Records Added in September 2020
Records added in September 2020
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024
Change month: January | February | March | April | May | June | July | August | September | October | November | December
Showing records 26 to 50 of 59. [First] Page: 1 2 3 Last
Relative Effect of Additional Solid Media on Bubble Hydrodynamics in Bubble Column and Airlift Reactors towards Mass Transfer Enhancement
Prajak Sastaravet, Saret Bun, Kritchart Wongwailikhit, Nattawin Chawaloesphonsiya, Manabu Fujii, Pisut Painmanakul
September 23, 2020 (v1)
Subject: Other
Keywords: airlift reactor, bubble column, bubble hydrodynamic, mass transfer, solid media
Many researchers have focused on multi-phase reactor development for improving mass transfer performance. However, solid particle addition in gas−liquid contactor for better oxygen mass transfer performance is still limited. Hence, this study aims to analyze the relative effect of different types of local solid media on the bubble hydrodynamic characteristics towards mass transfer enhancement in bubble columns (BCR) and airlift reactors (ALR). This was investigated by varying solid media types (ring, sphere, cylinder, and square), solid loadings (0%−15%), and superficial gas velocities (Vg) (2.6−15.3 × 10−3 m/s) in terms of the bubble hydrodynamic and oxygen mass transfer parameters. The result showed that bubble size distribution in BCR and ALR with additional plastic media was smaller than that without media addition, approximately 22%−27% and 5%−29%, respectively, due to the increase of the bubble breaking rate and the decrease of the bubble rising velocity (UB). Further, adding med... [more]
PAC Synthesis and Comparison of Catalysts for Direct Ethanol Fuel Cells
Alexandra Kuriganova, Daria Chernysheva, Nikita Faddeev, Igor Leontyev, Nina Smirnova, Yury Dobrovolskii
September 23, 2020 (v1)
Subject: Materials
Keywords: direct ethanol fuel cell, electrocatalysis, platinum-based catalyst, pulse alternating current
Pt/C, PtMOn/C (M = Ni, Sn, Ti, and PtX/C (X = Rh, Ir) catalyst systems were prepared by using the pulse alternating current (PAC) technique. Physical and electrochemical parameters of samples were carried out by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), and CO stripping. The catalytic activity of the synthesized samples for the ethanol electrooxidation reaction (EOR) was investigated. The XRD patterns of the samples showed the presence of diffraction peaks characteristic for Pt, NiO, SnO2, TiO2, Rh, and Ir. The TEM images indicate that the Pt, Rh, and PtIr (alloys) particles had a uniform distribution over the carbon surface in the Pt/C, PtRh/C, PtIr/C, and PtMOn/C (M = Ni, Sn, Ti) catalysts. The electrochemically active surface area of catalysts was determined by the CO-stripping method. The addition of a second element to Pt or the use of hybrid supported catalysts can evidently improve the EOR activity. A remarkable positive affecting shift of the onset... [more]
On the Degradation of 17-β Estradiol Using Boron Doped Diamond Electrodes
Sandra Maldonado, Manuel Rodrigo, Pablo Cañizares, Gabriela Roa, Carlos Barrera, Javier Ramirez, Cristina Sáez
September 23, 2020 (v1)
Keywords: 17β-estradiol, boron doped diamond, electrolysis, selective oxidation, urine
This work focuses on the evaluation of the degradation of 17β-estradiol in a mixture of synthetic urine and methanol, trying to determine in which conditions the hormone can be more easily degraded than the urine compounds. This is in the frame of an overall study in which the pre-concentration stage with adsorption/desorption technology is evaluated to improve electrolysis efficiency. Results show that this pollutant can be efficiently removed from mixtures of urine/methanol by electrolysis with diamond electrodes. This removal is simultaneous with the removal of uric acid (used as a model of natural pollutants of urine) and leads to the formation of other organic species that behave as intermediates. This opens the possibility of using a concentration strategy based on the adsorption of pollutants using granular activated carbon and their later desorption in methanol. Despite methanol being a hydroxyl radical scavenger, the electrolysis is found to be very efficient and, in the best... [more]
Conversion of Lignocellulosic Corn Agro-Waste into Cellulose Derivative and Its Potential Application as Pharmaceutical Excipient
Md. Saifur Rahman, Md. Ibrahim H. Mondal, Mst. Sarmina Yeasmin, M. Abu Sayeed, Md Ashraf Hossain, Mohammad Boshir Ahmed
