PhD Thesis Defence: Ms. Jinu Joji (12/12/24)
Thesis title:
Sustainable Strategies for E-Waste Management: Bio- Derived Substrates and Heavy metal Remediation Techniques
Faculty advisor(s):
Prof. Praveen Ramamurthy
When?
12th December, 2024 (Thursday), 10:30 AM (India Standard Time)
Where
KPA Auditorium, Dept of Materials Engineering
Abstract
Monitoring pollution levels and extent is crucial for preserving our environment’s sustainability. Advances in the technology sector, facilitated by new materials and methods, have significantly improved. Nonetheless, these advancements have resulted in an increase in electronic waste (e-waste), posing a significant environmental risk. If not properly managed, the disposal of e-waste can lead to the release of harmful metals and organic substances into soil and water, endangering ecosystems. This thesis delineates the various sources of e-waste and the current state of remediation, focusing on encapsulation, sensing, and the development of biodegradable alternatives. It specifically addresses two primary sources of electronic waste: lead-perovskite solar cells and plastic substrates used in PCB (Printed Circuit Board) applications and electronic substrates.
The renewable energy sector’s extensive use of solar cells, particularly perovskites, has propelled forward the search for new materials. Lead-containing perovskite solar cells have shown to increase photovoltaic power conversion efficiency significantly. Despite the exploration of lead-free alternatives, current research suggests that the most efficient and dependable perovskite solar cells (PSCs) utilize lead salts, which are harmful to both human health and the environment. This research integrates encapsulation modifications and sensing technologies to address lead leaching from perovskite solar cells effectively. Encapsulation involves the physical containment of a device within a polymer film that has functional groups capable of binding with lead ions, thereby enhancing the effectiveness of Surlyn beyond its traditional use in photovoltaic packaging. This method leverages the affinity of lead for amine-functionalized molecules for both sensing and encapsulation purposes. A metal-organic framework, ZIF-67, coated over Surlyn, demonstrated a remarkable reduction in lead leakage. Appropriately functionalized ZIF, was used to detect lead from degraded perovskite solar cells, with a detection limit of 60 ppb. This sensor exhibited remarkable sensitivity in detecting lead ions in water samples, proving its efficacy in practical applications.
Another focal point of this thesis is the development of flexible cellulose films and composites for packaging, electronic substrates for PCBs, and flexible devices. Cellulose extracted from sugarcane bagasse was crosslinked to create a biodegradable film with a water vapor transmission rate of 350 g/m²/day, suitable for both packaging and device substrates. Additionally, an innovative approach involved replacing conventional plastic PCB substrates with those incorporating biodegradable components. Epoxy-silane functionalized microcrystalline cellulose (SMC) composites were developed, exhibiting a dielectric constant ranging from 10 to 14 across frequencies from 1 Hz to 1 MHz while maintaining adequate mechanical properties.