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1.
Sci Total Environ ; 929: 172477, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38621544

ABSTRACT

To study thermal behaviour during spontaneous combustion of an open-pit coal mine, mixed slag (coal, oil shale, and coal gangue) was taken as the research object. Laser thermal conductivity analyser and differential scanning calorimetry were used to test thermophysical parameters and heat release characteristics of the minerals. The parameters can be employed to calculate the apparent activation energy using the Arrhenius equation and evaluate the thermal behaviour of open-pit mixed slag. The results indicate that thermophysical parameters have stage characteristics. Thermal diffusivity and thermal conductivity of minerals, especially mixed slag, have a strong correlation with temperature. Heat flow of minerals exhibits five characteristic stages, and heat flow of the samples is consistent with the change in heating rate. During the heating process, thermal diffusivity and heat flow of the mixed slag are between those of a single mineral. Except for the mixed slag at 15 and 20 °C/min, the initial exothermic temperature of the other samples is mainly concentrated at 50-80 °C. Thermal energy release of the sample is mainly concentrated in the accelerated exothermic stage and rapid exothermic stage. Thermal energy release of mixed slag in rapid exothermic stage is always greater than that in accelerated exothermic stage, and the proportion of thermal energy release in these two stages exceeds 98 %. The apparent activation energy during the accelerated exothermic stage is lower, making it easier to release heat, and rapid exothermic stage is relatively high, which can readily lead to heat accumulation. Thermal analysis reveals that the thermal behaviour of mixed slag is significantly different from that of a single mineral. Its unique exothermic characteristics can provide a more accurate theoretical basis for the prevention and control of environmental pollution caused by slag spontaneous combustion.

2.
Ecotoxicol Environ Saf ; 266: 115572, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37837695

ABSTRACT

With urbanization and increasing consumption, there is a growing need to prioritize sustainable development across various industries. Particularly, sustainable development is hindered by air pollution, which poses a threat to both living organisms and the environment. The emission of combustion gases containing particulate matter (PM 2.5) during human and social activities is a major cause of air pollution. To mitigate health risks, it is crucial to have accurate and reliable methods for forecasting PM 2.5 levels. In this study, we propose a novel approach that combines support vector machine (SVM) and long short-term memory (LSTM) with complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) to forecast PM 2.5 concentrations. The methodology involves extracting Intrinsic mode function (IMF) components through CEEMDAN and subsequently applying different regression models (SVM and LSTM) to forecast each component. The Naive Evolution algorithm is employed to determine the optimal parameters for combining CEEMDAN, SVM, and LSTM. Daily PM 2.5 concentrations in Kaohsiung, Taiwan from 2019 to 2021 were collected to train models and evaluate their performance. The performance of the proposed model is evaluated using metrics such as mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE), and coefficient of determination (R2) for each district. Overall, our proposed model demonstrates superior performance in terms of MAE (1.858), MSE (7.2449), RMSE (2.6682), and (0.9169) values compared to other methods for 1-day ahead PM 2.5 forecasting. Furthermore, our proposed model also achieves the best performance in forecasting PM 2.5 for 3- and 7-day ahead predictions.


Subject(s)
Air Pollutants , Air Pollution , Humans , Air Pollutants/analysis , Support Vector Machine , Particulate Matter/analysis , Air Pollution/analysis , Algorithms , Forecasting
3.
Geriatrics (Basel) ; 8(5)2023 Sep 15.
Article in English | MEDLINE | ID: mdl-37736893

ABSTRACT

This aim of this research was to explore the appraisal of the use of smart alert bracelets by older adults diagnosed with dementia. Convenience sampling was adopted to recruit older adults with dementia in Yunlin County, Taiwan. A manual questionnaire survey was conducted, and SPSS 26.0 statistical software was used for analysis. The results of this study showed noticeable positive correlation results in the post-test for the modes "wearing device", "degree of dementia", and "field configuration". Based on the experimental results, the following suggestions are provided: (1) in terms of statistical calculation, the statistical results were affected by changes in some participants; (2) as for the design of equipment, to be more suitable for adult use, the size and color of bracelets need to be optimized; (3) as for the problem of battery charging of the device, because the charging location of the device is not easy to find, it is better to extend device standby time; (4) regarding the selection of equipment, older adults with early-stage dementia could be concerned about the function of the wearable device, so it is recommended to provide a device designed with clear functions, such as a watch, so that older adults are more willing to wear it. Patients diagnosed with moderate and severe dementia should be advised to use concealed non-sensory devices, such as charms and cards, to better facilitate assistance from caregivers in wearing them; and (5) as for the device, in case of a loss event, in addition to mobile phone notifications, other light and sound device notifications can be added, allowing caregivers to pay more attention to information in real time. In summary, the feedback from caregivers and older adults suggests that if the device is to be used without charging, the overall design should be light and small, which is more suitable for service designs.