September 23, 2020 (v1)
Keywords: CMC, degree of substitution, excipient, holocellulose, lignocellulosic biomass
Lignocellulosic biomass is widely grown in many agricultural-based countries. These are typically incinerated or discarded in open spaces, which further may cause severe health and environmental problems. Hence, the proper utilization and conversion of different parts of lignocellulosic biomasses (e.g., corn wastes derived leave, cob, stalk, and husk) into value-added materials could be a promising way of protecting both health and environments. In addition, they have high-potential for myriads applications (e.g., pharmaceuticals, cosmetics, textiles, and so on). In this context, herein, we isolated holocellulose (a mixture of alpha α, beta β, and gamma γ cellulose) from corn waste, and then it was converted into carboxymethyl cellulose (CMC). Subsequently, the prepared CMC was evaluated successfully to be used as a pharmaceutical excipient. Different characterization tools were employed for structural, morphological, and thermal properties of the extracted holocellulose and synthesize... [more]
Spray Freeze-Drying as a Solution to Continuous Manufacturing of Pharmaceutical Products in Bulk
Merve B. Adali, Antonello A. Barresi, Gianluca Boccardo, Roberto Pisano
September 23, 2020 (v1)
Keywords: atomization, continuous manufacturing, freezing, pharmaceuticals, spray freeze-drying
Pharmaceutical manufacturing is evolving from traditional batch processes to continuous ones. The new global competition focused on throughput and quality of drug products is certainly the driving force behind this transition which, thus, represents the new challenge of pharmaceutical manufacturing and hence of lyophilization as a downstream operation. In this direction, the present review deals with the most recent technologies, based on spray freeze-drying, that can achieve this objective. It provides a comprehensive overview of the physics behind this process and of the most recent equipment design.
Compact Heat Integrated Reactor System of Steam Reformer, Shift Reactor and Combustor for Hydrogen Production from Ethanol
Watcharapong Khaodee, Tara Jiwanuruk, Khunnawat Ountaksinkul, Sumittra Charojrochkul, Jarruwat Charoensuk, Suwimol Wongsakulphasatch, Suttichai Assabumrungrat
September 23, 2020 (v1)
Keywords: compact reactor, ethanol steam reforming, hydrogen production, water gas shift
A compact heat integrated reactor system (CHIRS) of a steam reformer, a water gas shift reactor, and a combustor were designed for stationary hydrogen production from ethanol. Different reactor integration concepts were firstly studied using Aspen Plus. The sequential steam reformer and shift reactor (SRSR) was considered as a conventional system. The efficiency of the SRSR could be improved by more than 12% by splitting water addition to the shift reactor (SRSR-WS). Two compact heat integrated reactor systems (CHIRS) were proposed and simulated by using COMSOL Multiphysics software. Although the overall efficiency of the CHIRS was quite a bit lower than the SRSR-WS, the compact systems were properly designed for portable use. CHIRS (I) design, combining the reactors in a radial direction, was large in reactor volume and provided poor temperature control. As a result, the ethanol steam reforming and water gas shift reactions were suppressed, leading to lower hydrogen selectivity. On th... [more]
Fabrication of Biopolymer Based Nanoparticles for the Entrapment of Chromium and Iron Supplements
Nishay Patel, Mohammed Gulrez Zariwala, Hisham Al-Obaidi
September 23, 2020 (v1)
Subject: Materials
Keywords: chromium, iron, nanoparticles, oral drug delivery, whey protein isolate
The objective of this study was to encapsulate iron and chromium into novel nanoparticles formulated using chitosan (CS), dextran sulfate (DS) and whey protein isolate (WPI) for oral drug delivery. Empty and loaded CS-DS nanoparticles were prepared via complex coacervation whilst whey protein nanocarriers were produced by a modified thermal processing method using chitosan. The physiochemical properties of the particles were characterized to determine the effects of formulation variables, including biopolymer ratio on particle size and zeta potential. Permeability studies were also undertaken on the most stable whey protein−iron nanoparticles by measuring Caco-2 ferritin formation. A particle size analysis revealed that the majority of samples were sub-micron sized, ranging from 420−2400 nm for CS-DS particles and 220−1000 nm for WPI-CS samples. As expected, a higher chitosan concentration conferred a 17% more positive zeta potential on chromium-entrapped WPI nanoparticles, whilst a hi... [more]
