National Engineering Laboratory for Clean Technology of Leather Manufacture

Chengdu, China

National Engineering Laboratory for Clean Technology of Leather Manufacture

Chengdu, China
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Zhang J.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Zhang J.,Key Laboratory for Leather Chemistry and Engineering of the Education Ministry | Gao Y.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Chen W.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Chen W.,Key Laboratory for Leather Chemistry and Engineering of the Education Ministry
Leather and Footwear Journal | Year: 2017

In order to explain the reason of chromium released from chrome tanned leather to effluent in neutralizing, the chromium complex composition, structure and property in neutralizing effluent were characterized. Hide powder was tanned by chromium sulfate liquor with 33% basicity (BCS), and then the tanned hide powder was treated by conventional neutralizing to prepare neutralizing effluent (NE). Ion exchange chromatography (IEC) and gel filtration chromatography (GFC) were used to separate NE to study its chromium composition firstly; then ultraviolet-visible absorption spectroscopy (UV) and Fourier Transform Infrared Spectroscopy (FT-IR) were combined to analyze the structure of chrome complexes in NE; at last, chromium from NE was used for tanning and the thermal properties of the tanned hide powder were measured by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The results indicated that NE mainly consisted of anionic-zero valent, monovalent and bivalent chrome complexes and the molecular volume was small also. The Cr(III) complexes in NE were mainly combined with ligands like SO4 2- and HCOO- through single point coordination. Compared with the control, higher weightlessness rate but lower maximum thermal decomposition temperature (Tmax), thermal denaturation temperature (Td) and enthalpy (ΔH) of NE chrome tanned hide powder demonstrated poor tanning ability of the chromium. In short, the characteristics of chromium complexes released from neutralizing process were: anionic-zero valent and low positive charge composition, small molecular volume, mainly combined with ligands through single point coordination and poor tanning ability. The study would provide foundation and reference for developing chromium solidifying methods in neutralizing. © 2017 by the author(s).


Yang H.,Clean Chemistry | Deng Y.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Xu S.,Key Laboratory of Leather Chemistry and Engineering Ministry of Education | Liu W.,Key Laboratory of Leather Chemistry and Engineering Ministry of Education | Li G.,Clean Chemistry
Journal of Applied Polymer Science | Year: 2017

Collagen solutions in the presence of 0.1-2.0M acetic acid (AA) were investigated to understand the interaction between collagen molecules and an acidic solvent. Fluorescence measurements of pyrene showed that the critical aggregation concentration (CAC) of collagen increased from 0.518 to 1.581mg/mL for AA concentrations ranging from 0.1 to 2.0M, indicating that the aggregated state of collagen molecules was associated with AA concentration. The size of the collagen aggregates, determined by dynamic light scattering, demonstrated that their disaggregation was enhanced with increasing electrostatic repulsion between the collagen chains. The variations in the intrinsic viscosity and Huggins coefficient depended on the molecular interaction among the collagen molecules. Furthermore, the increased AA concentration has a different influence on the rigidity of collagen molecules above and below the CAC. This observation was manifested by the changes in the morphology of collagen molecules observed by atomic force microscopy. © 2017 Wiley Periodicals, Inc.


Zhang J.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Zhang J.,Key Laboratory for Leather Chemistry and Engineering of the Education Ministry | Zhang C.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Wu J.,National Engineering Laboratory for Clean Technology of Leather Manufacture | And 3 more authors.
Leather and Footwear Journal | Year: 2017

The leather was dried by microwave and compared with the leather dried by oven in mechanical properties, softness, shrinkage temperature, microstructure as well as uniformities of chrome tanning agent, fatliquoring agent and dyestuff as new method for soft leather drying to keep and improve its softness and comprehensive properties. The results indicated that microwave drying would not damage leather collagen structure. Meanwhile, as microwave drying was even and would promote the combinations of collagen with other chemicals, the softness and mechanical properties of microwave dried leather were improved, in addition, the shrinkage temperature and uniformities of chrome tanning agent, fatliquoring agent and dyestuff were also promoted. Moreover, much more orderly and porous arrangement but less adhesion in collagen matrix of microwave dried leather were observed. These phenomena illustrated microwave dried leather could meet the high quality demands of leather better in softness and uniformity. To sum up, microwave has many advantages in drying soft leather products. © 2017 by the author(s).


