Cinzia Tonetti

Study of Methylene Blue adsorption on keratin nanofibrous membranes.

In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16kJmol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters.

Antibacterial efficacy of polypyrrole in textile applications

This paper describes application and evaluation of polypyrrole as an antibacterial polymer. Polypyrrole was produced embedding two doping agents: chloride and dicyclohexyl sulfosuccinate ions. Stability of the antibacterial efficacy of polypyrrole deposited on cotton fabrics was assessed before and after three different kinds of washing (namely, laundering with anionic and non-ionic detergents and dry-cleaning). Polypyrrole showed excellent antibacterial properties (100 % of bacterial reduction) against Escherichia coli for both doping agents. Treated fabrics were further characterised by scanning electron microscopy, energy dispersive X-ray analysis and infrared spectroscopy. The antibacterial efficacy diminished after launderings with anionic and non-ionic detergents because of two different mechanisms: the neutralisation of positive charges under alkali conditions (dedoping), and a partial removal of polypyrrole by abrasion and surfactant action. After dry-cleaning, polypyrrole embedding chloride and dicyclohexyl sulfosuccinate ions still showed excellent antibacterial efficacy. Moreover, scanning electron microscopy investigations were used to intuitively explain the bactericidal mechanism of polypyrrole on Escherichia coli bacteria.

A UPLC/ESI–MS method for identifying wool, cashmere and yak fibres:

A new objective method has been developed for the identification of animal hair fibres, in particular wool, cashmere and yak. Enzymatic digestion of keratin extracted from these fibres and peptide analysis by ultra-performance liquid chromatography/electrospray–mass spectrometry (UPLC/ESI–MS) allows not only qualitative determination of the presence of fibres derived from these species but also a quantitative assessment of the relative percentages present in blends. Such an analysis will provide reliable objective data about the authenticity of commercial products. The effectiveness of the UPLC/ESI–MS method was assessed by analysing known samples of these fibres and confirmed using unknown wool/cashmere/yak blends, and the results were compared with those obtained by SEM method IWTO 58–00.

Immunological method for the identification of animal hair fibres

A new approach to the objective identification of the different animal hair fibres based on the application of monoclonal antibodies has been discussed. Three different extraction methods including metabisulphite/urea, dithiothreitol/urea, thiourea/urea/dithiothreitol were compared to evaluate efficiency and repeatability in extracting keratin from wool and cashmere fibres.  ‘Anti-cashmere’ monoclonal antibodies were produced by immunization of mice with Type II intermediate filament proteins extracted from cashmere, purified by 2D preparative electrophoresis. Two monoclonal antibodies (named P21 and I6) were tested with both wool and cashmere blends for both qualitative and quantitative analysis. The interaction of P21 and I6 antibodies was studied by the immunoblot method.  After a calibration carried out on both the antibodies, the method was applied to unknown wool/cashmere blends and compared with the results of the analysis carried out by the SEM (scanning electron microscopy) method IWTO 58-00 in order to preliminarily assess the method.

Differential scanning calorimetry for the identification of animal hair fibres

Differential scanning calorimetry (DSC) was studied as an alternative qualitative method to identify different textile animal hair fibres. Differentiation of speciality or luxury fibres (such as cashmere) from other animal cheaper fibres (such as sheep’s wool or yak) is essential to repress adulteration of textile products. Moreover, DSC analysis can be used to distinguish fibres of different types and affected by industrial textile treatments like bleaching, steaming, descaling and stretching. Cashmere, wool, yak and goat fibres were analysed by DSC and their traces were compared. The traces were mathematically elaborated to establish criteria for fibres identification. These criteria were applied to study changes in the fibre traces due to industrial treatment. Differences in the DSC traces are evident from cashmere, yak, wool and goat due to differences in transition enthalpy and temperature of the crystalline material that constitutes the ortho- and para-cortex of animal hairs. Furthermore, it is possible to see changes in traces of the same fibres subjected to different treatments.

Identification and quantification of different species in animal fibres by LC/ESI‐MS analysis of keratin‐derived proteolytic peptides

In the present paper, a proteomic method for species determination in fibres has been developed. Keratin was extracted from yak, wool and cashmere fibres and digested by trypsin, providing peptide mixtures that were analyzed by liquid chromatography coupled with electrospray mass spectrometry (LC/ESI-MS) in order to identify peptidic species-specific markers able to differentiate the fibres. Several suitable peptide markers were identified and validated in different fibres of different origin and having undergone different technological treatments, showing 100% specificity and 100% selectivity. Most of the peptide markers were also identified by means of high-resolution mass spectrometry, confirming the origin from species-specific keratin sequences. Some peptides were also used for the quantification of the different species in mixed fibres by LC/ESI-MS. Validation experiments and blind tests confirmed their ability to act as very specific quantitative and qualitative markers. The method here developed is a valid complement to the standard benchmark methods for fibre identification and quantification and will be very useful for assessing the authenticity of textile products.

Validation of UPLC/ESI-MS method used for the identification and quantification of wool, cashmere and yak fibres

Abstract The method based on the ultra-performance liquid chromatography coupled with electrospray mass spectrometry (UPLC/ESI–MS) instrument was used for the identification and quantification of the most commercial Bovidae fibres (wool, cashmere and yak). In the present paper, this method was developed and validated by the authors and confirmed by many analyses of, known and unknown, wool/cashmere/yak blends at different stages of manufacture (fibres, slivers, yarns, fabrics, and raw materials) and with different treatments (dyed, depigmented, bleached, finished forms).

Removal of Cu(II) ions from water using thermally-treated horn–hoof powder as biosorbent

AbstractIn this work, thermally-treated “horn–hoof” powder was studied as biosorbent to remove copper (II) ions from aqueous solutions. Adsorption of copper onto horn–hoof powder was tested in batch process at different experimental conditions. The effect of the initial metal ion concentration, biosorbent dosage, contact time, pH and temperature were investigated with respect to the biosorption characteristics of Cu(II) ion on the horn–hoof powder. The biosorbent characterization was carried out by Fourier transform infrared spectroscopy, mini-cell electrophoresis, BET and particle sizing analysis. According to the tests, the adsorption equilibrium time was reached within 48 h and the optimum adsorption of Cu(II) ions took place at the pH value of 5.5. The Langmuir adsorption isotherm was successfully applied to the biosorption process of Cu(II) ions onto horn–hoof powder. The thermodynamic and kinetic data suggested that the biosorption process is an endothermic process involving chemical reactions and f...