查看更多>>摘要：According to the existing research results, this paper reviews the influent and effluent concentrations, migration and transformation, and influencing factors of quinolone antibiotics in sewage treatment plants (STPs) with activated sludge treatment processes. Animal breeding and slaughtering wastewater, pharmaceutical wastewater and medical and domestic sewage may be the main sources of quinolone antibiotics. The compounds and concentrations of quinolone antibiotics in influents and effluents around the world are quite different, which is generally due to the difference in social and environmental factors in different regions, and the different treatment processes and operating parameters adopted. The migration and transformation of quinolone antibiotics is usually the result of the synergistic effect of sludge adsorption, biodegradation and photolysis. Sludge adsorption based on electrostatic interaction, hydrophobic forces and other mechanisms is the dominant route to remove quinolone antibiotics, but it does not reduce the total amount of the target antibiotics. An appropriate selection of conditions and control of process variables are beneficial to improve the removal of quinolone antibiotics by biodegradation with co-metabolism. Sources control, treatment processes improvement, fate understanding and prediction, monitoring strategies and risks assessment are potential options for improving the elimination and controlling the pollution of quinolone antibiotics in the future.
查看更多>>摘要：Pyrolysis kinetics was carried out for Calligonum polygonoides (C. Polygonoides) in an inert atmosphere at three different heating temperatures such as 10, 15, and 20 °C/min using thermogravimetric analysis. Physicochemical properties were studied using bomb calorimeter, elemental analyzer, and Fourier Transform Infrared Spectroscopy. C. Polygonoides have a calorific value of 16.33 MJ/kg. Gas chromato-graphy-mass spectrometry was used to identify gases produced during pyrolysis. Thermogravimetric analysis was used to investigate the pyrolysis characteristics of biomass. Activation energy for the three zones of pyrolysis were determined using Kissinger and Ozawa model-free methods. Activation energy calculated for zone I, zone II and zone III using Ozawa and Kissinger model was 133.73,164.50, 254 KJ/mol and 135.61,165.88, and 253.00 KJ/mol, respectively. Thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy were calculated for the three different zones. Kinetic and thermodynamic study confirmed that C Polygonoides can be used as useful and potential bioenergy feedstock.
查看更多>>摘要：This paper experimental investigated the shock wave propagation characteristics and self-ignition produced by the high-pressure hydrogen release in the three-way tubes. Two Y-shaped tubes (60°, 120°) and one T-shaped tube (180°) were used in the experiments and the initial release pressure was 3-8 MPa. The pressure and photoelectric signals in tubes were recorded by the sensor. The results showed that the intensity of shock wave was enhanced or attenuated during the entire releasing process, but the dominant effect was distinct under different conditions and the two effects synergistically affected the occurrence possibility of self-ignition. The critical release pressure for self-ignition in the three-way tubes decreased with the increasing of the bifurcation angle, and the most difficult to occur the self-ignition was the 60° Y-tube in this study. In addition, quenching occurred in the 60° Y-tube when the initial release pressure was 6 MPa, because the temperature of the mixture dropped by the expansion effect. Furthermore, the intensity of the reflected shock wave was not strong enough to promote hydrogen rekindled. This experimental results have reference value for the safety of high-pressure hydrogen production, storage and transportation, and are helpful to understand the influence of bifurcation structure on self-ignition in energy application.
Chandra M.R. VendraAshish V. ShelkeJonathan E.H. Buston
13页
查看更多>>摘要：High energy density lithium-ion batteries (LIBs) are well suited for electrical vehicle applications to facilitate extended driving range. However, the associated fire hazards are of concern. Insight is required to aid the development of protective and mitigation measures. The present study is focused on 4.8 Ah 21700 cylindrical LiNixCoyMnzO (NMC) LIBs at 100% state of charge (SOC) with the aim to develop a viable predictive tool for simulating LIB fires, quantifying the heat release rate and temperature evolution during LIB thermal runaway (TR). To aid the model development and provide input parameters, thermal abuse tests were conducted in extended volume accelerating rate calorimetry (EV-ARC) and cone calorimetry. Some cells were instrumented with inserted temperature probe to facilitate in-situ measurements of both cell internal and surface temperatures. The mean peak values of the heat release rate, cell surface and internal temperatures were experimentally found to be 3.6 kW, 753 °C and 1080 °C, respectively. An analytical model has been developed to predict cell LIB internal pressure evolution following vent opening. The model uses the measured cell internal temperature and EV-ARC canister pressure as input data. Its predictions serve as boundary condition in the three-dimensional computational fluid dynamics (CFD) simulation of TR induced fire using opensource code OpenFOAM. The predicted transient heat release rate compare favourably with the measurements in the cone calorimetry tests. Predictions have also been conducted for an open cluster to assess the likelihood of TR propagation in the absence of cell side rupture. The present modelling approach can serve as a useful tool to assess the thermal and environment hazards of TR induced fires and aid design optimisation of mitigation measures in enclosed cell clusters/modules.
