Nanotechnology Questions and Answers – Micro Porous Materials

This set of Nanotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Micro Porous Materials”.

1. Which of the following factor does not influence the removal of ammonium from wastewaters using zeolites?
a) Contact time
b) Water density
c) Zeolite loading
d) pH value
View Answer

Answer: b
Explanation: Zeolites are versatile materials used to treat various pollutants present in wastewater. One of them is ammonium, a cationic pollutant, which is the most significant grey water contaminant. Zeolites show 97% of removal of these impurities depending on contact time, zeolite loading, initial ammonium concentration and pH value.

2. What is the size range of pores in microporous materials?
a) < 2nm
b) < 100nm
c) 2 – 50nm
d) > 50nm
View Answer

Answer: a
Explanation: Microporous materials are the ones containing pores in the size range of 2nmor lesser. Zeolites and metal organic frameworks are good examples of this material. Materials in the size range of 2 and 50nm are referred to as mesoporous where macroporous materials have pore diameter of greater than 50nm.

3. Identify a mechanism not used by zeolites to treat wastewater.
a) Surface modifications
b) Exchanges cations with NH4+ ions
c) Electrostatic interactions between amine molecules
d) Radical formation
View Answer

Answer: d
Explanation: Zeolites are extensively used for the treatment of wastewater. When added to wastewater they exchange extra-framework cations such as Na+, K+, Ca2+ with NH4+ ions. Heavy metal ions such as Pb2+, Ni2+ etc. can also be removed using zeolites. Inorganic anions such as F, CN etc. are removed from wastewater via ion exchange or surface modification of zeolites with surfactants. Zeolites have the ability to remove organic dyes from water by absorbing them. Mechanism involves electrostatic interactions between the amine molecules on the zeolite surface.

4. Match the following: –

(1) Clinoptilolite zeolite              (i) Petrochemical industry
(2) Herschelite zeolite                (ii) Additive in laundry detergent
(3) Mordenite zeolite                  (iii) Fukushima nuclear accident
(4) Zeolite A (LTA)                        (iv) Waste water treatment

a) (1) – (iii); (2) – (ii); (3) – (iv); (4) – (i)
b) (1) – (i); (2) – (iv); (3) – (iii); (4) – (ii)
c) (1) – (ii); (2) – (i); (3) – (iv); (4) – (iii)
d) (1) – (iv); (2) – (iii); (3) – (i); (4) – (ii)
View Answer

Answer: d
Explanation: Clinoptilolite zeolite is used in wastewater treatment for the removal of heavy metal ions such as Ag+, Cu2+, Cr3+ etc. Herschelite zeolite in a sodium form was used to remove 137Cs in the Fukushima nuclear accident in 2011. Mordenite zeolite is used as a catalyst in the petrochemical industry in various processes. Commercially, zeolite A (LTA) is mainly used as an additive in laundry detergent.

5. Why are zeolites applied as artificial kidneys?
a) Ion exchange capacity
b) Molecular sieving
c) Active adsorption
d) Acidity
View Answer

Answer: c
Explanation: Zeolites have exceptional adsorption properties which facilitates the adsorption of uremic toxins like urea, uric acid, creatinine and p-cresol. Mordenite zeolite has the ability to eliminate 75% of creatinine, in its acid form while 60% of p-cresol using the silicate -1 zeolite. Henceforth, zeolites are applied as artificial kidneys.

6. Zeolites have the ability to adsorb only anionic dyes.
a) True
b) False
View Answer

Answer: b
Explanation: Organic dyes generated by textile and printing industries are released into the river water but before that they are treated with zeolites which remove such dyes. Zeolites adsorb both cationic dyes such as Rhodamine B and anionic dyes such as Reactive Black 5, Reactive Red 239 etc., thus ridding the water of dyes.

