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Q50 (IAS/2025) Science & Technology › New Materials, Energy & Environment-linked Tech › Advanced materials and nanotech Answer Verified

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

Both Statement II and Statement III are correct and both of them explain Statement I

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

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

Neither Statement II nor Statement III is correct

Result

Your answer: — · Correct: A

Explanation

The correct answer is option A because both Statement II and Statement III are accurate and together explain why activated carbon is an effective tool for pollution control (Statement I).

Activated carbon can remove pollutants from water due to its wide specific surface area (SSA) and pores[1], and water pollutants including heavy metals have exhibited greater removal efficiency by AC[2]. This validates Statement II about its large surface area and strong adsorption potential for heavy metals.

Regarding Statement III, various approaches to producing activated carbon focus on utilizing waste materials as precursors, thereby contributing to sustainability[3], and biochar prepared from agricultural residues exhibited strong affinity for Pb(II) and cationic dyes[4]. This confirms that activated carbon can be synthesized from environmental wastes.

Both statements directly explain Statement I: the large surface area and adsorption capacity make it effective for pollutant removal, while the ability to synthesize it from waste materials makes it an economically attractive tool. Adsorption technology using activated carbon has gained promising importance due to its simplicity in design, low preparation cost, and high treatment efficiency[5].

Sources

[1] https://link.springer.com/article/10.1007/s41101-024-00287-3
[2] https://www.sciencedirect.com/science/article/pii/S2369969821000311
[3] https://link.springer.com/article/10.1007/s41101-024-00287-3
[4] https://www.nature.com/articles/s41598-025-30904-7
[5] https://pubs.acs.org/doi/10.1021/acsomega.0c06029

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PROVENANCE & STUDY PATTERN

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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.

Q. Consider the following statements : Statement I : Activated carbon is a good and an attractive tool to remove pollutants from effluent …

At a glance

Origin: Mostly Current Affairs Fairness: Low / Borderline fairness Books / CA: 0/10 · 10/10

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This is a classic 'Applied Science' question that rewards scientific common sense over rote learning. It sits at the intersection of Waste Management (Statement III) and Pollution Control (Statement II). It is fair because 'Activated Carbon' is the most ubiquitous water filter material (e.g., in RO purifiers), and its production from biomass is a standard 'Waste-to-Wealth' topic in current affairs.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1: Is activated carbon an effective material for removing pollutants from industrial effluent streams?
Statement 2: Is activated carbon used to remediate contaminants across various industries?
Statement 3: What is the typical specific surface area (in m^2/g) of activated carbon?
Statement 4: Does activated carbon have a high adsorption capacity for heavy metals in aqueous solutions?
Statement 5: Can activated carbon be synthesized from environmental wastes with high carbon content (e.g., agricultural residues, nutshells, sewage sludge)?
Statement 6: Is the production of activated carbon from environmental wastes generally considered an easy and cost-effective synthesis route?

Statement 1

Is activated carbon an effective material for removing pollutants from industrial effluent streams?

Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source

Presence: 4/5

"It is capable of removing pollutants from water due to its great potential for adsorption of these chemicals, which is attributable to its wide specific surface area (SSA) and pores."

Why this source?

Explicitly states activated carbon (AC) is capable of removing pollutants from water via adsorption because of its large specific surface area and pores.
Also notes modified AC can remove persistent contaminants though manufacturing, recycling, and selectivity limit large-scale wastewater use (nuanced support).

Web source

Presence: 5/5

"Activated carbon is an adsorbent commonly used in the treatment of low concentrations of air emission and odor... It is a form of carbon commonly used to filter pollutants from water and air"

Why this source?

Describes activated carbon as an adsorbent commonly used to filter pollutants from water and air.
Explains the mechanism: adsorbing organic matter onto a porous solid surface to remove odor and low-concentration emissions.

Web source

Presence: 5/5

"Recently, the adsorption technol. exploiting on activated carbon has gained promising importance in the treatment of landfill leachate due to its simplicity in design and low prepn. cost of activated carbon in addn. to high treatment efficiency."

Why this source?

Reports that adsorption using activated carbon has gained importance in treating landfill leachate due to high treatment efficiency.
Highlights simplicity of design and low preparation cost of AC as factors in its performance removing pollutants from complex wastewaters.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Control measuresi > p. 69

Strength: 5/5

“• (i) destroying the pollutants by thermal or catalytic combustion • (ii) conversion of the pollutants to a less toxic form • (iii) collection of the pollutant Different types of air pollutants can be eliminated / minimized by following methods: • a) Control of particulate matter: Two types of devices - arresters and scrubbers are used to remove particulate pollutants from air. These are arresters and scrubbers. i. Arresters: These are used to separate particulate The gaseous pollutants can be controlled through the techniques of Combustion, absorption and adsorption' • c) Control of Automobile Exhaust • i. use of efficient engines (e.”

