Performance of combined PTFE hydrophilic and hydrophobic membrane during laundry/detergent wastewater treatment by air gap membrane distillation (AGMD): an experimental study
Membrane distillation (MD) is making a rapid progress in desalination and wastewater treatment research. Though MD produces lower distillate yield compared with other membrane processes, its ability to be used with varieties of renewable and waste energy source coupled to produce ultrapure water...
| Summary: | Membrane distillation (MD) is making a rapid progress in desalination and wastewater treatment
research. Though MD produces lower distillate yield compared with other membrane processes, its
ability to be used with varieties of renewable and waste energy source coupled to produce ultrapure
water makes it a competitive choice. One of the major drawbacks of MD is the fouling and pore wetting
of the membrane surface, and therefore modifications to membrane surface characteristics and
combining MD with other techniques are necessary for successful rejection of all sorts of organic,
inorganic and biological contaminants, except few. One of them is household wastewater containing
common laundry detergent sodium dodecylbenzenesulfonate. Although it has been reported that
alkaline surfactant causes pore wetting in hydrophobic membranes, but the extent of damage and
the severe drop in permeate quality has not been reported. In this work, the preliminary experiments
have been carried out with standard laundry wastewater and it has been observed that commercially
available hydrophobic polytetrafluroethylene membrane permits all the constituents of the feed
water in presence of small amount of laundry detergent. Complete pore wetting of the membrane
makes it reach very high permeate flux (40 L/m2 h) and the distillate quality is near to the feed water
(>2,400 µS/cm). A simple technique was developed to prevent pore wetting, by combining hydrophilic
and hydrophobic membrane without using any interfacial-bonding agent or crosslinking agent. This
simple technique successfully produced pure distillate from feed water containing detergent with a
conductivity of 12–20 µS/cm. |
|---|