Papers by Gustavo Capannelli
Studies in Surface Science and Catalysis, 1998
This paper describes the oxidehydrogenation reaction in catalytic membrane reactors using V2O5 as... more This paper describes the oxidehydrogenation reaction in catalytic membrane reactors using V2O5 as catalyst active phase. A simplified model of the catalytic membrane reactor is outlined and used to rationalize the kinetic data. Despite its simplicity, the model is capable to describe the effect of the relevant process variables: temperature, residence time, and oxygen- to-hydrocarbon molar ratio. Further work is
Water science and technology : a journal of the International Association on Water Pollution Research, 2001
Treatment of textile wastewaters by means of an ozonation pilot plant are described. Wastewaters ... more Treatment of textile wastewaters by means of an ozonation pilot plant are described. Wastewaters used were produced by a dyeing and finishing factory and were first treated in an active sludge plant and filtrated through sand. In the appropriate conditions very high colour removal (95-99%) was achieved and the effluent could be reused in production processes requiring water of high quality as dyeing yarns or light colorations. Even if the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease of up to 60%) that was usually considered to be too high for recycling purposes, recycling experiments were successful. The economical viability of the techniques implementation was also demonstrated and the industrial plant is currently under realisation under an EU financed project. The paper considers also the possible improvement of ozone diffusion by means of membrane contactors realised in a second pilot plant, in order to further reduce operating costs of ...
Journal of Membrane Science
Two sulfonated polyvinylidene fluoride membranes of different porosity, prepared by the casting a... more Two sulfonated polyvinylidene fluoride membranes of different porosity, prepared by the casting and gelation technique, were tested in an ultrafiltration laboratory-scale pilot plant with hydrosoluble polymer feed solutions. Polyethyleneglycols and dextrans of different average molecular weight were used as solutes for the feed solutions. Flux and rejection of the membranes were determined as functions of operating conditions (pressure, temperature and recirculation rate). The effect of properties of feed solutions (solute, concentration and molecular weight) on the performance of the membranes was also investigated.
Journal of Materials Science
The aim of this study was to develop a simple and reliable procedure in order to prepare composit... more The aim of this study was to develop a simple and reliable procedure in order to prepare composite membranes through the deposition of thin porous layers of perovskite-like oxides onto ceramic porous supports. BaTiO3 nanopowders with controlled properties were obtained by Low Temperature Aqueous Synthesis (LTAS) and used as starting materials for the thin film deposition. Process parameters were determined in order to obtain a stable suspension of the nanopowder. The nanopowder was then effectively used to realize the layers with controlled properties. The results of characterisation tests indicated that the porosity of the deposited layers was of a mesoporous type and that the starting nanopowder did not undergo structural changes after the deposition process.
Membrane Technology, 2001
This article briefly considers several ways of treating different streams that are generated by t... more This article briefly considers several ways of treating different streams that are generated by textile manufkturing processes, using techniques which are based on membrane separation technology.
Desalination, 2011
Liquid–liquid displacement porometry (LLDP), is proposed to estimate the molecular weight cut-off... more Liquid–liquid displacement porometry (LLDP), is proposed to estimate the molecular weight cut-off value of Ultrafiltration (UF) membranes.Several commercial UF membranes are analysed by using LLDP and their pore size distributions have been used to estimate the molecular weight cut-off as should be obtained by dextran retention.Results compared reasonably with nominal cut-off values given by manufacturers. The method offers a fast
Separation Science and Technology, 1994
This paper deals with the evaluation of pore size and pore size distribution of inorganic membran... more This paper deals with the evaluation of pore size and pore size distribution of inorganic membranes by liquid-liquid displacement porometry. Carbon and ceramic membranes were tested with a fully automatic porometer, and different results were obtained depending on the type of membrane. Membranes were also examined with the aid of a scanning electron microscope. The results of porosimetric measurements are
Separation and Purification Technology, 2004
Hydrogenation and oxidation reactions can be carried out in very mild conditions using a three-ph... more Hydrogenation and oxidation reactions can be carried out in very mild conditions using a three-phase catalytic reactor. The challenge is to overcome the diffusion resistance that affects this type of reactor. The catalytic membrane reactor (CMR), where the membrane is used not only as physical selective barrier but also as a chemical reactor, can be an efficient alternative to more conventional systems in improving the contact among solid catalyst, gas and liquid. The performances of different catalytic membranes were explored in the hydrogenation-isomerisation of methylenecyclohexane, in a temperature range between 288 and 343 K. Comparisons between a classic batch stirred tank and CMR were also carried out. Various characteristics of the reacting system, such as the overall process rate, the effect of temperature, the reaction order with reference to the substrate and the hydrogen and reaction selectivity were studied.