Iron Oxide/Salicylic Acid Nanoparticles as Potential Therapy for B16F10 Melanoma Transplanted on the Chick Chorioallantoic Membrane
Maria Cristina Predoi, Ion Mîndrilă, Sandra Alice Buteică, Ștefana Oana Purcaru, Dan Eduard Mihaiescu, Ovidiu Marcel Mărginean
September 23, 2020 (v1)
Subject: Biosystems
Keywords: B16F10 melanoma, CAM assay, iron oxide nanoparticles, salicylic acid, xenotransplant
Unfavorable prognoses and low survival rates are specific features of metastatic melanoma that justify the concern for the development of new therapeutic strategies. Lately, nanotechnology has become an attractive field of study due to recent advances in nanomedicine. Using a chick chorioallantoic membrane (CAM) implanted with xenografts harvested from C57BL/6 mice with B16F10 melanoma cells, we studied the effects of iron oxide nanoparticles functionalized with salicylic acid (SaMNPs) as a form of therapy on the local development of xenotransplants and CAM vessels. The SaMNPs induced an anti-angiogenic effect on the CAM vessels, which accumulated preferentially in the melanoma cells and induced apoptosis and extensive xenograft necrosis. As a result, this slowed the increase in the xenograft volume and reduced the melanoma cells’ ability to metastasize locally and distally. Further, we demonstrate the use of the chick CAM model as a tool for testing the action of newly synthesized nan... [more]
A Review of the Criteria and Methods of Reverse Logistics Supplier Selection
Xumei Zhang, Zhizhao Li, Yan Wang
September 23, 2020 (v1)
Keywords: MCDM, Renewable and Sustainable Energy, reverse logistics, supplier selection
This article presents a literature review on reverse logistics (RL) supplier selection in terms of criteria and methods. A systematic view of past work published between 2008 and 2020 on Web of Science (WOS) databases is provided by reviewing, categorizing, and analyzing relevant papers. Based on the analyses of 41 articles, we propose a three-stage typology of decision-making frameworks to understanding RL supplier selection, including (a) establishment of the selection criteria; (b) calculation of the relative weights and ranking of the selection criteria; (c) ranking of alternatives (suppliers). The main discoveries of this review are as follows. (1) Attention to the field of RL supplier selection is increasing, as evidenced by the increasing number of papers in the field. With the adaption of circular economy legislation and the need resource and business resilience, it is expected that RL and RL supplier selection will be a hot topic in the near future. (2) A large number of paper... [more]
Automatic Implementation of a Self-Adaption Non-Intrusive Load Monitoring Method Based on the Convolutional Neural Network
Xin Wu, Dian Jiao, Yu Du
September 23, 2020 (v1)
Keywords: convolutional neural network, load identification, non-intrusive load monitoring
Non-intrusive load monitoring (NILM) is an effective way to achieve demand-side measurement and energy efficiency optimization. This paper studies a method of non-intrusive on-line load monitoring under a high-frequency mode of electric data acquisition, which enables the NILM to be automated and in real-time, including the short-term construction of a dynamic signature library and continuous on-line load identification. Firstly, in the short initial operation phase, load separation and category determination are carried out to construct the load waveform library of the monitoring user. Then, the continuous load monitoring phase begins. Based on the data of each user’s signature library, the decomposition waveforms are classified by convolutional neural network models that are constructed to be suitable for each signature library in order to realize load identification. The real-time power consumption status of the load can be obtained continuously. In this paper, the electricity data... [more]
Linking CFD and Kinetic Models in Anaerobic Digestion Using a Compartmental Model Approach
Yohannis Mitiku Tobo, Jan Bartacek, Ingmar Nopens
September 23, 2020 (v1)
Keywords: ADM1, CM, Computational Fluid Dynamics, kinetics, non-Newtonian fluid, spatial variation