4.
Int J Biol Macromol ; 246: 125675, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37414311

ABSTRACT

In the present work, a novel Fe3O4-GLP@CAB was successfully synthesized via a co-precipitation procedure and applied for the removal of methylene blue (MB) from aqueous environment. The structural and physicochemical characteristics of the as-prepared materials were explored using a variety of characterization methods, including pHPZC, XRD, VSM, FE-SEM/EDX, BJH/BET, and FTIR. The effects of several experimental factors on the uptake of MB using Fe3O4-GLP@CAB were examined through batch experiments. The highest MB dye removal efficiency of Fe3O4-GLP@CAB was obtained to be 95.2 % at pH 10.0. Adsorption equilibrium isotherm data at different temperatures showed an excellent agreement with the Langmuir model. The adsorption uptake of MB onto Fe3O4-GLP@CAB was determined as 136.7 mg/g at 298 K. The kinetic data were well-fitted by the pseudo-first-order model, indicating that physisorption mainly controlled it. Several thermodynamic variables derived from adsorption data, like as ΔGo, ΔSo, ΔHo, and Ea, accounted for a favourable, spontaneous, exothermic, and physisorption process. Without seeing a substantial decline in adsorptive performance, the Fe3O4-GLP@CAB was employed for five regeneration cycles. Because they can be readily separated from wastewater after treatment, the synthesized Fe3O4-GLP@CAB was thus regarded as a highly recyclable and effective adsorbent for MB dye.


Subject(s)
Nanoparticles , Psidium , Water Pollutants, Chemical , Adsorption , Powders , Methylene Blue/chemistry , Alginates/chemistry , Hydrogels , Magnetic Phenomena , Plant Leaves , Water Pollutants, Chemical/chemistry , Kinetics , Hydrogen-Ion Concentration
5.
Sci Total Environ ; 897: 165475, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37442472

ABSTRACT

Coal spontaneous combustion often wastes resources and causes environmental pollution. Rapid and accurate identification of high temperature areas in coal is essential to reducing such combustion and environmental pollution. The acoustic thermometry method has the benefits of large temperature measurement space, non-contact, and high interference resistance. Determining the attenuation characteristics of acoustic waves in loose coal is the basis and premise for realizing acoustic temperature measurement. Four types of bituminous coal were scanned by computer tomography equipment. A self-designed acoustic attenuation test device was used to test coal samples under different temperatures and particle sizes. The study result demonstrates that the distribution characteristics of loose coal voids are mainly related to the particle size. The smaller the particle size range, the more uniform the void distribution. As the size of the coal particles increases, the voids become larger. The acoustic attenuation coefficients of four coal samples showed an increasing trend as frequency increased. The influence of coal particle size distribution on the acoustic attenuation coefficient was greater than that of temperature and metamorphic degree. The peak values of coal sound attenuation for different particle sizes were around 400, 700, 1100, and 1600 Hz. This indicated that the distribution of voids was the main factor affecting the propagation of acoustic waves. By analysing the attenuation mechanism of the acoustic wave in loose coal, the attenuation of acoustic temperature measurement signal was caused by the combined effect of loose coal on acoustic wave absorption and scattering. The study results provide theoretical support for the realization of acoustic wave detection of high temperature point in loose coal spontaneous combustion.

