Sharif Digital Repository

The present study was aimed at investigating the use of platinum and platinum nanoparticles stabilized on zeolite as catalyst for the reduction reaction of p-nitrotoluene as one of the dangerous pollutants. The adsorption properties of platinum based on zeolite have been studied for some heavy metals. Monodispersed platinum nanoparticles were synthesized through reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer, and then were immobilized on four types of zeolites. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. In order to investigate the catalytic properties, operating... 

Three Keggin-type heteropolyacids were impregnated upon halloysite to produce heterogeneous acidic catalysts for synthesizing 5-hydroxymethylfurfural (5-HMF). Comparing the effectiveness of variously prepared catalysts in producing 5-HMF from fructose revealed the important role of halloysite in the final catalyst's acidic properties and performance in the reaction of halloysite-supported silicotungstic acid. Adjusting the reaction parameters for obtaining optimal results for the catalyst of choice was conducted via Response Surface Methodology and it was found that use of catalyst with 11 wt.% active ingredient at 125 °C in DMSO solvent yielded the target compound with 99.5% after 43 min.... 

A new magnetic catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This was characterized through the XRD,... 

5-Hydroxymethylfurfural (5-HMF) is a valuable organic compound commonly derived from sugars such as fructose and glucose. Silicotungstic acid (HSiW), a unique Keggin-type heteropolyacid, is a typical catalyst for organic compound production. To synthesize 5-HMF from fructose, we developed a novel catalyst, HSiW@F-HNTs, by combining HSiW and functionalized halloysite nanotubes (F-HNTs) modified with (3-amino-propyl) triethoxysilane (APTES), 2,4,6-trichloro-1,3,5-triazine (TCT), and L-Arginine. We analyzed the physicochemical properties of HSiW@F-HNTs using the FT-IR, XRD, BET, FESEM, EDS, and XPS characterization techniques, confirming its suitability for fructose-to-5-HMF conversion. Through... 

Hand in hand with the flourish of the biodiesel industries, glycerol has turned into an abundant waste chemical posing obstacles to their large-scale implementation. Devising measures for efficient transformation of glycerol into value added products is a promising alternative to its large-scale disposal into the nature that would also increase the competitiveness of biodiesel fuels. In this study, production of lactic acid (LA) as a valuable chemical with wide applicability is studied in a continuous process with glycerol as a cheap and convenient feedstock. In this regard, the state-of-the-art approaches in catalytic conversion of glycerol to LA are reviewed. A catalytic method using...