Removal of Minerals or Heavy Metals

Dual systems were also used for the flocculation of mineral suspensions [27,28] or for the precipitation of heavy metals such as Cu , Co , Zn, Ni , and Pb [29, 30]. Glover [27] investigated the effect of a dual system on the compressive yield stress and 

The removal of various heavy metal ions such as Cu , Co , Zn , and from aqueous solutions was conducted [29]. Heavy metal binding with a phosphono-methylated derivative of PEI (PPEI) was initially allowed to occur and then, upon equilibration, PEI was added to initiate precipitation of the PEC together with the heavy metal ion. The PPEI-PEI system was found effective for heavy metal scavenging purposes, even in the presence of high concentrations of non-transition metal ions like Na . The PPEI-PEI PEC was found to be more effective than traditional precipitation methods however, the result was not obtained by the application of premixed complexes, but by a step-by-step addition of PPEI and PEI (similar to other dual systems described here). 

GohUce described the separation of heavy metal ions with a PEC comprising a polycation and a polyphosphone compound [30]. 

Another field of an advanced separation is the flocculation and efficient dewatering of ultrfine coal ( 150 pm) with a polymer blend (tmmodified and sonicated flocculant) as dual system [31]. The authors proved that ultrasonic conditioning may be an effective alternative for a dual system in which two different flocculants are used. 

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