6.
Environ Res ; 216(Pt 2): 114525, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36243055

ABSTRACT

1-butyl-3-methylimidazolium bis(triflouromethylsufonyl)imide functionalization to Na-X zeolite (IFZ) is the primary goal of this study in order to evaluate its ability to remove heavy metals (Cd2+), (Zn2+), dyes Rhodamine 6G (R6), and Alizarin Red S (AR) from aqueous streams. IFZ was thoroughly examined using analytical techniques XRD, BET, FE-SEM, and FTIR, to better understand its physical and chemical properties. The surface area and the volume of pores (IFZ; 19.93 m2/g, 0.0544 cm3/g) were reduced in comparison to the parent zeolite (Na-X; 63.92 m2/g, 0.0884 cm3/g). According to SEM, the crystal structure of the zeolite (Na-X) has not been significantly altered by XRD analysis. The mechanism, kinetics, isotherms, and thermodynamic properties of adsorption were all studied using batch adsorption experiments under various operating conditions. IFZ adsorbs dyes (AR; 76.33 mg/g, R6; 65.85 mg/g) better than metal ions (Cd2+; 30.68 mg/g, Zn2+; 41.53 mg/g) in acidic conditions. The Langmuir isotherm and pseudo-second order models were found to be the most accurate models for equilibrium data. Adsorption is endothermic and spontaneous, as revealed by the thermodynamics of the process. The IFZ can be used in three (Cd2+), two (Zn2+), four (AR), and five (R6) cycles of desorption and regeneration. For these reasons, IL-modified zeolite can be used to remove multiple types of pollutants from water in one simple step.


Subject(s)
Ionic Liquids , Water Pollutants, Chemical , Zeolites , Zeolites/chemistry , Adsorption , Cadmium/analysis , Coloring Agents/analysis , Water Pollutants, Chemical/analysis , Ions , Kinetics , Thermodynamics , Water/chemistry , Zinc/analysis , Hydrogen-Ion Concentration
7.
Gondwana Res ; 114: 93-116, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35136377

ABSTRACT

The novel coronavirus (2019-nCoV) was extended to 213 countries globally by August 2021. The world has been threatened by rising infection rates and emerged as the catastrophic event in the field of health triggering the international emergency panic button. COVID-19's sudden arrival wreaked havoc on the world economic picture, particularly in the energy sector. A steep drop in oil prices, as well as an imbalance in energy, was the result of strict travel restrictions, fewer transportation options, and people's fears of a flu pandemic. However, confined mobility and a drop in energy demand coated the environment with a silver line and drowned the nation's economic opportunities. Industrial transport, and not to mention every conventional energy-related thing, is completely devastated, but renewables were immunized. Wind, solar, hydrothermal, hydrogen, biomass-based energy systems were on high gear yielding maximum results in counterbalancing the demand-supply chain. Moreover, the pandemic created an opportunity to showcase the importance of renewable energy and tackle the difficult emergency like now. In addition to this, the mindset of the investors was slowly fading away from conventional fuels and shifting towards renewable energy. However, it is too early to state the booming renewables at the moment, and no idea about its long-time survival. Thus, the present review gives a clear picture of the current status of fossils and renewables, the impact of a pandemic, energy investments, government policy standings, threats, and opportunities, and finally, the key takeaways avoiding energy scarcity in once a lifetime disaster situation.

8.
Int J Phytoremediation ; 25(2): 146-160, 2023.
Article in English | MEDLINE | ID: mdl-35475946

ABSTRACT

In this study, we used a simple and low-toxicity chemical treatment to make a carboxylate-functionalized dragon fruit peel powder (CF-DFPP) from dragon fruit peel to improve its capacity for adsorbing Rhodamine B (RhB) from an aqueous medium. Field Emission-Scanning Electron Microscopy/Energy-Dispersive X-ray (FE-SEM/EDX), point of zero charges (pHPZC), Brunauer-Emmett-Teller (BET), and Fourier Transform Infrared (FT-IR) analyses were performed to characterize the adsorbent materials. The adsorption performance and mechanism for the removal of RhB were examined. The kinetic, isotherm and thermodynamic parameters were employed to evaluate the adsorption mechanism. Compared to other models, the Langmuir isotherm and PSO kinetic models better defined the experimental data. CF-DFPP adsorbent exhibited a maximum adsorption efficiency of 228.7 mg/g at 298 K for RhB adsorption. Thermodynamic analysis revealed that the adsorption of RhB by CF-DFPP was spontaneous (ΔGo < 0) and exothermic (ΔHo < 0) nature of the process. Different eluting agents were used in desorption tests, and NaOH was revealed to have greater desorption efficiency (96.8%). Furthermore, regeneration examinations revealed that the biosorbent could effectively retain RhB, even after six adsorption/desorption cycles. These findings demonstrated that the CF-DFPP might be a novel material for removing RhB from an aqueous medium.


