Mechanistic analysis of ultrasound assisted enzymatic desulfurization of liquid fuels using horseradish peroxidase

Peroxidase Encapsulated in Peroxidase Mimics via in situ Assembly with Enhanced Catalytic Performance

“…The contents of β‐pleated sheet (1610–1640 cm −1 ), random coil (1640–1650 cm −1 ), α‐helix (1650–1658 cm −1 ) and β‐turn (1660–1700 cm −1 ) were calculated by using PeakFit 4.2 software . As shown in Figure S1 and Table S1, random coil constituted 29.34 % of the secondary structure in PB@Cyt c composite, which showed a 2.52 % increase compared with that of free Cyt c. While β‐pleated sheet of PB@Cyt c composite accounted for 14.42 %, lower than that of free Cyt c. The increase of random coil and decrease of β‐pleated sheet in PB@Cyt c may lead to a favorable secondary structure, which can partly explain hyperactivation of PB@Cyt c composite . Fluorescence spectroscopy can reveal the tertiary structure change of protein.…”

Effect of frequency and reaction time in focused ultrasonic pretreatment of energy cane bagasse for bioethanol production

“…An optimum frequency was established for polymerization (Kojima et al, 2001) whereas other researchers concluded that the highest latex degradation occurred at the optimal time and frequency combination (Utara & Moonart, 2013).However, these studies have different application and reactions from the ones investigated in this study. Even though the effect of ultrasonic frequency on disruption of organic biomass as a method of pre-treatment has been very recently shown to be relatively insignificant up to 50 kHz (Bhasarkar et al, 2015), current literature does not present the effect of frequency when using either a clamp-on transducer (which allows for in-pipe continuous processing) or a multimode-variable-frequency loadtracking ultrasonic generator.In addition to the frequency, other pretreatment parameters that were shown to affect the performance are power, temperature and time, and were investigated herein.The ultrasonic performance is greatly influenced by the power level, since higher power produces greater cavitation that induces the structural change in the biomass (Rehman et al, 2013) but maximum power does not always lead to maximum yields. An increase in ultrasonic power leads to increase in the ultrasonic effects on liquefaction, dissolution times, and hydrolysis yields (Sasmal et al, 2012).Time-wise, it is reported thatan ultrasonic treatment with alkali for short time period (5-10 min) did not achieve significant delignification compared to alkali pretreatment without ultrasound (Sun & Tomkinson, 2002)suggesting that reaction time needs to exceed these values in order for the pretreatment to have a significant effect in removal of lignin.…”

Oxidative desulfurization of diesel fuel oil using supported Fenton catalysts and assisted with ultrasonic energy

“…Two main contributions may be assigned to this effect. First, a physical issue since the cavitation causes microturbulence facilitating, in this way, the mass transfer phenomena of the oxidized species in the extraction step (Bhasarkar et al 2015b;Deshpande et al 2005). Second, a chemical issue because many…”

“…reactions happen during cavitation through thermal dissociation of gas and solvent vapor at extreme temperature and pressure conditions reached in the bubble during transient collapse (Bhasarkar et al 2015b;Dai et al 2011;Margeta et al 2016a, b). The main reaction that would enhance the oxidation process is the following:…”

“…Experimental results show similar yields compared to other works that use the heterogeneous catalytic oxidative desulfurization approach under the same experimental conditions: 20 min of reaction time, and room temperature. Most of the references report a sulfur removal between 25% and 40% after 20 min of reaction time at room temperature, using different types of metallic catalyst and organic and ionic liquid solvents (Bhasarkar et al 2015b;Hao et al 2016;Jiang et al 2018;Lü et al 2014a;Margeta et al 2016a;Safa et al 2017;Yang et al 2017;Yu et al 2018b;Zhu et al 2015). In the present work, the low-cost raw materials (coal fly ash and distilled ethanol) in the chemical processes approach were used in order to reduce operating cost.…”