查看更多>>摘要：Atmospheric water harvesting has been inexorably proliferated as a potential source of freshwater, notably for remote areas that lack access to water and electricity. This technology could be significantly operated with renewable energy sources. The current study comprehensively reviews the state-of-the-art atmospheric water harvesters and their desiccant materials. Firstly, a detailed survey on desiccant materials, silica gel, Metal-organic frameworks (MOFs), hydrogels, zeolite, hygroscopic salts and composite desiccant materials is illustrated. The review particularly focuses on the materials adsorption capability, kinetics, proper matching with climate conditions. Moreover, the most suitable adsorbents are thoroughly surveyed for a wide range of climate conditions, especially for water scarcity regions (i.e., arid zones) that are characterized by low relative pressures. Moreover, various designs of solar-powered atmospheric water harvesters are comparatively summarized, including fixed and portable installations. It can be concluded that MOF-801, MOF-808, MOF-841, HKUST-1, and CPO-27(Ni) have a superior potential for water harvesting in arid areas. Additionally, MIL-lOl(Cr) has superior water uptake and kinetic at high relative pressure (i.e., humid areas), and it is irrelevant for water harvesting at dry zones. It is found that the cost of the collected water from atmospheric water harvesting technology is about 0.062-0.86 $/kg of adsorbent. This work provides beneficial perspectives for selecting the most relevant desiccant materials beside the appropriate solar system for water harvesting applications.
查看更多>>摘要：Fire accidents caused by the leakage of combustible gas pose a serious threat to the offshore platform, probably resulting in local damage and even progressive collapse of the platform structure. The aim of this paper is to systematically assess the structure safety of platform under fire accidents. The uniqueness of this study is the integration of fluid-thermal-structural coupling simulations with the advantage of considering an accidental fire scenario. The dispersion behavior of leaked gas is studied and the development of elevated temperature generated on the offshore platform during the combustion process is predicted based on Computational Fluid Dynamics (CFD)-Finite Element Analysis (FEA) coupling method. Then, the thermal-mechanical coupling analysis is performed to predict the responses of structure under high temperature. Eventually, the criteria of ultimate bearing capacity of the component and the overall offshore structure are utilized to evaluate the safety of the offshore platform. The results show that with the development of fire, the high temperature zone spreads to cover the space between two neighboring decks, and the maximum temperature in the platform reaches 877 °C. The structural strength of the platform is significantly affected by high temperature. Under the vertical load, the ultimate bearing capacity of the platform at high temperature is decreased by 78% compared to that at ambient temperature. The methodology proposed could be applied to the safety assessment of other similar offshore or marine facilities, so as to support to the process safety in fire accidents.
查看更多>>摘要：The present study delineated to explore the possibility of using cyclodextrins as an environmentally friendly solubilizer for enhancing the desorption efficiency of petroleum hydrocarbons (PHs) in the contaminated soil. The results showed that cyclodextrins could promote the transfer of PHs from the soil solid phase to the aqueous phase. Through the batch desorption experiments, single-factors influencing the desorption efficiency, including desorption time, species of cyclodextrin, solid to liquid ratio (S/L ratio) of soil to solvent, concentrations of solubilizer and concentrations of the contaminated soil were investigated. In addition, the response surface methodology analysis were used to identify the optimal desorption conditions, and the optimal desorption parameters were concluded as the follows: desorption time of 34 h, S/L ratio of soil to solvent of 1:25, concentration of p-CD of 0.75 g/L (for PAHs), desorption time of 18 h, S/L ratio of soil to solvent of 1:5, concentration of p-CD of 4.8 g/L (for n-alkanes). The highest desorption efficiency of two representative PHs, polycyclic aromatic hydrocarbons (PAHs, phenanthrene, fluoranthene and pyrene) and n-alkane (C16, C20, C24, C28 and C32), were 63.0% and 61.7%, respectively. This study presented new-positive evidence of cyclodextrins for enhancing desorption of PHs, was of great importance for enhancement of bioavailability of PHs, and further revealed the great potential of cyclodextrins as a solubilizer in-situ assisting removal of PHs in the petroleum-contaminated sites.
