Phytoextraction uses plants to accumulate valuable elements into their biomass from soil or water. The hyperaccumulator plant Eleocharis acicularis was used to extract indium, a strategic element, from end-of-life liquid crystal display (LCD) waste. Plants were exposed to 300 and 600 mg indium/L indium tin oxide (ITO) solutions at pH 5 for 15 days. Indium biomass accumulation levels were 58.9 ± 0.0 and 122.4 ± 13.8 mg indium/g dry weight, respectively. To simulate real-world e-waste phytomining, plants were exposed to a suspension with 800 g LCD particles/L at pH 3. Indium uptake after 15 days of exposure was 52.8 ± 0.9 mg indium/g biomass dry weight. Additionally, E. acicularis tolerated high acidity and salinity (up to 20 g salt/L and pH 3), making it a good candidate for metal phytoextraction from e-waste. The resulting indium-containing biomass was then submitted to pyrolysis, which produced a layered graphite-like material containing dispersed indium and characterized by higher electrical conductivity (1.47 ± 0.45 S/m) than commercial graphite under similar conditions. Our results showed for the first time that E. acicularis is efficient in the extraction of indium from e-waste and that indium-exposed biomass can be used as a precursor for production of high-value metal graphite biocomposites.

The present study was conducted in Lucknow city to assess the impact of firecracker burning during Diwali, from 2 November 2021–6 November 2021 including the pre and post-Diwali days. The concentrations of PM10, PM2.5, SO2, NO2, CO, O3, benzene and toluene, were monitored from the Central Pollution Control Board site on an hourly basis. The Air Quality Index was also recorded for PM10, PM2.5, SO2 and NO2. A questionnaire survey was done with 51 doctors to know the reported complaints post-Diwali. On Diwali night the PM2.5 value reached 262 µg m−3 around 22:00 hours and the maximum value (900 µg m−3) was obtained on 5 November, reported from the Central School monitoring station. From Gomti Nagar highest PM2.5 value obtained on Diwali day was 538 µg m−3 at 23:00 hours reaching 519 µg m−3 post-Diwali. Areas belonging to the old part of the city witnessed higher variations as PM2.5 crossed 900 µg m−3, in Lalbagh and Talkatora areas. The multivariate analysis showed that on Diwali night there was an increase of 204, 386, 344 and 341 in the PM2.5 concentration reported from Gomtinagar, Central School, Talkatora and Lalbagh stations, showing that firecracker burning resulted in a significant increase in air pollution. The Toluene/Benzene ratio was mostly more than 1 indicating that toluene and benzene may be emitted from other sources as well including the mobile sources. Around 50–75% rise was seen in the number of patients post-Diwali. 57.1% of the reported cases had respiratory issues, followed by allergic reactions. The data obtained from Lalbagh, Talkatora and Central School showed that although the values remained high, a decreasing trend was seen in the AQI compared to previous years which is a good sign and may be attributed to public awareness and the ongoing pandemic making people conscious.

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