Francesco Dalena

Performance and Long-Term Stability of Pd/PSS and Pd/Al2O3 Membranes for Hydrogen Separation

The present work is focused on the investigation of the performance and long-term stability of two composite palladium membranes under different operating conditions. One membrane (Pd/porous stainless steel (PSS)) is characterized by a ~10 µm-thick palladium layer on a porous stainless steel substrate, which is pretreated by means of surface modification and oxidation; the other membrane (Pd/Al2O3) is constituted by a ~7 µm-thick palladium layer on an asymmetric microporous Al2O3 substrate. The operating temperature and pressure ranges, used for studying the performance of these two kinds of membranes, are 350–450 °C and 200–800 kPa, respectively. The H2 permeances and the H2/N2 selectivities of both membranes were investigated and compared with literature data. At 400 °C and 200 kPa as pressure difference, Pd/PSS and Pd/Al2O3 membranes exhibited an H2/N2 ideal selectivity equal to 11700 and 6200, respectively, showing stability for 600 h. Thereafter, H2/N2 selectivity of both membranes progressively decreased and after around 2000 h, dropped dramatically to 55 and 310 for the Pd/PSS and Pd/Al2O3 membranes, respectively. As evidenced by Scanning Electron Microscope (SEM) analyses, the pinholes appear on the whole surface of the Pd/PSS membrane and this is probably due to release of sulphur from the graphite seal rings.

Spanish Broom (Spartium junceum L.) fibers impregnated with vancomycin-loaded chitosan nanoparticles as new antibacterial wound dressing: Preparation, characterization and antibacterial activity

Abstract In this work, we propose as new wound dressing, the Spanish Broom fibers impregnated with vancomycin (VM) loaded chitosan nanoparticles. Spanish Broom fibers were extracted by patented method DiCoDe and the morphological, physical and mechanical properties were investigated. Chitosan nanoparticles were prepared by ionic gelation using different weight ratios between chitosan (CH) and tripolyphosphate (TPP). Nanoparticles were characterized in terms of size, zeta potential, yield, encapsulation efficiency, stability and drug release. Finally, the antibacterial activity against Staphylococcus aureus as well as in vitro cytotoxicity on HaCaT cells were evaluated. The best formulation CH/TPP 4:1 was selected based on the encapsulation efficiency and yield. Spanish Broom fibers impregnated with loaded nanoparticles showed an increased antibacterial activity against S. aureus compared to the same fibers containing VM without nanoparticles. Moreover, these fibers were not toxic to HaCaT keratinocytes cells. In conclusion, Spanish Broom fibers impregnated with VM loaded CH/TPP nanoparticles would appear to be a promising candidate for wound dressing application.

Association of Lactobacillus crispatus with fructo-oligosaccharides and ascorbic acid in hydroxypropyl methylcellulose vaginal insert.

The aim of this work was to develop a synbiotic vaginal insert containing the probiotic strain Lactobacillus crispatus BC5, the prebiotic substrate fructo-oligosaccharide and the antioxidant agent ascorbic acid, for the prophylaxis and therapy of vaginal infections. Mucoadhesive in situ gelling vaginal inserts based on hydroxypropyl methylcellulose were prepared by freeze-drying, stored at +2-8 °C for 90 days and characterized in terms of technological and functional properties. Complete survival of L. crispatus BC5 was found immediately after insert preparation (96.08%) as well as after 90 days of storage (95.82%) in the vaginal inserts containing fructo-oligosaccharide, ascorbic acid and skimmed milk. Synbiotic inserts showed improved mucoadhesion ability (from three- to five-fold) with respect to a standard formulation based on hydroxypropyl methylcellulose alone. Moreover, inserts allowed to modulate lactobacilli release in virtue of the different amounts of fructo-oligosaccharide. Finally, antimicrobial activity was exerted by L. crispatus BC5 released from the vaginal formulation.

