Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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Cryosphere: a frozen home of microbes and a potential source for drug discovery
No full textThe world is concerned about the emergence of pathogens and the occurrence and spread of antibiotic resistance among pathogens. Drug development requires time to combat these issues. Consequently, drug development from natural sources is unavoidable. Cryosphere represents a gigantic source of microbes that could be the bioprospecting source of natural products with unique scaffolds as molecules or drug templates. This review focuses on the novel source of drug discovery and cryospheric environments as a potential source for microbial metabolites having potential medicinal applications. Furthermore, the problems encountered in discovering metabolites from cold-adapted microbes and their resolutions are discussed. By adopting modern practical approaches, the discovery of bioactive compounds might fulfill the demand for new drug development
Upcycling of epoxy resin from waste wind turbine blades: Pyrolysis-methylation tandem reaction to methylated phenols and hexamethylbenzene
No full textThe pyrolysis products of epoxy resin consist of mixed phenolic compounds, which can be transformed into methylated phenolic compounds, pentamethylbenzene, hexamethylbenzene, and other high-value chemicals through methylation. However, the mechanism of methylation for pyrolysis products of epoxy resin remains unclear. In this study, using thermosetting epoxy resin and waste wind turbine blades as feedstocks, we investigated the methylation performance of different solid acid catalysts (gamma-Al2O3, alpha-Al2O3, ZSM-5, MCM-41) through a pyrolysis-methylation cascade reactor. The study unveils the impact of reaction temperature and reaction time on the pyrolysis reaction and the product distribution. The optimal reaction parameters are determined to be 500 degrees C and a reaction time of 20 min. Under these conditions, the reforming products exhibited the highest selectivity for methylated phenolic compounds and hexamethylbenzene (42.57 wt%). The proposed methyl substitution reaction pathway for isopropenylphenol was supported by a(13)C methanol isotope experiment. On nanoscale gamma-Al2O3 catalyst, the methylation reaction displays a non-position-selective methylation pattern. Methyl substitution occurs by directly replacing the methylating agent on the isopropyl/isopropenyl group, leading to the breaking of the C-arom-C-aliph bond. Additionally, Density Functional Theory (DFT) simulations reveal that methyl serves as an intermediate in the methylation substitution reaction. The study also conducted a material flow assessment for the recycling of epoxy resin waste through the pyrolysis-methylation pathway
Investigation of permeability and growth habits in hydrate-bearing porous media considering pore irregularity
No full textThe permeability of hydrate-bearing sediments critically affects gas production rate and efficiency. Reported permeability from artificial and natural cores is widely scattered owing to porous media particle size, porosity and hydrate saturation (S-H), but pore irregularity was ignored. Therefore, analyzing the effects of pore irregularity on growth habits and permeability is crucial. In this study, we used glass beads (represent regular pores, well-rounded grain) and quartz sands (represent irregular pores, angular grain) with nearly the same particle size distribution (mean and median particle size is around 103 mu m and 100 mu m, respectively) and porosity (about 39%) as the porous media, to determine the hydrate growth habits and the permeability as a function of S-H. First, the hexagonal prism model (HP model) was proposed for well-rounded porous media with regular pores, and a fractal model was recommended for angular porous media with irregular pores. The fitting permeability reduction exponents (N) in these two models indicated that both pore-filling (5% < S-H < 25%, N = 30) and grain-coating (0 < S-H < 5%, N = 15) hydrates existed within glass beads, and only pore-filling (0 < S-H < 25%, N = 15) hydrates were dominant in quartz sands. The permeability values in glass beads were consistently higher than those in quartz sands due to more pore connections, smooth surfaces, and grain-coating hydrates in glass beads. This study provides the permeability reduction model based on pore irregularity
Fractionating softwood lignocellulose using APW system for enhanced enzymatic hydrolysis
No full textThe pretreatment effects of acetone/phenoxyethanol/water (APW) system on three common softwoods (Chinese fir, cypress, and Pinus massoniana) were investigated in this study. Under 125 degrees C for 150 min, more than 80% of lignin and nearly 100% of hemicellulose were removed from these softwoods without coupling with other pretreatment methods. Moreover, the enzymatic hydrolysis efficiency of these wet residues was more than 88%. The characterization of the residue revealed that the APW system could effectively destroy the structure of lignocellulose and expose the cellulose to the surface, which enhanced enzymatic hydrolysis. Furthermore, the beta-O-4, beta-5, and beta-beta linkages between the lignin were destroyed, and the condensation structure appeared between G(2) and G(5) units. The Mw and Mn of lignin were reduced to 5642 and 1293 g/mol, and lignin with well pyrolysis activity was achieved. This study provides a potentially effective way to fractionate softwoods for biorefinery
Science and Technology Program of Science and Technology Project of China Southern Power Grid Co., Ltd.[037700KK52220041]
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Exposure to OPFRs Is Associated with Obesity and Dysregulated Serum Lipid Profiles: Data from 2017-2018 NHANES
