Papers by Constantinos E Salmas
Journal of The Electrochemical Society
For environmental and cost purposes, solvent-free electrode manufacturing techniques are needed f... more For environmental and cost purposes, solvent-free electrode manufacturing techniques are needed for lithium-ion cell technology. In this work, we present a stand-alone lithium-ion anode, containing graphene and Poly-lactic acid (PLA) as active and binding material, respectively, manufactured in a free-solvent process. To this purpose, PLA and graphene were thoroughly mixed and a hot-press was used to form the resulting electrode. At a half-cell configuration, the electrodes exhibited a stable reversible specific capacity of more than 300 mAh g−1 at C/15 for over 450 cycles and a promising C-rate performance of around 90 mAh g−1 at 6 C of constant current mode. After cyclic voltammetry analysis of the electrochemical behavior and the kinetics of the prepared electrodes, the Li atom diffusion coefficient was calculated around 1.2 × 10−8 cm2/s during lithiation and 0.6 × 10−8 cm2/s during delithiation. Finally, we show that this electrode manufacturing technique can be upscaled for hig...
Studies in Surface Science and Catalysis, 2002
ABSTRACT Mesoporous silica was gradually functionalized with silano-(trimethoxy)-propyl-imidazole... more ABSTRACT Mesoporous silica was gradually functionalized with silano-(trimethoxy)-propyl-imidazole (STPI) groups. The degree of surface functionalization n=0, 0.23, 0.30, 0.40, 0.52, 0.60 and 0.85 was controlled by previous knowledge of surface acidity, determined by TPD/NH3. From N2 adsorption/desorption measurements the specific surface area Sp (m2 g1), the specific pore volume Vp (cm3 g1) and the corresponding pore size distributions PSD were determined while the connectivity c of the solids was calculated according to the method of Seaton. The increase of functionalization resulted in a linear drop of Sp and VP while the maximum Dmax of the PSD and the Full Width at Half Maximum, FWHM~2σ of distribution drop in a regular way whereas the ratio (Dmax/2σ) remains practically constant. The connectivity c also decreases from c=12.5 at n=0 to c=3 at n=0.60–0.85 presumably because of blocking of channels connecting various pores. Next, the co-called Corrugated Pore Structure Model, CPSM, was employed for the estimation of tortuosity τ of the porous solids and the simulation of the experimental adsorption/desorption isotherms. From those CPSM simulations the corresponding specific surface areas SCPSM (m2 g1), specific pore volume VCPSM (cm3 g1) and the corresponding pore size distribution PSDCPSM were estimated. The tortuosity τ of the system drops with the degree of functionalization from τ=4.22 at n=0 to τ=3.37 at functionalization n=0.23 while subsequently remains practically constant at about τ=3.40±0.10, for the same reasons which affect the connectivity i.e. blocking of various pore channels. The comparison between the parameters VP on one hand and VCPSM, is quite satisfactory while the SCPSM values appear systematically higher by almost 8–23% compared to the Sp ones. Similarities and discrepancies between the results obtained by the two methods are discussed.
Studies in Surface Science and Catalysis, 2002
ABSTRACT
Industrial & Engineering Chemistry Research, 2000
The present article deals with the development of a new statistical model (corrugated pore struct... more The present article deals with the development of a new statistical model (corrugated pore structure model: CPSM) simulating capillary condensation-evaporation hysteresis. The formulation of analytical expressions is based on probability principles, an adsorbed layer thickness correlation, Kelvin equation, and a random corrugated pore concept. When the model is fitted over experimental hysteresis loop data, the respective intrinsic pore size distribution (psd) and the corrugated pore parameter, N S (frequency of pore cross-sectional area variation), can be determined. The predictive potential of the CPSM was successfully tested in part 1 (this work) by generating hysteresis loops that reproduced those included in the IUPAC classification as well as those of novel nanoporous MCM-41 materials. CPSM evaluations of intrinsic pore size distributions have been more realistic and accurate than those deduced by applying the conventional methods (e.g., Roberts). The model has been further tested successfully in part 2 (Ind. Eng. Chem. Res. 2000, 39, 3764) by the fitting of experimental hysteresis data of various porous materials, e.g., HDS catalysts, anodic oxide films, lignite, montmorillonite, pillared clays, and MCM-41 mesopore molecular sieves.
