Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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Pretreatment and enzymatic hydrolysis optimization of lignocellulosic biomass for ethanol, xylitol, and phenylacetylcarbinol co-production using <i>Candida magnoliae</i>
No full textCellulosic bioethanol production generally has a higher operating cost due to relatively expensive pretreatment strategies and low efficiency of enzymatic hydrolysis. The production of other high-value chemicals such as xylitol and phenylacetylcarbinol (PAC) is, thus, necessary to offset the cost and promote economic viability. The optimal conditions of diluted sulfuric acid pretreatment under boiling water at 95 degrees C and subsequent enzymatic hydrolysis steps for sugarcane bagasse (SCB), rice straw (RS), and corn cob (CC) were optimized using the response surface methodology via a central composite design to simplify the process on the large-scale production. The optimal pretreatment conditions (diluted sulfuric acid concentration (% w/v), treatment time (min)) for SCB (3.36, 113), RS (3.77, 109), and CC (3.89, 112) and the optimal enzymatic hydrolysis conditions (pretreated solid concentration (% w/v), hydrolysis time (h)) for SCB (12.1, 93), RS (10.9, 61), and CC (12.0, 90) were achieved. CC xylose-rich and CC glucose-rich hydrolysates obtained from the respective optimal condition of pretreatment and enzymatic hydrolysis steps were used for xylitol and ethanol production. The statistically significant highest (p <= 0.05) xylitol and ethanol yields were 65% +/- 1% and 86% +/- 2% using Candida magnoliae TISTR 5664. C. magnoliae could statistically significantly degrade (p <= 0.05) the inhibitors previously formed during the pretreatment step, including up to 97% w/w hydroxymethylfurfural, 76% w/w furfural, and completely degraded acetic acid during the xylitol production. This study was the first report using the mixed whole cells harvested from xylitol and ethanol production as a biocatalyst in PAC biotransformation under a two-phase emulsion system (vegetable oil/1 M phosphate (Pi) buffer). PAC concentration could be improved by 2-fold compared to a single-phase emulsion system using only 1 M Pi buffer
Facile and sustainable recovery of spent LiFePO<sub>4</sub> battery cathode materials in a Ca(ClO)<sub>2</sub> system
No full textSpent LiFePO4 batteries are gradually increasing in popularity and interest, and their stable and insoluble olive-shaped structure poses a great challenge for the sustainable recycling of Li. In this study, a simple and sustainable Ca(ClO)(2) system was proposed for the recovery of spent LiFePO4 battery cathode materials. The effects of both mechanochemical activation and hydrometallurgical enhanced leaching on the deconstruction of LiFePO4 and the leaching rates of Li and Fe in the Ca(ClO)(2) system were studied. Compared with mechanochemical activation, Ca(ClO)(2)-assisted hydrometallurgical enhanced leaching can simultaneously achieve the separation and enrichment of the target components Li+ and Fe3+ and the Ca2+ impurities. The transformation path and reaction mechanism of LiFePO4 in the Ca(ClO)(2) system were proposed based on the phase composition and micromorphology of the reaction products. In addition, the economic evaluation results show that Ca(ClO)(2)-assisted hydrometallurgical enhanced leaching has a high recovery economy. The developed Ca(ClO)(2) system realizes the strong dissolution of spent LiFePO4 battery cathode materials and the sustainable comprehensive recovery of valuable components
Nonempirical fractal permeability model and experimental verification of hydrate-bearing sediments based on heterogeneous distribution of particles
No full textThe one of the factors limiting production of gas-water is affected by sediments ' permeability. Evaluating the normalized permeability ( K n ) of sediments containing hydrates is necessary for analyzing the saturation (decomposition level) and flow capacity. The mistakes in K n prediction are frequently brought about by the assumption such as homogenous particles distribution and ignoring microscopic pore structure. To address the issue, a fractal-based nonempirical prediction model of K n was developed by modeling, parameter acquisition using SEM and Analyzer, experiment validation, error comparison with published data, and sensitivity analysis for evolution, respectively. Assuming that sediment skeleton particles were misaligned spherical particles of equal diameter. The heterogeneity of sediments was described by the vertical and horizontal distance ratio ( m ) and offset angle ( theta ) of the particles. This led to a novel approach for determining average tortuosity ( tau av,0 ) and tortuosity fractal dimension ( D tau,0 ). The viability of the model was confirmed by permeability measurement experiments. Additionally, using the measuring function of SEM, the maximum pore diameter of sediments was obtained. Furthermore, a comparison with earlier data demonstrated the effect. Considering heterogeneity, the average accuracy of Geometric Mean Variance in K n has increased to 9.66%. Finally, each parameter ' s impact on prediction was examined. At m = 1.357, D tau,0 grows symmetrically. K n,GC varies 15 times more with an increase in D tau,0 than K n,PF . All findings indicate that the new model is more likely to be forecasted K n for a variety of systems, including clayey-silt, sand, and silty-sand system, and especially in reflecting the heterogeneity
Young Talent Support Project of Guangzhou Association for Science and Technology[2024A04J4601]
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Liquid-Liquid Equilibrium Behavior of Ternary Systems Comprising Biodiesel plus Glycerol and Triglyceride plus Methanol: Experimental Data and Modeling
No full textHaving a comprehensive knowledge of phase equilibrium is advantageous for industrial simulation and design of chemical processes. For further acquisition of primary data to facilitate the separation and purification of waste oil biodiesel systems, a liquid-liquid equilibrium (LLE) tank is deployed for the ternary system of waste oil biodiesel + methanol + glycerin, thereby enhancing the precision and efficiency of the process. The phase equilibrium system was constructed under the influence of atmospheric pressure at precise temperatures of 303.15 K, 313.15 K, and 323.15 K. The equilibrium components of each substance were analyzed by employing high-temperature gas chromatography, a sophisticated analytical method that enables the identification and quantification of individual components of a sample. Moreover, the ternary liquid-liquid equilibrium data were correlated by implementing the NRTL and UNIQUAC activity coefficient models. Subsequently, the binary interaction parameters of the ternary system were derived by conducting regression analysis. The experimental data demonstrated that the presence of lower methanol content in the system resulted in nearly immiscible biodiesel and glycerol phases, which ultimately facilitated the separation of biodiesel and glycerol. Conversely, with the increase in methanol content, the mutual solubility of biodiesel and glycerol was observed to increase gradually. The results showed that the calculated values of the NRTL and UNIQUAC models aligned well with the experimental values. The root-mean-square deviations of the NRTL and UNIQUAC models at 313.15 K were 2.76% and 3.56%, respectively
Generation of environmentally persistent free radicals on photoaged tire wear particles and their neurotoxic effects on neurotransmission in <i>Caenorhabditis elegans</i>
No full textTire wear particles (TWP) are a prevalent form of microplastics (MPs) extensively distributed in the environment, raising concerns about their environmental behaviors and risks. However, knowledge regarding the properties and toxicity of these particles at environmentally relevant concentrations, specifically regarding the role of environmentally persistent free radicals (EPFRs) generated during TWP photoaging, remains limited. In this study, the evolution of EPFRs on TWP under different photoaging times and their adverse effects on Caenorhabditis elegans were systematically investigated. The photoaging process primarily resulted in the formation of EPFRs and reactive oxygen species (O-2(center dot-) , center dot OH, and O-1(2)), altering the physicochemical properties of TWP. The exposure of nematodes to 100 mu g/L of TWP-50 (TWP with a photoaging time of 50 d) led to a significant decrease in locomotory behaviors (e.g., head thrashes, body bends, and wavelength) and neurotransmitter contents (e.g., dopamine, glutamate, and serotonin). Similarly, the expression of neurotransmission-related genes was reduced in nematodes exposed to TWP-50. Furthermore, the addition of free-radical inhibitors significantly suppressed TWP-induced neurotoxicity. Notably, correlation analysis revealed a significantly negative correlation between EPFRs levels and the locomotory behaviors and neurotransmitter contents of nematodes. Thus, it was concluded that EPFRs on photoaged TWP induce neurotoxicity by affecting neurotransmission. These findings elucidate the toxicity effects and mechanisms of EPFRs, emphasizing the importance of considering their contributions when evaluating the environmental risks associated with TWP
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