查看更多>>摘要：Halophytes are dominant plants in the phytoremediation of heavy metal contaminated saline soils. Arbuscular mycorrhizal (AM) fungi can improve plant abiotic stress tolerance and chelating agents nitrilotriacetic acid (NTA) can alleviate heavy metal stress. However, the combined effects and mechanisms of two amendments on halophytes grown in heavy metal contaminated saline soils are largely unknown. Pot experiment was conducted to explore the molecular mechanisms of Funneliformis mosseae (Fm) and NTA (10 mmol-kg~(-1)) on Suaeda salsa tolerance to combined stress of Cd (5 mg-kg~(-1)) and NaCl (2.5 g-kg~(-1)). The results showed that AM fungi and NTA promoted growth of S. salsa, increased accumulations of Na+, Cd and mineral elements, but decreased Na+, Cd and malondialdehyde (MDA) concentrations in shoots under combined stress. Transcriptomic analysis presented various regulation pathways of the single or combined application of AM fungi and NTA on S. salsa. The identified differentially expressed genes (DEGs) in (Fm +NTA)/CK were mainly involved in antioxidant defense, osmoregulation, and photosynthesis; the DEGs in (Fm+NTA)/Fm were related to the maintenance of the cell membrane integrity and plant abiotic stress tolerance; and the DEGs in (Fm+NTA)/NTA were related to the enhancement ability of secondary cell wall synthesis and transcription factor. Our study provides new insights into the molecular mechanisms of AM fungi and NTA on halophytes tolerance to combined stress of heavy metal and salt.
查看更多>>摘要：The sustainability and innovation of a novel leachate treatment technology is a matter of vital significance. Bio-electrochemical-driven wastewater and leachate treatment methods, particularly MFC, and their improvements have attracted scientists' attention recently. This study developed a new MFC system, which consisted of an anodic chamber, a cathode chamber with fixed biofilm carriers and a low-cost sheet of carbon felt between them as a membrane-like separator. The study was conducted to evaluate the capacity of MFC coupled with integrated fixed-film activated sludge (IFAS), to enhance the efficiency of the treatment and the amount of energy produced. Three MFC systems with different cathode processes were compared, namely, conventional activated sludge (MFC-AS), MFC-IFAS, and microalgae coupled MFC-IFAS (MFC-IFAS/MA). The experimental results revealed that MFC-IFAS/MA produced higher power density and nitrogen removal than the other two systems. The average removals of COD, NH4+-N, and total nitrogen (TN) were, 69.9%, 84.2% and 60.5% for MFC-AS, 84.3%, 79.2% and 71.6% for MFC-IFAS; and 82.0%, 90.3% and 88.6% for MFC-IFAS/MA. MFC-IFAS/MA demonstrated its superior electrochemical behaviors and nitrogen removal and this behavior was referring to the dual effect of fixed-biofilm and microalgae assimilation. This study investigated for the first time the symbiosis between microalgae and IFAS in an MFC reactor, which may open a new prospect for MFC application.
查看更多>>摘要：The typical combustion mode of underground coal fires (UCFs) is smoldering during which the reaction zone is not exposed to a constant oxygen concentration. Understanding the macro-kinetics of coal-oxygen reactions under varying oxygen concentrations, especially the extremely oxygen-depleted condition, is of both theoretical importance and practical relevance to the control and extinguishment of UCFs. Considering the actual conditions of UCFs, thermal analysis tests under four oxygen concentrations (from 21% to 3%) and three heating rates (1,2 and 5 °C /min) were carried out. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results were obtained for a bituminous coal sample from Inner Mongolia, China. With the global reaction assumption, the macro-kinetics parameters (the apparent activation energy, the pre-exponential factor and the kinetics model function) were determined. On the profiles of the apparent activation energy (Ea), three peak values were observed, physically interpreted as the depletion of volatiles, the formation of plastic mass and the depletion of char, respectively. This interpretation was verified by characteristic temperatures extracted from the experimental data. With the decrease of the oxygen concentration from 21% to 9%, two peak values diminish gradually. The case with 3% oxygen concentration gives a nearly monotonically declining Ea, indicating that under that particular condition, oxygen diffusion stands as the only limiting factor across all stages of coal-oxygen reactions. The best-fit kinetics model functions suggest that the char oxidation stage falls into the kinetics-controlled regime when the oxygen concentration is as low as 9%. For the volatiles burning stage, the universal ignition index (Fz) is found to be effectively related to the reaction regime for a variety of coal ranks. The quantitative results obtained can be integrated into any CFD multi-physics models as a sub-model for chemical kinetics.
NSTL