Journal of Polymer Science Part B: Polymer Physics, 1988
The solubility behavior of poly(vinylidene fluoride) (PVDF) in about 50 liquids was investigated.... more The solubility behavior of poly(vinylidene fluoride) (PVDF) in about 50 liquids was investigated. The results were input to a computer program to obtain a three-dimensional representation of the polymer solubility region in the Hansen space; the values of dispersion, hydrogen bonding, and polar components of the total solubility parameter were evaluated. The latter was also estimated from limiting viscosity number data in the eight solvents found. Both experimental methods gave values in very good agreement. Comparisons among our findings, the literature. and calculated results are discussed.
Journal of Membrane Science, 2000
Poly(vinylidene fluoride) (PVDF) was modified by chemical treatments in order to obtain a functio... more Poly(vinylidene fluoride) (PVDF) was modified by chemical treatments in order to obtain a functionalized polymer suitable for the preparation of ultrafiltration membranes with improved hydrophilicity and fouling resistance. Membranes obtained from the modified polymer as well as from the unmodified one were characterized through pure water permeability measurements and ultrafiltration tests with a dilute solution of skim milk. The fouling
Journal of Membrane Science, 2004
Two commercial nanofiltration (NF) membranes (FilmTec NF-45 and Desal-5 DK) and two new NF-1 memb... more Two commercial nanofiltration (NF) membranes (FilmTec NF-45 and Desal-5 DK) and two new NF-1 membranes made by BPT (Bio Pure Technology) for the purpose of a European Union funded research project (RENOMEM) were tested under extreme acidic conditions. The polyethersulphone (PES) ultrafiltration (UF) supports used for casting the BPT-NF-1 membranes were also tested under similar conditions. The 006 and 015 UF supports were found to be stable in 5% nitric acid at 20 and 80 • C for 4 and 3 months, respectively. Both supports (006 and 015) showed a significant reduction in flux after immersion in sulphuric acid at both temperatures. The BPT-NF-1 membranes showed excellent resistance to 20% sulphuric acid for up to 4 months at 20 • C but were attacked by the nitric acid solution. The resistance of the two commercial membranes in 20% sulphuric acid at 20 • C was generally lower than that of the BPT-NF-1 membranes. The NF-45 membrane was slightly more stable in 5% nitric acid at 20 • C. Degradation of the membrane occurred only after 2 months while both the Desal-5 DK and BPT-NF-1 membranes degraded during the first month. At the higher temperature of 80 • C in 5% nitric acid all membranes degraded in the first month.
Journal of Membrane Science, 2004
Liquid-liquid displacement porosimetry (LLDP) has been used to analyse very regular track-etched ... more Liquid-liquid displacement porosimetry (LLDP) has been used to analyse very regular track-etched polymeric membranes in the ultrafiltration (UF) range, with a nominal pore diameter of 50 nm. A fully automated porosimeter has been used in the evaluation of pore size distributions and results have been compared with image analysis performed on scanning electron micrographs (SEM-CIA) of the membranes. Comparison gives a nice agreement between both results (mean pore radius of 23.6 nm for LLDP results and 24.0 nm for SEM-CIA performed on the same samples used for LLDP). A not so satisfactory agreement is obtained for other indirectly evaluated parameters as porosity (means of 1.4 and 2.1%) or the mean total number of pores (19.6 Ă— 10 12 pores/m 2 , from LLDP and 11.1 Ă— 10 12 pores/m 2 for SEM-CIA).
