Dynamic membranes hyperfiltration, properties

Following a brief review of the development of dynamic membranes and an overview of the current state of the art, Spencer (10) discusses dynamic polyblend membranes. In particular, he looks at the Influence that polymer selection and membrane preparation procedures have on membrane performance. Dynamic membranes composed of a poly(acrylic acid)/basic polyamine blend deposited on a ZOSS (hydrous zirconium oxide on stainless steel) ultrafiltration membrane are discussed. Their hyperfiltration or reverse osmosis properties are compared to the more traditional ZOPA (zirconium oxide plus poly(acrylic acid)) membrane. 

The poineering research and subsequent development of useful dynamic membranes was accomplished by Johnson and co-workers at the Oak Ridge National Laboratory. This very extensive research has been reported in a series of reports and in numerous publications and patents. Papers of special interest are the detailed report of the initial process for forming dynamic membranes with attractive hyperfiltration properties by Marcinkowsky, et al. (1 ), an early review of the research properties by Johnson ( ), and a subsequent review of hyperfiltration models and the development of hyperflltra-tion membranes by Dresner and Johnson ( ). These reviews cite the major references related to the formation, theory, properties, and applications of dynamic membranes. 

CARRE, Inc. also produces a series of dynamic hyperfiltration membranes on porous metal tubes. The major product is the ZOPA hyperfilter hydrous zirconium oxide-poly(acrylic acid) on porous stainless steel tubes. The hyperfiltration properties of the ZOPA membranes are also listed in Table I. The most attractive properties of the ZOPA membrane are durability at temperatures of at least 100 C, high membrane permeability, and reformation capability. The hydrous zirconium oxide-poly(acrylic acid) membranes provide modest rejection of simple electrolytes. Although the membrane permeability is high compared to most cast reverse osmosis /hyper-... 

Table II. Hyperfiltration Properties of a Dynamic Polyelectrolyte Membrane and its Precursors...

Shor, A.J. et al.. Hyperfiltration studies. XI. Salt-rejection properties of dynamically formed hydrous zirconium(IV) oxide membranes, J. Phys. Chem., 72, 2200, 1968. 

---