The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 06, 2007
Filed:
Oct. 31, 2002
Kurt Huber, Sisseln, CH;
Rolf Lucas, Grenzach-Wyhlen, DE;
Jacek Malisz, Grenzach-Wyhlen, DE;
Ernst Wagner, Rheinfelden, DE;
Kurt Huber, Sisseln, CH;
Rolf Lucas, Grenzach-Wyhlen, DE;
Jacek Malisz, Grenzach-Wyhlen, DE;
Ernst Wagner, Rheinfelden, DE;
Ciba Specialty Chemicals Corporation, Tarrytown, NY (US);
Abstract
The present invention relates to a method of reducing the total organic carbon (TOC) content of waste water in the course of the preparation of concentrated solutions or suspensions of anionic organic compounds, which method comprises increasing the concentration of an aqueous solution or suspension of an anionic organic compound in the form of its free acid or its alkali metal salt, having a salt content of less than 5% of extraneous salt by weight based on the total solution or suspension, by microfiltration, ultrafiltration and/or nanofiltration, a) the membrane pore size being so selected that compounds having molecular weights in the range from 300 to 1000 Daltons or higher are retained, and b) the content of anionic compound in the concentrate being so adjusted to from 10 to 50% by weight that the total organic carbon (TOC) content of the permeate is less than 0.5% by weight, based on the total permeate, and c) optionally, after increasing the concentration of a suspension, dissolving the anionic organic compound by adding a suitable base. The invention relates also to the solutions and suspensions prepared by that means and to the use of such solutions or suspensions in dyeing or optically whitening paper or textile materials.