Wastewater
treatment is in a dilemma: more energy and efforts have
to be put forth to obtain an effluent with better quality, while a
significant amount of sludge is generated and the treatment or disposal
expenses are high. Even if the sludge is disposed of properly, the
components can be released and pollute the environment again. Therefore,
conversion and recovery of the contaminants to resources is the way
out of the dilemma. An ion exchange membrane (IEM) is a special type
of membrane, which allows charged solutes to pass through it while
retaining uncharged components. Attributed to this character, IEMs
are taking more important roles in separation and conversion processes
recently. They act as key elements in many resource recovery systems,
such as in separation and concentration, salt valorization, energy
conversion, and even in microbial systems. This review summarizes
the important processes for waste conversion and resource recovery
from wastewaters by using IEMs. Drawbacks and perspectives are summarized
in view of the development of the processes and the membranes.