MEMBRANE SEPARATION

Question 1

Produced by casting a film from a solution of polymer and solvent and immersing the cast film in a nonsolvent for the polymer

Answer 1

phase inversion

Question 2

this type of membrane have broadly similar pore structure and chemical composition. many of the early membranes of this type were based on cellulose

Answer 2

isotropic

Question 3

Other term for asymmetrical membranes

Answer 3

anisotropic

(one side of the membrane possesses a thin layer of thin polymer

Question 4

Most popular anisotropic membrane

Answer 4

polysulfone

Question 5

Another term for nylon and is also another common membrane polymer

Answer 5

polyamide

Question 6

External factors affecting membrane performance

Answer 6

concentration polarization

fouling

Question 7

Accumulation of solute at the membrane surface

Answer 7

concn polarization

Question 8

long term and frequently irreversible deterioration of flux

Answer 8

Fouling

Question 9

Strategies to reduce flux declining

Answer 9

pretreatment of feed
frequent cleaning
careful selection of membrane
cross filtration

Question 10

Mass transfer coefficient in the analyses of concn polarization can be found using

Answer 10

Sherwood number

Question 11

It is four times the flow area over channel perimeter

Answer 11

hydraulic diameter

Question 12

driving force for Dialysis

Answer 12

concentration difference

Question 13

Driving force for pervaporation

Answer 13

partial pressure difference

Question 14

Mechanism of electrodialysis

Answer 14

ion migration

Question 15

Flux across the membrane is proportional to applied force which is equal to

Answer 15

applied pressure minus osmotic pressure

Question 16

It is essentially a sterile filtration and it most closely resembles conventional particle filtration in that it separates larger structures

Answer 16

Microfiltration

Question 17

Commonly used membrane in Microfiltration

Answer 17

Polypropylene

PTFE( polytetrafluoroethylen)

Question 18

At lab scale, microfiltration is applied in what mode

Answer 18

dead end mode

Question 19

Employed in situations where it is desired to separate low molecular weight solutes from high molecular weight solutes

Answer 19

ultrafiltration

Question 20

Frequently used to characterize Ultrafiltration membranes

Answer 20

Nominal molecular weight cutoff (NMWCO)

Question 21

Artificial kidneys used for haemodialysis is an example of

Answer 21

Dialysis

Question 22

Membrane process where separation is accompanied by a phase change

Answer 22

Pervaporation

Question 23

Membrane separation where a gas mixture is pressurized on one side of the membrane and a low pressure is maintained on the permeate side

Answer 23

Gas separation