MODIFIED HZSM-5 AND H-MORDENITE ZEOLITES AS SUPPORTS FOR PLATINUM CATALYST

Bifunctional Pt/HZSM-5 and Pt/HMOR catalysts were prepared and applied to the isomerization of n-Hexane. Catalysts containing 0.3wt% Pt on both catalysts with potentially high acidity were prepared by impregnation method. The tested catalysts show that optimum selectivity with maximal isomer yield was obtained for Pt/HZSM-5 catalysts. The nanoparticles were characterized by inductively coupled Plasma (ICP), X-Ray Diffraction (XRD), BET Surface Area, and Transmission Electron Microscopy (TEM). TEM was revealed uniformly dispersed platinum particles on the substrate with average particle size ranging from ~6.893 to 8.847nm. It was demonstrated that the loading content and particle size of the nanoparticles deposited on zeolites could be tuned by changing the weight of precursor and the conditions of loadin

Kinetic and equilibrium study of graphene and copper oxides modified nanocomposites for metal ions adsorption from binary metal aqueous solution

Presently, the main cause of pollution of natural water resources is heavy metal ions. The removal of metal ions such as nickel (Ni2+) and cadmium (Cd2+) has been given considerable attention due to their health and environmental risks. In this regard, for wastewater treatment containing heavy metal ions, graphene oxide (GO) nanocomposites with metal oxide nanoparticles (NPs) attained significant importance. In this study, graphene oxide stacked with copper oxide nanocomposites (GO/CuO-NCs) were synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and atomic force microscopy (AFM) analytical procedures. The prepared GO/CuO-NCs were applied for the removal of Ni2+ and Cd2+ ions from a binary metal ion system in batch and continuous experiments. The obtained results revealed that GO/CuO-NCs exhibited the highest removal efficiencies of Ni2+ (89.60% ± 2.12%) and Cd2+ (97.10% ± 1.91%) at the optimum values of pH: 8, dose: 0.25 g, contact time: 60 min, and at 50 ppm initial metal ion concentration in a batch study. However, 4 mL/min flow rate, 50 ppm initial concentration, and 2 cm bed height were proved to be the suitable conditions for metal ion adsorption in the column study. The kinetic adsorption data exhibited the best fitting with the pseudo-second-order model. The adsorption isotherm provided the best-fitting data in the Langmuir isotherm model. This study suggested that the GO/CuO nanocomposites have proved to be efficient adsorbents for Ni2+ and Cd2+ ions from a binary metal system

Catalytic Activity of Pt Loaded Zeolites for Hydroisomerization of <i>n</i>-Hexane Using Supercritical CO₂

The present study investigates the synthesis of novel strontium (Sr) and barium (Ba) modified crystalline zeolites including Zeolite Socony Mobil-5 (ZSM-5) and Mordenite (MOR) utilizing a batchwise ion-exchange method with an appropriate chloride solution of 3 N at pH 7.2 and 50 °C. Modified zeolites (Ba-ZSM-5 and Ba-MOR, Sr-ZSM-5 and Sr-MOR) were coated with an inert metal (Pt) by a novel supercritical CO2 method using PtMe2COD as a precursor for n-hexane hydroisomerization in a microreactor unit at different temperatures (250–325 °C), H2/HC ratios of 3, 6, and 9, and a pressure of 5 bar. The acidic and physical features of Pt loaded zeolites were systematically characterized using FT-IR, XRD, BET surface area measurements, TGA, and TEM techniques. It is found that the metal loading in scCO2 results in more uniform and very small metal nanoparticle (1.37 nm) dispersion with high stability after reduction. It is also revealed that high loading pressure in scCO2 (280–300 bar) results in higher catalytic activity and surface area. The maximum conversion and selectivity of about 80 and 90% were achieved for n-hexane isomerization at 275 °C and a H2/HC ratio of 6 for Pt/Sr-ZSM-5 catalyst. Results reported that Pt loaded over all zeolites (H-MOR, Sr-MOR, Ba-MOR, H-ZSM-5, Ba-ZSM-5, and Sr-ZSM-5) by the scCO2 method showed the minimum production of cracking products (C1–C5) and maximum isomeric products including iso-C6 isomers (2,2-DMB, 2,3-DMB, 2-MP, and 3-MP). Furthermore, the overall results of the rate of reaction revealed that Pt/Sr-ZSM-5 and Pt/Ba-ZSM-5 catalysts showed a better rate of isomerization (46.44%) and conversion (47%) for n-hexane at 300 °C and a H2/HC ratio of 9 with a minimum rate of cracking. However, it is concluded that the small, pored size Pt loaded ZSM-5 zeolite showed the highest catalytical activity compared to large pored MOR zeolite making it of great interest for diesel and gasoline formation in the oil refining industry