Question

What is a significant environmental challenge associated with the bottom-up approach in nanotechnology?

• A. It requires high-energy conditions which are not sustainable.
• B. It produces nanoparticles that can be difficult to recycle.
• C. It involves toxic chemicals that can contaminate water sources.
• D. It is highly labor-intensive and not scalable.

Hint:

Nanotechnology Challenges. Top-down: Precision limits, defects. Bottom-up: Size/shape control, agglomeration, potential toxicity of precursors/reagents, scalability. Environmental concerns often relate to chemical usage and nanoparticle release.

Answer 1

The Correct Option is C

Bottom-up approaches in nanotechnology involve building nanostructures from molecular or atomic precursors, often using chemical synthesis methods (e.
g.
, wet chemical synthesis, sol-gel processes).
- Many chemical synthesis routes (Option 3) involve the use of precursor chemicals, solvents, reducing agents, or stabilizing agents that can be toxic or hazardous.
Improper handling, disposal, or accidental release of these chemicals or the nanoparticle byproducts can lead to environmental contamination, particularly of water sources.
- While some processes might require energy (Option 1), it's not universally true or the *most* significant challenge compared to chemical hazards.
- Recycling nanoparticles (Option 2) is a general challenge for nanomaterials regardless of synthesis method.
- Scalability and labor intensity (Option 4) are economic/manufacturing challenges rather than primarily environmental ones.
The use and potential release of toxic chemicals associated with many wet chemical bottom-up synthesis routes pose a significant environmental challenge.