr 2 O 4 as relative humidity (RH) sensors, the dried samples were exposed to different humidities between 22 to 92%. The electrical behaviors of humidity samples were measured to investigate the humidity sensing. AC conductivity of both the dry and the humidity samples indicate that the conductivity increases as the humidity increase from 27 to 80 RH%. The variation of conductivity for both dried and humidity samples shows that as the humidity increases from 22 to 80, the conductivity increases while above 80% the conductivity greatly increase. From the dependence of the electrical properties of MgCr 2 O 4 on water content, it may conclude that, MgCr 2 O 4 can be used as humidity sensors between 27 to 90%.

To study the effects of the precursor materials on the structure, the morphology, and the thermal stability of Mg(OH) 2 particles, five samples were prepared by using the same method. The produced powder was characterized by using FTIR, XRD, SEM, and TEM, and the thermal stability was studied by using the thermogravimetric analysis. This study aims to use the advantage prepared material as a flame-retardant for the polymeric materials. The characterization of the obtained samples shows that Mg(OH) 2 is formed in hexagonal phase and arranged in different shapes. The analysis of the data obtained from the TGA shows that Mg(OH) 2 in general decomposed in three steps, the first one due to the water content and the other volatile materials, the second step represents the decomposition of Mg(OH) 2 to produce MgO, and the third step represents the conversion of MgO to glassy layer. The samples prepared in presence of the surfactants gave a higher value for the formation of the glassy layer so that it is recommended to use this sample as flame retardant for the polymeric materials.

Fire performance of polypropylene (PP) containing different percentages of ammonium polyphosphate (APP) with montmorillonite (Mt) or treated montmorillonite (MtT) was carried out by using the cone calorimeter test (CCT). Different samples from ammonium polyphosphate and montmorillonite were mixed with 90% polypropylene. The characterization of the prepared samples indicates that there is incorporation between the components of the samples. Heat release rate (HRR), peak heat release rate (PHRR), average heat release rate (Av-HRR), and time to ignition (TTI) of the samples were obtained from the cone calorimeter test. Also, the fire performance index (FPI) and the fire growth rate (FIGRA) were calculated. The interpretation of the curves and the parameters results from the cone calorimeter test which indicates that the addition of montmorillonite to APP increases its action as a flame retardant for PP. Moreover, the samples contain acid treatment montmorillonite showed an increase in the efficiency of ammonium polyphosphate when used. This result may be due to an increase in the SiO2 content by acid treatment.

Due to the bioactivity and the excellent properties of the rare earth elements, the effects of adding different amounts of La and Ce to the familiar base glass materials were studied. Different samples with and without rare earth elements were tested without farther calcinations. X-ray diffraction and IR spectrum were used to characterize the produced mixture where scanning and EDAX were used to study the change in the morphology by adding the rare earth elements or the immersion of the produced samples in simulated body fluid (SBF) liquid. The characterization of the samples specified the formation of some phases such as CaCe(PO4)2 and Ca3La(PO4)3. Also, it is found that the produced powder have a nano-particle size ranging from 5 to 50 nm. On other hand, it is found that the base glass materials include rare earth elements (La and Ce) have an bioactive effects on the bacteria and the fungi.

Phosphogypsum (PG) derived from the manufacturing of phosphoric acid by wet process method was converted to nano-particle hydroxyapatite (HAP). Also, the effects of the calcination temperature and the doping with some rare earth elements (La and/or Ce) on the structure of the produced HAP particles were studied. The produced samples were characterized by scanning electron microscope (SEM), Transmission electron microscope (TEM), IR absorption, X-ray diffraction and the thermogravimetric analysis (DTA&DTG). The results of characterization show that PG converted to nano-particle HAP and crystalize in the form of hexagonal structure. The crystalline formation increased by heat treatment up to 900° C. Also, it is found that the doping with different percentage of La or Ce improved the crystallinity of the doped hydroxyapatite. The thermogravimeter analysis shows that the doping of HAP increases the thermal stability and other produced samples and the doped and undoped samples are thermally stable up to 1000 °C.

The flammability of a mixture of (APP/DE)/PP was studied by using both the thermogravimetric analysis and the cone- calorimeter test. In this study the (APP/DG)/PP system was characterized by using the IR spectra, the X-ray diffraction and the morphology of their mixture. The IR spectra indicate that there are incorporate of DE into the APP structure, while X-ray patterns shows that when the percentage of DE equals to 0.4 the system converted to the amorphous state. The SEM of the samples show an interference of the DE particles through the APP units. The analyses of the obtained data from the thermogravimetric and the cone- calorimeter measurements indicate that when mixing DE with APP the flammability of PP was improved. Also, the obtained results indicate that mixing of DE with APP up to 0.6 ratio is the more preferable sample. The mechanisms of the retardant the flammability of PP in presence of APP and DE may due to the formation of phosphoric acid and nitrogen from decomposition of APP and formation of Al and Si oxides from the degradation of DE.

Diatomite (DE), Ferrihidrite- modified diatomite (DFe) and microemulsion modified diatomite (DEM) were used for removal of phosphate ions from their aqueous solutions. The diatomite (DE) and the modified diatomite [DFe and DEM] were characterized by X-ray, IR and SEM also surface area was estimated. The results of characterization indicated that, the phosphate ions sorption capacities of diatomite were improved after modifying by ferrihydrite or microemulsion. The surface area of the modified diatomite increased according to DEM > DFe > DE, so the efficiency of removing phosphate ions with DEM was higher than that of DFe and DE. This behavior may due to the difference in the electrostatic force between phosphate ions and the surface of DE, DFe and DEM. Also, it is found that the removal of phosphate ions by the three samples improved by increase the phosphate concentration in the initial solutions.

The aim of this work is stydying the removal of some divalent cations, Cd, Cu, and Co from their aqueous solutions by using the natural materials, diatomite. The diatomite material was characterized by the chemical analysis, IR, X-ray and TEM also the surface area was calculated. The results of characterization indicate that diatomite consist mainly from silica with some other oxide. The effect of pH values and the initial concentrations of the aquous solution on the efficiency of removing was studied. The results indicate that the efficienc of removing dependsgreatly on the pH values and the initial concentration of the cations with optimum value for each case. In general the effeciency of removing for these cations follows the following sequence Cd>Cu>Co. This behavior may due to the electronegativity and the ionic radius as well as the different species of these cations in their solutions.

Y PO4 and Mg2P2O7 mixed ceramic semiconductor samples were prepared and investigated to be used as humidity sensors. The samples were characterized using XRD. Surface area, SEM, and electrical conductivity under the effect of humidity at room temperature were measured and discussed. X-ray patterns showed the formation of YPO4 in tetragonal phase and Mg2P2O7 in monoclinic form. Adding Mg2P2O7 improves the surface area of YPO4 which affected the electric conductivity. The humidity sensing of the pure and mixture samples was studied by dependences of the electrical conductivity on the mixture content and the sensitivity was also calculated. The results indicated that the electrical conductivity increased as relative humidity increased up to 76% due to the proteinic conductivity which specified the action of water content on the phosphate molecules. After 76% relative humidity (RH), the value the electrical conductivity and sensitivity started to decrease due to the blocking of the phosphates molecules under high humidity value.