Role of Anionic Chromium Species in Leather Tanning

Chrome tanned leathers are definitely unique in comparison with leather made from any other known tanning agents, especially in terms of thermal stability, cost and its reactive mechanism with collagen fibers. In our current studies, self basifying chrome tanning materials masked with different percentages of organic acid were prepared and applied after the de-liming stage of leather processing. This eliminated the need for pickling and basification steps. Tanned leathers resisted shrinkage up to 103 and 105±2°C while conventional chrome tanned leathers resisted up to 108±2°C. Also, interaction of anionic chrome species in tanning was studied. It was observed that the percentage of anionic species in the experimental chrome tanning material was higher than conventional chrome tanning material and the shrinkage temperature achieved by application of experimental tanning material proves that anionic species do involve in tanning. Tanned leathers were crusted and analysed for strength and organoleptic properties.

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Synthesis of Formaldehyde Free Amino Resin to Produce Green Eco-Labelled Leather with Improved Retanning Properties

Journal of the American Leather Chemists Association ◽

10.34314/jalca.v115i4.3799 ◽

2020 ◽

Vol 115 (4) ◽

pp. 132-139

Author(s):

Muhammad Naveed Ashraf ◽

Shahzad Maqsood Khan ◽

Shahid Munir ◽

Rashid Saleem

Keyword(s):

Thermal Stability ◽

Water Solubility ◽

Thermo Gravimetric Analysis ◽

Sulfanilic Acid ◽

Gravimetric Analysis ◽

Melamine Resin ◽

Organoleptic Properties ◽

Formaldehyde Content ◽

Leather Processing ◽

Percentage Efficiency

Formaldehyde has many applications in the chemical industry including synthesis of amino resins which are used in leather processing. After application in leather, these resins are hydrolyzed under certain conditions to release free formaldehyde which has high environmental concerns due to its proven carcinogenic effects. The objective of this work is to develop a formaldehyde free melamine-based resin to produce green leather with improved retanning properties and thermal stability. The optimum melamine resin was synthesized by condensing melamine with glyoxal instead of formaldehyde. Further, the water solubility and improved thermal stability of synthesized melamine resins were achieved by introduction of sulfanilic acid in resin structure. Synthesized resin was used in leather retanning in comparison with commercially available melamine resin as a control. Both leathers were tested for mechanical properties, organoleptic properties, grain surface and fiber structure analysis. Comparative free formaldehyde content was measured in resultant leathers. Effluents of retanning baths were comparatively analyzed. Optimum resin was also characterized by thermo gravimetric analysis and FTIR. The results of this study showed that the experimental resin has imparted significant improvement in mechanical and organoleptic properties of leather as compared to the control resin. Analysis of free formaldehyde content confirmed the absence of free formaldehyde in leather treated with optimum resin while 141 mg/kg formaldehyde was detected in leather treated with control resin. Free formaldehyde was also absent in effluent of experimental resin while 305 mg/kg formaldehyde was detected in effluent of control resin. Moreover, percentage efficiency in COD, TDS and TSS load of effluent was observed as 9.62, 7.2 and 6.31 respectively. Resultant leather was free from formaldehyde making it safe for human along with reduction in pollution load of tannery.

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Eco-friendly Chrome Tanning of Leather using Ultrasound Technique

10.21203/rs.3.rs-926494/v1 ◽

2021 ◽

Author(s):

Md. Abu Sayid Mia ◽

Shamima Yeasmin ◽

Mohammad Nurnabi ◽

Md. Zahangir Alam

Keyword(s):

Cross Section ◽

Conventional Method ◽

Scanning Calorimetry ◽

Ultrasound Technique ◽

Environment Friendly ◽

Shrinkage Temperature ◽

Leather Processing ◽

Chrome Tanning ◽

Tanning Process ◽

Sem Analyses

Abstract This article describes the development of an environment friendly chrome tanning of leather using ultrasound. Most of the leathers are tanned by the conventional method using basic chromium sulphate. It is one of the most polluting and time-consuming steps in leather processing. In this study, investigations were carried out on ultrasound assisted eco-friendly tanning process so that the chrome tanning agent could provide better quality leather without creating any environmental problem. Effects of using ultrasound in chrome tanning process were studied at different pH, tanning time, tanning agent dosage, and then compared with that of conventional method. Tanned leathers were characterized by scanning electron microscopy (SEM), photomicrographic analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray (EDX), etc. SEM analyses of the surface and cross-section of the tanned leather showed that fibre structures were not affected by ultrasound. It was also found that the shrinkage temperature of leather tanned with ultrasound was increased by about 5–29°C. Chrome uptake and content were found to increase by 30–50% and 1–7%, respectively. Tanning time was shortened from 6 hours to 2 hours and the quantity of leachable chromium in the leather was also decreased significantly. The noteworthy enhancing effects have been attributed largely because of the increased penetration of tanning agents into pickled leather. Photomicrographic analysis of the cross-section of the tanned leather also showed a higher penetration of tanning agents in presence of ultrasound.

