As CNTs are insoluble in water and
not consumed, there is no need for replenishment. However,
as direct contact is required for inactivation, long term filtration
experiments are needed to determine the impact of
fouling on the antimicrobial activity of CNTs. Addition of
oxidized MWNT at low weight percentage (up to 1.5 wt%) also
increases the hydrophilicity and permeability of polysulfone
membranes (Choi et al., 2006b).