Enhancement of chromium uptake in tanning using oxazolidine

Sundarapandiyan, S.; Brutto, Patrick; Siddhartha, G.; Ramesh, R.; Ramanaiah, Beeram China; Palanivel, Saravanan; Mandal, Asit Baran

doi:10.1016/j.jhazmat.2011.03.117

Cited by 49 publications

(22 citation statements)

References 14 publications

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“…Also, pre-tanning with Zoldine ZE is understood to enhance the uptake of chromium salts by making carboxylic acid side chains of the glutamic acid and aspartic acid residues more accessible to chrome, thereby enhancing its even distribution and xation in the collagen matrix. 21 We speculate that the axial periodicities are unchanged because of the exhaustion of terminal amino acid side chain groups by the Zoldine ZE. Maxwell and co-workers observe an increase in D-period with the addition of chromium salts in the absence of Zoldine ZE, 22,25 further reinforcing the idea that chromium interactions with collagen is specic to carboxylic acid groups.…”

Section: -6mentioning

confidence: 88%

“…20,21 Pre-tanning agents such as Zoldine ZE are commonly used to improve the penetration of main tanning agents through the collagen matrix in the skin, by decreasing the availability of amino acid side chain groups on the collagen molecule. When the samples were treated with the main tanning agents BCS, So-Si or So-Si + BCS (stage 3), different rates of xation were observed based on the colour of the oats and the cross-sections of the skins.…”

Section: -6mentioning

confidence: 99%

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Can sodium silicates affect collagen structure during tanning? Insights from small angle X-ray scattering (SAXS) studies

et al. 2017

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The effect of sodium silicates on collagen structure during leather processing was investigated. Small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) reveal that the molecular structure and thermal stabilities of the sodium silicate treated leathers (So-Si and So-Si + BCS) were different to the conventionally processed chromium treated leathers (BCS). The collagen fibrils were observed to be coated by aggregates of silica, which did not affect the axial periodicity (D-period) of the collagen molecules. However, an increase in collagen fibril diameter was observed during the main tanning step when sodium silicates were used. This could be due to the swelling of collagen fibers from the high alkaline conditions of sodium silicates. From DSC studies, it was also found that sodium silicate treated samples impart no effect on collagen stabilization in the absence of chromium(III). However, a pseudostabilization effect is observed in the So-Si + BCS samples, possibly due to the inability of the collagen molecules to undergo conformational changes due to the silica coating on the collagen fibrils.The tanning of leather involves chemically intense processes leading to environmental pollution, resulting in a demand for cleaner but effective collagen stabilization mechanisms for the leather industry.1,2 Basic chromium(III) sulphate is the most common mineral tanning agent and, is preferred industrially because of the high hydrothermal stability. It has excellent properties in addition to relative short times required to produce nished leathers.3 However, poor uptake of chromium salts leads to high chemical and biological oxygen demand, and toxicity concerns relating to hexavalent chromium(VI) exposure, have led researchers to seek more environmentally friendly alternatives. 4-6Mineral tanning agents such as chromium, zirconium, aluminium, titanium and iron can all stabilize collagen and impart varying degrees of hydrothermal stability.3,7 Synthetic tanning agents (syntans) and vegetable tanning agents from plant polyphenols along with aldehydic cross-linkers are also commonly used, but typically in conjunction with mineral tannages.8 Combination tannages however, with or without mineral tanning agents, can overcome the issues that single tanning systems have with hydrothermal stability.9,10 For example, Vitolo and co-workers observed an increase in chromium uptake when sodium silicate was used in combination with basic chromium sulphate.11 Whilst pre-tans can improve the penetration and even distribution of the main tanning agents in the collagen matrix, a co-stabilizing agent can increase the efficiency of chrome uptake by reducing the amount of chrome required.8 With this idea of combining a weak and strong tanning agent, further studies have been carried out by investigating combinations of a number of tanning options and their effect on collagen stabilization. 4,6,9,12 Soluble silicates such as sodium silicate belong to a group of compounds that contain varying compositions of an alkali met...

