Clay deposit removal from membranes
Membrane clay deposits
Within the lifetime of most reverse osmosis (RO) systems
some fouling will adversely affect membrane performance, with
the nature of the foulant generally being determined through
membrane autopsy. Autopsy results show that the major
constituents of these deposits are aluminosilicates or clays.
Clay minerals are generally categorized as being <2μm in size and
are formed by the gradual chemical weathering of silica bearing
rocks which over time are transported into natural water sources.
They will therefore occur in all RO feed waters. Their small size
make them difficult to extract from feed water using conventional
physical-chemical pretreatment methods.
Clay minerals have traditionally proved difficult to remove
effectively from membranes using conventional cleaning chemicals.
The incomplete removal of these deposits leads to a higher
cleaning frequency, an increase in operational costs and also an
enhanced potential for membrane damage.
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