Understanding mixing behavior and its impact on conversion processes is essential for the operational stability and conversion efficiency of anaerobic digestion (AD). Mathematical modelling is a powerful tool to achieve this. Direct linkage of Computational Fluid Dynamics (CFD) and the kinetic model is, however, computationally expensive, given the stiffness of the kinetic model. Therefore, this paper proposes a compartmental model (CM) approach, which is derived from a converged CFD solution to understand the performance of AD under non-ideal mixing conditions and with spatial variation of substrates, biomass, pH, and specific biogas and methane production. To quantify the effect of non-uniformity on the reactor performance, the CM implements the Anaerobic Digestion Model 1 (ADM1) in each compartment. It is demonstrated that the performance and spatial variation of the biochemical process in a CM are significantly different from a continuously stirred tank reactor (CSTR) assumption. H... [more]
The Effects of pH Change through Liming on Soil N2O Emissions
Muhammad Shaaban, Yupeng Wu, Lei Wu, Ronggui Hu, Aneela Younas, Avelino Nunez-Delgado, Peng Xu, Zheng Sun, Shan Lin, Xiangyu Xu, Yanbin Jiang
September 23, 2020 (v1)
Subject: Other
Keywords: lime, microbial biomass, mineral nitrogen, N2O, organic carbon, soil pH
Nitrous oxide (N2O) is an overwhelming greenhouse gas and agricultural soils, particularly acidic soils, are the main source of its release to the atmosphere. To ameliorate acidic soil condition, liming materials are added as an amendment. However, the impact of liming materials has not been well addressed in terms of exploring the effect of soil pH change on N2O emissions. In the present study, a soil with pH 5.35 was amended with liming materials (CaMg(CO3)2, CaCO3, Ca(OH)2 and CaO) to investigate their effects on N2O emissions. The results indicate that application of liming materials reduced the magnitudes of N2O emissions. The maximum reduction of soil N2O emissions took place for Ca(OH)2 treatment when compared to the other liming materials, and was related to increasing soil pH. Mineral N, dissolved organic C, and microbial biomass C were also influenced by liming materials, but the trend was inconsistent to the soil pH change. The results suggest that N2O emission mitigation is... [more]
Industrial-Scale Study of the Chemical Composition of Olive Oil Process-Derived Matrices
Haifa Jebabli, Houda Nsir, Amani Taamalli, Ibrahim Abu-Reidah, Francisco Javier Álvarez-Martínez, Maria Losada-Echeberria, Enrique Barrajón Catalán, Ridha Mhamdi
September 23, 2020 (v1)
Keywords: by-product, industrial process, olive oil, olive paste, phenolic compounds
The effect of the industrial process and collecting period on produced olive oil and by-products was evaluated. Obtained results showed significant variations for the majority of quality indices before and after vertical centrifugation between all samples from the three collecting periods. All samples were rich in monounsaturated fatty acid: Oleic acid (C18:1) with a maximum of 69.95%. The total polyphenols and individual phenolic compounds varied significantly through the extraction process, with a significant variation between olive oil and by-products. Notably, the percentage of secoiridoids and their derivatives was significant in paste and olive oil, highlighting the activity of many enzymes released during the different extraction steps. Regarding antioxidant capacity, the most remarkable result was detected in olive oil and olive mill wastewater samples.
3D Integrated Modeling of Supersonic Coherent Jet Penetration and Decarburization in EAF Refining Process
Yuchao Chen, Armin K. Silaen, Chenn Q. Zhou
September 23, 2020 (v1)
Keywords: Computational Fluid Dynamics, decarburization, EAF, steel refining, supersonic coherent jet
The present study proposes a complete 3D integrated model to simulate the top-blown supersonic coherent jet decarburization in the electric arc furnace (EAF) refining process. The 3D integrated model avoids the direct simulation of the supersonic coherent jet interacting with the liquid steel bath and provides a feasible way to simulate the decarburization in the liquid steel-oxygen two-phase reacting flow system with acceptable computational time. The model can be used to dynamically predict the details of the molten bath, including 3D distribution of in-bath substances, flow characteristics and bath temperature and provide a basis for optimizing the decarburization rate or other required parameters during the refining process.
