Mehdi Taghdiri; Mohammad Golzari
Abstract
A novel hybrid catalyst based on phosphotungstic acid–hexamine–cobalt (PTA–HMT–Co) was synthesized and evaluated for the oxidative desulfurization (ODS) of thiophenic compounds. The Taguchi L9 orthogonal design was employed to optimize key reaction parameters including temperature, ...
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A novel hybrid catalyst based on phosphotungstic acid–hexamine–cobalt (PTA–HMT–Co) was synthesized and evaluated for the oxidative desulfurization (ODS) of thiophenic compounds. The Taguchi L9 orthogonal design was employed to optimize key reaction parameters including temperature, reaction time, catalyst dosage, and oxidant-to-sulfur ratio. The optimized conditions achieved 99.84% desulfurization efficiency for model oil containing benzothiophene and 92.94% for real gas condensate samples. The catalyst exhibited strong oxidative activity, thermal stability, and recyclability for at least six cycles. The high catalytic performance is mainly attributed to the Keggin-type phosphotungstic acid framework, while cobalt incorporation contributes to structural stabilization and catalyst durability rather than acting as a primary active site. This study demonstrates the potential of PTA–HMT–Co as a green and efficient catalyst for deep desulfurization under mild conditions.
Mehdi Taghdiri; Ehsan Hassani-Hemmatabadi; Ehsan Mostofi; Fatemeh Banifatemeh
Abstract
Phosphomolybdate-hexamine-cobalt (PMA-HMT-Co), a new hybrid prepared by coprecipitation method, was used for coating of titanium dioxide nanoparticles in order to improve photocatalytic activity to visible light. PMA-HMT-Co and TiO2-PMA-HMT-Co were characterized by Fourier transform infrared spectroscopy, ...
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Phosphomolybdate-hexamine-cobalt (PMA-HMT-Co), a new hybrid prepared by coprecipitation method, was used for coating of titanium dioxide nanoparticles in order to improve photocatalytic activity to visible light. PMA-HMT-Co and TiO2-PMA-HMT-Co were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction and scanning electron microscopy. The diffuse reflectance spectroscopy was used to evaluate the band gap variation. The band gap of PMA-HMT-Co decreased and hence, its photocatalytic activity was enhanced under sunlight irradiation. With the incorporation of PMA-HMT-Co, the band gap of titanium dioxide was transferred from UV to visible region successfully. Rhodamine B (RhB) decolorization tests indicated higher photocatalytic activity of TiO2-PMA-HMT-Co under sunlight irradiation. Photodegradation takes place through the excitation of modified titanium dioxide and the creation of holes (h+) and oxidation of dye.
Mehdi Taghdiri; Farzaneh Ghanei; Marzieh Ardakania; Hossein Banitaba; Hossein Aarabi Ardakani
Abstract
Two new organic hybrids of phosphomolybdic acid (PMA) were prepared by means of hexamine (HMT) and HMT-Ni2+ complex. The effects of hybridization of HMT and Ni2+ were investigated on the photocatalytic activity of PMA. Characterization of hybrids were carried out by elemental analyses, Fourier transform ...
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Two new organic hybrids of phosphomolybdic acid (PMA) were prepared by means of hexamine (HMT) and HMT-Ni2+ complex. The effects of hybridization of HMT and Ni2+ were investigated on the photocatalytic activity of PMA. Characterization of hybrids were carried out by elemental analyses, Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry. The band gaps of PMA, phosphomolybdate-hexamine (PMA-HMT) and phosphomolybdate-hexamine-nickel (PMA-HMT-Ni) were determined from the diffuse reflectance spectra using the Tauc plots. Dye adsorption and photocatalytic properties of PMA-HMT and PMA-HMT-Ni hybrids were examined by studying the decolorization of model dyes methylene blue (MB), rhodamine B (RhB) and mixtures of MB and methyl orange (MO) solutions. The results show that the band gap of PMA-HMT-Ni is narrower and hence, its photocatalytic activity is higher for the degradation of dyes under sunlight irradiation. Mechanism of photodegradation was studied by adding scavengers. Removal is via combination of adsorption and then photocatalytic degradation through oxidation by radicals.
