Waste Water Engineering Multiple Choice Questions on “Reverse Osmosis Membrane Properties – 1”.
1. Where did the research on reverse osmosis begin?
a) University of Bangalore
b) University of Florida
c) University of Columbia
d) University of California
Answer: b
Clarification: Research on Reverse Osmosis began in the 1950’s at the University of Florida where Reid and Breton were able to demonstrate desalination properties of cellulose acetate membrane.
2. What is the membrane that selectively allows certain species to pass through called?
a) Permeable membrane
b) Semi-permeable membrane
c) Impermeable membrane
d) Membrane
Answer: b
Clarification: Semi-permeable refers to a membrane that selectively allows certain species to pass through it while retaining others. In actuality, many species will pass through the membrane, but at significantly different rates.
3. In RO, the solvent passes through the membrane at a much faster rate than the dissolved solids.
a) True
b) False
Answer: a
Clarification: In RO, the solvent (water) passes through the membrane at a much faster rate than the dissolved solids (salts). The net effect is that a solute-solvent separation occurs, with pure water being the product.
4. Which of the following membrane is used in the osmosis process?
a) Impermeable membrane
b) Semi-permeable membrane
c) Permeable membrane
d) Non-porous membrane
Answer: b
Clarification: Osmosis is a natural process involving the fluid flow of across a semi-permeable membrane barrier. Pure water has no net flow across the membrane because the chemical potential is equal on both sides.
5. The chlorine resistant polyamide membranes are prepared from aliphatic polypiperazine amides.
a) True
b) False
Answer: a
Clarification: An aliphatic polypiperazineamide or some complicated polymeric system (where water flux is less) is used to prepare chlorine resistant polyamide membranes.
6. Which of the following materials is not used in the preparation of nanocomposite support membranes?
a) Silica (50 nm)
b) Zeolite (250 nm)
c) Silica (120 nm)
d) Zinc (135 nm)
Answer: d
Clarification: The silica particles in the size range of 34-130 nm and zeolite particles in the size range of 250-300 nm are used to prepare nano-composite support membranes.
7. What is the pore size of LTA-type zeolite nanoparticle?
a) 0.2 nm
b) 0.4 nm
c) 0.6 nm
d) 0.8 nm
Answer: b
Clarification: Normally the pore size is 0.4 nm of LTA-type zeolite particles and 0.56 m for MFI-type membranes which are lower than the size of the ions present in the contaminated water.
8. What is the pore size of MFI-type zeolite nanoparticle?
a) 0.32 nm
b) 0.48 nm
c) 0.56 nm
d) 0.62 nm
Answer: c
Clarification: MFI-type has 0.56 nm pores which are lower than the size of the common ions presents in contaminated water but bigger than the size of a water molecule (0.278nm).
9. What is the material used in the making of NS-200 membrane?
a) Sulphonated polyfuran
b) Sulphonated polysulphone
c) Polypiperazine-amide
d) Aromatic polyamide
Answer: a
Clarification: RO membrane NS-200 is made up of Sulphonated polyfuran, CP is made of Sulphonated polysulphone, NS-300 is made of Polypiperazine-amide and BARC-TFC2 is made of fully aromatic polyamide.
10. What is the material used in the making of BARC-TFC2 membrane?
a) Aromatic polyamide
b) Polyamide
c) Sulphonated polyfuran
d) Sulphonated polysulphone
Answer: b
Clarification: RO membrane BARC-TFC2 is made of fully aromatic polyamide, BARC-TFC1 is made of Polyamide, NS-200 is made up of Sulphonated polyfuran and CP is made of Sulphonated polysulphone.
11. What is the percentage of salt rejection of NS-100 RO membrane?
a) 99.8%
b) 99 %
c) 98.5 %
d) 97 %
Answer: b
Clarification: The percentage of salt rejection for RO membrane NS-100 is 99 %, NS-200 is 99.8 %, NS-300 is 68 %, FT-30 is 99%, CP is 98 %, PES-1000 is 99.9% and UTC series is 98.5 %.
12. Which among the following has the highest percentage of salt rejection?
a) NS-100
b) NS-200
c) NS-300
d) CP
Answer: b
Clarification: The percentage of salt rejection for RO membrane CP is 98 %, NS-100 is 99 %, NS-200 is 99.8 %, NS-300 is 68 %, FT-30 is 99% PES-1000 is 99.9% and UTC series is 98.5 %.
13. What is the permeate flux of the RO membrane FT-30?
a) 0.5
b) 0.8
c) 1
d) 1.2
Answer: c
Clarification: The permeate flux of the RO membrane FT-30 is 1, NS-200 is 0.8, PES-1000 is 0.5, CP is 0.06, NS-100 is 0.7, PA-300/RC-100 is 1 and NS-300 is 3.3.