Chemical Engineering Communications, 2008
Anodic alumina materials exhibiting regular pore structure, microporosity, and extensive surface ... more Anodic alumina materials exhibiting regular pore structure, microporosity, and extensive surface areas were prepared and characterized. The effects of current density, (J = 12–35 mA/cm), anodization time (t = 30–150 min), and hydrothermal treatment on pore structure were investigated. Nitrogen sorption hysteresis was simulated using the corrugated pore structure model (CPSM). Pore size distributions, relative specific surface area (SCPSM/Sext = 870–8645), microporosity (max ∼ 33.0%), pore tortuosity (TCPSM = 3.1–5.7), pore connectivity
Chemical Engineering Communications, 2000
ABSTRACT
Applied Catalysis A: General, 2001
Nitrogen sorption hysteresis of a selective catalytic reduction (SCR) catalyst in its "fresh" and... more Nitrogen sorption hysteresis of a selective catalytic reduction (SCR) catalyst in its "fresh" and "used" form [Catal. Today 56 (2000) 335] was analysed by employing the Corrugated Pore Structure Model (CPSM-nitrogen) reported elsewhere [Ind. Eng. Chem. Res. 39 (2000) 3747 and Ind. Eng. Chem. Res., 39 (2000) 3764]. The BET surface area and intrinsic pore volume, and surface area distributions were deduced via the CPSM fitting over the relevant hysteresis loop and compared to those obtained by applying various conventional methods. CPSM predictions of the total specific pore surface area, are in perfect agreement with BET estimates, while those calculated by the Roberts method, irrespective of the hysteresis loop branch chosen, deviate substantially. CPSM prediction of tortuosity factors (CPSM-tortuosity [Ind. Eng. Chem. Res., in press]) for the catalysts under consideration were found to be: τ CPSM, fresh = 4.6 and 4.5. These values are typical of porous catalysts and approach those determined experimentally (i.e. τ = 5-6 [Appl. Catal. 10 (1996) 299]). The pore volume distribution of the latter catalyst obtained from mercury porosimetry measurements approaches that deduced by the CPSM method.
Drying Technology, 2000
ABSTRACT
C
Sodium polyacrylate is the superabsorbent waterlock polymer used in disposable diapers, which are... more Sodium polyacrylate is the superabsorbent waterlock polymer used in disposable diapers, which are the third largest single consumer item in landfills. As diapers are difficult to recycle, their use produces an incredible amount of environmental waste. In the present article, we present a reliable and facile approach to transform sodium polyacrylate, the main constitute in the used diapers, in a carbon-based magnetic sorbent material, capable for use in environmental applications. A nanoporous carbon magnetic hybrid material was prepared by reacting NaPA with iron acetate species under chemical activation conditions. Analysis of the characterization results revealed, the creation of a nanoporous structure, with high specific surface area value (SgBET = 611 m2/g), along with the formation of nanosized zero valent iron nanoparticles and iron carbide (Fe3C), inside the carbon pore system. 57Fe Mössbauer spectroscopy verified also the existence of these two main iron-bearing phases, as w...
Applied Sciences
Over the years, there has been an effort to extend food shelf life so as to reduce global food wa... more Over the years, there has been an effort to extend food shelf life so as to reduce global food waste. The use of natural biodegradable materials in production procedures is more and more adopted nowadays in order to achieve cyclic economy targets and improve environmental and human health indexes. Active packaging is the latest trend for food preservation. In this work, polystyrene was mixed with natural NaMt, OrgNaMt montmorillonite, and oregano essential oil to develop a new packaging film. Strength, oxygen and water-vapour permeation, blending and homogeneity, and antimicrobial and antioxidant activity were measured as basic parameters for food packaging films characterization. Instruments such as a tensile measurement instrument, XRD, FTIR, DMA, OPA (Oxygen Permeation Analyzer), and other handmade devices were used. Results showed that polystyrene could be modified, improved, and exhibits food odour prevention characteristics in order to be used for applications on food active p...
Nanomaterials
The great concern about the use of hazardous additives in food packaging materials has shown the ... more The great concern about the use of hazardous additives in food packaging materials has shown the way to new bio-based materials, such as nanoclays incorporating bioactive essential oils (EO). One of the still unresolved issues is the proper incorporation of these materials into a polymeric matrix. The in situ polymerization seems to be a promising technique, not requiring high temperatures or toxic solvents. Therefore, in this study, the bulk radical polymerization of styrene was investigated in the presence of sodium montmorillonite (NaMMT) and organo-modified montmorillonite (orgMMT) including thyme (TO), oregano (OO), and basil (BO) essential oil. It was found that the hydroxyl groups present in the main ingredients of TO and OO may participate in side retardation reactions leading to lower polymerization rates (measured gravimetrically by the variation of monomer conversion with time) accompanied by higher polymer average molecular weight (measured via GPC). The use of BO did no...
Molecules
An innovative process for the adsorption of the hydrophobic Basil-Oil (BO) into the hydrophilic f... more An innovative process for the adsorption of the hydrophobic Basil-Oil (BO) into the hydrophilic food byproduct chitosan (CS) and the development of an advanced low-density polyethylene/chitosan/basil-oil (LDPE/CS_BO) active packaging film was investigated in this work. The idea of this study was the use of the BO as both a bioactive agent and a compatibilizer. The CS was modified to a CS_BO hydrophobic blend via a green evaporation/adsorption process. This blend was incorporated directly in the LDPE to produce films with advanced properties. All the obtained composite films exhibited improved packaging properties. The film with 10% CS_BO content exhibited the best packaging properties, i.e., 33.0% higher tensile stress, 31.0% higher water barrier, 54.3% higher oxygen barrier, and 12.3% higher antioxidant activity values compared to the corresponding values of the LDPE films. The lipid oxidation values of chicken breast fillets which were packaged under vacuum using this film were me...
