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1 |
Chemical adsorption on 2D dielectric nanosheets for matrix free nanocomposites with ultrahigh electrical energy storage
جذب شیمیایی روی نانوصفحات دی الکتریک دوبعدی برای نانوکامپوزیت های بدون ماتریس با ذخیره انرژی الکتریکی فوق العاده بالا-2021 Relaxor ferroelectric polymers display great potential in capacitor dielectric applications because of their
excellent flexibility, light weight, and high dielectric constant. However, their electrical energy storage
capacity is limited by their high conduction losses and low dielectric strength, which primarily originates
from the impact-ionization-induced electron multiplication, low mechanical modulus, and low thermal
conductivity of the dielectric polymers. Here a matrix free strategy is developed to effectively suppress
electron multiplication effects and to enhance mechanical modulus and thermal conductivity of a dielectric polymer, which involves the chemical adsorption of an electron barrier layer on boron nitride
nanosheet surfaces by chemically adsorbing an amino-containing polymer. A dramatic decrease of leakage current (from 2.4 106 to 1.1 107 A cm2 at 100 MV m1) and a substantial increase of breakdown strength (from 340 to 742 MV m1) were achieved in the nanocompostes, which result in a
remarkable increase of discharge energy density (from 5.2 to 31.8 J cm3). Moreover, the dielectric
strength of the nanocomposites suffering an electrical breakdown could be restored to 88% of the original
value. This study demonstrates a rational design for fabricating dielectric polymer nanocomposites with
greatly enhanced electric energy storage capacity.
Keywords: Boron nitride nanosheets | Electron barrier layer | Relaxor ferroelectric polymers | Nanocomposites | Electrical energy storage |
مقاله انگلیسی |
2 |
Anthropogenic and biogenic hydrophobic VOCs detected in clouds at the puy de Dôme station using Stir Bar Sorptive Extraction: Deviation from the Henrys law prediction
VOC های ضد آب و انسان و بیولوژیکی آبگریز شناسایی شده در ابرها در ایستگاه پوی دووم با استفاده از استخراج Stir Bar Sorptive: انحراف از پیش بینی قانون هنری-2020 Cloud droplets are able to trap many gaseous compounds and represent a very reactive media in the atmosphere.
However, phase-partitioning of Volatile Organic Compounds (VOCs) between gaseous phase (interstitial air) and
atmospheric liquid phase (cloud droplets) is still poorly characterized. In the present work, air samples and cloud
water were collected simultaneously and hydrophobic organic compounds from anthropogenic and biogenic
origins were quantified in order to evaluate their air/water partitioning. For this, cloud events were sampled at
the puy de Dôme station (PUY). A new analytical approach was optimized to explore dissolved VOCs in the
aqueous phase by Stir Bar Sorptive Extraction (SBSE) and gaseous samples were collected using sorbent tubes.
All samples were analyzed by Thermal Desorption (TD) Gas Chromatography (GC) coupled with Mass
Spectrometry (MS). Extraction efficiencies by SBSE vary between 22% and 97% and the detection limit of VOCs
in aqueous cloud samples lies between 1.0 and 8.7 ng L−1. Experimental partitioning is evaluated towards the
theoretical one described by the Henrys Law constants. Our results show that observed concentrations of hydrophobic
VOCs are supersaturated by a factor of 10–103 in comparison with Henrys law equilibrium.
Calculations have been performed to evaluate the potential role of adsorption at the air/water interface and of
sorption with non-dissolved organic carbon. However, the supersaturation in the cloud droplets requires more
laboratory experiments to understand processes at the air/water interface and constrain cloud chemistry models. Keywords: Volatile organic compounds (VOCs) | Cloud | Gas-liquid partitioning | Henrys law | PUY station | Stir Bar Sorptive Extraction (SBSE) |
مقاله انگلیسی |
3 |
Study of competitive adsorption of the N2O-CO2-CH4-N2 quaternary mixture on CuBTC
مطالعه جذب رقابتی از مخلوط چهارتایی N2O-CO2-CH4-N2 در CuBTC-2020 For the widespread use of Metal Organic Frameworks as adsorbents for gas separation and purification, it is
crucial to understand the multicomponent adsorption mechanism occurring in them. In this paper, we first
provide experimentally consistent and comprehensive set of a quaternary mixture (N2O-CO2-CH4-N2) adsorption
data on CuBTC. The measurements were performed at 297 K using a home-made recirculating volumetric apparatus.
