The Study Of Deactivation And Regeneration Of A Fluid Cracking Zeolite Catalysts

The catalytic activities of modified and unmodified sodium Y-Zeolites catalysts was investigated. Modification by framework dealumination and gallium oxide incorporation led to an increase in catalytic activity. The catalytic activities of both parent and the modified samples were reduced in a time dependent manner due to coke deposition. Incorporation of gallium oxide altered the reaction pathways of C8 intermediates from n-butane reactions, thusproducing more aromatic products. However, Ga2O3 in excess of 1% resulted in a large decrease of catalytic activity due to loss in Bronsted acidity. As Bronsted sites are removed, direct protonation of the alkane became difficult and catalytic activity was lowered at high Ga2O3 loading. The oxygen adsorption isotherms of the various coked catalysts showed that the deactivation process involved blockage of the zeolite pore sites by the deposited coke. Interestingly, regeneration of the coked sample was seen to completely restore the catalytic activity of both samples

Kinetic Evaluation of Naphthalene Removal using Acid - Modified and Unmodified Bentonite Clay Mineral

Kinetic evaluation of naphthalene onto acid – modified and unmodifiedbentonite clay mineral was investigated by means of the effects of  concentration, contact time and pH. The amount of naphthalene adsorbed was determined spectrophotometrically. The optimum pH value and  equilibrium contact time for the adsorption of naphthalene onto acid –modified and unmodified samples were found to be 6.0 and 30 minutes, respectively. The maximum adsorption capacity (qm) for acid – modified and unmodified adsorbents was found to be 10.52 mg/g and 5.56 mg/g. These values were close with the experimental data (qe) obtained from the adsorption of naphthalene onto acid – modified (9.0 mg/g) and  unmodified (4.0 mg/g) adsorbents. The adsorption isotherm fitted well with Langmuir equation model for the acid – modified than the unmodified adsorbent. Kinetic evaluations of the adsorption showed that the process followed the pseudo – second – order equation model. The results obtained showed that modified bentonite clay mineral was reasonably effective adsorbent for the removal of naphthalene (organic contaminant), which is an important source for environmental pollutant. ©JASEMKEYWORDS: Naphthalene, equilibrium, kinetics, sorption, acid – modified bentonite.

The effect of natural antioxidants (from groundnut shell extracts) on the oxidation stability of lubricating oil

The effect of Catechin-containing natural antioxidants, on the stability of lubricating oil has been assessed and evaluated. The base and the formulated oils samples were both subjected to the same reaction conditions designed to simulate a working crankcase engine environment. The kinematic viscosity, pH and the total acid number (TAN) were determined to assess the effectiveness of catechins (from groundnutshell extract) as an oil additive. The values of the kinematic viscosity for the formulated oil were much higher than the base oil, while the total acid number content for the base oil was found to be higher. Both the base oil and the formulated oil, showed similar pattern of deterioration as temperature of the reaction increased. However, the formulated oil proved to be more stable than the base oil due to the presence of the antioxidant

Competitive Adsorption of Xylene and Toluene on Modified and Unmodified Magnesium Exchanged Bentonite Clay Mineral

Cetyltrimethylammonium bromide (CTAB) – modified and unmodified magnesium exchanged bentonite were used for the competitive adsorption of m-xylene and toluene from their aqueous solution. Infrared spectroscopy (IR, adsorption capacity and Foster swelling measurements were performed using Fourier Transform Infrared Spectrophotometer to evaluate the performance of the adsorbents. The FT-IR results indicated that the quaternary ammonium salts (Cetyltrimethylammonium bromide) were intercalated between the layers of the bentonite clay. The Foster swelling test results indicated that the affinity of CTAB occurred in the treated clay as tested in all organic solvents (diesel, kerosene, gasoline, toluene and m-xylene), with and without agitation. The result showed that modified magnesium bentonite swelled more than the unmodified and the order of the swelling factor is; m- xylene > toluene > gasoline > diesel > DPK > water. However, when the assay was performed under agitation, it yielded higher swelling capacity and all the organic solvents used in this investigation showed good compatibility after organophilization. The modified clay exhibited very high capacity of adsorption compared to unmodified samples. The m-xylene and toluene uptake follows a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves the two adsorbates competitively adsorbed on the adsorbent sites. Modified magnesium bentonite has a higher percentage removal and higher adsorption capacity than raw or unmodified magnesium bentonite. These adsorbents (modified magnesium bentonite) are therefore recommended for use by water treatment and petrochemical industries for removal of hydrocarbons (m- xylene and toluene) from their waste water and effluents

Kinetic Evaluation of Naphthalene Removal using Acid - Modified and Unmodified Bentonite Clay Mineral

Kinetic evaluation of naphthalene onto acid \u2013 modified and unmodified bentonite clay mineral was investigated by means of the effects of concentration, contact time and pH. The amount of naphthalene adsorbed was determined spectrophotometrically. The optimum pH value and equilibrium contact time for the adsorption of naphthalene onto acid \u2013 modified and unmodified samples were found to be 6.0 and 30 minutes, respectively. The maximum adsorption capacity (qm) for acid \u2013 modified and unmodified adsorbents was found to be 10.52 mg/g and 5.56 mg/g. These values were close with the experimental data (qe) obtained from the adsorption of naphthalene onto acid \u2013 modified (9.0 mg/g) and unmodified (4.0 mg/g) adsorbents. The adsorption isotherm fitted well with Langmuir equation model for the acid \u2013 modified than the unmodified adsorbent. Kinetic evaluations of the adsorption showed that the process followed the pseudo \u2013 second \u2013 order equation model. The results obtained showed that modified bentonite clay mineral was reasonably effective adsorbent for the removal of naphthalene (organic contaminant), which is an important source for environmental pollutant

The effect of stability treatmetn on the surface energetics of inhalation grade lactose

No Abstract. Global Journal of Pure and Applied Physics Vol. 14 (1) 2008 pp.85-8

Investigations Of Powder Surface Properties Of Drug Substances Using Inverse Gas Chromatography (IGC)

In this study, Inverse Gas Chromatography (IGC) was used to characterize the surface energetics of different batches of two drug substances (Salmetrol Xinafoate, SX and Fluticasone Propionate, FP) manufactured under identical conditions. The results obtained demonstrate the potential of IGC technique to reveal batch-to-batch variability of these drugs. It is shown that the surface energy differences detected by IGC can be ascribed to secondary processing operations such as milling, micronisation and, or blending. This technique in practice therefore, provided an assurance of the same surface energy between batches of materials and eliminates the batches which may ultimately affect the quality and performance of the final products. Keywords: Gas Chromatography, Dispersive Energy, Acid/base Probe molecules. Global Journal or Pure and Applied Sciences Vol. 14 (4) 2008: pp. 407-41