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Inverse Chrome Tanning Technology

Journal of the American Leather Chemists Association ◽

10.34314/jalca.v115i5.3811 ◽

2020 ◽

Vol 115 (5) ◽

pp. 176-182

Author(s):

Yue Yu ◽

Yunhang Zeng ◽

Tao Liang ◽

Jianfei Zhou ◽

Bi Shi

Keyword(s):

Potential Risk ◽

Absorption Capacity ◽

Solid Wastes ◽

Leather Industry ◽

Organoleptic Properties ◽

Shrinkage Temperature ◽

Oxidized Starch ◽

Chrome Tanning ◽

One Year ◽

High Absorption

Conventional chrome tanning technology (CCTT) generates a remarkable quantity of Cr(III)-containing wastewater and solid wastes, which may pose a potential risk to the environment. In this work, an inverse chrome tanning technology (ICTT) was developed based on chrome-free tanning by Al–Zr complexes and highly oxidized starch (AZ–HOS) to minimize Cr(III) discharge. The 7.5% AZ–HOS exhibited sufficient tanning effect and gave wet white a shrinkage temperature of over 80o C. Thus, wet white can be stably stored for one year and possessed high absorption capacity to post-tanning chemicals (85%–90%) because its pI (7.1) was as high as that of wet blue. Terminal chrome tanning with 1.0% chrome tanning agent after post-tanning gave the ICTT crust leather physical and organoleptic properties that are comparable to those of CCTT crust leather. Moreover, the Cr and TOC loads in ICTT wastewater decreased by 99.9% and 42.4%, respectively. Therefore, this work provides a clean and practical tanning system for the sustainable leather industry.

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Preparation and Properties of Chrome Tanning Agent from Chrome Sludge

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.2538 ◽

2012 ◽

Vol 468-471 ◽

pp. 2538-2541

Author(s):

Na Liu ◽

Zhi Wen Ding ◽

Bao Zhen Cheng ◽

Xiao Yan Pang ◽

Zheng Ping Cheng

Keyword(s):

Hydrogen Peroxide ◽

Organic Acid ◽

Masking Effect ◽

Peroxide Oxidation ◽

Shrinkage Temperature ◽

Chrome Tanning ◽

Hydrogen Peroxide Oxidation ◽

Good Feeling

In this study, Regenerated chrome tanning agent is prepared from chrome sludge by hydrogen peroxide oxidation. The regenerated chrome tanning agent was characterized by IR which reveals that organic acid and protein polypeptide combined with chrome have been mostly removed. A small part of organic acid and protein polypeptide, not oxidized, increases the masking effect of the product. The application results show that the shrinkage temperature (Ts) of wet blue leather can reach 100°C and the leather has good feeling of handle and fullness which shows it has same properties with commercial chrome tanning agent.

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The role of the substrate on the mechanical and thermal stability of Pd thin films during hydrogen (de)sorption

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2020.10.163 ◽

2021 ◽

Vol 46 (5) ◽

pp. 4137-4153

Author(s):

Neha Verma ◽

Rob Delhez ◽

Niek M. van der Pers ◽

Frans D. Tichelaar ◽

Amarante J. Böttger

Keyword(s):

Thin Films ◽

Thermal Stability ◽

Thermal Stability Of

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Mossbauer Study of the Role of Aluminum and Chromium in Nitrogen Implanted Iron

MRS Proceedings ◽

10.1557/proc-235-509 ◽

1991 ◽

Vol 235 ◽

Cited By ~ 2

Author(s):

M. Kopcewicz ◽

J. Jagielski ◽

A. Turos ◽

D. L. Williamson

Keyword(s):

Thermal Stability ◽

Ion Implantation ◽

Metallic Iron ◽

Conversion Electron ◽

Alloying Elements ◽

Mössbauer Study ◽

Conversion Electron Mössbauer Spectroscopy ◽

Conversion Electron Mossbauer Spectroscopy ◽

Thermal Stability Of

ABSTRACTThe role of alloying elements such as Cr and Al in the formation and stability of the nitride phases formed due to N ion implantation into metallic iron was studied by conversion electron Mössbauer spectroscopy (CEMS). The thermal stability of nitride phases upon 1 h annealing was greatly increased as a result of co-implanting either Cr or Al with N as compared to pure α-Fe implanted only with N.

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Role of a disulfide bond in the thermal stability of the LamB protein trimer in Escherichia coli outer membrane

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)52373-5 ◽

1991 ◽

Vol 266 (3) ◽

pp. 1866-1871

Author(s):

M Luckey ◽

R Ling ◽

A Dose ◽

B Malloy

Keyword(s):

Escherichia Coli ◽

Thermal Stability ◽

Outer Membrane ◽

Disulfide Bond ◽

Thermal Stability Of

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Investigating the role of GeO2 in enhancing the thermal stability and proton mobility of proton-conducting phosphate glasses

Journal of Materials Chemistry A ◽

10.1039/d1ta04445a ◽

2021 ◽

Author(s):

Takahisa Omata ◽

Aman Sharma ◽

Takuya Kinoshita ◽

Issei Suzuki ◽

Tomohiro Ishiyama ◽

...

Keyword(s):

Thermal Stability ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Phosphate Glasses ◽

Proton Mobility ◽

Proton Conducting

In this study, the effect of GeO2 on the thermal stability and proton mobility (μH) of proton-conducting phosphate glasses was experimentally investigated using 22HO1/2−3NaO1/2−(12−x)LaO3/2−xGeO2−63PO5/2 glasses. Increasing glass transition temperature (Tg)...

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