Subject(s)
Fruit , Water Pollutants, Chemical , Powders/analysis , Fruit/chemistry , Adsorption , Spectroscopy, Fourier Transform Infrared , Biodegradation, Environmental , Thermodynamics , Kinetics , Water Pollutants, Chemical/chemistry , Hydrogen-Ion Concentration
9.
ACS Omega ; 7(24): 21207-21219, 2022 Jun 21.
Article in English | MEDLINE | ID: mdl-35755398

ABSTRACT

An exothermic reaction in a semibatch reactor can potentially cause thermal runaway due to evolved energy accumulation or a secondary reaction. This research aims to propose safety criteria for solid-liquid reactions in semibatch reactors. Simulation modeling was carried out to build thermal runaway criteria for solid-liquid reactions in semibatch reactors. A new model for the energy and mass balance of solid-liquid reactions was successfully established. Criteria for the safety boundary diagram and the temperature diagram were ameliorated for solid-liquid reactions. The results showed that the dissolution heat has a great influence on the thermal behavior of the reaction. Experiments to neutralize citric acid and sodium hydroxide were carried out to determine the critical parameters for the neutralization reaction using the temperature diagram criterion. The proposed criteria would be reasonably expected to provide some guidance for chemical process optimization and safety design for engineering.

10.
ACS Omega ; 7(20): 16980-16989, 2022 May 24.
Article in English | MEDLINE | ID: mdl-35647439

ABSTRACT

To facilitate the flame retardancy of phenolic resin (PF), a series of novel flame retardants with nano-SiO2, melamine, and aluminum diethylphosphinate (ADP) were freshly prepared and tested. A thermogravimetric analysis, cone calorimeter, and scanning electron microscopy were employed to determine the thermal decomposition, flame retardancy, combustion properties, and structure of the carbon residue layer of PF. The pyrolysis kinetic parameters of modified PF were then computed, and the pyrolysis process was appraised. The results indicated that when 1.5 wt % of nano-SiO2, 3 wt % of melamine, and 15 wt % of ADP were added to PF, the limiting oxygen index value reached 39.6%, and UL-94 passed the V-0 level. A substantial synergistic effect was also observed. The thermogravimetric analysis revealed that the char residue at 800 °C reached 59.93 wt %. Furthermore, in the cone calorimeter test, the total thermal release and thermal release rate decreased to 30.7 MJ/m2 and 105.7 kW/m2, respectively.

11.
Int J Phytoremediation ; 24(2): 131-144, 2022.
Article in English | MEDLINE | ID: mdl-34057865

ABSTRACT

NOVELTY STATEMENT: In the modern era, dyes are inevitable and their surging usage leads to colossal contamination of aqueous streams, thereby threatening both the land and aquatic species. One among such dye is anionic Reactive Red 195 (RR 195), and traceable even at minute concentrations of aqueous streams, posing a severe threat to living species. Moreover, RR 195 is highly recalcitrant offering resistance to biodegradation due to the presence of an azo (-N=N-) group within its structure. Thus, there is a definite need to address the issue of eliminating RR 195 from industrial wastewater effluents. In lieu of this, the primitive objective of this study is to test the effectiveness of the natural adsorbent lotus leaf (Nelumbo nucifera) for the selective sorption of RR 195 from the aqueous stream. Although ample literature is available on the direct utilization of lotus leaf as adsorbent, yet no study was performed on the chemical modification (dimethylamine) of the aforementioned adsorbent. Hence, an attempt has been made in this direction to add a new sorbent into the adsorbents database.


