Chemically active textile materials as efficient means for water purification

Fibrous ion exchangers (FIBAN) have been studied in a model process of water softening and removal from water simultaneously present heavy metal ions: Co2+, Ni2+, Zn2+, Cd2+, Cu2+, Pb2+. The effect of the following factors on the efficiency of Ca2+ removal from a model solution has been studied: the filtering bed height (7–40 mm); density of the column packing corresponding to the volume capacity, 0.17–0.83 meq/cm3; solution flow rate (4–37 cm/min). A fibrous sulfonic-type ion exchanger in shallow beds has exhibited a high efficiency in removal Ca2+ from water, greatly exceeding efficiency of a conventional sulfostyrene resin studied in parallel. In all cases high breakthrough capacities corresponding to the degree of column utilization, 0.6–0.9, have been observed. In the processes of water purification from heavy metal ions the highest efficiency was observed for chelating fibrous ion exchanger with iminodiacetete groups. A granular resin of the same type had much lower efficiency. Fibrous ion exchangers can find a wide application in water treatment processes.

Fibrous ion exchangers have high efficiency in water treatment processes due to extremely fast ion exchange on their filaments. Their small diameter (5–50µ) predetermines high rate of all diffusion-controlled processes on these materials. This property is combined with high and easily controlled permeability of the filtering bed. The ion-exchange, non-woven fabrics have a con-tinuous uniform structure allowing their installation in absorbers with filtering area of the ion exchanger 50–30m2/m3 if the filtering bed thickness, h, is 10–20mm. Such values of h provide a high efficiency of ion-exchange process, and theoretical productive capacity of the ion exchange absorber is much higher than an apparatus of comparable size with granular ion exchangers. Selective to heavy metal ions fibrous ion exchangers exhibited a high efficiency in purification of potable water. Ion-exchange textile materials can provide all benefits offered by shallow bed technology RECOFLO and can be used in the same or similar systems. At the same time, they offer further progress in ion- exchange technologies because they allow the reduction of the height of the filtering beds by a power of magnitude without losing their efficiency. They also open a new possibilities in construction of another apparatus unsuitable for granular ion exchangers.