RESUMO
This research elucidates novel insights into the electrochemical properties and degradation phenomena of propylene carbonate (PC)-based supercapacitors at a large-scale 18650 cylindrical jelly-roll cell level. Central to our findings is the identification of 2-ethyl-4-methyl-1,3-dioxolane (EMD) as a hitherto undocumented decomposition by-product, highlighting the nuanced complexity of PC electrolyte stability. We further demonstrate that elevated operational voltages precipitate accelerated electrolyte degradation, underscoring the criticality of defining the operational voltage window for maximizing device longevity. Employing advanced analytical techniques, including gas chromatography-mass spectrometry (GC-MS), this study meticulously analyzes electrolyte decomposition mechanisms. The outcomes offer pivotal insights into the operational constraints and chemical resilience of PC-based supercapacitors, contributing significantly to the optimization of supercapacitor design and application. By delineating a specific decomposition pathway, this investigation enriches the understanding of electrochemical dynamics in supercapacitor systems, providing a foundation for future research and technological advancement in energy storage devices.
RESUMO
The development of low-cost purification technology is an indispensable need for industrial biorefinery. Xylose is easily obtained from hydrothermal pretreatment of lignocellulosic biomass. This current study emphasizes the chromatographic monosaccharide separation process using commercial cation-exchange resins (CER) including Amberlite 120 and Indion 225 to separate xylose from a mixture of hydrolysates. To understand the performance of the two CER, the studies of equilibrium, thermodynamics, and kinetics were evaluated. In this study, with different xylose concentrations, the adsorption equilibrium was found to follow the Freundlich isotherm model well (R2 > 0.90 for both CER). The results indicated that a pseudo-second-order model represented the xylose adsorption kinetics. In addition, the activation energy of xylose adsorption onto both CER, i.e., Amberlite 120 and Indion 225 was 34.9 and 87.1 kJ/mol, respectively. The present adsorption studies revealed the potential of these commercial CER to be employed as effective adsorbents for monosaccharide separation technology.
RESUMO
Pretreatment is a crucial process in a lignocellulosic biorefinery. Corncob is typically considered as a natural renewable carbon source to produce various bio-based products. This study aimed to evaluate the performance of the hydrothermal-mechanical pretreatment of corncob for biofuels and biochemical production. Corncob was first pretreated by liquid hot water (LHW) at different temperatures (140-180 °C) and duration (30, 60 min) and then subjected to centrifugal milling to produce bio-powders. To evaluate the performance of this combined pretreatment, the energy efficiency and waste generation were investigated. The results indicated that the maximum fermentable sugars (FS) were 0.488 g/g biomass obtained by LHW at 180 °C, 30 min. In order to evaluate the performance of this combined pretreatment, the energy efficiency and waste generation were 28.3 g of FS/kWh and 7.21 kg of waste/kg FS, respectively. These obtained results indicate that the combined hydrothermal-mechanical pretreatment was an effective pretreatment process to provide high energy efficiency and low waste generation to produce biofuels. In addition, the energy efficiency and waste generation will be useful indicators for process scaling-up into the industrial scale. This combined pretreatment could be a promising pretreatment technology for the production of biofuels and biochemicals from lignocellulosic valorization.