Effect of Purification Methods on Commercially Available Cellulose Nanocrystal Properties and TEMPO Oxidation
Manali Banerjee, Sisira Saraswatula, Anna Williams, Blair Brettmann
September 15, 2020 (v1)
Subject: Materials
Keywords: cellulose, nanocellulose, purification, surface modification, TEMPO oxidation
Cellulose nanocrystals (CNCs) are attractive for use in polymer composites, biomedical applications, and barrier packaging. In all of these applications they are mixed with other components and compatibility is a major design consideration, as CNCs naturally have a high density of surface hydroxyl groups and primarily disperse well in polar media. Numerous surface modification approaches have been used to address these issues, but challenges remain due to the variability in the commercially available CNC materials. CNCs can be produced from biomass using several extraction methods, most notably acid hydrolysis and biomass extraction, also known as the American Value Added Pulping process. The production method of the CNC material has an impact on both physical and surface properties of CNCs, including size, shape, crystal structure, and zeta potential. In addition, post-treatments can be used to purify the CNC material and further alter these properties. This work studies the propertie... [more]
Physico-Chemical Changes, Microbiological Properties, and Storage Shelf Life of Cow and Goat Milk from Industrial High-Pressure Processing
Sok Fern Tan, Nyuk Ling Chin, Tuan Poy Tee, Sook Kuan Chooi
September 15, 2020 (v1)
Keywords: high pressure processing, milk quality, milk storage, pasteurization, shelf life
Industrial high-pressure processing (HPP) was conducted on cow and goat milk in comparison to conventional heat pasteurization. No significant changes were found in the physico-chemical properties of the treated milk except for pH, where pasteurized cow milk experienced a decrease while goat milk’s pH increased for both pasteurized and HPP treated. HPP-treated cow and goat milk both achieved microbial shelf life of 22 days at 8 °C storage with no increase in Bacillus cereus, mesophilic aerobic spores, coliform, yeast and mold but slight increase in psychrotrophic bacteria and total plate count. Pasteurized goat milk was spoilt at the end of storage with exceeding count of psychrotrophic bacteria (9.0 × 108 CFU/mL) and total plate count (3.5 × 108 CFU/mL). HPP-treated cow milk exhibited higher physico-chemical stability than goat milk as evidenced by non-significant change of titratable acidity but goat milk experienced an increase of 0.04% averagely.
Unconfined Dense Plunging Jets Used for Brine Disposal from Desalination Plants
Aaron C. Chow, Ishita Shrivastava, E. Eric Adams, Fahed Al-Rabaie, Bader Al-Anzi
September 15, 2020 (v1)
Subject: Other
Keywords: aeration, air entrainment, bubble penetration, dense jet, desalination, multiphase flow, plunging jet
Laboratory experiments were conducted to measure entrained air bubble penetration depth and dilution of a dense vertical unconfined plunging jet to evaluate its performance as an outfall to dilute brine from desalination plants as well as a means to aerate water column. Experiments involved neutrally buoyant or dense plunging jets discharging in quiescent receiving water. The density difference between effluent and receiving water, the plunging jet length (height above water surface), and the receiving water salinity were varied in the experiments. Observed penetration depth for neutrally buoyant jets was somewhat greater than previously reported, and increased modestly with jet density. Increasing density also resulted in an increasing number of fine bubbles descending together with the dense plume. These observations can help guide the design of plunging jets to mitigate anoxic conditions in the water column when brine is introduced to a receiving water body, as with seawater desalin... [more]
A Nodes-Based Non-Structural Model Considering a Series Structure for Heat Exchanger Network Synthesis
Yue Xu, Heri Ambonisye Kayange, Guomin Cui
September 15, 2020 (v1)
Keywords: HENS design, NNM model, random walk with compulsive evolution, series matches, stream splits
The aim of heat exchanger network synthesis is to design a cost-effective network configuration with the maximum energy recovery. Therefore, a nodes-based non-structural model considering a series structure (NNM) is proposed. The proposed model utilizes a simple principle based on setting the nodes on streams such that to achieve optimization of a heat exchanger network synthesis (HENS) problem. The proposed model uses several nodes to quantify the possible positions of heat exchangers so that the matching between hot and cold streams is random and free. Besides the stream splits, heat exchangers with series structures are introduced in the proposed model. The heuristic algorithm used to solve NNM model is a random walk algorithm with compulsive evolution. The proposed model is used to solve four scale cases of a HENS problem, the results show that the costs obtained by NNM model can be respectively lower 3226 $/a(Case 1), 11,056 $/a(Case 2), 2463 $/a(Case 3), 527 $/a(Case 4) than the... [more]
Kaempferol Rhamnosides from Geranium sibiricum as Aldose Reductase Inhibitors and Their Content by HPLC Analysis
Norman G. Quilantang, Kyung Choi, Bog-Hieu Lee, Sanghyun Lee
September 15, 2020 (v1)
Subject: Biosystems
Keywords: aldose reductase, flavonoid rhamnoside, Geranium sibiricum, HPLC-UV
The study aimed to assess the aldose reductase (AR) inhibition of selected Geranium species and determine the bioactive flavonoid constituents. Flavonoids are known to be good AR inhibitors. Among the species examined, G. sibiricum exhibited potent inhibition of AR (IC50 value, 2.4 µg/mL). Further examination of G. sibiricum, after solvent extraction and fractionation, revealed that the ethyl acetate fraction (IC50 value, 0.41 µg/mL) had a potent AR inhibitory effect. Kaempferol rhamnosides were the active compounds from this fraction. Moreover, G. sibiricum showed the highest content of kaempferol-7-O-rhamnoside and kaempferol-3,7-O-dirhamnoside among the samples examined with a concentration in the extracts of 28.1 and 2.2 mg/g, respectively. This study shows that G. sibiricum exhibits promising AR inhibitory activity, which can be explored further as a natural therapy for treating and managing complications associated with diabetes.
