Recycling waste cigarette filters for green applications

An international team of scientists from India and Singapore has successfully developed a novel method to recycle waste cigarette filters for use in making the triboelectric nano generator, a clean energy generating device.

From cigarette butts to clean energy generation

An international team of researchers from India and Singapore has successfully developed a method to recycle waste cigarette filters for use in energy generating devices. Cigarette ends or filters are the most littered material on the planet. Cigarette filters are made of a plastic called cellulose acetate which is very harmful and takes several years to degrade. Degradation or break down of this plastic can results in microplastics. Moreover, the cigarette butts carry many toxic materials that are harmful to nearby marine life.

The team has discovered a new way that proved the used cigarette filter could be a low cost valuable resource for use in the development of clean energy harvesting devices, known as triboelectric nanogenerators (or better known as TENG), a futuristic source of clean energy for various applications including smart green city. As a secondary outcome of this recycling approach, the study has also found that the upcycled cigarette filters could be used for making efficient CO2-capturing adsorbents. The proposed methodology is indeed promising as it can protect the environment from plastic pollution as well as global warming through the capture of CO2. Moreover, the idea of producing the TENG from the filter could reduce the dependency of the world on fossil fuels.

The study has been published in ACS Applied Materials and Interfaces [1] which can be viewed at https://doi.org/10.1021/acsami.2c06463. In this paper, it showed that selective amine functionalization was carried out to  the cigarette filter. By applying the treated filter as a substrate layer for the TENG, it enabled the new TENG device to generate an output voltage of 96.63 V and current 9.37 μA that are, respectively, 43 and 8 times higher than the TENGs which employed the pristine untreated cigarette filters. The new TENG device can readily light-up 100 colorful LEDs by simple pressing the TENG by finger tips. The new TENG device displayed outstanding durability to humidity and high-performance stability when it is subjected to cyclic loading (i.e., 12,000 cycles of loading−unloading). Besides that, the amine-treated cigarette filter fibers also show excellent CO2 adsorption capacity of 1.93 mmol/ 21 g, which is 9.2 times higher than that obtained using the pristine cigarette filter fibers.

This work on recycling cigarette filters for TENG application came after the first study on the use of another alternative sustainable material, notably recycled Polyethylene Terephthalate (PET) plastics, for making the TENG devices. This PET-TENG study was published in the journal, Chemical Engineering Journal [2]. The link to the report is https://doi.org/10.1016/j.cej.2020.127409. In this study on PET for the TENG application, the team came up with a sustainable approach for making flexible 3D aerogel from waste PET bottles that can be used not only for the TENG device but the aerogel can also be employed for waste water treatment. This aerogel can function as an adsorbent with an extremely high capability in removing various heavy metals such as Pb(II), Hg(II), and Zn(II) from the contaminated water with adsorption capacity between 94.5 and 98.3%

Dr. Roy Sunanda, the lead investigator of the team, received his PhD degree in 2012 from Nanyang Technological University (NTU) Singapore and Massachusetts Institute of Technology (MIT), MA, USA under the Singapore-MIT Alliance Programme. He received his M.TECH in 2007 from IIT-Kharagpur, India. After pursuing his postdoctoral research at NTU, in 2017 he joined Inha University, South Korea as an Assistant Professor. He also served GLA University at Mathura in Uttar Pradesh as an Associate Professor and IIT-Roorkee as a Research Consultant. For the cigarette-TENG project, the other researchers in the international team comprises Prof. Kheng Lim Goh (Newcastle University/Newcastle University in Singapore), Prof. Barnali Dasgupta Ghosh (Birla Institute of Technology, Mesra), Prof. Tanya Das (Techno India University, Salt Lake, Kolkata) Prof. Kamal Sharma (GLA University, Mathura) and Prof. Young-Wook Chang (Hanyang University, Korea). A major part of this project (especially the life cycle assessment, circular economy, etc.) has been taken care by the Newcastle team led by Prof Kheng Lim Goh.

 For further details and enquiry on potential collaboration, please contact Dr. Roy Sunanda at ([email protected]) or co-author Prof Kheng Lim Goh at [email protected].

References
[1] From Hazardous Waste to Green Applications: Selective Surface Functionalization of Waste Cigarette Filters for High-Performance Robust Triboelectric Nanogenerators and CO2 Adsorbents by Sunanda Roy, Tanya Das, Barnali Dasgupta Ghosh, Kheng Lim Goh, Kamal Sharma, Young-Wook Chang, ACS Appl. Mater. Interfaces 2022, 14, 31973−31985

[2] Sustainable design of flexible 3D aerogel from waste PET bottle for wastewater treatment to energy harvesting device by Sunanda Roy, Pradip K. Maji, Kheng-Lim Goh, Chemical Engineering Journal, 413 (2021) 127409

Published: 19 Jul 2022

Contact details:

Dr Kheng Lim Goh

172A Ang Mo Kio Avenue 8 #05-01
SIT Building @ Nanyang Polytechnic
Singapore 567739

+65 6908 6073
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Reference: 

"From Hazardous Waste to Green Applications: Selective Surface Functionalization of Waste Cigarette Filters for High-Performance Robust Triboelectric Nanogenerators and CO2 Adsorbents", ACS Applied Materials & Interfaces, 2022,
https://doi.org/10.1021/acsami.2c06463

Funding information:

The authors would like to acknowledge the QR SPF FUND- 728 NUCORE ENERGY (NU-007108), UK and Singapore for financial support.