Flocculant for oil-water separation and method for oil-water separation by flocculation

Abstract

A flocculant for separating and flocculating oily components and water components is provided so that no sludge is produced when the oily components and the water components contained in the emulsion having a high COD value; and the throughput of the active sludge is not decreased in the secondary treatment of the active sludge. A flocculant for separating and flocculating oily components and water components contained in oil-in-water type or water-in-oil type emulsion, comprises a unit (i), and at least one of units (ii) and (iii) represented by the following formulas: (i) —(C(R 1 R 2 )C(R 3 X))—, (ii) —(C(R 4 R 5 )C(R 6 Y))—, (iii) —(C(R 7 R 8 )C(R 3 Z))—; wherein X is a group having —SO 3 M, M is hydrogen or a metal element, Y is a group having a quaternary nitrogen atom, Z is an electrophilic group, each R 1 to R 9 is hydrogen or an alkyl group, and a ratio per molecule of these units (i):(ii):(iii) is (1 to 100):(1 to 100):(1 to 100).

What is claimed is:  
     
         1 . A flocculant for separating and flocculating oily components and water components contained in oil-in-water type or water-in-oil type emulsion, comprising: 
 a unit (i), and at least one of units (ii) and (iii) represented by the following formulas:                          wherein X is a group having —SO 3 M, M is hydrogen or a metal element, Y is a group having a quaternary nitrogen atom, Z is an electrophilic group, each R 1  to R 9  is hydrogen or an alkyl group, and a ratio per molecule of these units (i):(ii):(iii) is (1 to 100):(1 to 100):(1 to 100).    
     
     
         2 . A flocculant as claimed in  claim 1 , wherein the units are connected and terminated at their ends with —OSO 3 M groups, in which M is hydrogen or a metal element.  
     
     
         3 . A flocculant as claimed in  claim 1  or  2 , wherein at least one of the X, Y, and Z groups include an alkylene oxide moiety.  
     
     
         4 . A flocculant for separating and flocculating oily components and water components contained in oil-in-water type or water-in-oil type emulsion, comprising: 
 a mixture of a compound represented by the general formula R 0 —Q, and a compound having at least a cationic group,    wherein the R 0  is a hydrocarbon having at least an unsaturated linking in a molecule, and a residue group of the unsaturated linking of a derivative thereof, and Q is either an —SO 3 M group or an —OSO 3 M, in which M is hydrogen or a metal element.    
     
     
         5 . A flocculant as claimed in  claim 4 , wherein a non-ionic surfactant is added to the mixture of the compound represented by the general formula R 0 —Q, and the compound having at least a cationic group.  
     
     
         6 . A method for separating and flocculating oily components and water components contained in oil-in-water type or water-in-oil type emulsion, comprising the step of at least adding the flocculant as claimed in any one of  claims 1  to  5  to the oil-in-water type or the water-in-oil type emulsion.  
     
     
         7 . A method for separating and flocculating oily components and water components as claimed in  claim 4 , wherein the step of adding the flocculant as claimed in any one of  claims 1  to  5  is performed under the condition that an alkaline earth metal ion coexists.