Materials
The present study focuses on fabrication of magnetic activated carbon (M-AC) using tire waste and... more The present study focuses on fabrication of magnetic activated carbon (M-AC) using tire waste and its potential investigation for adsorption of Cr (VI) from wastewater. The composite material (M-AC) was synthesized by pyrolysis followed by in situ magnetization method, and characterized by FTIR, FESEM, EDX, and XRD analysis. The maximum adsorption of Cr (VI) ion over composite adsorbent was found (~99.5%) to occur at pH 2, sample volume 10 mL, adsorbent dose 100 mg, contact time 30 min. The adsorption process was endothermic, feasible, spontaneous, and was found to follow pseudo second order of the reaction. The Cr ion could be completely desorbed (~99.3%) from the composite adsorbent by using 20 mL of 2 M NaOH solution. The composite adsorbent was regenerated by continuous adsorption and desorption for 5 consecutive cycles by using 10 mL 0.1 M HCl solution. M-AC also performed well in case of tannery wastewater by removing about 97% of Cr (VI).
Foods
This study is a systematic literature review of geographical origin authentication by elemental a... more This study is a systematic literature review of geographical origin authentication by elemental analytical techniques. Authentication and certification of geographic origin of agri-food products is a useful tool toward the protection of the quality for products. The aim of this work was to map the current state of research in the area of agricultural products and food, identifying emerging fields to the geographical origin of products. The article is divided in three parts. The first part of the article deals with the analytical techniques applied in the food authentication. Special mention is made to elemental analysis and multiple isotope ratio. The second section focuses on statistically published data concerning published research for geographical origin authentication for the period 2015–2019. Specific results are presented inter alia: number of articles according to the type of product, articles according to the type of the analytical techniques, and others. The third part con...
Dry Technol, 2001
The knowledge of the intrinsic pore structure of coals is significant in elucidating the kinetics... more The knowledge of the intrinsic pore structure of coals is significant in elucidating the kinetics of mass transport and chemical reaction that leads to design of more efficient coal combustion and conversion equipment. The results of pore structure studies of Greek lignite are reported in this work. Isothermal drying of Greek lignite samples, under vacuum, caused mesopore structure evolution despite
Ind Eng Chem Res, 2001
ABSTRACT
Chemie Ingenieur Technik, Jun 1, 2001
Results are reported on Lignite/CaO and Biomass/CaO gasification, using a rotary kiln gasifier, f... more Results are reported on Lignite/CaO and Biomass/CaO gasification, using a rotary kiln gasifier, for the production of hydrogen enriched synthesis gas in a CO 2 capture and sequestration integrated process. We study the effect of CaO (sorbent) and gasifier operating conditions upon gas production rate and composition. Indicative gasification testing of Olive Kernel wood/CaO, with limited moisture content, verified the production of gas moderately enriched in H 2 (i.e., ~59% v/v, at Τ rz ≈ 720°C, with X DMMF =42%) or (~51%, at Τ rz ≈ 800°C, with X DMMF =90%). Moreover, Lignite/CaO gasification experiments, at mean temperature Τ rz ≈ 730°C, validated the production of hydrogen enriched gas (H 2 : 70-80%) and reduced CO and CO 2 percentages (9.1 % and 9.6 % v/v) but moderate fuel conversion, X DMMF <50%. However, at Τ rz ≈ 810°C, we obtained X DMMF ≈ 80%, but reduced H 2 content (~61%), presumably due to higher CO proportion (~23%), while the gas produced from lignite gasification al...
Processes
Following the global trend toward a cyclic economy, the development of a fully biodegradable acti... more Following the global trend toward a cyclic economy, the development of a fully biodegradable active packaging film is the target of this work. An innovative process to improve the mechanical, antioxidant, and barrier properties of Poly(L-Lactic Acid)/Chitosan films is presented using essential basil oil extract. A Chitosan/Basil oil blend was prepared via a green evaporation/adsorption method as a precursor for the development of the Poly(L-Lactic Acid)/Chitosan/Basil Oil active packaging film. This Chitosan/Basil Oil blend was incorporated directly in the Poly(L-Lactic Acid) matrix with various concentrations. Modification of the chitosan with the Basil Oil improves the blending with the Poly(L-Lactic Acid) matrix via a melt-extrusion process. The obtained Poly(L-Lactic Acid)/Chitosan/Basil Oil composite films exhibited advanced food packaging properties compared to those of the Poly(L-Lactic Acid)/Chitosan films without Basil Oil addition. The films with 5%wt and 10%wt Chitosan/Ba...
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Papers by Constantinos E Salmas