Page 50 - Industrial Wastewater Treatment, Recycling and Reuse

Industrial Wastewater Treatment, Recycling, and Reuse: An Overview 33

Adsorbent-1/Resin-1 Effluent 3 Min. 2 Parameters ¼ Total Expt.
3 3 2 3 ¼ 54
Regeneration 3 – 2 ¼ 06
Total No. of Expt. ¼ 60

In light of the above typical experimental analysis that may be required
for evaluation of any application, design of experiments is a critical step.
Apart from the conventional evaluation, the solution to environmental
problems will continue to require inexpensive ion exchange materials that
can be used once only and discarded. Developing a highly selective material
at low cost is a daunting challenge in today’s context.

1.4.4 Membrane Separation
Membrane separation is based on permselectivity, which is determined by
differences in the transport rate of various components through the mem-
brane. This permeation rate in turn is determined by the structure of the
membrane, the size of the permeating component, the chemical nature
and the electrical charge of the membrane material and permeating compo-
nent, and the driving force due to the chemical or electrochemical potential
gradients (that is, concentration pressure and electrical potential differences).
The use of different membrane structures and driving forces has resulted in a
number of different membrane processes:
Conventional
– Reverse osmosis
– Nano/ultra/micro-filtration
Relatively Recent Developments
– Pervaporation
– Membrane distillation
– Dialysis/electrodialysis
– Emulsion liquid membranes
– MBR
– Hybrid membrane system.
Today, membranes are used on a large scale in three distinct areas:
1. Applications in which the use of membranes is technically feasible, but
where they must compete with conventional separation processes on the
basis of overall economics. This, for instance, is the case in seawater desa-
lination and the treatment of certain wastewater streams (UNEP, 2008).
Here, membranes must compete with processes such as distillation and
biological treatment.