Subject(s)
Lotus , Nelumbo , Water Pollutants, Chemical , Adsorption , Azo Compounds , Biodegradation, Environmental , Dimethylamines , Hydrogen-Ion Concentration , Kinetics , Naphthalenesulfonates , Plant Leaves/chemistry , Powders , Thermodynamics , Water Pollutants, Chemical/analysis
12.
Sci Rep ; 11(1): 24053, 2021 Dec 15.
Article in English | MEDLINE | ID: mdl-34912019

ABSTRACT

Nitrocellulose (NC) is widely used in both military and civilian fields. Because of its high chemical sensitivity and low decomposition temperature, NC is prone to spontaneous combustion. Due to the dangerous properties of NC, it is often dissolved in other organic solvents, then stored and transported in the form of a solution. Therefore, this paper took NC solutions (NC-S) with different concentrations as research objects. Under different atmospheric conditions, a series of thermal analysis experiments and different reaction kinetic methods investigated the influence of solution concentration and oxygen concentration on NC-S's thermal stability. The variation rules of NC-S's thermodynamic parameters with solution and oxygen concentrations were explored. On this basis, the spontaneous combustion characteristics of NC-S under actual industrial conditions were summarized to put forward the theoretical guidance for the spontaneous combustion treatment together with the safety in production, transportation, and storage.

13.
J Hazard Mater ; 416: 125925, 2021 08 15.
Article in English | MEDLINE | ID: mdl-34492857

ABSTRACT

SSZ-13 zeolite was successfully synthesized from coal bottom ash (CBA) upon hydrothermal treatment for selective sorption of Alizarin Red S (ARS) dye. The characterization of CBA, and SSZ-13 were performed using BET, SEM, FTIR, XRF, and XRD techniques. The optimal fusion ratio (CBA: NaOH) was identified as 1:3, resulting zeolite SSZ-13 with a specific surface area of 206.6 m2/g, compared to raw CBA (7.81 m2/g). The kinetics, isotherms, and thermodynamics of the ARS adsorption onto the SSZ-13, and CBA were assessed under various conditions. The results indicated that the adsorption phenomenon is optimal under acidic medium (pH = 2 for CBA, pH = 3 for SSZ-13); at ambient room temperature of 298 K; adsorbent dosage of 0.03 g, contact time of 120 min. Further, the equilibrium data fitted well to Langmuir isotherm (qe = 210.75 mg/g), following pseudo-second-order kinetics. Moreover, the chemisorption phenomenon is clearly described using Elovich kinetic model. Various thermodynamic parameters signifies the adsorption phenomenon is spontaneous, and endothermic in nature. Finally, regeneration studies revealed the sensitivity of SSZ-13 zeolite towards 0.1 M NaOH/EtOH eluent in recovery and the possibility of reuse to five successive adsorption/desorption cycles. Thus, hydrothermal treatment of CBA has potential in producing zeolites suitable to adsorption.


Subject(s)
Water Pollutants, Chemical , Zeolites , Adsorption , Anions , Anthraquinones , Coal , Coal Ash , Hydrogen-Ion Concentration , Kinetics , Thermodynamics
14.
Polymers (Basel) ; 13(11)2021 May 21.
Article in English | MEDLINE | ID: mdl-34064015

ABSTRACT

In recent years, the prosperous electric vehicle industry has contributed to the rapid development of lithium-ion batteries. However, the increase in the energy density of lithium-ion batteries has also created more pressing safety concerns. The emergence of a new flame-retardant material with the additive ethoxy (pentafluoro) cyclotriphosphazene can ameliorate the performance of lithium-ion batteries while ensuring their safety. The present study proposes a new polymer composite flame-retardant electrolyte and adopts differential scanning calorimetry (DSC) and accelerating rate calorimetry to investigate its thermal effect. The study found that the heating rate is positively correlated with the onset temperature, peak temperature, and endset temperature of the endothermic peak. The flame-retardant modified polymer electrolyte for new lithium-ion batteries has better thermal stability than traditional lithium-ion battery electrolytes. Three non-isothermal methods (Kissinger; Kissinger-Akahira-Sunose; and Flynn-Wall-Ozawa) were also used to calculate the kinetic parameters based on the DSC experimental data. The apparent activation energy results of the three non-isothermal methods were averaged as 54.16 kJ/mol. The research results can provide valuable references for the selection and preparation of flame-retardant additives in lithium-ion batteries.

