Procedimiento de osmosis inversa para el procesamiento de agua de lavado que contiene cationes metálicos polivalentes

摘要

#CMT# #/CMT# Processing rinsing water from the cleaning of wet-chemically treated components, comprising at least partially metalized surface having polyvalent metal cation (Me i), comprises: passing a portion of the rinsing water (A 0) through a cross-flow filtration step (F 1) or cascading the rinsing water through number (n) of cross-flow filtration steps (F 1....F n); and displacing the portion of rinsing water (A 0) or the rinsing water (A 1.... n - m) cascaded up to the m reverse osmosis steps (F 2) with an amount of water-soluble chelate-forming organic compound. #CMT# : #/CMT# Processing rinsing water from the cleaning of wet-chemically treated components, comprising at least partially metalized surface having polyvalent metal cation (Me i), comprises: passing a portion of the rinsing water (A 0) through a cross-flow filtration step (F 1) or cascading the rinsing water through number (n) of cross-flow filtration steps (F 1....F n), where each filtration step (F n) is fed with a permeate (A n - 1) of the prior filtration step (F n - 1), at least one filtration step represents reverse osmosis step (F 2), and the permeate of first reverse osmosis step does not pass through further step of another type of cross-flow filtration as the reverse osmosis; and displacing the portion of rinsing water (A 0) or the rinsing water (A 1.... n - m) cascaded up to the m reverse osmosis steps with an amount of water-soluble chelate-forming organic compound having at least one phosphonate group, where the molar ratio of phosphonate group to polyvalent metal cation in the retentate of the first reverse osmosis does not exceed a value for which the specific conductivity in permeate of the first reverse osmosis step is greater than 800 mu S/cm. #CMT#USE : #/CMT# The method is useful for processing rinsing water from the cleaning of wet-chemically treated components. #CMT#ADVANTAGE : #/CMT# The method exhibits excellent separation properties. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The diagram shows a schematic representation of a method for processing rinsing water from the cleaning of wet-chemically treated components. B1 : Cleaning and degreasing bath B2 : Rinsing water bath F 2 : Reverse osmosis step V1 : Volume stream W1 : Working tank. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Method: The portion of the rinsing water (A 0) or the rinsing water (A 1....n-m) cascaded up to the m reverse osmosis steps comprises a quantity of chelate-forming organic compound so that the specific conductivity in the permeate of the first reverse osmosis step does not exceed 500 (preferably 300) mu S/cm. The portion of the rinsing water (A 0) or the rinsing water (A 1.... n - m) cascaded up to the m reverse osmosis steps is displaced with the water-soluble chelate-forming organic compound so that the lowest solubility product of all salts (Me mX n) of the polyvalent metal cation (Me i) in the retentate of the reverse osmosis is greater than the corresponding ionic product from the corresponding anion concentration (X) with the concentration of the concerned polyvalent metal cation (Me i) in the retentate of the reverse osmosis reducing the concentration of the phosphonate group of the water-soluble chelate-forming organic compound weighed in the portion of metal cation (Me i) in the total content of the polyvalent metal cation. The portion of the rinsing water (A 0) or the rinsing water (A 1.... n - m) cascaded up to the m reverse osmosis steps is displaced with the water-soluble chelate-forming organic compound so that the molar ratio of phosphonate group to polyvalent metal cation in the retentate of the first reverse osmosis is greater than 1:1 but not greater than 3:1. At least one ultrafiltration step is present during cascading the portion of rinsing water (A 0) through n number of cross-flow filtration steps (F 1.... n), where the ultrafiltration in the cascade is carried out before the first reverse osmosis, where a ultrafiltration step with exclusion limit of less than 100 (preferably less than 40) kD is used. The permeate of the rinsing water of the last reverse osmosis step is directly fed back into the rinsing water for cleaning the wet-chemically treated components. The retentate of the first reverse osmosis step is fed back into the wet-chemical treatment step. Preferred Components: The water-soluble chelate-forming organic compound is: 1-hydroxyethylidene-1,1-diphosphoric acid, diethylene triamine-penta(methylene phosphonic acid) and/or 2-phosphonobutane-1,2-4-tricarboxylic acid and their alkali- or ammonium-salts; or amine compounds of formula (X 2O 3P-[-CH 2-N(CH 2-PO 3X 2)-CH 2] n-PO 3X 2) (I). X : H, alkali metal cation (both preferred), ammonium ion, quaternary ammonium compound or aliphatic group with not more than 4C. #CMT#POLYMERS : #/CMT# Preferred Components: The membrane of the first reverse osmosis step is prepared from polyamide.