Liu K.,University of Sichuan | Liu K.,Yibin Vocational and Technical College | Zheng J.,University of Sichuan | Zhao J.,University of Sichuan | And 3 more authors.
Chinese Journal of Applied and Environmental Biology | Year: 2012

In the view of the specificity of microbial communities in pit mud during brewing process, different types of soil samples and common strains in liquor brewing were investigated to assess the fingerprints of phospholipid fatty acid (PLFA) of microbial communities in Luzhou flavor pit mud. The results suggested the composition and content of PLFA significantly affected by physiological and environmental conditions which resulted in the significant differences (P<0.05) of PLFA fingerprints among the samples (the ratio of fungal/bacterial PLFA in garden and roadside soils were 0.30 and 0.66, respectively, which were both less than 1, the ratio in pit mud however was 1.17). The content of special PLFA changed significantly (P<0.05) when five pure cultured microorganisms were added. The content of al4:0 and al6:0 in pit mud adding SICCl.13 and CICC20633 were 1.44 and 9.92 times higher than those in blank respectively, while 18:2ω6,9 in SICC3398 and SICC31482 were 82.58 and 90.33 times higher than that in the blank. Furthermore, cy17:0 was identified in the pit mud adding DH5a. Principal component analysis (PCA) was performed to evaluate the changes of special PLFA's composition and content in pit mud after adding the microorganisms. The results of this study demonstrated that PLFA fingerprint method was a fast biochemical culture-independent method, which was beneficial to characterize the fingerprints of microbial communities during liquor process.


Xia Q.,University of Sichuan | Xia Q.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Wu C.,University of Sichuan | Wu C.,National Engineering Laboratory for Clean Technology of Leather Manufacture | And 4 more authors.
Journal of the Institute of Brewing | Year: 2014

Huangshui is a by-product of Chinese liquor and it has a high annual production owing to the popularity of the liquor in China. The aim of this study was to investigate the feasibility of Huangshui esterification by whole-cell enzymes produced from different microbial strains. Esterification of Huangshui was carried out for 16days via the addition of different preparations produced from Rhizopus chinensis strain 3.1149, Rhizopus chinensis strain 3.1166, Monascus purpureus SICC 3.19 and Rhizopus oryzae SICC 3.623. The results showed that the preparation GP1, produced from M. purpureus, exhibited the highest esterification efficiency compared with the other preparations based on physicochemical analysis in combination with volatile profile analysis. In addition, a characterization of preparation GP1 was performed and the optimal alcohol content and pH for esterification were 10% and pH3.5, respectively. Under the optimal conditions, the total ester content increased from 4.86 to 7.31g/L after esterification for 16days. An estimation of the sensory impact of the volatile compounds after esterification was performed by a calculation of the odour active values (OAVs). Radar diagrams of the OAVs demonstrated the differences in the sensory profiles in Huangshui, before and after esterification. Nearly all of the OAVs of the esters were increased by the esterification reaction and were above the human sensory threshold. Results presented in this manuscript provide a potential strategy for the efficient bio-conversion of Huangshui. © 2014 The Institute of Brewing & Distilling.


Liu K.-Y.,University of Sichuan | Chen S.,University of Sichuan | Zheng J.,University of Sichuan | Huang J.,University of Sichuan | And 2 more authors.
Chinese Journal of Applied Ecology | Year: 2012

Taking the nine common microbial strains in liquor-making process as test objects, this paper studied the characteristics of phospholipid fatty acid(PLFA), a characteristic component of the strains cell membrane, and the relationships between the detected amount of PLFA and the biomass of the strains. There existed significant differences in the PLFA fingerprints between test bacteria, actinomycetes, molds, and yeasts, and the PLFA fingerprint of each strain could be used as the basis to distinguish species and genus. Within a certain range of the strains biomass, the detected amount of total PLFA or 16:0 was linearly correlated with the biomass. After adding different biomass Gram positive(G+) bacteria, Gram negative(G-) bacteria, and fungi in fermented grains, a significant difference was observed in the relative amount of PLFA between experimental and control samples. It was suggested that the fingerprint of PLFA could quantitatively or semi-quantitatively characterize the microbial community structure and its dynamic variation in fermented grains. By detecting the PLFA profiles of fermented grains in various liquor industries and by analyzing the microbial community structure in the fermented grains, it was substantiated that PLFA fingerprinting was of general applicability.


Zhao J.-S.,University of Sichuan | Zhao J.-S.,National Alcohol and Processing Food Quality Supervision and Inspection Center | Zheng J.,University of Sichuan | Zhou R.-Q.,University of Sichuan | And 3 more authors.
Journal of the Institute of Brewing | Year: 2012

Pits are necessary solid bioreactors for the production of Chinese strong aromatic liquor, and the microbial community in these pits significantly affects the quality and yield of the liquor. In this study, the microbial community structures of different aged pit muds were evaluated by phospholipid fatty acid analysis. The results indicated that the microbial community was composed of bacteria, actinomycetes and fungi, with Gram-positive (G+) bacteria and anaerobic bacteria being dominant. The biomass of the pit mud increased and the microbial community shifted to G+ bacteria as the pit age increased. Principal component analysis showed that PC1 consisted mainly of fatty acids of saturated (15:0, 16:0 and 18:0), methyl-branched (a15:0, i16:0, a16:0, i17:0 and 8Me18:0), polyunsaturated (16:1ω7c, 16:1ω9) and cyclopropane (cy17:0 and cy19:0), and PC2 mainly of 18:1ω9, 18:1ω10 and a14:0, The characteristics of the microbial community structure in the pit mud resulted from the stress effects of low oxygen concentration, low pH and a high alcohol concentration. © 2013 The Institute of Brewing & Distilling.


