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Flocculation Behaviors of Collagen Protein-Al(III) Composite Flocculant 
by Ruiqin Li, Jianfei Zhou, Xuepin Liao, Wenhua Zhang and Bi Shi
Volume: 109      Number: 2     Page: 56-62     Year: 2014
Hydrolyzed collagen protein (HCP) was prepared by the hydrolysis of solid skin wastes, and then cross-linked with glycerol triglycidyl ether (GTE) to produce cross-linked collagen protein (CCP). By combination CCP with different amounts of Al2(SO4)3, a series of CCP-Al (III) composite flocculants (CCP-Al) were successfully synthesized. A kaolin suspension (5 g/L) was utilized as a model system to investigate the flocculation behaviors of the as-prepared flocculants. When the dosage of the CCP-Al was 50 mg/L, the flocculation extent reached 95% in 20 minutes with the sludge volume ratio lower than 15%. Under the same conditions, the CCP-Al exhibited better flocculation performance than the Al2(SO4)3. Scanning electron microscope (SEM) observations revealed that the size of flocs formed by CCP-Al was larger than that of Al2(SO4)3, suggesting a better aggregation of flocs.
 
 
Extraction of Keratin from Unhairing Wastes of Goatskin and Creating New Emulsion Formulation Containing Keratin and Calendula Flower (Calendula officinalis L.) 
by E. Bayramoglu, A. Yorgancioglu, G. Yeldiyar and E. Onem
Volume: 109      Number: 2     Page: 49-55     Year: 2014
This study demonstrates the use of keratin extracted from unhairing wastes of goatskin for cosmetics. Keratin has been purified from unhairing wastes of goatskin according to the oxidation method for producing emulsions. The experimental process to prepare the emulsions includes Oil/Water (O/W) emulsion method with keratin and Calendula officinalis flower extract (Calendula officinalis L.). Four emulsion creams with different ratios of keratin and calendula ingredients were formulated. Fourier transform infrared spectroscopy (FTIR) analysis of the keratin purified and pH, viscosity and average particle size analyses of the emulsions prepared have been carried out. The results of the study have shown that keratin obtained from unhairing wastes of leather industry could be smoothly used in producing emulsion formulations with calendula flower ingredient.
 
 
Associated Use of Enzymes and Hydrogen Peroxide for Cowhide Hair Removal 
by E. Andrioli and M. Gutterres
Volume: 109      Number: 2     Page: 41-48     Year: 2014
This study evaluated the use of enzymatic extract produced by a strain of Bacillus subtilis in combination with hydrogen peroxide for hair removal of cowhides. Were tested two concentrations of enzymatic extract (100 and 300 U g-1 of hide), and two concentrations of hydrogen peroxide (4% and 8%). The hides were evaluated visually, and wastewater was evaluated through analysis of total nitrogen, total, fixed and volatile dissolved solids, glycosaminoglycans, proteoglycans and hydroxyproline. The oxidative-enzymatic unhairing didnt cause destruction of hair and reduced the process time compared to the conventional and the enzymatic unhairing. The results showed that the oxidative-enzymatic unhairing can be a viable alternative to the use of lime and sodium sulfide on hair removal.
 
 
Preparation of Nonwoven and Green Composites from Collagen Fibrous Networks 
by C.K. Liu, N. Latona and M. Taylor
Volume: 109      Number: 2     Page: 35-40     Year: 2014
The disposal of solid wastes, such as trimmings and splits generated in various manufacturing processes in a tannery is a serious challenge to the hides and leather industries. Most of these wastes are transported out of processing plants for landfills, not only incurring the expense of transportation, but also creating environmental issues. Our effort to address these new challenges is to develop new uses and novel biobased products from solid wastes to improve prospective markets for the hides and leather industries. We hypothesize collagen fiber networks derived from solid fibrous wastes can be utilized to prepare high performance green composites and air filters, of which both have a great market potential. Collagen fiber networks were obtained from split hides that have been processed to remove the noncollagenous materials through the hair removal, liming, and bating steps. Earlier studies were devoted to understand the effects of dehydration on the resultant fiber networks and the effects of processing steps such as bating, pickling and crosslinking treatments on the morphology and physical properties of the fiber networks derived from un-tanned hides, which will be the starting material for constructing air filters and green composites. This study focuses on preparations of nonwoven and green composites derived from fiber networks. Non-woven sheets were prepared using paper-making technology. They were then used as reinforced components to make composites that use gelatin as the matrix. Mechanical properties were evaluated for the resultant composites; results showed that the fiber sizes and gelatin content have significant effects on the properties of the resultant nonwoven and composites.
 
 
Powdered Hide Model for Vegetable Tanning 
by E. Brown, R. Latona, M. Taylor and A. Gehring
Volume: 109      Number: 1     Page: 8-13     Year: 2014
To demonstrate the utility of the powdered hide model for vegetable tanning studies, interactions of quebracho with samples of powdered hide prepared from partially processed hides were investigated. Hides were dehaired by a typical sulfide or oxidative method and carried through the delime/bate step of a tanning process. Prior to tanning, the powdered hide from oxidative dehairing was on average slightly more susceptible to attack by collagenase than was the powdered hide from sulfide dehairing. After tanning with as little as 20% quebracho, powdered hide from both processes was well protected against collagenase degradation. Apparent shrinkage temperatures ranged between 79C and 87C, increasing with increased quebracho offer. Shrinkage temperatures for quebracho-treated oxidatively powdered hides were generally 2C lower than for sulfide dehaired samples. This contrasts with no difference in shrinkage temperature for chrome tanned powdered hides. Comparison of micrographs of powdered hide treated with crude and purified quebracho suggest that the tanning effect of quebracho is both a function of quebracho/collagen interactions, and the filling effect of other components of the crude quebracho.
 