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Section: -6mentioning

confidence: 88%

Section: -6mentioning

confidence: 99%

Can sodium silicates affect collagen structure during tanning? Insights from small angle X-ray scattering (SAXS) studies

et al. 2017

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“…substances (Krishnamoorthy et al, 2012;Nashy et al, 2012;Piccin et al, 2012;Sundarapandiyan et al, 2011). Chromium salts have also a high rate of penetration into the interfibrillar spaces of the skin, providing a saving in terms of production time and a better control of the process (Basegio et al, 2009;Cassano et al, 1996).…”

mentioning

confidence: 99%

The effectiveness of the stabilization/solidification process on the leachability and toxicity of the tannery sludge chromium

Montañés

Sánchez-Tovar

Roux

2014

Journal of Environmental Management

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ElsevierMontañés Sanjuan, MT.; Sánchez Tovar, R.; Roux, MSB. (2014). The effectiveness of the stabilization/solidification process on the leachability and toxicity of the tannery sludge chromium. Journal of Environmental Management. 143:71-79. doi:10.1016Management. 143:71-79. doi:10. /j.jenvman.2014 . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 do not improve it. The volume increase is lower as less sludge is replaced by cement and the relative amount of water decreases, and for the cement without additions of fly ashes or pozzolans. Therefore, the latter seems to be the most appropriate cement in spite of being more expensive. This is due to the fact that the minimum toxicity value is achieved with a lower amount of cement; and moreover, the volume increase in the mixtures is lower, minimizing the disposal cost to a landfill.

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“…In the chrome tanning process, basic chromium salt are popularly used to interact with the collagen molecules of the hide/skin to give leather its characteristic properties. However, in the conventional chrome tanning process, only 65-75% of the chrome is up-taken and effectively utilized [141,142]. It was found that 2% of chromium is simply adsorbed and 40% chromium appears to be bound to the collagen [143].…”

Section: An Overview Of the Leather Industrymentioning

confidence: 99%

“…Recently, lignin has been suggested as an environmentally friendly and cheap alternative for adsorbing pollutants such as heavy metals [110][111][112] and organic dyes [132,232] or for activated carbon production [142,233]. As we known, lignin is an amorphous phenolic network polymer and the content of the phenolic hydroxyl group is very low.…”

Section: Cr Removal From Wastewater By Using Ligninbased Biosorbentsmentioning

confidence: 99%

Fractionational and structural characterization of lignin and its modification as biosorbents for efficient removal of chromium from wastewater: a review

Wang

Sun

2019

J Leather Sci Eng

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The removal of chromium (Cr) from wastewater by various adsorbents has been investigated. As compared with the commercial activated carbon, the biosorbents with inexpensive and high adsorption capacities are developed from lignocellulosic wastes. Lignin, existing in lignocellulosic biomass, is the second most abundant resource in nature. Recently, lignin-based bio-sorbents were served as an advanced novel material for the metal ions and dye adsorption from wastewater. It has showed several advantages in the wastewater treatments because of the lowcost, high adsorption capacity, easy recover, and possibility of metal recovery. In this review, the isolation of lignin from lignocellulosic biomass was summarized, and the structural characteristics of lignin were comparably analyzed. The modification of lignin was performed to obtain a large surface area, strong binding-site, and high and quick adsorption properties of lignin-based adsorption materials. The adsorption efficiency of Cr ions was found to be strongly dependent on the pH of the wastewater. To further illustrate the adsorption process, the structural changes and the interactions between the metal ions and the functional groups of the lignin-based biosorbents in the adsorption process should be further investigated. Once the cost-effective and high-efficiency modification techniques are developed, lignin-based adsorbents can be expected to be the most suitable alternatives for Cr ions removal from wastewater in industry.

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Enhancement of chromium uptake in tanning using oxazolidine

Cited by 49 publications

References 14 publications

Can sodium silicates affect collagen structure during tanning? Insights from small angle X-ray scattering (SAXS) studies

Can sodium silicates affect collagen structure during tanning? Insights from small angle X-ray scattering (SAXS) studies

The effectiveness of the stabilization/solidification process on the leachability and toxicity of the tannery sludge chromium

Fractionational and structural characterization of lignin and its modification as biosorbents for efficient removal of chromium from wastewater: a review

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