Nanoscrubber removes acid-rain-forming gas
doi:10.1038/nindia.2018.162 Published online 7 December 2018
Researchers have developed a nanoscrubber that can remove hydrogen sulfide, a harmful gas found in gas streams emanating from various industrial plants and environmental sources1. The nanoscrubber could potentially be used in industry to curb hydrogen sulfide slippage from gas streams.
Hydrogen sulfide contributes to the formation of acid rain, which is known to corrode industrially important materials. Existing materials such as biofilters and wet scrubbers are not an efficient way of removing the gas.
In search of an effective gas-removing material, scientists from the research and development centre of the Indian Oil Corporation Limited in Faridabad, India, invented the nanoscrubber by smearing zinc oxide nanoparticles onto modified multi-walled carbon nanotubes.
To test the potential of the nanoscrubber, they made a scrubber set-up using a transparent cylindrical glass reactor cell, a gas supply system and a mass flow controller. After the reactor cell was loaded with the nanoscrubber, it was exposed to a flow of hydrogen sulfide gas.
The gaseous flow contained 100 parts per million hydrogen sulfide gas. The nanoscrubber removed the gas by adsorbing gas molecules, reducing its concentration to 23 parts per million. At ambient temperature, the nanoscrubber could remove 98 per cent of the gas in 15 minutes.
The scrubber owes such gas-removing efficiency to a large number of active sites on the surface that easily capture gas molecules. The scrubbing material can be reused up to 50 times. After being used for 50 times, the scrubber didn’t show any defects in its structure, retaining 90 per cent of its original gas-removing efficiency.
1. Singh, A. et al. ZnO-decorated MWCNTs as solvent free nano-scrubber for efficient H2S removal. Mater. Lett. 234, 172-174 (2019)