No full textWidespread exposure to organophosphorus flame retardants (OPFRs) has been observed in the general population. Emerging studies have revealed OPFRs possess endocrine-disturbing properties. The present study aims to assess the association between urinary metabolites of OPFRs, BMI, and serum lipid profiles. Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 were obtained, with 1334 adults enrolled in the current study. Urinary concentrations of bis (1-chloro-2-propyl) phosphate (BCIPP), bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), dibutyl phosphate (DBUP), and diphenyl phosphate (DPHP) were quantified to assess OPFR exposure. Covariate-adjusted linear and logistic regression models were conducted to explore the associations between log2-transformed concentrations of OPFR metabolites, BMI, obesity, and serum lipid profiles. Stratified analyses were performed to assess the heterogeneity of associations by age, gender, race, etc. Positive associations were found between OPFR exposure and the risk of obesity. The multivariate linear analysis indicated that a one-unit increase in log2-transformed urinary concentrations of BCEP and BDCPP was associated with 0.27 (95% CI: 0.02-0.52, p = 0.0338) and 0.56 (95% CI: 0.25-0.87, p = 0.0004) higher BMI value, respectively. One log2-unit increase in urinary BCEP and BDCPP concentrations was associated with 1.1-fold (95% CI: 1.02-1.18, p = 0.0096) and 1.19-fold (95% CI: 1.09-1.30, p = 0.0001) risk for developing obesity. Furthermore, the non-linear relationship between exposure to OPFRs and obesity was identified. Additionally, multivariable linear regression showed that urinary DPHP concentrations were inversely correlated with serum triglyceride (TG) levels (beta = -7.41, 95% CI: -12.13 to -2.68, p = 0.0022). However, no other OPFR metabolites were found to be significantly statistically associated with serum lipid levels after adjusting for potential confounders. In conclusion, environmental exposure to OPFRs might contribute to obesity and dysregulated TG concentrations in adults. Future prospective research is warranted to confirm the causal relationship between metabolites of OPFRs and obesity
LEAP model-based analysis to low-carbon transformation path in the power sector: a case study of Guangdong-Hong Kong-Macao Greater Bay Area
No full textAs a major carbon emitter, the power sector plays a crucial role in realizing the goal of carbon peaking and carbon neutrality. This study constructed a low-carbon power system based on the LEAP model (LEAP-GBA) with 2020 as a statistic base aiming of exploring the low-carbon transformation pathway of the power sector in the Guangdong-Hong Kong, and Macao Greater Bay Area (GBA). Five scenarios are set up to simulate the demand, power generation structure, carbon emissions, and power generation costs in the power sector under different scenarios. The results indicate that total electricity demand will peak after 2050, with 80% of it coming from industry, buildings and residential use. To achieve net-zero emissions from the power sector in the GBA, a future power generation mix dominated by nuclear and renewable energy generation and supplemented by fossil energy generation equipped with CCUS technologies. BECCS technology and nuclear power are the key to realize zero carbon emissions from the power sector in the GBA, so it should be the first to promote BECCS technology testing and commercial application, improve the deployment of nuclear power sites, and push forward the construction of nuclear power and technology improvement in the next 40 years
Catalytic production of 5-hydroxymethylfurfural from lignocellulosic biomass: Recent advances, challenges and opportunities
No full textLignocellulosic biomass is the only renewable source of organic carbon, presenting a sustainable alternative to fossil fuels in the green production of value-added chemicals, transportation fuels, and polymeric materials. The process for converting biomass into desired end-products typically involves multiple steps through the formation of intermediate molecules or "platform chemicals". One such pivotal platform chemical is 5-hydroxymethylfurfural (HMF). Therefore, the efficient and selective conversion of biomass into HMF emerges as an imperative research focus. This review highlights the latest breakthroughs in the catalytic production of HMF from biomass and derivative sugars. An in-depth exploration of various synthesis pathways for HMF is provided, shedding light on the critical roles played by raw materials, catalysts, solvents, and operating conditions in influencing reaction performance. Central to the discussion is elucidating the mechanisms and active sites involved in HMF synthesis, with a spotlight on the synergy effects of Lewis acid and Br & oslash;nsted sites within catalysts during the hydrolysis, isomerization, and dehydration phases of HMF production. The pivotal step of isomerization, which determines the reaction rate in HMF synthesis from biomass, is given particular attention. In conclusion, the review reflects on the state-of-the-art progress and charts out prospective avenues for enhancing HMF production from biomass. Through this, our ultimate aim is to guide future innovations in catalytic systems for HMF synthesis from biomass, fostering their swift transition into industrial applications
Mechanistic insights into Ga-modified hollow ZSM-5 catalyzed fast pyrolysis of cassava residue
No full textThe preparation of valuable chemicals by catalytic fast pyrolysis (CFP) is a promising and environmentallyfriendly approach for the selective upgrading of waste cassava residue (CR). This work systematically investigated the conversion mechanism and kinetic characteristics of CR pyrolysis over Ga-modified hollow ZSM-5, for the purpose of enhancing aromatics production. The hollow configuration significantly regulated the structural characteristics of ZSM-5, thus facilitating the diffusion, deoxygenation, and aromatization of pyrolysis intermediates. The incorporation of Ga species and generated Br & oslash; nsted acid sites remarkably accelerated the reaction rate and suppressed the carbonization at high temperatures, through enhancing the end scission of starch and cellulose components. With the aid of 5Ga/ZSM-H, the relative content of aromatics achieved 95.4% at 700 degrees C, and still maintained over 92.5% even after 5 cycles. The ring-opening and retro-aldol degradation were identified as crucial steps for the production of ketones and aldehydes separately, which were further transformed into hydrocarbon pools by deoxygenation and subsequently converted into aromatics via Diels-Alder reaction. Kinetic analysis demonstrated that the use of 5Ga/ZSM-H lowered the average activation energy of CR pyrolysis by 14.8%, particularly for the initial pyrolysis stage. Moreover, the plausible mechanism for aromatics formation from Ga-modified hollow ZSM-5 catalyzed CR pyrolysis was proposed
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