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Fast Pyrolysis of Biomass Residues in a Twin-screw Mixing Reactor
Published on: September 9, 2016
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Isoconversional Kinetic Analysis and ANN-Based Prediction of Metformin Pyrolysis for Sustainable Waste Management
Ramesh Potnuri1, Maheswata Lenka1, Chinta Sankar Rao1
1Control Systems & Machine Learning Research Laboratory, Department of Chemical Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore, Karnataka 575025, India.
ACS Omega
|October 27, 2025
Summary
Pyrolysis effectively converts metformin pharmaceutical waste into valuable products. This sustainable method allows for active pharmaceutical ingredient (API) recovery and byproduct valorization, supporting a circular economy.
Area of Science:
- Environmental Chemistry
- Chemical Engineering
- Green Chemistry
Background:
- Pharmaceutical waste presents significant environmental challenges due to its persistence and ecological risks.
- Effective and sustainable waste management strategies are crucial for mitigating these impacts.
- Valorization of pharmaceutical waste aligns with circular economy principles, promoting resource recovery and reuse.
Purpose of the Study:
- To investigate the pyrolysis of metformin as a method for pharmaceutical waste valorization.
- To analyze the thermal decomposition behavior and kinetics of metformin pyrolysis.
- To explore the potential for recovering active pharmaceutical ingredients (APIs) and utilizing byproducts.
Main Methods:
- Pyrolysis experiments were conducted on metformin samples (500 mg).
- Thermogravimetric analysis (TGA) was performed at various heating rates (10–40 °C/min).
- Kinetic and thermodynamic parameters were determined using isoconversional methods (KAS, FWO, Starink, FRD).
- Gas Chromatography-Mass Spectrometry (GC-MS) analyzed liquid-phase products.
- An Artificial Neural Network (ANN) model predicted mass loss based on temperature and heating rate.
Main Results:
- Pyrolysis yielded liquid products rich in the active pharmaceutical ingredient (API), carbonaceous, nitro, and acidic compounds.
- Thermogravimetric analysis provided insights into thermal decomposition behavior.
- Kinetic analysis yielded average activation energies ranging from 101.4 to 111.1 kJ/mol.
- The ANN model accurately predicted mass loss, demonstrating its utility in process optimization.
Conclusions:
- Pyrolysis is a promising technology for transforming metformin pharmaceutical waste into valuable resources.
- The study demonstrates the potential for recovering APIs for reuse and valorizing byproducts for energy or chemical synthesis.
- This approach supports sustainable pharmaceutical waste management and integration into a circular economy.
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