Wang R.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Wang R.,University of Sichuan | Zhang Z.,University of Sichuan | Liu H.,University of Sichuan
Advanced Materials Research | Year: 2012

Adsorption behavior disciplinarian of the immobilized tannins to metal ions was studied. Experiments showed that adsorption capacities of metal ions lied in ns grouse in the periodic table of elements were relatively low. For the metal ions lied in np grouse in the periodic table of elements, their adsorption capacity increased with the increasing in the radius of metal ions. Adsorption capacities of metal ions having low values in the first transition series in the periodic table of elements, such as Mn(II), Fe(II), Fe(III), Co(II) and Ni(II), were more lower than that of the metal ions having high values, such as Cr(VI), Mn(VII) and V(V). For the metal ions in the second, the third transition series and the actinide series, adsorption capacities were relatively higher than that of metal ions in lanthanide series.


Hu Z.,University of Sichuan | Yi S.,University of Sichuan | Wei H.,University of Sichuan | Tang Y.,University of Sichuan | And 2 more authors.
Journal of the Society of Leather Technologies and Chemists | Year: 2015

In order to develop an eco-friendly polymer, a novel superabsorbent polymer was synthesized by grafting the alkaline hydrolysis product of leather waste (LW) to a copolymer of acrylic acid (AA) and acrylamide (AM)(PLW-g-(AA-co-AM)) with microwave method assistance. The morphology of the samples was examined by scanning electron microscopy (SEM). Through a single factor experiment, various factors were explored which may affect the water absorption of such a superabsorbent polymer during preparation. The results showed that the optimum technological conditions of synthesizing PLW-g-(AA-co-AM) were: dosage of LW15wt.% of total monomer mass, cross-linking agent 0.06wt.% of monomer mass, neutralization degree 75%, AA: AM= 6:1, initiator 0.6wt.% of monomer mass. According to this procedure, the PLW-g-(AA-co-AM) with a water-absorbency of 1191.5g/g and saltabsorbency of 94.4g/g was obtained. The product was used as adsorbant for urea, the urea load rate reached 87.76% when the concentration of urea was 10g/L. Meanwhile, the release of urea from the loaded PLW-g-(AA-co-AM) in deionized water exhibited specific release properties.


Teng B.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Zhang W.,Key Laboratory for Leather Chemistry and Engineering of the Education Ministry | Jian X.,National Engineering Laboratory for Clean Technology of Leather Manufacture | Chen W.,Key Laboratory for Leather Chemistry and Engineering of the Education Ministry
XXXIII IULTCS Congress | Year: 2015

Recycling system has the advantage of reducing chemical consumption and providing an efficient way to decrease the cost of leather manufacture. High chemical oxygen demand, bio-chemical oxygen demand and microbial toxicity are all considered as the characters of vegetable tanning effluent, however, only a few recycling technologies were developed. In this study, larch tanning effluent (LTE) was obtained with a commercial larch tannin (CLT) through a common vegetable tanning process, then the polyphenols in the LTE and CLT were characterized with Fourier translation infrared spectrum, nuclear magnetic resonance, gel permeation chromatography and an elemental analysis. The collagen reaction ability was also tested through molecular modeling as well as a differential scanning calorimetry analysis. The results indicated polyphenols in the LTE and CLT were procyanidines with cis and trans configuration. However, obvious differences between these polyphenols were presented in the aspect of molecular weight and the quantity of sulfonic acid group. The Average molecular weight of the LTE was 1104 Dalton, in contrast to an obviously higher value in the CLT (3334 Dalton). Compared with the CLT, inactive properties were shown in the molecular modeling of the LTE collagen interaction, less amino acids residues were participated in the binding process and few hydrogen bonds were detected. Meanwhile, the non-bond energy and the denaturation temperature of the LTE-collagen complex also presented a lower value, which means the LTE-collagen binding was not stable compared with the CLT-collagen complex. The results indicated the molecular weight and the binding ability of the polyphenols should be increased before recycling of the LTE. The results will provide valuable references for the recycling technology and pollution control of the vegetable tanning effluent.

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