Convert mechanical energy to chemical energy to effectively remove organic pollutants by using PTO catalyst

Mechanism and kinetic of piezo-catalytic desulfurization of model and actual fuel samples over CexOy/SrO nanocomposite at room temperature

SOx emissions are primarily caused by compounds containing sulfur in petroleum and fuels, which lead to severe air pollution. For this reason, it is necessary to develop a fast and simple desulfurization method in order to comply with ever-increasing environmental regulations. The newly discovered piezo-catalyst nanocomposite CexOy/SrO can convert mechanical energy directly into chemical energy, thereby enabling mechanically oxidative sulfur desulfurization. 320 W of bath sonication were used to polarize and activate the prepared piezo-catalyst nanocomposite CexOy/SrO for sulfur removal from thiophene and dibenzothiophene as model fuels and kerosene as a real fuel. Using uniform and spherical CeO2/SrO nanocomposites resulted in the highest desulfurization rates of 95.4 %, 97.3 %, and 59.7 %, respectively, for thiophene and dibenzothiophene. This study examined the effect of several parameters, such as sulfur concentration, pH of fuel, dosage of CexOy/SrO nanocomposite, power and time of ultrasonic, and shaking time, on the piezo-desulfurization of thiophene (TP) and dibenzothiophene (DBTP). To identify the major active species in piezo desulfurization, radical trapping experiments were conducted. This study investigated the possibility of reusing the catalyst, and the piezo-desulfurization activity that was demonstrated in the removal of TP and DBTP after 11 cycles as well as the ability of the catalyst to remove real fuel even after 14 cycles was promising. As the kinetic results show, the reaction follows the second order with K = 0.0050. Also, thermodynamic results showed the oxidation of sulfide to sulfoxide and sulfoxide is endothermic. Activation energy for second order rate constant is (3.824 Kj/mole). 0.0236 mol-1. Sec-1 was calculated for Arrhenius Constant.

Studying the mechanism and kinetics of fuel desulfurization using CexOy/NiOx piezo-catalysts as a new low-temperature method

In order to advance desulfurization technology, a new method for excellent oxidative desulfurization of fuel at room temperature will be of paramount importance. As a novel desulfurization method, we developed piezo-catalysts that do not require adding any oxidants and can be performed at room temperature. A microwave method was used to prepare CeO₂/Ce₂O₃/NiO_x nanocomposites. Model and real fuel desulfurization rates were examined as a function of synthesis parameters, such as microwave power and time, and operation conditions, such as pH and ultrasonic power. The results showed that CeO₂/Ce₂O₃/NiO_x nanocomposites demonstrated outstanding piezo-desulfurization at room temperature for both model and real fuels. Furthermore, CeO₂/Ce₂O₃/NiO_x nanocomposites exhibited remarkable reusability, maintaining 79% of their piezo-catalytic activity even after 17 repetitions for desulfurization of real fuel. An investigation of the mechanism of sulfur oxidation revealed that superoxide radicals and holes played a major role. Additionally, the kinetic study revealed that sulfur removal by piezo-catalyst follows a second-order reaction kinetic model.

Kinetic and thermodynamic study in piezo degradation of methylene blue by SbSI/Sb2S3 nanocomposites stimulated by zirconium oxide balls

Mechanical energy harvesting by piezoelectric materials to drive catalysis reactions received extensive attention for environmental remediation. In this work, SbSI/Sb₂S₃ nanocomposites were synthesized as a catalyst. ZrO₂ balls were used as an alternative mechanical force to ultrasonic for stimulating the piezocatalyst for the first time. The kinetics and thermodynamics of the piezo degradation of methylene blue (MB) were studied deeply. Besides the effect of the type of mechanical force, the number of ZrO₂ balls, and temperature of the reaction on the degradation efficiency were studied. Here mechanical energy came from the collision of the ZrO₂ balls with the catalyst particles. Using ZrO₂ balls instead of ultrasonic vibration led to enhance degradation efficiency by 47% at 30 ± 5 °C. A kinetic study revealed that piezo degradation of methylene blue (MB) by SbSI/Sb₂S₃ catalyst followed pseudo-second-order kinetics. Based on thermodynamic results piezo degradation of MB was an exothermic reaction.

Piezoelectric-Fenton degradation and mechanism study of Fe2O3/PVDF-HFP porous film drove by flowing water

Piezocatalysis driven by a gentle force possesses broad application prospects for degrading organic pollutants, sterilisation, wound healing and tissue recovery. The flexible and industrially scalable poly(vinylidene fluoride) (PVDF) film is commonly used in piezocatalysis. However, under gentle force action, PVDF composite-based piezocatalysis is poor. Herein, a flexible porous film based on poly(vinylidene fluoride)-hexafluoro propylene (PVDF-HFP) is enhanced with Fenton fillers (α-Fe₂O₃ nanoparticles). α-Fe₂O₃ nanoparticles improve the piezoelectric catalysis performance of PVDF-HFP by the β-phase enhancement and provide Fe³⁺ to react with H₂O₂ generated by the piezoelectric film itself, leading to an additional Fenton reaction. Meanwhile, the Fe³⁺/Fe²⁺ cycle in the Fenton process accelerates under the piezoelectric field, promoting the Fenton reaction for 6.9% degradation improvement. The study on Fe₂O₃/PVDF-HFP porous film with the piezo-Fenton reaction under flowing water may help promote new piezocatalysis designs with high efficiency for self-powered environmental purification.

Cocatalyst engineering to weaken the charge screening effect over Au–Bi4Ti3O12 for piezocatalytic pure water splitting

The weak driving force and rapid carrier recombination severely restrict the development and utilization of piezocatalysis, but the important reason is the charge screening effect.