Separation of waste dyestuffs by adsorption process

Claim 1

A SEQUENTIAL PROCESS FOR SEPARATING A DYESTUFF FROM AN AQUEOUS MEDIUM CONTAINING AT LEAST ONE DISSOLVED DYESTUFF COMPRISING: A. CONTACTING THE AQUEOUS MEDIUM WITH PARTICLES OF AN ESSENTIALLY NON-IONOGENIC, MACRORETICULAR, WATERINSOLUBLE POLYMERIC ADSORBENT IN THE FORM OF BEADS HAVING AN OVERALL BEAD SIZE IN THE RANGE OF ABOUT 0.1 TO 3 MILLIMETERS AVERAGE DIAMTER, A POROSITY OF AT LEAST 30 PERCENT, A SURFACE AEA OF AT LEAST 100 UP TO 1,000 SQUARE METERS PER GRAM, AND PORES WITH AN AVERAGE PORE DIAMETER OF 20 TO 200 A, UNITS; AND B. TREATING THE EFFLUENT FROM THE FOREGOING STEP WITH PARTICLES SELECTED FROM THE CLASS CONSINTING OF THE SALT FORMS OF A WEAK ACID ION EXCHANGE RESIN, AN ALIPHATIC WEAK BASE ION EXCHANGE RESIN AND A COMBINATION OF A WEAK ACID AND AN ALIPHATIC WEAK BASE ION EXCHANGE RESIN, AND C. ELUTING THE ADSORBED DYESTUFFS, FROM THE NON-IONGENIC ADSORBENT WITH A POLAR, VOLATILE, WATER-MISCIBLE ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF ONE OR MORE VOLATILE KETONES OF 3 TO 10 CARBONS, LINEAR AND BRANCHED ALKANOLS, HAVING 1 TO 10 CARBONS, DIMETHYL FORMAMIDE AND DIMETHYL ACETAMIDE AND; D. ELUTING AND REGENERATING THE ION EXCHANGE RESIN BY TREATING THE RESIN WITH, I. AN AQUEOUS SOLUTION OF AN APPROPRIATE BASE OR ACID WHICH WILL CONVERT THE RESIN TO THE HYDROXIDE OR HYDROGEN FORM; II. ELUTING THE ADSORBED DYE-STUFFS WITH A POLAR, WATERMISICIBLE ORGANIC SOLVENT REGENERANT SELECTED FROM ONE OR MORE VOLATILE KETONES OF 3 TO 10 CARBON ALKYL ESTERS BRANCHED ALKANOLS HAVING 1 TO 30 CARBONS, AND DIMETHYL OF ALIPHATIC ACIDS FROM 1 TO 10 CARBONS, AND DIMETHYL FORMAMIDE, AND III. RECONVERTING THE REGENERATED RESIN TO ITS SALT FORM BY TREATING WITH AN AQUEOUS SOLUTION OF ONE OF A MINERAL ACID OR AN ALKALI METAL HYDROXIDE.