7. Microporous materials have their application in the printing industry.
a) True
b) False
View Answer

Answer: a
Explanation: Microporous media in the fluid management system of ink-jet receptor media is used in large format in printing applications. They are used alongside pigment management system for use as inkjet inks that produce vibrant and durable images. It also helps maintain the colour balance.

8. Match the following.

1. Rock climbers              i) Insulating material
2. Micropore                    ii) Prevent string burn
3. Metal furnaces            iii) Tape gloves
4. Yo-yoers                       iv) Hold gauge padding

a) 1. (i); 2. (ii); 3. (iv); 4. (iii)
b) 1. (iv); 2. (iii); 3. (ii); 4. (i)
c) 1. (iii); 2. (iv); 3. (i); 4. (ii)
d) 1. (ii); 2. (i); 3. (iii); 4. (iv)
View Answer

Answer: c
Explanation: Rock climbers use microporous tapes in order to wrap their hands in tape gloves to protect their skin from rock abrasion while rock climbing. Micropore is the trading name for microporous adhesive tapes introduced by the company 3M. They help in holding wounds and gauge paddings. Microporous materials are used as insulating substances in metal furnaces. Yo-yoers use microporous tapes to wrap their fingers to prevent string burn or irritation.

9. Which organization classifies the porous materials?
a) AiCHE
c) ASC
View Answer

Answer: b
Explanation: Porous materials are classified into different types in accordance with the classification adopted by IUPAC. The International Union of Pure and Applied Chemistry (IUPAC) applies the recommendations of its panel which classifies the materials according to the pore size as macro (> 50 nm), meso (2 – 50nm) and micro (< 2nm).

10. When was the first microporous tape used?
a) 1688
b) 1753
c) 1862
d) 1959
View Answer

Answer: d
Explanation: The 3M American multinational conglomerate corporation introduced in 1959 the microporous adhesive tapes by the name Micropore. These are surgical tapes used to hold wound dressings, bandages and gauze paddings in place. They are used as a temporary measure until a suitable dressing is applied.

11. Choose the incorrect statement from the following options.
a) Surface modification of zeolites increases adsorption of chromate ions
b) Zeolites were used to neutralize the effects of Chernobyl nuclear accident
c) Hospitals use zeolite Y as a filter for controlling bacteria and fungi
d) Zeolites are used in dressing components due to high Si/Al ratio that facilities greater water absorption
View Answer

Answer: d
Explanation: Inorganic chromate ions present in wastewater can be adsorbed by surface modified zeolites. The ion exchange capacity of zeolites increases their selectivity for radionuclides. This property was used in neutralizing the effects of the Chernobyl nuclear accident in 1986. Zeolites having low Si/Al ratio can adsorb greater amounts of water. This property led to the creation of a product that has dehydrated zeolite that can be used as a dressing component. Hospitals nowadays make use of zeolite Y as a filter against bacteria and fungi enhancing the internal quality of air.

12. How are microporous materials useful in laboratory environments?
a) Gas sensing
b) Ion exchange
c) Trapping contaminants
d) Tape gloves
View Answer

Answer: c
Explanation: Microporous materials facilitate the contaminant-free exchange of gases in the laboratories. Various air borne contaminants such as mold spores, microorganisms, bacteria, viruses etc., get trapped in the pores while the other gases pass through it. This helps in providing an absolutely sterile environment with the confined walls of the laboratory or any other contained area.

13. Which year marked the beginning of industrial zeolite catalysis?
a) 1962
b) 2001
c) 1985
d) 1860
View Answer

Answer: a
Explanation: Synthetic zeolites (X and Y) were introduced in the petrochemical industry in 1962. These are used as catalysts in FCC plants since they are more active and generate a higher gasoline yield than the previously used amorphous silica-alumina catalysts. Zeolites are used as catalysts in isomerization, disproportionation of toluene in benzene and xylene, removal of sulphur from fuels and so on.

Sanfoundry Global Education & Learning Series – Nanotechnology.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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