What is the difference between pervaporation and membrane distillation?

What is the difference between pervaporation and membrane distillation?

MD is similar to pervaporation process. The main difference between the two processes is the role of the membrane. The hydrophobic microporous membrane acts only as a support to the liquid–vapor interface and does not chemically distinguish solution components.

What is membrane pervaporation?

Pervaporation (PV) is a separation process for liquid mixtures by means of a nonporous membrane. The membrane acts as a barrier between a liquid phase (feed) and a vapour phase (permeate). The development of high performance PV membrane with long-term stability is still a challenge.

What is the pervaporation process?

The term pervaporation is a portmanteau of the two steps of the process: (a) permeation through the membrane by the permeate, then (b) its evaporation into the vapor phase. The membrane acts as a selective barrier between the two phases: the liquid-phase feed and the vapor-phase permeate.

What is the main advantage of pervaporation in separating ethanol water system as compared to distillation?

Pervaporation, a separation of liquid mixture using a selective membrane especially for the azeotropic and close-boiling point mixtures, is well known for less energy-intensive compared with azeotropic distillation, leading to more economically feasible processes for producing a high purity of ethanol (O’Brien et al..

Why are membranes distilled?

Membrane distillation (MD) is a promising technology for treating saline water and wastewater with high rejection factors, which cannot be accomplished by conventional technologies. MD is a thermally driven separation process in which only the vapor molecules pass through a microporous hydrophobic membrane.

What is pervaporation used for?

Pervaporation is a nonporous membrane separation process and has been widely employed to separate liquid mixtures comprising azeotropes or organic mixtures of liquids with close boiling points, such as for the separation of methanol from aromatic hydrocarbons (Smitha et al., 2004).

Why vacuum is used in pervaporation process?

The vacuum pump is only used for the removal of the inert gases, but has no other function in the process. In the vapour permeation process, saturated vapour instead of the liquid feed solution is passed through the module.

What is membrane distillation process?

Membrane distillation (MD) is a separation process where a micro-porous hydrophobic membrane separates two aqueous solutions at different temperatures. The hydrophobicity of the membrane prevents mass transfer of the liquid, whereby a gas-liquid interface is created.

What is membrane desalination?

Membrane desalination is the process by which salt and minerals are removed from water solution when it passes through a semipermeable membrane.

What is pervaporation desalination?

In pervaporation desalination, the heated feed (aqueous salt solution) is brought into contact with a permselective membrane and the permeated product (water) is continuously removed in the form of vapor from the permeate side.

What is membrane distillation used for?

What is membrane separation in chemistry?

Membrane separation is a technology which selectively separates (fractionates) materials via pores and/or minute gaps in the molecular arrangement of a continuous structure. Membrane separations are classified by pore size and by the separation driving force.