Hydrogen Production for PEM Fuel Cells

Today, hydrogen is seen as the most convenient energy carrier for a number of applications and, particularly, for proton exchange membrane fuel cells (PEMFCs). In the specialized literature, many studies address the production of hydrogen derived from renewables. Therefore, the scope of this chapter is to review the recent findings about hydrogen generation from reforming processes of bio-sources combined with membrane reactor technology. A deep discussion is presented about the general classification of the membranes, with special attention being paid toward palladium-based membranes. Furthermore, an overview on the representative results on the reforming of ethanol and methanol as renewable sources performed in membrane reactors is given.

Bilayered buccal films as child-appropriate dosage form for systemic administration of propranolol

Buccal mucosa has emerged as an attractive site for systemic administration of drug in paediatric patients. This route is simple and non-invasive, even if the saliva wash-out effect and the relative permeability of the mucosa can reduce drug absorption. Mucoadhesive polymers represent a common employed strategy to increase the contact time of the formulation at the application site and to improve drug absorption. Among the different mucoadhesive dosage forms, buccal films are particularly addressed for paediatric population since they are thin, adaptable to the mucosal surface and able to offer an exact and flexible dose. The objective of the present study was to develop bilayered buccal films for the release of propranolol hydrochloride. A primary polymeric layer was prepared by casting and drying of solutions of film-forming polymers, such as polyvinylpyrrolidone (PVP) or polyvinylalcohol (PVA), added with different weight ratios of gelatin (GEL) or chitosan (CH). In order to achieve unidirectional drug delivery towards buccal mucosa, a secondary ethylcellulose layer was applied onto the primary layer. Bilayered films were characterized for their physico-chemical (morphology, thickness, drug content and solid state) and functional (water uptake, mucoadhesion, drug release and permeation) properties. The inclusion of CH into PVP and PVA primary layer provided the best mucoadhesion ability. Films containing CH provided a lower drug release with respect to films containing GEL and increased the amount of permeated drug through buccal mucosa, thanks to its ability of interfering with the lipid organization. The secondary ethylcellulose layer did not interfere with drug permeation, but it could limit drug release in the buccal cavity.

Steam Reforming, Preferential Oxidation, and Autothermal Reforming of Ethanol for Hydrogen Production in Membrane Reactors

Abstract Today, hydrogen is seen as the most viable energy carrier useful for several applications. Meanwhile, hydrogen generation from ethanol, mainly producible from biomass, can be considered a new opportunity for exploiting renewable sources, taking care of the level of pollutants in the environment as well. The present chapter highlights the current state of the art about hydrogen production from ethanol reforming processes performed through Pd-based membrane reactor (MR) technology. In particular, they are described as an alternative to the conventional systems because of their ability to perform contemporarily the reforming process of an equilibrium limited reaction and the hydrogen separation/purification stage in a unique device. The benefits and the drawbacks of this technology are discussed and the most significant EU projects about ethanol reforming and MR technology are highlighted.

Ethanol From Biomass

Abstract Nowadays, the world’s energy requirements are based on the use of fossil fuels. Rapid growth in both global energy demand and carbon dioxide emissions associated with the use of these fuels have driven the research for alternative sources, which are renewable and have a lower environmental impact. Ethanol is considered one of them. In fact, it is considered one of the better biofuels for transport: it can be burned directly or blended with petrol to improve fuel combustion in vehicles, resulting in lower CO 2 emission to reduce greenhouse gases in the atmosphere. The optimization of the ethanol production processes from lignocellulosic biomass is considered an important research from both industrial and research point of view. In function of the nature of the raw material, it is possible to distinguish these three different feedstock generations. In the first generation, the substrate consists mainly of seeds, potato, and grains and the production process consists of the purification of simple sugars to obtain ethanol. Nevertheless, the first generation of biofuels has been perceived as sustainable mainly from both an environmental and limitation in food supply point of view. This has meant that research has switched to the development of more advanced technology to obtain an energy sustainability to minimize greenhouse gases emission. For these reasons, other two different production processes have been developed, focusing on the fermentation of cellulose and hemicellulose from mainly agricultural wastes (second generation) and algae (third generation). This chapter represents a critical analysis of published data on application and potentiality of the bioethanol production from first, second and third generation of feedstock.

