EP0621891A1 - Procede de recuperation de metaux contenus dans des produits de depart comprenant des substances proteiniques ainsi que materiau pouvant etre obtenu selon ce procede - Google Patents

Procede de recuperation de metaux contenus dans des produits de depart comprenant des substances proteiniques ainsi que materiau pouvant etre obtenu selon ce procede

Info

Publication number
EP0621891A1
EP0621891A1 EP92902122A EP92902122A EP0621891A1 EP 0621891 A1 EP0621891 A1 EP 0621891A1 EP 92902122 A EP92902122 A EP 92902122A EP 92902122 A EP92902122 A EP 92902122A EP 0621891 A1 EP0621891 A1 EP 0621891A1
Authority
EP
European Patent Office
Prior art keywords
treatment
removal
chromium
acid
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92902122A
Other languages
German (de)
English (en)
Inventor
Dimitris Katakis
John Konstantatos
Vassiliki Poulopoulou
Ersi Vrachnou-Dorier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
VRACHNOU DORIER ERSI
Original Assignee
VRACHNOU DORIER ERSI
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by VRACHNOU DORIER ERSI filed Critical VRACHNOU DORIER ERSI
Priority claimed from PCT/EP1992/000105 external-priority patent/WO1993014170A1/fr
Publication of EP0621891A1 publication Critical patent/EP0621891A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23J—PROTEIN COMPOSITIONS FOR FOODSTUFFS; WORKING-UP PROTEINS FOR FOODSTUFFS; PHOSPHATIDE COMPOSITIONS FOR FOODSTUFFS
    • A23J1/00—Obtaining protein compositions for foodstuffs; Bulk opening of eggs and separation of yolks from whites
    • A23J1/10—Obtaining protein compositions for foodstuffs; Bulk opening of eggs and separation of yolks from whites from hair, feathers, horn, skins, leather, bones, or the like
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09H—PREPARATION OF GLUE OR GELATINE
    • C09H1/00—Pretreatment of collagen-containing raw materials for the manufacture of glue
    • C09H1/04—Pretreatment of collagen-containing raw materials for the manufacture of glue of hides, hoofs, or leather scrap
    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
    • C14C3/00—Tanning; Compositions for tanning
    • C14C3/32—Recovering tanning agents from leather
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies

Definitions

  • the invention relates to a method for the removal of metals from starting materials comprising proteinaceous substances by treatment with chemical agents including leaching out, extraction, removal by means of redox and/or acid-base reactions.
  • Methods of this type are generally known. In particular these methods are used for the removal of chromium from leather, e.g. leather wastes in the wet-blue stage, which have undergone tanning with chromium salts only or with chromium salts in combination with other substances such as aluminum salts and complexing agents.
  • One of the known methods involves the use of enzymes to remove chromium from leather. This method yields hydrolyzed collagen.
  • the present invention relates to a method for the removal of metals from starting materials comprising proteinaceous substances by labilizing and solubilizing the metal with a treatment with chemical agent which includes leaching out, extraction, removal by means of redox and/or acid-base reactions, wherein this chemical treatment is combined with a treatment causing cross-linking of the proteins in the proteinaceous material.
  • cross-linking "cross-linking", “solubilization” and “labil- ization” are well known in the art. With respect to the last- mentioned expression reference is made to e.g. Cotton and Wilkinson, “Advanced Inorganic Chemistry”, . 4th Ed. , John Wiley & Sons, New York, 1980, page 1184; J.E. Huhee, “Inorganic Chemistry”, 2nd Ed., Harper International Edition, New York, 1978, page 497 and Purcell and Kotz, "Inorganic Chemistry", W.B. Saunders Company, Philadelphia, 1977, page 660.
  • the method of the invention has the combined effect of cross- linking, * labilization and solubilization.
  • the treatment of the invention comprises a treatment with free radical producing means including ionizing radiation, UV, ultrasonic treatment, heat treatment and/or treatment with chemical cross-linkers.
  • free radical producing means including ionizing radiation, UV, ultrasonic treatment, heat treatment and/or treatment with chemical cross-linkers.
  • the present invention is based on the finding that cross-linking of the proteinaceous substances brings the starting material in an apparently slightly modified condition which may be responsible for the effectiveness with respect to the removal of metal ions such as chromium, allowing use of strong labilizing and solubilizing agents, such as strong bases, without destruction of the protein.
  • the effec ⁇ tiveness of the removal of undesirable metals in the starting material can. further be improved by a pretreatment with an acid.
  • the treatment causing cross-linking may start with soaking in acid.
  • the mini- mum concentration of the acid used is 10 "3 normal (0.001 n) . This concentration may correspond with pH 3 (if strong acids are used) .
  • a maximum value of the acid concentration may be 1 normal.
  • the concentration of the acid used may depend on the size of the particles, the origin of the material treated, the nature of the protein, the* used chemicals, etc. Of course, there is also an interdependency between the acid strength and the period of the treating time.
  • the invention relates to a method as defined in the above, specifically directed to the removal of chromium from a starting material such as leather comprising the steps of a) subjecting the starting material to the treatment causing cross-linking and partial labilization and solubilization in an acid medium, b) separating off the acid medium from the material produced at step a) , c) subjecting the material produced at step b) to a treatment with a strong base in order to labilize and solubilize
  • step c) a strong base such as sodium hydroxide having a normality in the range of 0.5-2 n, e.g. 0.8-1 n is used and that in step e) the oxi ⁇ dizing agent is used at a pH-value between 6 and 8, but it can also be used at higher pH-values.
  • the oxidizing agent may be a hydrogen peroxide solution having a concentration of 0.1-30 % .
  • Suitable reducing agents are: chromium(II) , chromium metal, zinc metal, magnesium metal, all in acidic medium. Reducing can also be carried out electrochemically.
  • the method of the above specific embodiment may be comple- mented by treating the collageneous material obtained with water at a temperature of 50 ⁇ 8 ⁇ ° C to obtain sterilized and, high Bloom number gelatin or at higher temperature up to 100°C to obtain sterilized, lower Bloom number and technical gelatin. It should be noted that without separations, purifications, and additional sterilization the material obtained according to the invention is already sterilized.
  • proteinaceous substance comprises a variety of materials such as leather, fur, and other skin products originating from animals, but also composites of collagen with other polymers, e.g. biodegradable combinations thereof. Starting materials may be of biological origin or not.
  • Examples of metals which may be efficiently removed from the starting material are chromium and aluminum, examples of proteins thus obtained are collagen, elastin, keratines.
  • the known methods for the removal of metals from materials such as leather require a relatively long time for the chemical treatment. Furthermore, the reagents are often expensive and/or toxic or the protein structure is destroyed. This results in a decrease of the commercial value of the product or in products polluting the environment as the removal of metals such as chromium is insufficient and the contents of such a metal remains above the allowed limits for food products.
  • the invention solves the problem of the quantitative sepa ⁇ ration between metal such as chromium and collagen in the solid wastes of the tanneries. In this separation the collagen remains intact and in excellent quality and accordingly it can be used in the preparation of cosmetics, medical materials, edible and industrial gelatins of high quality, in food preparations and in animal feed including fodder for fish and chickens.
  • chromium relates to chromium(III) .
  • the chromium(VI) contents can " be .zero in the material which has been treated according to the invention is zero.
  • the treatment of the present invention can be carried out under mild conditions, at room temperature and with small consumption of the chemical reagents used. Moreover, chromium may be regained as chromium(III) , which may be directly recycled in the tannery.
  • the specific methods comprising the above steps a)-e) is used, in which method the basic medium contains sodium hydroxide and the acid medium contains sulfuric acid, the only chemical substance remaining after the treatment is sodium sulfate in neutral aqueous solution, which can be treated by the usual de ⁇ salination methods in order to recycle water and to obtain solid sodium sulfate, which has commercial value.
  • the present method can be used in old leather products, such as old shoes, clothing, leather suitcases, etc. after removal of the materials which have been applied after tanning, such as varnishes, paints, tannines etc.
  • the interrelated effects of the combined treatment on wet- blue wastes can be described as follows: in the pretreatment with the acid there is protonation of the amino group of glycine, which constitutes one third of the amino acids of collagen, and of the hydroxyl groups of hydroxyproline, which is ca. 11 % (g per 100 g of dry protein) .
  • the repulsion between positive charges thus created is very strong, and becomes evident even macroscopically, since the material swells.
  • the duration of the pretreatment and the concentra ⁇ tion of the acid depend on the origin of the material, the metals it contains and the particle size, and they must be adjusted so as to loosen up chromium-protein bonding, but without significant protein damage. The presence of chromium is essential in this respect.
  • chromium is removed with the redox reagents, oxidizing or reducing (examples: hydrogen peroxide and air-free Cr 2*" , respectively).
  • the treat ⁇ ments with the oxidizing agent and base are similar, namely they both involve negatively charged ions, which are repelled by the negatively charged sites of the protein.
  • the method for the removal of chromium from leather the following important aspects should be noted with respect to the method involving the above steps a) - e) .
  • Chromium is obtained in a form that can be recycled directly in. the tanneries essentially quantitatively.
  • the total time required for the treatment is relatively short.
  • the method can be applied to any kind of leather waste (old shoes, leather goods in general) after the appropriate pre-treat ⁇ ment.
  • the method of the invention can be used for any sensitive macromolecules of biological or other origin, which have been cross-linked using salts or oxides or other inorganic compounds and not just chromium salts. A non-destructive recovery of the treated materials is achieved.
  • Ionizing radiation may be used for the purposes of the present invention.
  • Such radiation is already used on a large scale for sterilization of various objects such as syringes or for cross- linking in polymers, etc.
  • the "excess of the radiation" from such sources can be used, i.e. the radiation passing through the irradiated objects, which hit the wall of the chamber containing the radiation source and which normally get lost.
  • the necessary doses for the present method are small.
  • the already existing facilities can be used, which means that it is possible to have a combination of different technologies.
  • Particles (ca. 1 mm) of the wet-blue leather waste are soaked in 1 n sulfuric acid (8 % suspension) for three hours under stirring, and then irradiated in a Co 60 source at a dose of 60 krad, in the presence or absence of air, and after settling for 8 hours are filtered and washed with water.
  • the solid is then added to a sodium hydroxide solution of 1 n and after 3 minutes filtered off and washed. After that follows the treatment with 3 % H 2 0 2 at pH 7. for 5 minutes, filtration and washing again.
  • the treatment with the peroxide is repeated two more times, and finally the solid is washed with plenty of water.
  • the solutions of the chemicals are used several times and finally they are mixed to the appropriate pH in order to have neu ⁇ tralization and simultaneously precipitation of chromium(III) .
  • the organic product is white, the protein retains its tex- ture, and as a result of all tests the chromium(III) content is 2-20 ppm. Drying is done by the known methods, e.g. freeze-drying. If drying is not thorough, the product is kept under refrigeration or by using preservatives.
  • Variations of the above operation involve use of X-rays or electron beams, instead of gamma rays and yield the same favourable results.
  • Example III 1 mm Particles tanned partly with aluminum salts are treated as in example II, but with shorter time of contact with the base. The results are the same as in the preceding examples.
  • Example IV Use of 20 kHz ultrasound instead of gamma-rays, for 30 minutes. The results are the same as in the preceding examples.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Zoology (AREA)
  • Biochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Treatment And Processing Of Natural Fur Or Leather (AREA)