 
Low Carbon Products to Design Innovative Leather Processes. Part II: Determination of the Optimal Physical Modification of Tara  
by L. Olle, C. Casas, J. Diaz, S. Sorolla and A. Bacardit
Volume: 109      Number: 1     Page: 25-31     Year: 2014
This study considers the fruit of the tara bush as a sustainable source for tanning agents and proposes alternatives to chromium and other mineral salts and vegetable extracts. Specifically, physical modifications have been developed in part II of the study to obtain a modified tara with a higher percentage of tannins and with a better level of penetration (see Low carbon products to design innovative leather processes. Part I: determination of the optimal chemical modification of tara).1 The physical modification of tara focused on milling and sieving. The different products obtained have been characterized and applied to leather samples in order to evaluate the degree of penetration and stabilization in the leather structure.
 
 
Characterization of Leather Structure via Metallographic Sample Preparation 
by Huayong Zhang, Yongmei Xia, Lei Shi and Tianduo Li
Volume: 109      Number: 1     Page: 1-7     Year: 2014
In this paper, the leather cross-sectional images based on metallographic sample preparation were introduced, including those of the vertical cross section of the grain layer and reticular layer, the fine fiber cross section and the black outlines surrounding the fiber bundles sections etc. The differences between the images of fiber bundles sections obtained by the light transmission mode and by the light reflective mode were explained. With the introduction and explain of this article, the images obtained by metallographic sample preparation can be well understood.
 
 
Removal of Chromium (III) from Tannery Wastewaters with Acidophilic Fungi 
by J. Lalueza, R. Puig, A. Rius, E. Marti, J. Marti, N. Rodriguez and R. Amils
Volume: 109      Number: 1     Page: 14-24     Year: 2014
Conventional methods for chromium removal from industrial effluents may be limited by technological or economical constraints, especially when they are applied to dilute metal solutions. Thus, biotechnological processes, which are efficient at low metal concentrations and require the use of fewer chemicals, may play an important role. The chromium recovery proposed here is based on the specific uptake of this metal by acidophilic fungi. Fifty acidophilic fungal isolates from the Ro Tinto basin, an extreme acidic environment, were tested. Most of them were resistant to Cr(III) and Cr(VI) solutions at concentrations up to 10 mmol/L. The influence of different experimental conditions was evaluated (medium concentration, kinetics, requirement of induction etc.). Fungal isolate 143 was able to remove 63% of Cr(III) at 0.1 mmol/L, 74% at 1 mmol/L and 21% at 10 mmol/L. These are the best Cr(III)-fungal-uptake results at acidic pH described in the literature so far. It should be possible to use these acidophilic fungi, for example in tannery wastewater, as they can resist chromium concentrations and pH values found in these effluents (between 6.5-7.5 mmol/L Cr (III) and pH as low as 3-4).
 
 
A Study on the Reliability of UNI EN ISO 17075 Method for the Determination of the Cr(VI) Content in Leather 
by A. Ballrdin and L.M. Iannone
Volume: 108      Number: 12     Page: 457-461     Year: 2013
The UNI EN ISO 17075 method for Cr(VI) detection in leather presents several drawbacks. One of these is the choice of an alkaline extraction pH, which produces severe false positive results. Summary: The hexavalent chromium content in 14 leather samples, resulted positive to the presence of Cr(VI) according to the UNI EN ISO 17075 method in two certified laboratories, was re-determined, using the official extracting method at pH 8 and a different phosphate extraction buffer at pH 4.4 containing 5% NaCl. The well-known transient nature of Cr6, that is the decrease of its amount in leather during time, required a re-activation by thermal treatment before analysis. The results show that the official method systematically gives false-positive values and that 10 of the 14 examined leather samples, when extracted with a buffer at pH 4.4, proved to have acceptable levels of Cr(VI). In addition we found that Solid Phase Extraction (SPE) cartridges, either normal or end-capped, absorb about 10% of chromate and this indicates that the calibration curves should be obtained after filtering each standard with the SPE employed.
 
 
Hydroxyapatite Nanoparticles and Polyethylene Glycol Treatment of Historical Leather: Mechanical Properties 
by A. Ershad-Langroudi and A. Mirmontahai
Volume: 108      Number: 12     Page: 449-456     Year: 2013
Historical leather objects are at risk of deterioration through mechanical stress such as viscoelastic and plastic deformation as well as natural aging erosion. So, it was expected that appropriate leather treatment should improve their mechanical properties. For this purpose, the mechanical behavior of goat historical leather treated with hydroxyapatite (HA) and polyethylene glycol 400 (PEG400) was studied and compared with the mechanical properties of untreated sample (control). The samples were subjected to a dynamic tensile stress by dynamic mechanical thermal analysis (DMTA) as well as static stress by tensile test. In addition, the treatment effects on the leather mechanical properties were investigated after accelerating aging test. It was shown that treated sample exhibited more softness, better mechanical properties and less structural changes than the untreated sample. The Scanning Electron Microscopy studies show uniform distribution of nanoparticles in the leather matrix as well as the nano hydroxyapatite particles, which are placed between collagen fibers.