Nanofibre Filter for Dye-Contaminated Wastewater

Why in news?

Researchers at the Institute of Nano Science and Technology (INST), Mohali, have developed a sustainable nanofibre filter to treat dye-contaminated wastewater.

• Nanofibre Filter – A sustainable, multifunctional machine learning-enabled filter that combines zinc oxide nanoparticles with biodegradable nanofibres to treat dye-contaminated wastewater.
• Developed by –  Institute of Nano Science and Technology (INST), Mohali, an autonomous institute of the Department of Science and Technology (DST).
• Need for development – The material addresses persistent organic dyes discharged by industries, particularly textiles; these compounds can be toxic, chemically stable and resistant to natural degradation.
• Conventional treatments vs new technology – Conventional treatments such as adsorption, sedimentation and flocculation can separate pollutants without necessarily destroying them, while biological treatment may be slow for highly stable dyes.
• Photocatalysis offers an alternative by degrading pollutants under relatively mild conditions.
• However, conventional systems face difficulties in recovering nanoparticle catalysts, separating them from treated water and maintaining efficient contact with pollutants.
• Their performance can also be limited by light availability and electron–hole recombination.
• Working – To address these challenges, researchers use light and mechanical vibrations to enhance pollutant degradation, while machine learning helps predict its dye-decolourisation performance.
• Zinc oxide (ZnO) nanoparticles are immobilised within porous polylactic acid (PLA) nanofibres and introduced mechanical excitation alongside light.
• Mechanical vibrations generated piezoelectric polarisation, suppressing the recombination of light-generated electrons and holes and increasing the formation of reactive species involved in pollutant degradation.
• Fabrication – Uses electrospinning to produce a porous, high-surface-area and mechanically stable PLA-ZnO membrane instead of using freely dispersed ZnO powder.
• The integration of photocatalysis and piezocatalysis enabled pollutant degradation using both light and mechanical vibrations.

• Nanoparticle Features – ZnO nanoparticles were synthesised using turmeric extract.
• Naturally occurring compounds, including curcumin, flavonoids and phenolic compounds, acted as reducing and stabilising agents, avoiding synthesis methods involving harmful reagents.
• Performance – Under combined light and ultrasonic excitation, the nanofibres achieved 98.6% decolourisation of MB dye and 96.7% of CR dye within 120 minutes.
• The material also demonstrated antibacterial activity, inactivating approximately 75% of E. coli and 71% of S. aureus after six hours.
• Machine learning was integrated to predict dye-decolourisation behaviour using parameters including wavelength, treatment time, catalyst quantity, ultrasonic frequency, light intensity and dye concentration.
• Applications – Identified potential applications in treating textile and industrial wastewater containing persistent dyes and microbial contaminants, as well as in environmental remediation and antibacterial water-treatment membranes.

References

1. PIB | New technology for treating dye-contaminated wastewater
2. DD News| New technology for treating dye-contaminated wastewater