Journal of Membrane Science, 2008
... José Ignacio Calvo a , Corresponding Author Contact Information , E-mail The Corresponding Au... more ... José Ignacio Calvo a , Corresponding Author Contact Information , E-mail The Corresponding Author , Aldo Bottino b , Gustavo Capannelli b and Antonio ... Computerized image analysis (CIA) of SEM pictures has been used to get information on the width of the active layer of the ...
Journal of Membrane Science, 1994
... 6, CPIC, Appl. Polym. Sci., 45 (1992) 1945. [ 15 ]AK Fritzsche, AR Arevalo MD Moore, CJ Weber... more ... 6, CPIC, Appl. Polym. Sci., 45 (1992) 1945. [ 15 ]AK Fritzsche, AR Arevalo MD Moore, CJ Weber, Nancy, 1992, pp. 59-64. ... Polym. Sci., 46 (1992) 167. [ 19 ] P. Grutter, W. Zimmermann-Edling and D. Brodbeck, [ 16]AK Fritzsche AR Arevalo, MD Moore, VB Elings, K. Kjoller and ...
Journal of Membrane Science, 1993
Four different microfiltration (MF) membranes were analysed with respect to porosity and protein ... more Four different microfiltration (MF) membranes were analysed with respect to porosity and protein adsorption. Liquid displacement porosity (LDP) and adsorption of "C-labelled /3-lactoglobulin were used as characterization methods. LDP showed a clear pore size distribution for all membranes analysed, with maximally 10% of the pores having at least 90% of the permeability. The protein adsorption came to equilibrium within 30 minutes, giving decreased permeabilities for all membranes. The permeability loss could not be modelled as a simple membrane pore restriction, but the protein load corresponded to a monolayer of protein adsorbed on and in the membranes.
Journal of Membrane Science, 1989
ABSTRACT Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on... more ABSTRACT Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on the combined bubble pressure and solvent permeability methods. Nuclepore membranes were first tested for calibration and reproducibility purposes. Measurements were then carried out both on membranes prepared in our labs and an commercial ones. Porosity results are discussed in relation to membrane preparation variables as well as to phenomena controlling membrane performance during ultrafiltration application.
Journal of Membrane Science, 2005
The paper demonstrates the capabilities of a number of newly proposed techniques in analyzing the... more The paper demonstrates the capabilities of a number of newly proposed techniques in analyzing the structural and morphological characteristics of the active layer of composite asymmetric membranes. The chemical stability of recently developed acid-stable nanofiltration membranes is analyzed in terms of the swelling, morphology and water vapor sorption. These characteristics are compared for pristine membranes and those exposed to hot 20% sulfuric acid solutions for various times. Swelling and morphological changes measured by atomic force microscopy (AFM) and transmission electron microscopy (TEM) indicate that swelling of the active layer gradually increases upon degradation, presumably due to disruption of the cross-links and/or generation of a larger number of hydrophilic groups. The change in swelling, which apparently proceeds in a uniform fashion throughout the active layer rather than via formation of pinholes, correlates well with deterioration in performance (flux and rejection). For some membranes, the results suggest a non-uniform degradation of the active layer, whereby the looser part of the active layer located inside the support layer degrades more rapidly. Attenuated total reflection Fourier transform infrared spectroscopy (FTIR) data on sorption kinetics and sorption of water vapor of moderate relative humidity by the active layer agree with the assumption that both generation of hydrophilic groups and decreasing cross-linking are responsible for increased swelling.
Journal of Membrane Science, 1983
ABSTRACT The investigation of factors governing membrane preparation is of paramount importance i... more ABSTRACT The investigation of factors governing membrane preparation is of paramount importance in order to understand the formation of the membrane and its behaviour under test conditions. A large amount of fundamental work on membrane formation has been carried out on cellulose acetate membranes, but less information is available for other polymers. The purpose of the present work is to provide a better understanding of the parameters governing the formation of polyvinylidene fluoride membranes. The parameters controlling the casting process have been investigated in some detail.
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Papers by Gustavo Capannelli