An Artificial Intelligence Approach to Predict the Thermophysical Properties of MWCNT Nanofluids
Balaji Bakthavatchalam, Nagoor Basha Shaik, Patthi Bin Hussain
September 15, 2020 (v1)
Keywords: Artificial Neural Networks, experimental data, nanofluids, prediction, thermophysical properties
Experimental data of thermal conductivity, thermal stability, specific heat capacity, viscosity, UV−vis (light transmittance) and FTIR (light absorption) of Multiwalled Carbon Nanotubes (MWCNTs) dispersed in glycols, alcohols and water with the addition of sodium dodecylbenzene sulfonate (SDBS) surfactant for 0.5 wt % concentration along a temperature range of 25 °C to 200 °C were verified using Artificial Neural Networks (ANNs). In this research, an ANN approach was proposed using experimental datasets to predict the relative thermophysical properties of the tested nanofluids in the available literature. Throughout the designed network, 65% and 25% of data points were comprehended in the training and testing set while the other 10% was utilized as a validation set. The parameters such as temperature, concentration, size and time were considered as inputs while the thermophysical properties were considered as outputs to develop ANN models of further predictions with unseen datasets. Th... [more]
Performance Assessment of SWRO Spiral-Wound Membrane Modules with Different Feed Spacer Dimensions
A. Ruiz-García, I. Nuez
September 15, 2020 (v1)
Keywords: desalination, feed spacers, membrane performance, permeability coefficients, reverse osmosis, seawater
Reverse osmosis is the leading process in seawater desalination. However, it is still an energy intensive technology. Feed spacer geometry design is a key factor in reverse osmosis spiral wound membrane module performance. Correlations obtained from experimental work and computational fluid dynamics modeling were used in a computational tool to simulate the impact of different feed spacer geometries in seawater reverse osmosis spiral wound membrane modules with different permeability coefficients in pressure vessels with 6, 7 and 8 elements. The aim of this work was to carry out a comparative analysis of the effect of different feed spacer geometries in combination with the water and solute permeability coefficients on seawater reverse osmosis spiral wound membrane modules performance. The results showed a higher impact of feed spacer geometries in the membrane with the highest production (highest water permeability coefficient). It was also found that the impact of feed spacer geometr... [more]
Covalently Cross-Linked Nanoparticles Based on Ferulated Arabinoxylans Recovered from a Distiller’s Dried Grains Byproduct
Yubia De Anda-Flores, Elizabeth Carvajal-Millan, Jaime Lizardi-Mendoza, Agustin Rascon-Chu, Ana Luisa Martínez-López, Jorge Marquez-Escalante, Francisco Brown-Bojorquez, Judith Tanori-Cordova
September 15, 2020 (v1)
Keywords: bioethanol industry, cross-linking, electrospray, ferulated arabinoxylans, nanoparticles
The purpose of this investigation was to extract ferulated arabinoxylans (AX) from dried distillers’ grains with solubles (DDGS) plus to investigate their capability to form covalently cross-linked nanoparticles. AX registered 7.3 µg of ferulic acid/mg polysaccharide and molecular weight and intrinsic viscosity of 661 kDa and 149 mL/g, correspondingly. Fourier transform infrared spectroscopy (FTIR) was used to confirm the identity of this polysaccharide. AX formed laccase induced covalent gels at 1% (w/v), which registered an elastic modulus of 224 Pa and a content of FA dimers of 1.5 µg/mg polysaccharide. Scanning electron microscopy pictures of AX gels exhibited a microstructure resembling a rough honeycomb. AX formed covalently cross-linked nanoparticles (NAX) by coaxial electrospray. The average hydrodynamic diameter of NAX determined by dynamic light scattering was 328 nm. NAX presented a spherical and regular shape by transmission electron microscopy analysis. NAX may be an attra... [more]
Sorbent Based on Polyvinyl Butyral and Potassium Polytitanate for Purifying Wastewater from Heavy Metal Ions
