Islam Hamdy Abd El Maksod

The use of nano supported nickel catalyst in reduction of p-nitrophenol using hydrazine as hydrogen donor

Abstract p-Aminophenol was prepared by hydrogenation of p-nitro phenol over nano-sized nickel catalysts supported on two different supports, SiO2 and Al2O3. Hydrazine hydrate was used as hydrogen source in this reaction. Several loadings of nano-sized Ni were used, thus 20, 5, and 2.5 wt% were prepared. X-ray diffraction (XRD) and electron spin resonance (ESR) were employed to investigate the prepared catalysts. The Ni/Al2O3 was found to be more effective and give high durability. The catalytic activity of the reaction was found to be influenced by both the crystallinity of the nickel and the strain among nano-sized nickel particles. The prepared catalysts showed higher catalytic activity, especially at lower loading. During the reaction, a detectable change of the color was observed from yellow to green and finally to colorless, which enable us to suppose a mechanism of this reaction.

The photocatalytic activity of TiO 2 -zeolite composite for degradation of dye using synthetic UV and jeddah sunlight

In this research different composites of impregnated TiO2 with LTA or FAU zeolites were used as different weight% ratio for photodegradation of organic dye. Normal laboratory UV-lamps were used as a source of UV irradiation. In addition a setup of system of mirrors was used to collect real Jeddah sunlight. A comparison of UV and real sunlight photodegradation activity showed that the real sunlight enhances new centers of active sites exhibiting higher catalytic activity than that of UV irradiated samples.

A Simulation Study for Trimetallic Nanosized Alloy (Ni, Cu, and Ag) in Hydrogenation of Organic Compounds: A Case Study of “Nitrophenols”

Trimetallic system (Ni, Cu, and Ag) supported on alumina was utilized for hydrogenation of nitrophenols. The catalytic active centers for hydrogenation were attributed only to the presence of Ni. However, the presence of bi- or trimetallic systems improves the catalytic activity via extra synergism. The catalytic activity was measured as the time for reaching 100% conversion. The function of synergism was fitted for both bimetallic systems (Ni:Ag; Ni:Cu) individually. Subsequently, three-dimensional function was fitted for trimetallic system (Ni:Cu:Ag) based on the linear combination of data for individual bimetallic system. After a complex calculation areal function was evaluated. An Excel program was written to simply evaluate the catalytic activity of trimetallic system with high accuracy. Characterization of catalysts was performed using EPR and pulsed chemisorption by hydrogen. These characterizations of samples enable us to evaluate particle size, metallic surface area, and degree of dispersion. These values were successfully correlated with the synergism function. The program written then could be capable of predicting these values for any trimetallic system.

New Method for Removal of Organic Dyes Using Supported Iron Oxide as a Catalyst

In this study, we perform a catalytic decomposition of organic dye over Fe2O3-CeO2-TiO2-γ-Al2O3 catalyst in the presence of molecular oxygen and chlorate ions. The results showed that organic dye acts as a sensitizer during this process. The mechanism of the allover process is hypothesized. Several techniques were employed for the characterization of the catalyst, including XRD, SEM, EDAX, and thermal analysis and catalytic activity. The analysis showed that iron is the main active centers, and we have two types of active centers in this process: surface iron and dissolved iron in titanium dioxide. The dissolved iron was found to be the most active center; however, after Fe/Ti = 2.76, a synergism was observed to be occurring between the two active centers.

New Surface Aspects towards Photocatalytic Activity of Doped Supported Titanium Dioxide

The present work aims to synthesize nanoscale well dispersed TiO2/SiO2 and TiO2/Al2O3 nanoparticle photocatalysts via an impregnation method for the removal of methyl orange, which was used as a model compound of organic pollutant in wastewater, from an aqueous medium. Also within this frame work, La and Ce metals were loaded onto the surfaces of TiO2/SiO2 and TiO2/Al2O3 by an impregnation method to enhance the photocatalytic activity of the nanoparticles; the activities and physicochemical properties of the photocatalysts were compared before and after loading of metallic La and Ce. The oxide system was characterized by different techniques, including XRD, UV-Vis spectroscopy, FT-IR spectroscopy, SEM, and EDX spectroscopy. Finally, the optimal conditions to complete the photocatalytic oxidation of methyl orange dye were studied. This work holds promise for the efficient photodegradation of pollutants by nanoparticle photocatalysts.