Question 57 from UPSC CSE 2025 - Environme nt & Ecology

Question

Consider the following statements:
1. Activated carbon is a good and an attractive tool to remove pollutants from effluent streams and to remediate contaminants from various industries.
2. Activated carbon exhibits a large surface area and a strong potential for adsorbing heavy metals.
3. Activated carbon can be easily synthesized from environmental wastes with high carbon content.
Which one of the above statements is correct?

IASCODEX · Accepted Answer

Correct Option: A. Both Statement II and Statement III are correct and both of them explain Statement I

Strategy: Careful reading of Statement I reveals it is a broad claim about activated carbon's utility in pollutant removal. Statement II provides the essential property—large surface area and adsorption potential—that directly supports Statement I. Statement III notes easy synthesis from environmental (waste) sources, explaining its attractiveness and widespread use, which again justifies Statement I. Confirming the correctness of both II and III, and seeing each explain why activated carbon is a good and attractive choice, leads to option A.

Key Info: Activated carbon is a highly porous form of carbon with exceptional adsorption properties, widely used in environmental engineering and industrial effluent control. 
* Its large surface area (ranging from 500 to over 1500 m2/g) and microporous structure enable it to adsorb a wide range of contaminants, including organic pollutants, dyes, and heavy metals like lead, mercury, cadmium, and arsenic from water and air. 
* It is manufactured from carbon-rich precursors such as coconut shells, wood, peat, coal, and various agricultural and environmental wastes. The production involves carbonization followed by activation (physical or chemical), which develops its internal pore structure. 
* The ease of sourcing precursors from waste material makes activation carbon both economical and sustainable, contributing to waste valorization and resource recovery. 
* Its effectiveness and ease of production make it a standard in wastewater treatment, air purification, and even domestic water filters. 
* Besides adsorption, activated carbon is also used as a catalyst or catalyst support in various chemical reactions due to its chemical inertness and high surface reactivity.

IASCODEX · Answer

Option B: Both Statement II and Statement III are correct but only one of them explains Statement I

IASCODEX · Answer

Option C: Only one of the Statements II and III is correct and that explains Statement I

IASCODEX · Answer

Option D: Neither Statement II nor Statement III is correct