IISc Develops a Sustainable method to eliminate toxic heavy metals

Source: The post on Sustainable method to eliminate toxic heavy metals is based on the article “IISc develops method to remove heavy metal contaminants from groundwater” published in The Hindu on  11 June 2024

What is the News?

Recently, scientists at the Indian Institute of Science (IISc) in Bengaluru have invented a sustainable three-step method to eliminate toxic heavy metals such as arsenic from contaminated groundwater.

About sustainable method to eliminate toxic heavy metals

1. Scientists at the Indian Institute of Science (IISc) in Bengaluru have invented a sustainable three-step method to eliminate toxic heavy metals such as arsenic from contaminated groundwater.

2. Developed by: Researchers at IISc’s Centre for Sustainable Technologies (CST).

3. Objective: To remove heavy metals and ensure their safe disposal, preventing re-entry into the environment.

4. Novel Remediation Process: It is three-Step Method involving:

i) Adsorption: Contaminated water is passed through a bed of chitosan-based adsorbent doped with iron and aluminium compounds. This bed captures inorganic arsenic through electrostatic forces. The alkaline wash used to regenerate the adsorbent bed is recycled within the system.

ii) Membrane Separation: A membrane process separates arsenic from the alkaline wash solution, concentrating the toxic metal for the next phase.

iii) Bioremediation: Microbes in cow dung convert highly toxic inorganic arsenic into less harmful organic forms through methylation. The remaining cow dung sludge containing organic arsenic can be safely disposed of in landfills.

5. Benefits: 

i) Reduced Toxicity: Organic arsenic species are approximately 50 times less toxic than inorganic forms.

ii) Ease of Assembly and Operation: The system is easy to assemble and operate, suitable for community-level implementation and maintenance by local residents.

6. Researchers believe their cost-effective and sustainable solution could be scaled up to address arsenic contamination in various parts of the country with the necessary funding support.

What is Arsenic?

1. Arsenic is a natural component of the earth’s crust and is widely distributed throughout the environment in the air, water and land. However, it is highly toxic in its inorganic form.

2. People are exposed to elevated levels of inorganic arsenic through drinking contaminated water, using contaminated water in food preparation and irrigation of food crops among others.

3. Long-term intake of arsenic-contaminated water leads to arsenic poisoning or arsenicosis, with cancer of skin, bladder, kidney or lung or diseases of the skin (colour changes, and hard patches on palms and soles), or blood vessels of legs and feet.

4. In India, the states of West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam, Manipur and Chhattisgarh are reported to be most affected by arsenic contamination of groundwater above the permissible level.

UPSC Syllabus: Science and technology, Environment