15.
Sci Total Environ ; 792: 148392, 2021 Oct 20.
Article in English | MEDLINE | ID: mdl-34147787

ABSTRACT

In the present study, similarities and variances in thermochemical behavior and composition of degradation products among cellulose, lignin, and agricultural residues (sawdust, black tea, barley, bagasse, rice husk, and corncob) were assessed using TG analysis, DSC, TG-FTIR, and Py-GC/MS. The experimental results indicated the temperature range of maximum mass loss between 295-430 °C for cellulose, 155-600 °C for lignin, and 150-500 °C for agricultural residues representing the feedstock's active pyrolysis region. The FTIR analysis established the presence of CO, CC, CO2, CO, CO, and CH4 gaseous functional groups with a strong synergistic effect. The CO2 was the primary product in gaseous mixtures, and their yield enhanced at elevated temperature. The characteristically dependent pyrolysis product groups were anhydro-sugars (84.9%-90.1%) and furans (4.1%-5.6%) in cellulose; phenols (69.6%-77.4%) and aldehydes (5.9%-7.9%) in lignin; furans (1.4%-47.7%) and acids (15.8%-37.3%) in agricultural residues, respectively. Bagasse and corncob trailed similar thermal behavior with furans (30.8%-47.7%) as major pyrolysis products, whereas acids (83.1%-88.7%) were prevalent in rice husk. The mean values of apparent activation energy evaluated by the isoconversional Friedman method were 174.8, 123.1, 160.7-217.3 kJ mol-1, respectively, for cellulose, lignin, and agricultural residues. The results presented comprehensive data in elucidating the influence of individual biomass components at optimized temperatures for higher selectivity of value-added chemicals and bioenergy.


Subject(s)
Lignin , Biomass , Kinetics , Spectroscopy, Fourier Transform Infrared
16.
Polymers (Basel) ; 13(5)2021 Feb 26.
Article in English | MEDLINE | ID: mdl-33652664

ABSTRACT

Lithium-ion batteries with conventional LiPF6 carbonate electrolytes are prone to failure at high temperature. In this work, the thermal stability of a dual-salt electrolyte of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluoro(oxalato)borate (LiODFB) in carbonate solvents was analyzed by accelerated rate calorimetry (ARC) and differential scanning calorimetry (DSC). LiTFSI-LiODFB dual-salt carbonate electrolyte decomposed when the temperature exceeded 138.5 °C in the DSC test and decomposed at 271.0 °C in the ARC test. The former is the onset decomposition temperature of the solvents in the electrolyte, and the latter is the LiTFSI-LiODFB dual salts. Flynn-Wall-Ozawa, Starink, and autocatalytic models were applied to determine pyrolysis kinetic parameters. The average apparent activation energy of the dual-salt electrolyte was 53.25 kJ/mol. According to the various model fitting, the thermal decomposition process of the dual-salt electrolyte followed the autocatalytic model. The results showed that the LiTFSI-LiODFB dual-salt electrolyte is significantly better than the LiPF6 electrolyte in terms of thermal stability.

17.
Sci Prog ; 104(3_suppl): 368504221086707, 2021 Jul.
Article in English | MEDLINE | ID: mdl-35322743

ABSTRACT

This study recycling the industrial byproducts of furnace slag and fly ash to produce slag/ash based zeolite. A scanning electron microscopic/energy dispersive X-ray spectroscopic (SEM/EDS) analysis of this zeolite indicates a high SiO2 content of 53.94%, an Al2O3 content of 23.20%, a silicon-to-aluminum ratio of 2.049, a density of 2.88 g/cm3, and a water content of 0.13% while the zeolite appears as a porous crystalline structure. Results of weighing experiments revealed effective adsorption of liquid salad oil and highly volatile organic solvents after reusing the zeolite up to 6 times. When an adsorbed liquid pollutant was desorbed and the heating temperature exceeded 170 °C and 350 °C, the samples exhibited two exothermic reactions, respectively, the mean maximum enthalpy were 0.427 and 0.461 mW, and the mean per gram of accumulated heat were 80.92 and 45.64 J/g. For all samples, the mean maximum loss of mass rate was 9.26%. Analogously, for gaseous pollutants, the samples exhibited an exothermic reaction when the heating temperature exceeded 180 °C; the average maximum enthalpy was 0.395 mW, the average per gram of accumulated heat was 119.60 J/g, and the average maximum loss of mass rate was 4.79%. This slag/ash based zeolite has the advantages of low cost, high thermal stability, reusability, etc., and can be used as a new adsorbent material for indoor ventilation equipment.

