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Electro Membrane (separation) processes
Lenntech
Electromembrane
Processes consist of those technologies that apply the electric potential
gradient as the driving force of ion transport.
They are
increasingly important group of separation methods for removal of charged
components from solutions such as for producing potable water from brackish
water.
The main
electromembrane processes are:
1.
Electrodeionization (EDI)
2.
Electrodialysis (ED)
3.
Electrodialysis reversal (EDR)
4.
Electrodialysis with bipolar membrane (EDBM)
5.
Capacitive deionization (CDI)
Lately
these processes they have started to be applied into such areas as energy
production, food processing, personal care products, healthcare, production of
high-quality water, biomolecules separation, sensors, organic separation,
industrial effluent treatment, etc.
The basic
elements of the Electromembrane technologies can be ion-exchange or bipolar.
Ion
migration is taking place across these charged membranes (a polymeric matrix
with fixed charged groups, counterbalanced with mobile counter-ions) which are
placed in the electric field.
According
to the type of fixed ion-exchange (IX) groups, the membranes can be categorized
to
a.
Cation-exchange membranes (CM)
These membranes contain
in their polymeric matrix acid ion-exchange groups that have negative electric
charge (-SO3-, COO-), allowing for free passage only of those particles with
positive charge. Negatively charged particle passage is drastically reduced.
b. Anion-exchange membranes (AM)
These membranes contain
in their polymeric matrix basic cation-exchange fixed groups (-NR3+, where R is
hydrogen or alkyl group), allowing for free passage only of particles with
negative charge. Positively charged particle passage is drastically reduced.
a. Advantages
of electromembrane processes:
1. high
efficiency of separation of substances without phase transitions,
2. easy
continualization and automation, low demands for space,
3. lower
energy consumption, compared to traditional procedures,
4. possibility
to create closed waste-free technological junctions or entire technologies.
b. Disadvantages
of membrane processes:
1. removal
of so-called membrane poisons by pre-treatment of solutions,
2. fouling
(creation of coating of poorly soluble substances on the membrane surface).
The
overview of the most important and widely used electromembrane processes is
given in this section.
Lenntech provides water
treatment solutions for all type of applications, from domestic equipment to
industrial turnkey plants up to 5000 m3/day.
Our wide
range of technologies and extended know-how in all water-related sectors will
guarantee you a cost-efficient solution meeting your water quality
requirements.
Lenntech
deals daily with clients from various origin: municipalities, water bottlers,
hotels and resort requiring safe drinking water for their visitors, farmers
needing specific irrigation water for their plants, but also industries like
power plants, oil and gas, chemical factories, requiring specific process water
for their equipment.
https://www.lenntech.com/processes/electro-membrane-processes.htm
https://www.lenntech.com/processes/electro-membrane-processes.htm
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