IIT Roorkee Develops Sustainable Tech Tackling Plastic & E-waste

Indian Institute of Technology (IIT) Roorkee researchers are developing sustainable technologies to tackle plastic and e-waste. The large generation of plastic waste and electronic waste (e-waste) has become a matter of concern due to environmental pollution and its hazardous effects on living beings.

A research group headed by Prof. K K Pant, Director, IIT Roorkee, (formerly part of IIT Delhi) is working on the development of sustainable technology to tackle the ever-growing menace of plastic waste and e-waste along with the generation of wealth via a zero-waste discharge concept.

The Researchers have developed e-waste recycling processes that are in accordance with Indian ‘Smart Cities’ and ‘Swachh Bharat Abhiyan’ initiatives via a zero-waste discharge concept. The adopted methodology is divided into two steps:

I. Pyrolysis of e-waste and separation of metal fraction, and 

II. Individual recovery of metals.

The proposed closed-loop recycling process can potentially be scaled-up and used as a viable environmentally benign alternative to traditionally used acid-leaching techniques posing immense hazardous risks.

Elaborating on the importance of such research, Prof. K K Pant, said, “It is important to develop sustainable processes to handle plastic and e-waste, which are being generated in huge quantities in India, especially with the exponential increase in the use of electronic devices. If such processes are not developed and implemented across the country at the earliest, the e-waste could lead to long-term ecological and environmental degradation.”

The Research Group of Prof. KK Pant is working on several initiatives on ‘circular economy,’ a model of production and consumption, which involves utilizing and recycling existing materials and products as long as possible. Such initiatives are being supported by several major Government organisations and industries.

Research on e-waste processing

Initially, e-waste was shredded and pyrolysed to convert e-waste plastic into liquid and gaseous fuels. Furthermore, metal fraction and char were separated using a novel separation process - ultrasonication. The efficiency of metal fraction recovery was around 90-95 per cent.

Based on the lab-scale experiment results, a 10 kg/h continuously operated pyrolysis pilot plant has been designed. The gaseous and liquid fuel obtained from the pilot plant has a calorific value of 28 MJ/kg and 30 MJ/kg respectively. H2 and CH4 are the major components of the gaseous product obtained from the pilot plant. In the next step, the obtained metal fraction was treated in various methods such as low-temperature roasting, alkali leaching, and methanesulfonic acid leaching for extraction of various critical metals like Cu, Ni, Pb, Zn, Ag, and Au and more than 90 per cent of these metals were efficiently leached with help of these processes. Moreover, for individual separation of metals precipitation, electro-deposition, and cementation techniques were employed.

Research on plastic waste

In the case of plastic waste, the IIT Roorkee researchers focused on developing an integrated waste management approach involving the efficient use of waste polymer materials for the production of liquid range hydrocarbons using catalytic cracking. The developed two-step approach leads to the 100 per cent conversion of waste plastic into value-added products comprising 75 per cent liquids, and approximately 25 per cent of gas fraction.

The results obtained suggest that the carbon chain length was narrowed to C5-C28 majorly when the metal-based zeolite catalysts were employed, indicating that the obtained liquids are fuel-like products. Thermo-chemical conversion is expected to open up new possibilities for the large-scale treatment of waste plastics, thus supporting the overall economic viability of the developed process