Method for recycling wash-water resulting from film treatment

• US 20020185440A1
• Filed: 01/10/2002
• Published: 12/12/2002
• Est. Priority Date: 02/02/2001
• Status: Abandoned Application

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Martin, Didier J.
• Application Number:
  US10/044,099
• Publication Number:
  US 20020185440A1
• Time in Patent Office: Days
• US Class Current: 210/650
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: G03C 5/395 Regeneration of photographic processing agents other than developers; Replenishers therefor

Abstract

The invention relates to a method of recycling wash-water resulting from the treatment of a film provided with a carbon particles based backing layer, and especially from a washing treatment to remove the said carbon particles based backing layer. The method comprises the step of passing the wash-water through an ultrafiltration unit equipped with an electrically charged hydrophilic ultrafiltration membrane, e.g. an acrylonitrile copolymers based membrane. The method enables the recycling of the wash-water made uncolored with a high efficiency and considerable lowering of the water consumption used in this step of the processing.

Claims

1. A method of recycling wash-water resulting from the treatment of a film provided with a carbon particles based backing layer, said treatment comprising a washing treatment to remove said carbon particles based backing layer, wherein said method comprises the step of passing said wash-water through an ultrafiltration unit equipped with a hydrophilic ultrafiltration membrane whose surface is electrically charged, wherein a permeate is obtained, and wash-water free of at least said carbon particles is obtained in said permeate.

2. The method of claim 1, comprising the step of recovering wash-water from the permeate and recycling it for said washing treatment.

3. The method of claim 1, wherein said ultrafiltration membrane has a wet contact angle less than 70°

.

4. The method of claim 3, wherein said ultrafiltration membrane has a wet contact angle between 10°

and 60°

.

5. The method of claim 3, wherein said ultrafiltration membrane is made in a hydrophilic material chosen from among the group comprising acrylonitrile, acrylic acid, and cellulose acetate based polymers and copolymers.

6. The method of claim 1, wherein the ultrafiltration unit is a tangential ultrafiltration unit.

7. The method of claim 1, wherein said hydrophilic ultrafiltration membrane has a positively charged membrane surface to further remove dyes.

8. The method of claim 1, wherein said ultrafiltration membrane has a molecular weight cut-off between 40 and 50 kD.

9. The method of claim 1, comprising further the step of cleaning said ultrafiltration membrane by rinsing using a hydrochloric acid solution.

10. The method of claim 1, comprising the step of prefiltering the wash-water through a polypropylene based filter.