For the first time, we combine existing results from molecular simulations of the single-gas adsorption
and the new experimental quaternary mixture data to get insights in competitive adsorption mechanism. For
pure-component adsorption, the affinity of CuBTC for the components is in the following decreasing order N2O,
CO2, CH4 and N2. A comparison of the components electronic properties shows that the dipole moment and the
polarizability play more role in the adsorption on non-polar adsorbent CuBTC than does the quadrupole moment.
The competition in the mixed adsorbed phase is proven by the big difference between the adsorbed
quantities of all the components in the single-component phase and the mixture. The experimental data unequivocally
confirms that the secondary adsorption sites e.g. sites which adsorption is favoured by adsorption on
primary sites, play an important in the adsorption of all the components on CuBTC. For instance, the fact that the
secondary adsorption sites of some components represent the primary adsorption sites of others is at the origin of
the high competition in adsorption on CuBTC. On the other hand, it is shown that screening adsorbent separation
performance with only pure-component data is not appropriate, as evidenced by the high difference between
selectivities calculated from experimental mixture data and only pure-component isotherms. Moreover, the
working selectivity has been proven to be more useful than the equilibrium selectivity, as it encompasses information
on optimal feed gas and desorption pressures. Keywords: Quaternary mixture adsorption | Competition | CuBTC | Equilibrium selectivity | Working selectivity |
مقاله انگلیسی |
4 |
Prediction of adsorption capacity for pharmaceuticals, personal care products and endocrine disrupting chemicals onto various adsorbent materials
پیش بینی ظرفیت جذب داروها ، محصولات مراقبت شخصی و مواد شیمیایی مختل کننده غدد درون ریز روی مواد مختلف جاذب-2020 Adsorption is a common process used to remove pharmaceuticals, personal care products and endocrine
disrupting chemicals (PPCPs/EDCs) from water. However, as PPCPs/EDCs cover a wide range of molecules
and chemical structures, prediction of the adsorption capacity is very challenging. In this study, a novel
model was developed to predict adsorption isotherms of PPCPs/EDCs onto various types of adsorbents
using a combination of Polanyi potential theory, molecular connectivity indices (MCIs) and molecular
characteristics. Polanyi theory provided the basic mathematical form for the correlation. MCIs, hydrophobicity
and H-bond count were used to normalize the Polanyi equation based on the molecular
structure and interactions among the chemicals, the adsorbents, and the solution. In total, adsorption
data were collected from 158 reports for 55 PPCPs/EDCs onto 306 different adsorbent materials. The
correlation was first trained with 46 PPCPs/EDCs adsorbed onto 162 carbonaceous adsorbents (CAs), with
44.8% SDEV. Then the model was employed to predict 46 PPCPs/EDCs onto 118 other CAs and 9 new
PPCPs/EDCs onto 23 CAs in ultrapure water, with error from 42 to 48% SDEV. When applying to noncarbonaceous
adsorbents, the models can still predict the adsorption of PPCPs/EDCs with 90.09%
SDEV. For the first time, a model, the PD e MCI e hydrophobic e H bond model, was developed to
predict adsorption of a wide group of complicated PPCPs/EDCs onto a big variety of carbonaceous and
non-carbonaceous adsorbents. The proposed model approach may provide a simple means for predicting
adsorption capacities of PPCPs/EDCs onto various adsorbents. Keywords: Adsorption | Polanyi e Dubinin model | Activated carbon | PPCPs/EDCs | Water treatment |
مقاله انگلیسی |
5 |
Application of power law in conductivity of binary mixed rhamnolipid surfactant systems
کاربرد قانون قدرت در رسانایی سیستم های سورفاکتانت رامنولیپید باینری مخلوط شده-2020 The limiting molar conductivity (Λ0) reflects the dissociation and the interaction of the electrolyte, and for the
surfactant, it also reflects the interface adsorption and aggregation behavior of the molecules. A commonly used
calculation method of Λ0 is the extrapolation of conductivity. In this article, a new approach known as Power law
were used to improve the accuracy of the determination of Λ0 comparing the Ostwalds dilution law. The Law of
independent migration proposed by Kohlrausch was used to explain the ionization and aggregation of surfactants