18.
ACS Omega ; 5(42): 27607-27617, 2020 Oct 27.
Article in English | MEDLINE | ID: mdl-33134724

ABSTRACT

To explore the micromechanism of the structural changes of anthracite due to heat accumulation by water and pyrite, during oxidation, anthracite with coal samples was selected in this work from Baijiao Coalmine, Sichuan, China. The samples were added with water of 1, 5, 10, 15, and 20 mass % and pyrite of 1, 2, 4, and 6 mass % and were conducted to experimented torts. As compared with the raw coal sample, the effects of water and pyrite on the microstructure of anthracite were studied. The results indicate that the oxygen-containing functional group of coal increases with the addition of water. The content of the aromatic structure in coal was thought to be due to water and pyrite synergistic effects. The synergistic effect of water and pyrite accelerates the oxidation process of seven types of active groups in coal samples. The water content was 10-15 mass %, and the associated pyrite content was 2-4 mass %; the contribution to the oxidation activity of the main active groups of coal was the largest under oxidizing conditions.

19.
J Hazard Mater ; 400: 123251, 2020 Dec 05.
Article in English | MEDLINE | ID: mdl-32947691

ABSTRACT

The specific heat capacity (Cp), thermal conductivity (λ), and thermal diffusion coefficient (D) of coal gangue (CG) are the main factors that affect the self-ignition potential for heat transferring from burning center to the ground surface. In this paper, the thermophysical properties of CG were investigated by transient plane source method. The correlations and sensitivity analysis were performed to characterize the degree of influence of the thermophysical parameters (Cp, λ, and D) dependence on temperature. The mean values of Cp, λ, and D for CG were at a range of 0.73-0.89 J g-1 K-1, 0.44-0.76 W m-1 K-1, and 0.26-0.43 mm2 s-1, respectively. Compared with coal, CG were located in the low area (Sc < 2) with higher value of λ and D, but lower value of Cp. Results also showed that 70 °C was a critical point for CG at which some kinds of mutation took place in thermophysical properties. The comparison between the experimental data and the correlation outputs exhibited consistency.

20.
J Environ Manage ; 261: 110234, 2020 May 01.
Article in English | MEDLINE | ID: mdl-32148304

ABSTRACT

Electronic and electrical equipment (EEE) became an integral part of daily life and had an immense influence on the economy. The skyrocketing demand, progressive technologies, and high dependency resulted in inconceivable utilization of EEE. However, these scientific expansions shortened the life span of EEE, thereby generating massive volumes of waste electronic and electrical equipment (WEEE). On a global perspective, Oceania generates a per capita of 17.3 kg/inh (inhabitants), followed by Europe 16.6 kg/inh, America 11.6 kg/inh, Asia 4.2 kg/inh and the least contribution by Africa 1.9 kg/inh. As known, EEE comprises complex metallic and non-metallic fractions causing severe discrepancies within the ecosystem, endangering the living species; if not dealt with properly. Thus, there is a pressing need of immediate addressal on the effective e-waste management strategies both from developed and developing countries. On the spin side, the separation of the precious fractions from the EEE on the end-of-life may be a twin dimensional strategy of economic addition, and plummeting the alarming level threats to ecology. However, these menaces are well tackled by the developed countries to some extent by the stringent law enactments, establishing proper recycling facilities, and trading to the underdeveloped and developing nations. But, the majority of the developing and under developed nations lacks the statutes, gaps in policy making, socio-economic-cultural barriers, technology, and the appropriate treatment facilities. In addition, the review identified ten major shortfalls (10L's) refraining the effective e-waste management, especially in the developing and under developed nations. Among which, integration of the formal and informal sectors, mandated network registry, stringent law enforcements, regulated transboundary movements, manufacturers responsibility, consumer awareness and improved eco designs, investing on effective recycling facilities, and improved disposal facilities holds the key. Further, replacing the traditional and conventional procedures with the futuristic and eco-friendly approaches such as chelation, inducing ionic liquids, integrated processes or hybrid technologies, micro factories, photo catalysis, and green adsorption will substantially harness the current barriers of the e-waste management. Finally, the present review will be a thorough glancing for the future research of e-waste management of meso-micro-macro scales.


Subject(s)
Electronic Waste , Waste Management , Africa , Asia , Developing Countries , Ecosystem , Europe , Recycling
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