Researchers at the Institute of Nano Science and Technology (INST) have developed an affordable method to remove toxic chromium from industrial wastewater.
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- Use of Sunlight: Sunlight is used as a catalyst to convert the toxic Cr(VI) into the less harmful Cr(III).
- Microfluidic Technology: The method uses a continuous flow photoreduction process with the help of microfluidic reactors and TiO2 nanoparticles.
About Chromium

- It is a steely-grey, shiny, hard, and brittle transition metal.
- Unique feature: Chromium is known for its strong resistance to corrosion and its hardness.
- Applications
- It is used to produce alloys.
- Used in production of stainless steel.
- Its plating is used to give polished mirror finish to steel.
- Its compound is used as an industrial catalyst and pigments.
- Chromium is used to tan leather.
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Chromium Toxicity Overview
- Hexavalent Chromium Risks: Hexavalent chromium (Cr(VI)) is very toxic and can cause serious health problems such as lung cancer, allergies, and eczema.
- WHO Guidelines
- Hexavalent chromium: The World Health Organization (WHO) recommends that Cr(VI) in drinking water should be no more than 0.05 mg/L.
- Trivalent Chromium: For trivalent chromium (Cr(III)), the limit is 5 mg/L.
Challenges in Removing Chromium
- High soluble: Removing Cr(VI) from wastewater is a challenging task because it is highly soluble and resistant to traditional treatment methods.
- Costly and inefficient methods: Existing techniques like ion exchange, adsorption, and chemical reduction are costly and often inefficient in removing Cr(VI).
- Harmful byproduct: Additionally, these methods may produce hazardous byproducts.

Advantages of the New Method
- Cost-Effective: The process is affordable and uses renewable energy.
- Environmentally Friendly: The method utilizes sunlight as a catalyst which makes it a sustainable and cost-effective approach.
- High Efficiency
- 95% Degradation: The researchers achieved a high degradation efficiency of 95% using a serpentine microreactor at a flow rate of 50 µl/min.
- Reusability: The photocatalyst can be reused without the need for recovery agents or complicated processes.
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