in extremely dilute solutions. The effect of additives (N-Butanol, Diethanolamine (DEA) and PEG400) on
Rhamnolipid (RL) aqueous solution were studied by conductivity method. From the obtained conductive results,
we can calculate the critical aggregation concentration (CAC), the counter ion dissociation degree (α), the Gibbs
standard free energy of micellization (ΔGmic°), molar conductivity (Λ), and aggregation numbers (nagg). Henrys
law coefficient (H) and surface tension (γ) were also tested. The result shows that the α calculated by Power law
is in good agreement with obtained by the conductivity method, and the CAC, α, Λ0, γ, nagg and H had a good
correlation. Keywords: Rhamnolipid | Power law | Limited mole conductivity | Pre-micellar |
مقاله انگلیسی |
6 |
Adsorption characteristics of supercritical CO2/CH4 on different types of coal and a machine learning approach
ویژگی های جذب CO2 / CH4 فوق بحرانی در انواع مختلف ذغال سنگ و رویکرد یادگیری ماشین-2019 The injection of CO2 into deep coal beds can not only improve the recovery of CH4, but also contribute to the
geological sequestration of CO2. The adsorption characteristics of coal determine the amount of the greenhouse
gas that deep coal seams can store in place. Using self-developed adsorption facility of supercritical fluids, this
paper studied the adsorption behavior of supercritical CO2 and CH4 on three types of coal (anthracite, bituminous
coal A, bituminous coal B) under different temperatures of 35 °C, 45 °C and 55 °C. The influence of
temperature, pressure, and coal rank on the Gibbs excess and absolute/real adsorption amount of supercritical
CO2/CH4 on coal samples has been analyzed. Several traditional isotherm models are applied to interpret the
experimental data and Langmuir related models are verified to provide good performances. However, these
models are limited to isothermal conditions and are highly depended on extensive experiments. To overcome
these deficiencies, one innovative adsorption model is proposed based on machine learning methods. This model
is applied to the adsorption data of both this paper and four early publications. It was proved to be highly
effective in predicting adsorption behavior of a certain type of coal. To further break the limit of coal type, the
second optimization model is provided based on published data. Using the second model, one can predict the
adsorption behavior of coal based on the fundamental physicochemical parameters of coal. Overall, working
directly with the real data, the machine learning technique makes the unified adsorption model become possible,
avoiding tedious theoretical assumptions, derivations and strong limitations of the traditional model. Keywords: Supercritical CO2 | Supercritical CH4 | Coal | Adsorption model | Machine learning |
مقاله انگلیسی |
7 |
Cellulosic adsorbent functionalized with macrocyclic pyridone pentamer for selectively removing metal cations from aqueous solutions
جاذب سلولزی عملکردی با پنتامر پیریدون ماکروسیکلیک برای حذف انتخابی کاتیونهای فلزی از محلولهای آبی-2019 Metal selective adsorbent (MCPP-SA-MCC) was synthesized by the reaction of macrocyclic pyridone pentamer
(MCPP) with succinic acid anhydride modified microcrystalline cellulose (SA-MCC). Selectivity of the tailormade
adsorbent to metal cations was studied by measuring its competitive adsorption ability to nine metal
cations (Ba2+, Pb2+, Cd2+, Mn2+, Cu2+, Co2+, Ni2+, and Cr3+). It was found that MCPP-SA-MCC exhibited a
patterned recognition of metal cations remarkably correlated with the metal cation radius. In the simulated
wastewater effluent containing nine metal cations, MCPP-SA-MCC dominantly adsorbed Ba2+, which has a
larger ion radius than others, and 75% of Ba2+ was removed while others less than 18%. These features indicated
the promise of MCPP-SA-MCC as a candidate to remove heavy metal cations from aqueous solution
selectively. Keywords: Cellulosic adsorbent | Metal cation | Pyridone pentamer | Macrocycle | Selective removal |
مقاله انگلیسی |
8 |
On the feasibility of metal oxide gas sensor based electronic nose software modification to characterize rice ageing during storage
امکان سنجی اصلاح نرم افزار الکترونیکی بینی حسگر گاز اکسید فلزی برای توصیف پیری برنج در حین ذخیره سازی-2019 The aroma change of aromatic and non-aromatic rice was traced during storage using electronic nose (E-nose).