Abstract

Procédé de récupération de métaux contenus dans des produits de départ comprenant des substances protéiniques par labilisation et solubilisation du métal, grâce à un traitement à l'aide d'agent chimique qui consiste à procéder au lessivage, à l'extraction, à la récupération à l'aide de réactions d'oxydoréduction et/ou acide-base. Selon le procédé, ce traitement chimique est combiné avec un traitement provoquant la réticulation des protéines contenues dans le matériaux protéinique. L'invention permet de traiter, entre autres, les déchets de cuir en vue de la récupération du chrome. Une fois terminé le traitement approprié, on obtient du collagène. Ce collagène garde sa structure intacte, est exempt de chrome et se prête à des utilisations telles que dans les produits cosmétiques, les médicaments, la gélatine de qualité et les aliments.
EP92902122A 1992-01-15 1992-01-15 Procede de recuperation de metaux contenus dans des produits de depart comprenant des substances proteiniques ainsi que materiau pouvant etre obtenu selon ce procede Withdrawn EP0621891A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CZ941701A CZ170194A3 (en) 1992-01-15 1992-01-15 Process for removing metals from starting materials containing proteinaceous substances and materials prepared in such a manner
PCT/EP1992/000105 WO1993014170A1 (fr) 1992-01-15 1992-01-15 Procede de recuperation de metaux contenus dans des produits de depart comprenant des substances proteiniques ainsi que materiau pouvant etre obtenu selon ce procede
CA 2128245 CA2128245A1 (fr) 1992-01-15 1992-01-15 Methode d'elimination des metaux contenus dans les materiaux de depart renfermant des substances proteiques ainsi que le materiau qu'on peut obtenir par cette methode

Publications (1)

Publication Number Publication Date
EP0621891A1 true EP0621891A1 (fr) 1994-11-02

Family

ID=25677379

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92902122A Withdrawn EP0621891A1 (fr) 1992-01-15 1992-01-15 Procede de recuperation de metaux contenus dans des produits de depart comprenant des substances proteiniques ainsi que materiau pouvant etre obtenu selon ce procede

Country Status (5)

Country Link
EP (1) EP0621891A1 (fr)
AU (1) AU1162492A (fr)
CA (1) CA2128245A1 (fr)
CZ (1) CZ170194A3 (fr)
SK (1) SK85594A3 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102702984A (zh) * 2012-06-07 2012-10-03 成都海康生物技术有限公司 一种工业化生产鱼皮明胶的工艺

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9314170A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102702984A (zh) * 2012-06-07 2012-10-03 成都海康生物技术有限公司 一种工业化生产鱼皮明胶的工艺
CN102702984B (zh) * 2012-06-07 2014-05-07 成都海康生物技术有限公司 一种工业化生产鱼皮明胶的工艺

Also Published As

Publication number Publication date
CA2128245A1 (fr) 1993-07-22
AU1162492A (en) 1993-08-03
CZ170194A3 (en) 1995-01-18
SK85594A3 (en) 1995-02-08

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