Why relevant

Lists adsorption as a recognized control technique for gaseous pollutants (alongside combustion and absorption), which establishes adsorption as a general pollutant-removal mechanism.

How to extend

A student aware that activated carbon works by adsorption can reasonably infer activated carbon might be applicable for removing adsorbable pollutants from effluents and then check which effluent pollutants are adsorbable.

Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 6.32 Environment and Ecology > p. 37

Strength: 5/5

“(vii) Miscellaneous Water Pollutants: Water is also polluted by thermal discharge from power plants, and other industries. Solid wastes accumulated on land in the form of landflls also pollute the surface and underground water tables. All the pollutants described above have a disastrous efect upon human health, ecosystems, and environment and ecology. • Type of Industry: 1. Chemical Plants; Inorganic Pollutants: Various acids and alkalies, chlorides, sulphates, nitrates of metals, phosphorous, silica and sus pended particles.; Organic Pollutants: Aromatic compounds solvents, organic acids dyes, etc. • Type of Industry: 2. Food Processing; Inorganic Pollutants: ; Organic Pollutants: Highly putrescible organic mat ter and pathogens • Type of Industry: 3.”

Why relevant

Describes types of industrial water pollutants, notably organic pollutants such as aromatic compounds, solvents and dyes.

How to extend

Knowing activated carbon is commonly used to remove organic compounds, a student can connect this list to likely target pollutants for activated carbon in effluent treatment and seek examples or performance data for those organics.

CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > RIVER POLLUTION > p. 23

Strength: 3/5

“On the other hand, a heavy load of untreated sewage and industrial effluents are emptied into the rivers. This affects not only the quality of water but also the self-cleansing capacity of the river. For example, given the adequate streamflow, the Ganga water is able to dilute and assimilate pollution loads within 20 km of large cities. But the increasing urbanisation and industrialisation do not allow it to happen and the pollution level of many rivers has been rising. Concern over rising pollution in our rivers led to the launching of various action plans to clean the rivers. Have you heard about such action plans?”

Why relevant

Emphasises heavy loads of untreated industrial effluents entering rivers and the need for action plans to clean rivers, implying the need for effective treatment technologies.

How to extend

A student can use this to justify investigating which treatment technologies (including activated carbon) are used in municipal/industrial effluent treatment or river-cleaning programs.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > S.4.3. Control Measures > p. 77

Strength: 3/5

“• Riparian buffers • Treatment of sewage water and the industrial effluents should be done before releasing it into water bodies. • Cooling hot water before release from power plants • Prohibition of domestic cleaning in tanks, streams and rivers that supply drinking water • Avoiding excessive use of fertilizers and pesticides • Promoting organic farming and efficient use of animal residues as fertilizers The steps taken i:y the Government to address the issues of water pollution include the following:- • i. Preparatian of action plan for sewage management and restoration of water quality in aquatic resources by State Governments; • ii. installation of Online Effluent Monitoring System to check the discharge of effluent directly into the rivers and water bodies; • iii.”

Why relevant

Specifically states that 'Treatment of sewage water and the industrial effluents should be done before releasing it into water bodies,' pointing to the policy/operational requirement for effluent treatment methods.

How to extend

A student could use this as a basis to look up standard unit processes prescribed/used in effluent treatment (e.g., adsorption beds with activated carbon) to evaluate suitability.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > r. Effect$ oa aquatic eco$ystem: > p. 75

Strength: 3/5

“Polluted water reduces Dissolved Oxygen (DO) content, thereby eliminating sensitive organisms like plankton, molluscs and fish etc. However, a few tolerant species like Tilibifex (annelid worm) and some insect larvae may survive in highly polluted water with low DO content. Such species are recognized as indicator species for polluted water. • ii) Biocides, polychlorinated biphenyls (PCBs) and heavy metals directly eliminate sensitive aquatic organisms. • iii) Hot waters discharged from industries, when added to water bodies, lowers its DO content.”

Why relevant

Identifies pollutant classes such as biocides, PCBs and heavy metals that have different properties and environmental effects.

How to extend

A student can combine this with the fact adsorption favors certain chemical classes to reason which of these pollutants are likely or unlikely to be effectively removed by activated carbon and then seek specific performance data.

Statement analysis