New Delhi, Mar 02 (India Science Wire): India is the third-largest producer of e-waste and has
generated 3.23 MMT E-waste in 2019 alone. Paltry e-waste management makes the situation
even more challenging.
Notably, e-waste contains several toxic materials such as lead, cadmium, chromium, brominated
flame retardants, or polychlorinated biphenyls. Therefore, unregulated accumulation, landfilling,
or inappropriate recycling processes poses a severe threat to human health and the
environment.
On the contrary, e-waste can also be considered an “Urban Mine” for metal recovery and energy
production. Led by Professor K.K. Pant, his research group in the Catalytic Reaction Engineering
Laboratory at Chemical Engineering Department, Indian Institutes of Technology (IIT) Delhi, has
developed a sustainable technology to tackle the menace of e-waste. The adopted methodology
is a three-step process which involves pyrolysis of e-waste, separation of metal fraction, and
recovery of individual metals. The developed technology will cater to the need of “Smart Cities,”
“Swachh Bharat Abhiyan,” and “Atmanirbhar Bharat” initiatives of the Indian government via
waste to wealth generation in decentralized units, researchers said.
e-waste is shredded and pyrolyzed to yield liquid and gaseous fuels, leaving behind a metal-rich
solid fraction. On further separation using a novel technique, the leftover solid residue yields a
90-95% pure metal mixture and some carbonaceous materials. The carbonaceous material is
further converted to aerogel for oil spillage cleaning, dye removal, carbon dioxide capture, and
use in supercapacitors. In the next step, a low-temperature roasting technique is employed to
recover individual metals such as copper, nickel, lead, zinc, silver and gold from the metal
mixture. It gives a recovery of nearly 93% copper, 100% nickel, 100% zinc, 100% lead, and 50%
gold and silver each. It is a green process in which no toxic chemicals are released into the
environment.
The research team has successfully installed a 10 kg/h (Kilogram per hour) pyrolysis plant for e-
waste recycling at IIT Delhi. It converts all types of e-waste to combustible gases of 28 MJ/kg
(Megajoule per Kilogram) calorific value, liquid fuel of 30 MJ/kg calorific value, and a metal-rich
solid residue. The gaseous product obtained from the pilot plant is primarily composed of
hydrogen and methane whereas the liquid product is rich in hydrocarbons suitable for energy
generation. The pilot plant is also equipped with a scrubbing system that captures halogenated
compounds traces in the combustible gases.
Prof. K.K. Pant, Project Lead and Head of Chemical Engineering Department, IIT Delhi said,
“Electronic waste (e-waste) generation is inevitable and if the problem is not addressed now, it
will lead to mountains of solid waste sooner or later. The technology pioneered by our research
group is an integrated approach that will provide an environment-friendly solution to treat e-
waste with the added advantage of metal recovery and fuel production. We have successfully
demonstrated the application of our technology for recycling the Waste Printed Circuit Boards
(WPCBs) of computers and mobile phones – a highly complex part of any e-waste. Therefore, the
developed technology can be employed for recycling all types of e-waste as well as plastic waste,
and it does not emit any toxic chemicals to the environment. Besides providing a sustainable
solution for e-waste recycling, successful implementation of this technology has the potential to
generate large number of jobs in the waste recycling industry.”
This technology is an outcome of the Department of Science and Technology, Government of
India, funded project and has been further included for a scale-up in the project supported by the
Office of Principal Scientific Advisor (PSA), Government of India under the Delhi Research
Implementation and Innovation (DRIIV) initiative.
For their project titled, ‘Self- Sustainable e-waste Recycling: Generating Wealth from Waste via
Zero Discharge Technology’, the team was awarded the SRISTI-GYTI (Gandhian Young
Technological Innovation) Appreciation for the year 2020 and several other awards in the last
five years.
The technology has also been patented and published in internationally reputed journals such as
the Journal of Cleaner Production, Journal of Hazardous Materials, Waste Management and the
Journal of Environmental Chemical Engineering. (India Science Wire)