Insect-Infested Wood Remediation by Microwave Heating and Its Effects on Wood Dehydration: A Case Study of Hylotrupes bajulus Larva

ABSTRACT Wood artefacts are subject to damage by biologic infestations due to bacteria, insects, and fungal species. One of the worst feared attacks is due to the xylophagous insects whose larvae feed on wood by boring galleries, at the expense of building timbers and worked woods. These beetles are responsible for daily destruction of the world’s wooden cultural heritage, and their elimination has been always a big problem for conservation of wood. The need to avoid the use of chemical methods in conservation for pest control has led to the development of various non-chemical, non-toxic treatments. Among these, heating with microwaves (MW) seems to be one of the most promising, since it has already shown its high efficacy in destroying pests. Insect-infested wood remediation by MW heating in conservation is based on the larger thermal increment induced in larvae than in wood, due to their different dielectric permittivity in the GHz frequency range. However, the side effects that may occur due to MW heating of wood, such as dehydration, have never been discussed so far. Here we study the possible application of microwave heating as a remediation method for wood samples infested by the larvae of the insect Hylotrupes bajulus. We show that it is possible to set up exposure conditions able to achieve 100% of larvae death and that are sufficiently mild not to induce significant dehydration of the exposed wood from which shrinkage effects may derive. Indeed, under these conditions, MW-induced wood dehydration on cubic and parallelepiped sweetgum samples can be kept under control and to percentages as low as 0.4% (w/w).

Advances in Methanol Production and Utilization, with Particular Emphasis toward Hydrogen Generation via Membrane Reactor Technology

Methanol is currently considered one of the most useful chemical products and is a promising building block for obtaining more complex chemical compounds, such as acetic acid, methyl tertiary butyl ether, dimethyl ether, methylamine, etc. Methanol is the simplest alcohol, appearing as a colorless liquid and with a distinctive smell, and can be produced by converting CO2 and H2, with the further benefit of significantly reducing CO2 emissions in the atmosphere. Indeed, methanol synthesis currently represents the second largest source of hydrogen consumption after ammonia production. Furthermore, a wide range of literature is focused on methanol utilization as a convenient energy carrier for hydrogen production via steam and autothermal reforming, partial oxidation, methanol decomposition, or methanol–water electrolysis reactions. Last but not least, methanol supply for direct methanol fuel cells is a well-established technology for power production. The aim of this work is to propose an overview on the commonly used feedstocks (natural gas, CO2, or char/biomass) and methanol production processes (from BASF—Badische Anilin und Soda Fabrik, to ICI—Imperial Chemical Industries process), as well as on membrane reactor technology utilization for generating high grade hydrogen from the catalytic conversion of methanol, reviewing the most updated state of the art in this field.

Vaginal Bifidobacterium breve for preventing urogenital infections: Development of delayed release mucoadhesive oral tablets

Graphical abstract Figure. No Caption available. Abstract Bifidobacteria are predominant microorganisms in the intestinal flora, but at the same time represent a subdominant group of the vaginal microbiota. For this reason, oral administration of these probiotic bacteria can provide beneficial effect for both intestinal and urogenital ecosystems. The first aim of this study was to test the strain Bifidobacterium breve BC204, isolated from a vaginal swab of a healthy woman, for its capability to adhere to human cells, to survive to gastric acids and bile salts and to exert antimicrobial activities. The second aim of the work was to develop an oral formulation able to guarantee bacterial survival during storage and administration, thus favouring intestinal and vaginal colonization. B. breve BC204 was encapsulated by spray‐drying and subsequently formulated in time‐dependent erodible tablets. B. breve BC204 showed good ability to adhere to Caco‐2 cells and moderate ability to resist to gastrointestinal stress. Moreover, it exerted a strong antimicrobial activity against urogenital and enteric pathogens. Microencapsulation followed by tablet production allowed high loading and survival of B. breve BC204, associated to a delayed release and mucoadhesive ability. These characteristics are required to achieve appropriate amount and persistence of viable microbial cells in the treatment site.