Anna Ermolenko, Maria Vikulova, Alexey Shevelev, Elena Mastalygina, Peter Ogbuna Offor, Yuri Konyukhov, Anton Razinov, Alexander Gorokhovsky, Igor Burmistrov
September 15, 2020 (v1)
Subject: Materials
Keywords: heavy metals, polymer composite, polyvinyl butyral, potassium polytitanate, sorbent, Wastewater
Currently, the rapid development of industry leads to an increase in negative anthropogenic impacts on the environment, including water ecosystems. This circumstance entails toughening environmental standards and, in particular, requirements for the content of pollutants in wastewater. As a result, developing technical and cost-effective ways for wastewater purification becomes relevant. This study is devoted to the development of a novel composite sorbent, based on polyvinyl butyral and potassium polytitanate, designed to purify water from heavy metal ions. The co-deposition of a mixture based on a polymer solution and a filler suspension was used to obtain a composite material. In this work, the influence of the deposition conditions on the structure and properties of the resulting composites was studied, as well as the optimal ratio of components, including solvent, precipitant, polymer binder, and filler, were established. In the course of this study on the sorption properties of t... [more]
A Fractal-Based Correlation for Time-Dependent Surface Diffusivity in Porous Adsorbents
Vassilis J. Inglezakis, Marco Balsamo, Fabio Montagnaro
September 15, 2020 (v1)
Keywords: Adsorption, fractal-like dynamics, hindered diffusion, hopping, surface diffusivity, zeolites
Fluid−solid adsorption processes are mostly governed by the adsorbate transport in the solid phase and surface diffusion is often the limiting step of the overall process in microporous materials such as zeolites. This work starts from a concise review of concepts and models for surface transport and variable surface diffusivity. It emerges that the phenomenon of hindered surface diffusion for monolayer adsorption, which is common in zeolites, and models able to fit a non-monotonic trend of surface diffusivity against adsorbate solid phase concentration, have received limited attention. This work contributes to the literature of hindered diffusion by formulating a time-dependent equation for surface diffusivity based on fractal dynamics concepts. The proposed equation takes into account the contributions of both fractal-like diffusion (a time-decreasing term) and hopping diffusion (a time-increasing term). The equation is discussed and numerically analyzed to testify its ability to rep... [more]
New, Aqueous Radical (Co)Polymerization of Olefins at Low Temperature and Pressure
Devid Hero, Gergely Kali
September 15, 2020 (v1)
Keywords: cyclodextrin, free-radical polymerization, poly(ethylene-co-vinyl acetate), polyethylene, polypropylene
In this communication, we describe our preliminary results for the development of a new method of ethylene and propene (co)polymerization at low pressure at room temperature, using cyclodextrin-assisted aqueous radical polymerization for the first time. For polypropylene homopolymerization, the cyclodextrin was entirely removed, and the partially soluble polymer was characterized. The purification of polyethylene was not complete, since the threaded cyclodextrins remained on the polymer chain, enhancing its solubility and enable to analyze the sample. With this environmentally benign method, polyolefines could be produced, for the first time. The estimated yield was low, and therefore the conditions should be further tuned for industrial application. This straightforward approach could also be applied to synthesize poly(ethylene-co-vinyl acetate) copolymer with an ethylene content of 20 mol% and enhanced yield. Although the procedure in this stage of research has some limitations, the... [more]
Showing records 26 to 50 of 59. [First] Page: 1 2 3 Last
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024
Change month: January | February | March | April | May | June | July | August | September | October | November | December