Various steady-state and transient features were derived from the adsorption and desorption phases of the E-nose
responses to characterize the ageing process and classify the storage durations. Principal component analysis was
utilized to analyse the ageing in terms of seven classes related to the storage duration of 6 months. The aromatic
samples followed a specific pathway in its timeline with separately distinctive grouping, revealing the reduction
of ageing indices. The aromatic rice underwent crucial changes in its volatile compounds, mainly in the early
stages of storage. While, confused grouping of the non-aromatic rice proved its stability due to less diverse range
of the aroma compounds. Several artificial neural networks, namely back propagation (BP), radial basis function
(RBF), and learning vector quantization (LVQ) were used to classify the storage durations. For the aromatic
samples, full classification was achieved by using all the networks. For the non-aromatic rice, the developed RBF
and LVQ networks represented full classification by using the features of rise time and polynomial curve fitting
parameters. It is concluded that the E-nose system along with the developing methods could be utilized to
control the rice ageing. Keywords: Electronic nose | Feature extraction | Pattern recognition | Rice aging | Sensor array |
مقاله انگلیسی |
9 |
جذب ستونی از 2- نفتول برای محلول ابی با استفاده از جاذب کامپوزیتی مبتنی بر نانولوله کربنی
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 37 - تعداد صفحات فایل doc فارسی: 21 یک ساختار لایه هسته جاذب کامپوزیتی مبتنی بر نانولوله کربنی ساخته شده است و برای حذف 2- نفتول از محلول ابی در یک سیستم ستونی ثابت در این مطالعات پذیرفته شده است. اثری از پارامترهای عملیاتی شامل جرم جاذب، سرعت جریان نفوذی و غلظت ورودی در عملکرد جذب از ستون مورد بررسی قرار گرفته است. منحنی موفق دستابی شده نشان می دهد که در نگهداری موثر از 2- نفتول با استفاده از ستون جذب شده همراه جاذب کامپوزیتی مبتنی بر نانولوله کربنی بدست امده است. مقدار جذب تعادلی از 2- نفتول در جاذب کامپوزیتی مبتنی بر نانولوله کربنی از 122.7 میلی گرم بر کیلو گرم تا 286.6 میلی گرم بر کیلو گرم در این منطقه ازمایشگاهی متنوع است. افزایش جرم جاذب طول زمان موفقیت را افزایش می دهد و افزایش کل برداشت ها از ستون جاذب را افزایش می دهد. یک سرعت نفوذ بالاتر یا غلظت ورودی برای بهبود میزان جذب 2- نفتول در جاذب کامپوزیتی مبتنی بر نانولوله کربنی مفید است. رفتار دینامیکی از بسته های ستونی جاذب همراه جاذب کامپوزیتی مبتنی بر نانولوله کربنی با کمک مدل تامسون، مدل یان نلسون و مدل سرویس زمانی بد دیپ BDST توصیف شده است. سرویس زمانی از ستون برای وابستگی خطی برای عمق بستر یافت می شود. نتایجی از مطالعات نشان می دهد که جاذب کامپوزیتی مبتنی بر نانولوله کربنی می تواند در ستون بستر ثابت برای حذف موثر 2-نفتول از اب بکار برده شود.
کلمات کلیدی: جذب | نانولوله کربنی (CNT) | جاذب کامپوزیت | بستر ثابت ستون | مدل سازی | نفتول |
مقاله ترجمه شده |
10 |
حذف اثرات تولوئن و پارا-زایلین در هوای داخلی با استفاده از بیوفیلتراسیون و یک سیستم هیبریدی (بیوفیلتراسیون + جذب سطحی)
سال انتشار: 2017 - تعداد صفحات فایل pdf انگلیسی: 11 - تعداد صفحات فایل doc فارسی: 23 تکنولوژی بیوفیلتراسیون و سیستم هیبریدی با ترکیب بیوفیلتراسیون و جذب سطحی (بر روی کربن فعال) بهعنوان روشهای احتمالی برای تولوئن و پارا-زایلین در قسمتهایی در هر میلیون سطح غلظت (2 و 45 و ppb 33-1) مقایسه شد. مواد آلي بهعنوان مواد بستهبندی براي فرآيند بيوفيلتراسيون استفاده شدند. حتی در زمانهای ماند بستر خالی (EBRTها) و غلظتهای پایین، بازده حذف تولوئن به 100٪ رسید و پارا-زایلین روند افزایشی بازده حذف آنها در طول زمان را با استفاده از بیوفیلتراسیونران نشان داد. ارزیابی فرآوردهها و تولید ذرات توسط بیوفیلتر و سیستم هیبریدی در نظر گرفته شدند. استون و اسید استیک بهعنوان فرآوردههای جانبی بیوفیلتر شناسایی شدند. انتشار ذرات در محدوده 0.03 تا 10 میکرومتر برای هر دو سیستم ثبت شد. |
مقاله ترجمه شده |